happyDomain/checker-ssh
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Initial commit

Browse source
This commit is contained in:
nemunaire 2026-04-23 12:17:44 +07:00
commit 06036c89d9
29 changed files with 4891 additions and 0 deletions
Download patch file Download diff file Expand all files Collapse all files

2
.gitignore vendored Normal file
View file

@ -0,0 +1,2 @@
checker-ssh
checker-ssh.so

17
Dockerfile Normal file
View file

@ -0,0 +1,17 @@
FROM golang:1.25-alpine AS builder
ARG CHECKER_VERSION=custom-build
WORKDIR /src
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 go build -tags standalone -ldflags "-X main.Version=${CHECKER_VERSION}" -o /checker-ssh .
FROM scratch
COPY --from=builder /checker-ssh /checker-ssh
USER 65534:65534
EXPOSE 8080
HEALTHCHECK --interval=30s --timeout=3s --start-period=5s --retries=3 \
CMD ["/checker-ssh", "-healthcheck"]
ENTRYPOINT ["/checker-ssh"]

682
LICENSE Normal file
View file

@ -0,0 +1,682 @@
happyDomain Licensing
SOFTWARE LICENSING
You may be licensed to use source code to create compiled versions not produced
by the happyDNS team in one of two ways:
1. Under the AGPL v3, subject to the exceptions outlined in this policy;
2. Under a commercial license available from the happyDNS team by contacting
contact@happydns.org.
happyDNS and happyDomain TRADEMARK GUIDELINES
Your use of the mark happyDNS and happyDomain is subject to the happyDNS team's
prior written approval and our organization’s Trademark Standards of Use at
http://www.happydomain.org/trademark-standards-of-use/. For trademark approval
or any questions you have about using these trademarks, please email
contact@happydns.org
------------------------------------------------------------------------------------------------------------------------------
GNU AFFERO GENERAL PUBLIC LICENSE
Version 3, 19 November 2007
Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
Preamble
The GNU Affero General Public License is a free, copyleft license for
software and other kinds of works, specifically designed to ensure
cooperation with the community in the case of network server software.
The licenses for most software and other practical works are designed
to take away your freedom to share and change the works. By contrast,
our General Public Licenses are intended to guarantee your freedom to
share and change all versions of a program--to make sure it remains free
software for all its users.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
free programs, and that you know you can do these things.
Developers that use our General Public Licenses protect your rights
with two steps: (1) assert copyright on the software, and (2) offer
you this License which gives you legal permission to copy, distribute
and/or modify the software.
A secondary benefit of defending all users' freedom is that
improvements made in alternate versions of the program, if they
receive widespread use, become available for other developers to
incorporate. Many developers of free software are heartened and
encouraged by the resulting cooperation. However, in the case of
software used on network servers, this result may fail to come about.
The GNU General Public License permits making a modified version and
letting the public access it on a server without ever releasing its
source code to the public.
The GNU Affero General Public License is designed specifically to
ensure that, in such cases, the modified source code becomes available
to the community. It requires the operator of a network server to
provide the source code of the modified version running there to the
users of that server. Therefore, public use of a modified version, on
a publicly accessible server, gives the public access to the source
code of the modified version.
An older license, called the Affero General Public License and
published by Affero, was designed to accomplish similar goals. This is
a different license, not a version of the Affero GPL, but Affero has
released a new version of the Affero GPL which permits relicensing under
this license.
The precise terms and conditions for copying, distribution and
modification follow.
TERMS AND CONDITIONS
0. Definitions.
"This License" refers to version 3 of the GNU Affero General Public License.
"Copyright" also means copyright-like laws that apply to other kinds of
works, such as semiconductor masks.
"The Program" refers to any copyrightable work licensed under this
License. Each licensee is addressed as "you". "Licensees" and
"recipients" may be individuals or organizations.
To "modify" a work means to copy from or adapt all or part of the work
in a fashion requiring copyright permission, other than the making of an
exact copy. The resulting work is called a "modified version" of the
earlier work or a work "based on" the earlier work.
A "covered work" means either the unmodified Program or a work based
on the Program.
To "propagate" a work means to do anything with it that, without
permission, would make you directly or secondarily liable for
infringement under applicable copyright law, except executing it on a
computer or modifying a private copy. Propagation includes copying,
distribution (with or without modification), making available to the
public, and in some countries other activities as well.
To "convey" a work means any kind of propagation that enables other
parties to make or receive copies. Mere interaction with a user through
a computer network, with no transfer of a copy, is not conveying.
An interactive user interface displays "Appropriate Legal Notices"
to the extent that it includes a convenient and prominently visible
feature that (1) displays an appropriate copyright notice, and (2)
tells the user that there is no warranty for the work (except to the
extent that warranties are provided), that licensees may convey the
work under this License, and how to view a copy of this License. If
the interface presents a list of user commands or options, such as a
menu, a prominent item in the list meets this criterion.
1. Source Code.
The "source code" for a work means the preferred form of the work
for making modifications to it. "Object code" means any non-source
form of a work.
A "Standard Interface" means an interface that either is an official
standard defined by a recognized standards body, or, in the case of
interfaces specified for a particular programming language, one that
is widely used among developers working in that language.
The "System Libraries" of an executable work include anything, other
than the work as a whole, that (a) is included in the normal form of
packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that
Major Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form. A
"Major Component", in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system
(if any) on which the executable work runs, or a compiler used to
produce the work, or an object code interpreter used to run it.
The "Corresponding Source" for a work in object code form means all
the source code needed to generate, install, and (for an executable
work) run the object code and to modify the work, including scripts to
control those activities. However, it does not include the work's
System Libraries, or general-purpose tools or generally available free
programs which are used unmodified in performing those activities but
which are not part of the work. For example, Corresponding Source
includes interface definition files associated with source files for
the work, and the source code for shared libraries and dynamically
linked subprograms that the work is specifically designed to require,
such as by intimate data communication or control flow between those
subprograms and other parts of the work.
The Corresponding Source need not include anything that users
can regenerate automatically from other parts of the Corresponding
Source.
The Corresponding Source for a work in source code form is that
same work.
2. Basic Permissions.
All rights granted under this License are granted for the term of
copyright on the Program, and are irrevocable provided the stated
conditions are met. This License explicitly affirms your unlimited
permission to run the unmodified Program. The output from running a
covered work is covered by this License only if the output, given its
content, constitutes a covered work. This License acknowledges your
rights of fair use or other equivalent, as provided by copyright law.
You may make, run and propagate covered works that you do not
convey, without conditions so long as your license otherwise remains
in force. You may convey covered works to others for the sole purpose
of having them make modifications exclusively for you, or provide you
with facilities for running those works, provided that you comply with
the terms of this License in conveying all material for which you do
not control copyright. Those thus making or running the covered works
for you must do so exclusively on your behalf, under your direction
and control, on terms that prohibit them from making any copies of
your copyrighted material outside their relationship with you.
Conveying under any other circumstances is permitted solely under
the conditions stated below. Sublicensing is not allowed; section 10
makes it unnecessary.
3. Protecting Users' Legal Rights From Anti-Circumvention Law.
No covered work shall be deemed part of an effective technological
measure under any applicable law fulfilling obligations under article
11 of the WIPO copyright treaty adopted on 20 December 1996, or
similar laws prohibiting or restricting circumvention of such
measures.
When you convey a covered work, you waive any legal power to forbid
circumvention of technological measures to the extent such circumvention
is effected by exercising rights under this License with respect to
the covered work, and you disclaim any intention to limit operation or
modification of the work as a means of enforcing, against the work's
users, your or third parties' legal rights to forbid circumvention of
technological measures.
4. Conveying Verbatim Copies.
You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy an appropriate copyright notice;
keep intact all notices stating that this License and any
non-permissive terms added in accord with section 7 apply to the code;
keep intact all notices of the absence of any warranty; and give all
recipients a copy of this License along with the Program.
You may charge any price or no price for each copy that you convey,
and you may offer support or warranty protection for a fee.
5. Conveying Modified Source Versions.
You may convey a work based on the Program, or the modifications to
produce it from the Program, in the form of source code under the
terms of section 4, provided that you also meet all of these conditions:
a) The work must carry prominent notices stating that you modified
it, and giving a relevant date.
b) The work must carry prominent notices stating that it is
released under this License and any conditions added under section
7. This requirement modifies the requirement in section 4 to
"keep intact all notices".
c) You must license the entire work, as a whole, under this
License to anyone who comes into possession of a copy. This
License will therefore apply, along with any applicable section 7
additional terms, to the whole of the work, and all its parts,
regardless of how they are packaged. This License gives no
permission to license the work in any other way, but it does not
invalidate such permission if you have separately received it.
d) If the work has interactive user interfaces, each must display
Appropriate Legal Notices; however, if the Program has interactive
interfaces that do not display Appropriate Legal Notices, your
work need not make them do so.
A compilation of a covered work with other separate and independent
works, which are not by their nature extensions of the covered work,
and which are not combined with it such as to form a larger program,
in or on a volume of a storage or distribution medium, is called an
"aggregate" if the compilation and its resulting copyright are not
used to limit the access or legal rights of the compilation's users
beyond what the individual works permit. Inclusion of a covered work
in an aggregate does not cause this License to apply to the other
parts of the aggregate.
6. Conveying Non-Source Forms.
You may convey a covered work in object code form under the terms
of sections 4 and 5, provided that you also convey the
machine-readable Corresponding Source under the terms of this License,
in one of these ways:
a) Convey the object code in, or embodied in, a physical product
(including a physical distribution medium), accompanied by the
Corresponding Source fixed on a durable physical medium
customarily used for software interchange.
b) Convey the object code in, or embodied in, a physical product
(including a physical distribution medium), accompanied by a
written offer, valid for at least three years and valid for as
long as you offer spare parts or customer support for that product
model, to give anyone who possesses the object code either (1) a
copy of the Corresponding Source for all the software in the
product that is covered by this License, on a durable physical
medium customarily used for software interchange, for a price no
more than your reasonable cost of physically performing this
conveying of source, or (2) access to copy the
Corresponding Source from a network server at no charge.
c) Convey individual copies of the object code with a copy of the
written offer to provide the Corresponding Source. This
alternative is allowed only occasionally and noncommercially, and
only if you received the object code with such an offer, in accord
with subsection 6b.
d) Convey the object code by offering access from a designated
place (gratis or for a charge), and offer equivalent access to the
Corresponding Source in the same way through the same place at no
further charge. You need not require recipients to copy the
Corresponding Source along with the object code. If the place to
copy the object code is a network server, the Corresponding Source
may be on a different server (operated by you or a third party)
that supports equivalent copying facilities, provided you maintain
clear directions next to the object code saying where to find the
Corresponding Source. Regardless of what server hosts the
Corresponding Source, you remain obligated to ensure that it is
available for as long as needed to satisfy these requirements.
e) Convey the object code using peer-to-peer transmission, provided
you inform other peers where the object code and Corresponding
Source of the work are being offered to the general public at no
charge under subsection 6d.
A separable portion of the object code, whose source code is excluded
from the Corresponding Source as a System Library, need not be
included in conveying the object code work.
A "User Product" is either (1) a "consumer product", which means any
tangible personal property which is normally used for personal, family,
or household purposes, or (2) anything designed or sold for incorporation
into a dwelling. In determining whether a product is a consumer product,
doubtful cases shall be resolved in favor of coverage. For a particular
product received by a particular user, "normally used" refers to a
typical or common use of that class of product, regardless of the status
of the particular user or of the way in which the particular user
actually uses, or expects or is expected to use, the product. A product
is a consumer product regardless of whether the product has substantial
commercial, industrial or non-consumer uses, unless such uses represent
the only significant mode of use of the product.
"Installation Information" for a User Product means any methods,
procedures, authorization keys, or other information required to install
and execute modified versions of a covered work in that User Product from
a modified version of its Corresponding Source. The information must
suffice to ensure that the continued functioning of the modified object
code is in no case prevented or interfered with solely because
modification has been made.
If you convey an object code work under this section in, or with, or
specifically for use in, a User Product, and the conveying occurs as
part of a transaction in which the right of possession and use of the
User Product is transferred to the recipient in perpetuity or for a
fixed term (regardless of how the transaction is characterized), the
Corresponding Source conveyed under this section must be accompanied
by the Installation Information. But this requirement does not apply
if neither you nor any third party retains the ability to install
modified object code on the User Product (for example, the work has
been installed in ROM).
The requirement to provide Installation Information does not include a
requirement to continue to provide support service, warranty, or updates
for a work that has been modified or installed by the recipient, or for
the User Product in which it has been modified or installed. Access to a
network may be denied when the modification itself materially and
adversely affects the operation of the network or violates the rules and
protocols for communication across the network.
Corresponding Source conveyed, and Installation Information provided,
in accord with this section must be in a format that is publicly
documented (and with an implementation available to the public in
source code form), and must require no special password or key for
unpacking, reading or copying.
7. Additional Terms.
"Additional permissions" are terms that supplement the terms of this
License by making exceptions from one or more of its conditions.
Additional permissions that are applicable to the entire Program shall
be treated as though they were included in this License, to the extent
that they are valid under applicable law. If additional permissions
apply only to part of the Program, that part may be used separately
under those permissions, but the entire Program remains governed by
this License without regard to the additional permissions.
When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part of
it. (Additional permissions may be written to require their own
removal in certain cases when you modify the work.) You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.
Notwithstanding any other provision of this License, for material you
add to a covered work, you may (if authorized by the copyright holders of
that material) supplement the terms of this License with terms:
a) Disclaiming warranty or limiting liability differently from the
terms of sections 15 and 16 of this License; or
b) Requiring preservation of specified reasonable legal notices or
author attributions in that material or in the Appropriate Legal
Notices displayed by works containing it; or
c) Prohibiting misrepresentation of the origin of that material, or
requiring that modified versions of such material be marked in
reasonable ways as different from the original version; or
d) Limiting the use for publicity purposes of names of licensors or
authors of the material; or
e) Declining to grant rights under trademark law for use of some
trade names, trademarks, or service marks; or
f) Requiring indemnification of licensors and authors of that
material by anyone who conveys the material (or modified versions of
it) with contractual assumptions of liability to the recipient, for
any liability that these contractual assumptions directly impose on
those licensors and authors.
All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10. If the Program as you
received it, or any part of it, contains a notice stating that it is
governed by this License along with a term that is a further
restriction, you may remove that term. If a license document contains
a further restriction but permits relicensing or conveying under this
License, you may add to a covered work material governed by the terms
of that license document, provided that the further restriction does
not survive such relicensing or conveying.
If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.
Additional terms, permissive or non-permissive, may be stated in the
form of a separately written license, or stated as exceptions;
the above requirements apply either way.
8. Termination.
You may not propagate or modify a covered work except as expressly
provided under this License. Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights under
this License (including any patent licenses granted under the third
paragraph of section 11).
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the copyright
holder fails to notify you of the violation by some reasonable means
prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from that
copyright holder, and you cure the violation prior to 30 days after
your receipt of the notice.
Termination of your rights under this section does not terminate the
licenses of parties who have received copies or rights from you under
this License. If your rights have been terminated and not permanently
reinstated, you do not qualify to receive new licenses for the same
material under section 10.
9. Acceptance Not Required for Having Copies.
You are not required to accept this License in order to receive or
run a copy of the Program. Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer transmission
to receive a copy likewise does not require acceptance. However,
nothing other than this License grants you permission to propagate or
modify any covered work. These actions infringe copyright if you do
not accept this License. Therefore, by modifying or propagating a
covered work, you indicate your acceptance of this License to do so.
10. Automatic Licensing of Downstream Recipients.
Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License. You are not responsible
for enforcing compliance by third parties with this License.
An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations. If propagation of a covered
work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or could
give under the previous paragraph, plus a right to possession of the
Corresponding Source of the work from the predecessor in interest, if
the predecessor has it or can get it with reasonable efforts.
You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License. For example, you may
not impose a license fee, royalty, or other charge for exercise of
rights granted under this License, and you may not initiate litigation
(including a cross-claim or counterclaim in a lawsuit) alleging that
any patent claim is infringed by making, using, selling, offering for
sale, or importing the Program or any portion of it.
11. Patents.
A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based. The
work thus licensed is called the contributor's "contributor version".
A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner, permitted
by this License, of making, using, or selling its contributor version,
but do not include claims that would be infringed only as a
consequence of further modification of the contributor version. For
purposes of this definition, "control" includes the right to grant
patent sublicenses in a manner consistent with the requirements of
this License.
Each contributor grants you a non-exclusive, worldwide, royalty-free
patent license under the contributor's essential patent claims, to
make, use, sell, offer for sale, import and otherwise run, modify and
propagate the contents of its contributor version.
In the following three paragraphs, a "patent license" is any express
agreement or commitment, however denominated, not to enforce a patent
(such as an express permission to practice a patent or covenant not to
sue for patent infringement). To "grant" such a patent license to a
party means to make such an agreement or commitment not to enforce a
patent against the party.
If you convey a covered work, knowingly relying on a patent license,
and the Corresponding Source of the work is not available for anyone
to copy, free of charge and under the terms of this License, through a
publicly available network server or other readily accessible means,
then you must either (1) cause the Corresponding Source to be so
available, or (2) arrange to deprive yourself of the benefit of the
patent license for this particular work, or (3) arrange, in a manner
consistent with the requirements of this License, to extend the patent
license to downstream recipients. "Knowingly relying" means you have
actual knowledge that, but for the patent license, your conveying the
covered work in a country, or your recipient's use of the covered work
in a country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.
If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate, modify
or convey a specific copy of the covered work, then the patent license
you grant is automatically extended to all recipients of the covered
work and works based on it.
A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that are
specifically granted under this License. You may not convey a covered
work if you are a party to an arrangement with a third party that is
in the business of distributing software, under which you make payment
to the third party based on the extent of your activity of conveying
the work, and under which the third party grants, to any of the
parties who would receive the covered work from you, a discriminatory
patent license (a) in connection with copies of the covered work
conveyed by you (or copies made from those copies), or (b) primarily
for and in connection with specific products or compilations that
contain the covered work, unless you entered into that arrangement,
or that patent license was granted, prior to 28 March 2007.
Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.
12. No Surrender of Others' Freedom.
If conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License. If you cannot convey a
covered work so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you may
not convey it at all. For example, if you agree to terms that obligate you
to collect a royalty for further conveying from those to whom you convey
the Program, the only way you could satisfy both those terms and this
License would be to refrain entirely from conveying the Program.
13. Remote Network Interaction; Use with the GNU General Public License.
Notwithstanding any other provision of this License, if you modify the
Program, your modified version must prominently offer all users
interacting with it remotely through a computer network (if your version
supports such interaction) an opportunity to receive the Corresponding
Source of your version by providing access to the Corresponding Source
from a network server at no charge, through some standard or customary
means of facilitating copying of software. This Corresponding Source
shall include the Corresponding Source for any work covered by version 3
of the GNU General Public License that is incorporated pursuant to the
following paragraph.
Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU General Public License into a single
combined work, and to convey the resulting work. The terms of this
License will continue to apply to the part which is the covered work,
but the work with which it is combined will remain governed by version
3 of the GNU General Public License.
14. Revised Versions of this License.
The Free Software Foundation may publish revised and/or new versions of
the GNU Affero General Public License from time to time. Such new versions
will be similar in spirit to the present version, but may differ in detail to
address new problems or concerns.
Each version is given a distinguishing version number. If the
Program specifies that a certain numbered version of the GNU Affero General
Public License "or any later version" applies to it, you have the
option of following the terms and conditions either of that numbered
version or of any later version published by the Free Software
Foundation. If the Program does not specify a version number of the
GNU Affero General Public License, you may choose any version ever published
by the Free Software Foundation.
If the Program specifies that a proxy can decide which future
versions of the GNU Affero General Public License can be used, that proxy's
public statement of acceptance of a version permanently authorizes you
to choose that version for the Program.
Later license versions may give you additional or different
permissions. However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.
15. Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
16. Limitation of Liability.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGES.
17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely approximates
an absolute waiver of all civil liability in connection with the
Program, unless a warranty or assumption of liability accompanies a
copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
How to Apply These Terms to Your New Programs
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least
the "copyright" line and a pointer to where the full notice is found.
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
Also add information on how to contact you by electronic and paper mail.
If your software can interact with users remotely through a computer
network, you should also make sure that it provides a way for users to
get its source. For example, if your program is a web application, its
interface could display a "Source" link that leads users to an archive
of the code. There are many ways you could offer source, and different
solutions will be better for different programs; see section 13 for the
specific requirements.
You should also get your employer (if you work as a programmer) or school,
if any, to sign a "copyright disclaimer" for the program, if necessary.
For more information on this, and how to apply and follow the GNU AGPL, see
<https://www.gnu.org/licenses/>.

28
Makefile Normal file
View file

@ -0,0 +1,28 @@
CHECKER_NAME := checker-ssh
CHECKER_IMAGE := happydomain/$(CHECKER_NAME)
CHECKER_VERSION ?= custom-build
CHECKER_SOURCES := main.go $(wildcard checker/*.go)
GO_LDFLAGS := -X main.Version=$(CHECKER_VERSION)
.PHONY: all plugin docker test clean
all: $(CHECKER_NAME)
$(CHECKER_NAME): $(CHECKER_SOURCES)
go build -tags standalone -ldflags "$(GO_LDFLAGS)" -o $@ .
plugin: $(CHECKER_NAME).so
$(CHECKER_NAME).so: $(CHECKER_SOURCES) $(wildcard plugin/*.go)
go build -buildmode=plugin -ldflags "$(GO_LDFLAGS)" -o $@ ./plugin/
docker:
docker build --build-arg CHECKER_VERSION=$(CHECKER_VERSION) -t $(CHECKER_IMAGE) .
test:
go test -tags standalone ./...
clean:
rm -f $(CHECKER_NAME) $(CHECKER_NAME).so

32
NOTICE Normal file
View file

@ -0,0 +1,32 @@
checker-ping
Copyright (c) 2020-2026 happyDomain
Authors: Pierre-Olivier Mercier, et al.
This product is currently licensed under the GNU Affero General Public
License v3.0 (see LICENSE), because it imports types from the happyDomain
server module which is itself licensed under AGPL-3.0.
A relicensing to the MIT License is planned once that dependency has been
removed. See README.md for the licensing roadmap.
-------------------------------------------------------------------------------
Third-party notices
-------------------------------------------------------------------------------
This product includes software developed as part of the checker-sdk-go
project (https://git.happydns.org/happyDomain/checker-sdk-go), licensed
under the Apache License, Version 2.0:
checker-sdk-go
Copyright 2020-2026 The happyDomain Authors
This product includes software developed as part of the happyDomain
project (https://happydomain.org).
Portions of this code were originally written for the happyDomain
server (licensed under AGPL-3.0 and a commercial license) and are
made available there under the Apache License, Version 2.0 to enable
a permissively licensed ecosystem of checker plugins.
You may obtain a copy of the Apache License 2.0 at:
http://www.apache.org/licenses/LICENSE-2.0

157
README.md Normal file
View file

@ -0,0 +1,157 @@
# checker-ssh
Deep SSH security checker for [happyDomain](https://www.happydomain.org/).
Given an `abstract.Server` service (A / AAAA / SSHFP records), the checker
connects to the advertised SSH port(s) and produces a comprehensive
audit: reachability, banner-to-CVE matches, full algorithm posture
(KEX / host-key / cipher / MAC / compression), observed host keys,
SSHFP fingerprint validation, and authentication method exposure.
## What it checks
### Reachability
- TCP connect to port 22 (and optionally extra ports) on every A/AAAA
address of the service.
- SSH-2.0 protocol banner read.
### Banner / CVE
The banner is parsed into an `OpenSSH_X.Ypz` tuple and matched against
a bundled subset of the [ssh-audit](https://github.com/jtesta/ssh-audit)
vulnerability database, including:
| CVE | Issue |
| --- | --- |
| CVE-2024-6387 | regreSSHion - unauth RCE as root (8.5p1 <= v < 9.8p1) |
| CVE-2023-38408 | ssh-agent PKCS#11 RCE (5.5 ≤ v < 9.3p2) |
| CVE-2023-48795 | Terrapin prefix-truncation (v < 9.6p1) |
| CVE-2021-41617 | AuthorizedKeysCommand privdrop (6.2 ≤ v < 8.8p1) |
| CVE-2020-15778 | scp command injection (v < 8.4p1) |
| CVE-2018-15473 | username enumeration (v < 7.8p1) |
### Algorithm posture
A raw `SSH_MSG_KEXINIT` is exchanged with the server to enumerate every
algorithm it advertises. Each entry is graded against a curated table
inspired by ssh-audit:
- **crit**: `diffie-hellman-group1-sha1` (Logjam), `3des-cbc` (Sweet32),
`arcfour*`, `hmac-md5*`, `hmac-sha1-96`, `ssh-dss`, `none`.
- **warn**: `ssh-rsa` (RFC 8332 deprecated), `diffie-hellman-group14-sha1`,
AES-CBC, non-ETM MACs, `hmac-sha1`, missing strict-KEX marker
(CVE-2023-48795 mitigation).
- **ok**: `curve25519-sha256`, `sntrup761x25519-sha512@openssh.com`,
`mlkem768x25519-sha256`, `ssh-ed25519`, AES-GCM/ChaCha20-Poly1305,
SHA-2 ETM MACs.
### SSHFP validation
For each observed host key, the checker:
- computes SHA-1 and SHA-256 fingerprints,
- matches them against the `abstract.Server.SSHFP` records declared in
the zone,
- flags `sshfp_missing`, `sshfp_not_covered`, `sshfp_only_sha1` or
`sshfp_mismatch` as appropriate, with copy-pasteable fix snippets.
### Authentication methods
A second connection is opened with a dummy user and no credentials. The
server replies with the auth-method list, which is surfaced as
`password`, `publickey`, `keyboard-interactive` chips. Password
authentication triggers a `password_auth_enabled` warning.
## HTML report
The iframe report is structured for "fix me fast":
1. **Overall status** banner + SSHFP verdict chips.
2. **What to fix**: top issues (crit -> warn), each with a
copy-pasteable remediation snippet (sshd_config lines, SSHFP DNS
records, ssh-keygen invocations).
3. **SSHFP table** with per-record match status.
4. **Per-endpoint details**: expandable sections with host-key
fingerprints, algorithm tables (broken entries highlighted), and
advertised auth methods.
## Usage
### Standalone HTTP server
```bash
make
./checker-ssh -listen :8080
```
Endpoints:
- `GET /health`
- `GET /definition`
- `POST /collect`
- `POST /evaluate`
- `POST /report`
### Docker
```bash
make docker
docker run -p 8080:8080 happydomain/checker-ssh
```
### happyDomain plugin
```bash
make plugin
# produces checker-ssh.so, loadable as a Go plugin
```
## Options
| Option | Type | Default | Description |
| --- | --- | --- | --- |
| `ports` | string | `""` | Comma-separated extra ports (port 22 is always probed). |
| `probeTimeoutMs` | number | `10000` | Per-endpoint dial + handshake timeout. |
| `includeAuthProbe` | bool | `true` | Open a second connection to enumerate auth methods. |
## Observation key
Writes a single observation under `ssh`:
```json
{
"domain": "...",
"endpoints": [
{
"host": "...", "port": 22, "address": "...",
"banner": "SSH-2.0-OpenSSH_9.3p1",
"kex_algorithms": ["curve25519-sha256", "..."],
"host_keys": [{"type": "ssh-ed25519", "sha256": "abc..."}],
"auth_methods": ["publickey"],
"issues": [ { "code": "...", "severity": "warn", ... } ]
}
],
"sshfp": { "present": true, "records": [...] },
"collected_at": "..."
}
```
## License & licensing roadmap
This project is currently licensed under the **GNU Affero General Public
License v3.0** (see `LICENSE`), because it still imports
`happydns.ServiceMessage` and `abstract.Server` from the happyDomain
server module (`git.happydns.org/happyDomain/model` and
`git.happydns.org/happyDomain/services/abstract`), which are themselves
distributed under AGPL-3.0 and a commercial license.
The core checker types (`CheckerOptions`, `CheckerDefinition`,
`ObservationProvider`, `CheckRule`, …) have already been migrated to
[`checker-sdk-go`](https://git.happydns.org/checker-sdk-go); only the
service-message types remain on the AGPL side.
**Planned relicensing:** as soon as the remaining `ServiceMessage` /
`abstract.Server` dependency has been removed (moved into a dedicated
permissively licensed module), this project will be relicensed under the
**MIT License**, in line with the rest of the happyDomain checker
ecosystem (see `checker-dummy` for the target shape).
**Contributors notice:** by submitting a contribution to this repository,
you accept that your contribution will be relicensed from AGPL-3.0 to MIT
at the time of the relicensing described above. If you do not agree with
this, please do not submit contributions until the relicensing has taken
place.
The third-party Apache-2.0 attributions for `checker-sdk-go` are recorded
in `NOTICE` and must accompany any binary or source redistribution of this
project.

285
checker/algorithms.go Normal file
View file

@ -0,0 +1,285 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"fmt"
"strings"
)
// The tables below encode the safety verdict for each common SSH
// algorithm name. They are a condensed, hand-curated view of the
// ssh-audit algorithm database
// (https://github.com/jtesta/ssh-audit/blob/master/src/ssh_audit/ssh2_kexdb.py)
// reduced to the severities this checker surfaces.
//
// The logic we apply is: an algorithm advertised by the server is OK
// if it is in safeAlgos, suspicious (warn) if in weakAlgos, and
// critical if in brokenAlgos. Anything unknown is silently passed
// through: SSH is extensible, we prefer false negatives to noise.
type algoVerdict struct {
severity string // "crit", "warn", "info"
reason string // short human-readable reason
}
// KEX (key exchange) algorithms.
var kexAlgos = map[string]algoVerdict{
"curve25519-sha256": {},
"curve25519-sha256@libssh.org": {},
"sntrup761x25519-sha512@openssh.com": {severity: SeverityOK, reason: "hybrid post-quantum"},
"mlkem768x25519-sha256": {severity: SeverityOK, reason: "hybrid post-quantum (ML-KEM)"},
"ecdh-sha2-nistp256": {},
"ecdh-sha2-nistp384": {},
"ecdh-sha2-nistp521": {},
"diffie-hellman-group-exchange-sha256": {},
"diffie-hellman-group14-sha256": {},
"diffie-hellman-group16-sha512": {},
"diffie-hellman-group18-sha512": {},
"kex-strict-s-v00@openssh.com": {}, // not a real KEX, advertises "strict-kex" per CVE-2023-48795
// Deprecated / suspicious.
"diffie-hellman-group14-sha1": {severity: SeverityWarn, reason: "SHA-1 hash; upgrade to -sha256 variant"},
"diffie-hellman-group-exchange-sha1": {severity: SeverityWarn, reason: "SHA-1 hash; group-exchange with SHA-1 is discouraged"},
"rsa1024-sha1": {severity: SeverityCrit, reason: "1024-bit RSA KEX with SHA-1"},
"rsa2048-sha256": {severity: SeverityWarn, reason: "RSA key transport is deprecated"},
// Broken.
"diffie-hellman-group1-sha1": {severity: SeverityCrit, reason: "weak 1024-bit MODP group; vulnerable to Logjam"},
"gss-group1-sha1-toWM5Slw5Ew8Mqkay+al2g==": {severity: SeverityCrit, reason: "weak 1024-bit MODP group"},
}
// Server host-key algorithms.
var hostKeyAlgos = map[string]algoVerdict{
"ssh-ed25519": {},
"ssh-ed25519-cert-v01@openssh.com": {},
"ecdsa-sha2-nistp256": {},
"ecdsa-sha2-nistp384": {},
"ecdsa-sha2-nistp521": {},
"rsa-sha2-512": {},
"rsa-sha2-256": {},
"ssh-rsa": {severity: SeverityWarn, reason: "RSA with SHA-1 signatures (RFC 8332 marks as deprecated)"},
"ssh-dss": {severity: SeverityCrit, reason: "DSA is obsolete (weak 1024-bit signatures)"},
"ssh-rsa-cert-v01@openssh.com": {severity: SeverityWarn, reason: "RSA/SHA-1 certificate signatures are deprecated"},
"ssh-dss-cert-v01@openssh.com": {severity: SeverityCrit, reason: "DSA certificate signatures are obsolete"},
}
// Symmetric encryption algorithms (ciphers).
var cipherAlgos = map[string]algoVerdict{
"chacha20-poly1305@openssh.com": {},
"aes256-gcm@openssh.com": {},
"aes128-gcm@openssh.com": {},
"aes256-ctr": {},
"aes192-ctr": {},
"aes128-ctr": {},
"aes256-cbc": {severity: SeverityWarn, reason: "CBC mode is vulnerable to oracle attacks; prefer CTR or GCM"},
"aes192-cbc": {severity: SeverityWarn, reason: "CBC mode; prefer CTR or GCM"},
"aes128-cbc": {severity: SeverityWarn, reason: "CBC mode; prefer CTR or GCM"},
"rijndael-cbc@lysator.liu.se": {severity: SeverityWarn, reason: "legacy AES-CBC alias"},
"3des-cbc": {severity: SeverityCrit, reason: "Triple-DES is obsolete (Sweet32 birthday attack)"},
"blowfish-cbc": {severity: SeverityCrit, reason: "Blowfish-CBC; 64-bit block size (Sweet32)"},
"cast128-cbc": {severity: SeverityCrit, reason: "64-bit block; Sweet32"},
"arcfour": {severity: SeverityCrit, reason: "RC4 is broken"},
"arcfour128": {severity: SeverityCrit, reason: "RC4 is broken"},
"arcfour256": {severity: SeverityCrit, reason: "RC4 is broken"},
"none": {severity: SeverityCrit, reason: "No encryption"},
"des-cbc@ssh.com": {severity: SeverityCrit, reason: "DES is broken"},
}
// MAC algorithms.
var macAlgos = map[string]algoVerdict{
"hmac-sha2-512-etm@openssh.com": {},
"hmac-sha2-256-etm@openssh.com": {},
"umac-128-etm@openssh.com": {},
"hmac-sha2-512": {severity: SeverityWarn, reason: "non-ETM MAC; prefer -etm@openssh.com variants"},
"hmac-sha2-256": {severity: SeverityWarn, reason: "non-ETM MAC; prefer -etm@openssh.com variants"},
"umac-128@openssh.com": {severity: SeverityWarn, reason: "non-ETM MAC; prefer umac-128-etm@openssh.com"},
"umac-64@openssh.com": {severity: SeverityWarn, reason: "64-bit tag; prefer umac-128-etm@openssh.com"},
"hmac-sha1": {severity: SeverityWarn, reason: "SHA-1 MAC; prefer SHA-2 ETM"},
"hmac-sha1-etm@openssh.com": {severity: SeverityWarn, reason: "SHA-1 MAC (ETM); prefer SHA-2 ETM"},
"hmac-sha1-96": {severity: SeverityCrit, reason: "truncated SHA-1 MAC; forbidden"},
"hmac-md5": {severity: SeverityCrit, reason: "MD5 MAC; broken"},
"hmac-md5-96": {severity: SeverityCrit, reason: "truncated MD5 MAC; broken"},
"hmac-ripemd160": {severity: SeverityWarn, reason: "RIPEMD-160 MAC; seldom used"},
"none": {severity: SeverityCrit, reason: "No MAC"},
}
// Unknown names produce an empty verdict (no severity); callers treat that as "don't report"
// to avoid noise from SSH extensions we can't classify.
func verdictFor(table map[string]algoVerdict, name string) algoVerdict {
if v, ok := table[name]; ok {
return v
}
return algoVerdict{}
}
// analyseWeakAlgos emits one Issue per weak/broken algorithm in values
// using the verdict table.
func analyseWeakAlgos(addr, family string, values []string, table map[string]algoVerdict) []Issue {
var issues []Issue
for _, a := range values {
v := verdictFor(table, a)
if v.severity == "" || v.severity == SeverityOK {
continue
}
issues = append(issues, Issue{
Code: fmt.Sprintf("weak_%s", family),
Severity: v.severity,
Message: fmt.Sprintf("%s algorithm %q is %s", family, a, v.reason),
Fix: fixForFamily(family),
Endpoint: addr,
})
}
return issues
}
// analyseStrictKex flags the absence of the Terrapin mitigation marker
// (CVE-2023-48795): any modern sshd advertises kex-strict-s-v00@openssh.com
// alongside its KEX algorithms when the patched transport is available.
func analyseStrictKex(addr string, kex []string) []Issue {
if len(kex) == 0 || contains(kex, "kex-strict-s-v00@openssh.com") {
return nil
}
return []Issue{{
Code: "missing_strict_kex",
Severity: SeverityWarn,
Message: "Server does not advertise strict-KEX (CVE-2023-48795 \"Terrapin\"). Upgrade OpenSSH to 9.6 or later.",
Fix: "Upgrade sshd; no client-side fix mitigates this server-side gap.",
Endpoint: addr,
}}
}
// analysePreauthCompression flags servers that offer pre-authentication
// zlib compression. Many setups use zlib@openssh.com safely post-auth.
func analysePreauthCompression(addr string, comp []string) []Issue {
for _, c := range comp {
if c == "zlib" {
return []Issue{{
Code: "preauth_compression",
Severity: SeverityInfo,
Message: "Server offers pre-authentication zlib compression. Prefer zlib@openssh.com which kicks in only after auth.",
Endpoint: addr,
}}
}
}
return nil
}
// analyseAlgorithms is a convenience used by the HTML report: returns
// every algorithm-related issue for a single endpoint.
func analyseAlgorithms(addr string, p *SSHProbe) []Issue {
var issues []Issue
issues = append(issues, analyseWeakAlgos(addr, "kex", p.KEX, kexAlgos)...)
issues = append(issues, analyseWeakAlgos(addr, "hostkey_alg", p.HostKey, hostKeyAlgos)...)
issues = append(issues, analyseWeakAlgos(addr, "cipher", uniqueMerge(p.CiphersC2S, p.CiphersS2C), cipherAlgos)...)
issues = append(issues, analyseWeakAlgos(addr, "mac", uniqueMerge(p.MACsC2S, p.MACsS2C), macAlgos)...)
issues = append(issues, analyseStrictKex(addr, p.KEX)...)
issues = append(issues, analysePreauthCompression(addr, p.CompC2S)...)
return issues
}
// fixForFamily returns a short generic hint to pair with the
// per-algorithm warning. The HTML report shows algorithm-specific
// verdicts alongside this so operators know what to edit.
func fixForFamily(family string) string {
switch family {
case "kex":
return "Edit /etc/ssh/sshd_config KexAlgorithms= to list only modern algorithms (curve25519-sha256, ecdh-sha2-nistp256, diffie-hellman-group16-sha512)."
case "hostkey_alg":
return "Set HostKeyAlgorithms= to ssh-ed25519,rsa-sha2-512,rsa-sha2-256 (drop ssh-rsa and ssh-dss)."
case "cipher":
return "Restrict Ciphers= to chacha20-poly1305@openssh.com, aes256-gcm@openssh.com, aes128-gcm@openssh.com and the -ctr variants."
case "mac":
return "Restrict MACs= to the -etm@openssh.com variants (hmac-sha2-256-etm, hmac-sha2-512-etm, umac-128-etm)."
}
return ""
}
// uniqueMerge returns the union of a and b, preserving first-seen order.
func uniqueMerge(a, b []string) []string {
seen := map[string]bool{}
var out []string
for _, v := range a {
if !seen[v] {
seen[v] = true
out = append(out, v)
}
}
for _, v := range b {
if !seen[v] {
seen[v] = true
out = append(out, v)
}
}
return out
}
func contains(haystack []string, needle string) bool {
for _, v := range haystack {
if v == needle {
return true
}
}
return false
}
// analyseAuthMethods flags the classic "password auth exposed to the
// internet" antipattern and complementary findings.
func analyseAuthMethods(addr string, p *SSHProbe) []Issue {
var issues []Issue
if p.AuthMethods == nil {
return nil
}
if p.PasswordAuth {
issues = append(issues, Issue{
Code: "password_auth_enabled",
Severity: SeverityWarn,
Message: "Server accepts password authentication. Combined with publicly exposed sshd this is the single largest source of compromises.",
Fix: "Set PasswordAuthentication no in /etc/ssh/sshd_config and rely on publickey (or keyboard-interactive + hardware MFA).",
Endpoint: addr,
})
}
if !p.PublicKeyAuth && len(p.AuthMethods) > 0 {
issues = append(issues, Issue{
Code: "no_publickey_auth",
Severity: SeverityWarn,
Message: "Server does not advertise public-key authentication. This is unusual for production SSH deployments.",
Fix: "Set PubkeyAuthentication yes in sshd_config.",
Endpoint: addr,
})
}
return issues
}
// lowerAll returns a copy of s with every element lowercased. Used by
// callers that want a case-insensitive membership check.
func lowerAll(s []string) []string {
out := make([]string, len(s))
for i, v := range s {
out[i] = strings.ToLower(v)
}
return out
}

218
checker/collect.go Normal file
View file

@ -0,0 +1,218 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
"encoding/json"
"fmt"
"log"
"net"
"strconv"
"strings"
"sync"
"time"
"github.com/miekg/dns"
sdk "git.happydns.org/checker-sdk-go/checker"
happydns "git.happydns.org/happyDomain/model"
"git.happydns.org/happyDomain/services/abstract"
)
// Collect resolves addresses + SSHFP records from the abstract.Server
// service attached to this check, probes every (address, port)
// combination in parallel, and returns a populated SSHData.
func (p *sshProvider) Collect(ctx context.Context, opts sdk.CheckerOptions) (any, error) {
server, err := resolveServer(opts)
if err != nil {
return nil, err
}
timeoutMs := sdk.GetIntOption(opts, OptionProbeTimeoutMs, DefaultProbeTimeoutMs)
if timeoutMs <= 0 {
timeoutMs = DefaultProbeTimeoutMs
}
timeout := time.Duration(timeoutMs) * time.Millisecond
includeAuthProbe := sdk.GetBoolOption(opts, OptionIncludeAuthProbe, true)
ports := parsePorts(optString(opts, OptionPorts, ""))
// Port 22 is always probed.
if !containsUint16(ports, DefaultSSHPort) {
ports = append([]uint16{DefaultSSHPort}, ports...)
}
host, ips := addressesFromServer(server)
if len(ips) == 0 {
return nil, fmt.Errorf("abstract.Server service has no A/AAAA records")
}
sshfp := sshfpFromServer(server)
data := &SSHData{
Domain: host,
SSHFP: sshfp,
CollectedAt: time.Now(),
}
// The fanout is small in practice (at most a handful of IPs × a
// handful of ports), but we still cap concurrency for consistency
// with the TLS checker.
var mu sync.Mutex
var wg sync.WaitGroup
sem := make(chan struct{}, MaxConcurrentProbes)
for _, ip := range ips {
for _, port := range ports {
wg.Add(1)
sem <- struct{}{}
go func(ip string, port uint16) {
defer wg.Done()
defer func() { <-sem }()
probe := probeEndpoint(ctx, host, ip, port, timeout, includeAuthProbe, sshfp)
log.Printf("checker-ssh: %s:%d banner=%q kex=%d hostkeys=%d stage=%s",
ip, port, probe.Banner, len(probe.KEX), len(probe.HostKeys), probe.Stage)
mu.Lock()
data.Endpoints = append(data.Endpoints, probe)
mu.Unlock()
}(ip, port)
}
}
wg.Wait()
return data, nil
}
// resolveServer extracts the *abstract.Server payload from the options.
// Two shapes are supported, same as the ping checker:
// - "service": ServiceMessage (in-process plugin path, or HTTP after
// sdk.GetOption JSON-round-trips).
func resolveServer(opts sdk.CheckerOptions) (*abstract.Server, error) {
svc, ok := sdk.GetOption[happydns.ServiceMessage](opts, OptionService)
if !ok {
return nil, fmt.Errorf("no service in options: did the host wire AutoFillService?")
}
if svc.Type != "abstract.Server" {
return nil, fmt.Errorf("service is %q, expected abstract.Server", svc.Type)
}
var server abstract.Server
if err := json.Unmarshal(svc.Service, &server); err != nil {
return nil, fmt.Errorf("unmarshal abstract.Server: %w", err)
}
return &server, nil
}
// addressesFromServer returns the service's owner domain name (used
// for SNI-like purposes in SSH banner/hostname exchange) and the list
// of IPs to probe.
func addressesFromServer(server *abstract.Server) (host string, ips []string) {
// We can't know the service's owner domain from the Server payload
// alone. The host value we use here is purely informational for
// the report; the ssh handshake itself doesn't need it.
if server.A != nil && len(server.A.A) > 0 {
host = strings.TrimSuffix(server.A.Hdr.Name, ".")
ips = append(ips, server.A.A.String())
}
if server.AAAA != nil && len(server.AAAA.AAAA) > 0 {
if host == "" {
host = strings.TrimSuffix(server.AAAA.Hdr.Name, ".")
}
ips = append(ips, server.AAAA.AAAA.String())
}
return
}
// sshfpFromServer flattens the SSHFP records attached to the service
// into our transport-neutral SSHFPSummary.
func sshfpFromServer(server *abstract.Server) SSHFPSummary {
out := SSHFPSummary{Present: len(server.SSHFP) > 0}
for _, rr := range server.SSHFP {
if rr == nil {
continue
}
out.Records = append(out.Records, SSHFPRecord{
Algorithm: rr.Algorithm,
Type: rr.Type,
Fingerprint: strings.ToLower(rr.FingerPrint),
})
}
return out
}
// Invalid port entries are silently discarded to avoid failing on a bad user input.
func parsePorts(raw string) []uint16 {
if raw == "" {
return nil
}
parts := strings.Split(raw, ",")
var out []uint16
for _, p := range parts {
p = strings.TrimSpace(p)
if p == "" {
continue
}
n, err := strconv.Atoi(p)
if err != nil || n <= 0 || n > 65535 {
continue
}
u := uint16(n)
if containsUint16(out, u) {
continue
}
out = append(out, u)
}
return out
}
func containsUint16(list []uint16, v uint16) bool {
for _, x := range list {
if x == v {
return true
}
}
return false
}
// optString returns a string option, tolerating json.Number / float64
// sneaking in for what should have been a bare string.
func optString(opts sdk.CheckerOptions, key, def string) string {
v, ok := opts[key]
if !ok {
return def
}
switch s := v.(type) {
case string:
return s
case fmt.Stringer:
return s.String()
}
return def
}
// Used to make golint happy about unused miekg/dns import if we ever
// stop using the abstract.Server.SSHFP path. Currently the import is
// effectively required transitively; kept as a guard.
var _ = dns.TypeSSHFP
// Used to make golint happy about unused net import if we ever stop
// touching IP parsing here.
var _ = net.IPv4len

88
checker/definition.go Normal file
View file

@ -0,0 +1,88 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"time"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// Version is the checker version reported in CheckerDefinition.Version.
// Defaults to "built-in"; standalone binaries and plugin builds override
// it via -ldflags "-X .../checker.Version=...".
var Version = "built-in"
// Definition returns the CheckerDefinition for the SSH checker.
func (p *sshProvider) Definition() *sdk.CheckerDefinition {
return &sdk.CheckerDefinition{
ID: "ssh",
Name: "SSH",
Version: Version,
Availability: sdk.CheckerAvailability{
ApplyToService: true,
LimitToServices: []string{"abstract.Server"},
},
ObservationKeys: []sdk.ObservationKey{ObservationKeySSH},
Options: sdk.CheckerOptionsDocumentation{
UserOpts: []sdk.CheckerOptionDocumentation{
{
Id: OptionPorts,
Type: "string",
Label: "Additional ports",
Placeholder: "22, 2222",
Description: "Comma-separated list of additional TCP ports to probe. Port 22 is always probed.",
Default: "",
},
{
Id: OptionProbeTimeoutMs,
Type: "number",
Label: "Per-endpoint probe timeout (ms)",
Description: "Maximum time allowed for dial + banner + KEXINIT + handshake on a single endpoint.",
Default: float64(DefaultProbeTimeoutMs),
},
{
Id: OptionIncludeAuthProbe,
Type: "bool",
Label: "Enumerate authentication methods",
Description: "Perform a second connection with a dummy user to discover which auth methods the server advertises. Harmless but adds a connection attempt per endpoint.",
Default: true,
},
},
ServiceOpts: []sdk.CheckerOptionDocumentation{
{
Id: OptionService,
Label: "Service",
AutoFill: sdk.AutoFillService,
Hide: true,
},
},
},
Rules: Rules(),
Interval: &sdk.CheckIntervalSpec{
Min: 6 * time.Hour,
Max: 7 * 24 * time.Hour,
Default: 24 * time.Hour,
},
HasHTMLReport: true,
}
}

246
checker/interactive.go Normal file
View file

@ -0,0 +1,246 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
//go:build standalone
package checker
import (
"encoding/json"
"errors"
"fmt"
"net"
"net/http"
"os"
"strconv"
"strings"
"github.com/miekg/dns"
sdk "git.happydns.org/checker-sdk-go/checker"
happydns "git.happydns.org/happyDomain/model"
"git.happydns.org/happyDomain/services/abstract"
)
// RenderForm implements server.Interactive: the human-facing form
// exposed at GET /check when the checker runs as a standalone binary.
func (p *sshProvider) RenderForm() []sdk.CheckerOptionField {
return []sdk.CheckerOptionField{
{
Id: "domain",
Type: "string",
Label: "Host name",
Placeholder: "ssh.example.com",
Required: true,
Description: "The SSH server hostname to probe. A/AAAA and SSHFP records are looked up live.",
},
{
Id: OptionPorts,
Type: "string",
Label: "Additional ports",
Placeholder: "22, 2222",
Description: "Comma-separated list of additional TCP ports to probe. Port 22 is always probed.",
},
{
Id: OptionProbeTimeoutMs,
Type: "number",
Label: "Per-endpoint probe timeout (ms)",
Default: float64(DefaultProbeTimeoutMs),
},
{
Id: OptionIncludeAuthProbe,
Type: "bool",
Label: "Enumerate authentication methods",
Default: true,
},
}
}
// ParseForm implements server.Interactive: resolves the submitted
// hostname into an abstract.Server payload and wraps it in the
// ServiceMessage shape that Collect expects.
func (p *sshProvider) ParseForm(r *http.Request) (sdk.CheckerOptions, error) {
domain := strings.TrimSpace(r.FormValue("domain"))
domain = strings.TrimSuffix(domain, ".")
if domain == "" {
return nil, errors.New("host name is required")
}
fqdn := dns.Fqdn(domain)
resolver, err := systemResolver()
if err != nil {
return nil, fmt.Errorf("resolver: %w", err)
}
server := &abstract.Server{}
if a, err := lookupA(resolver, fqdn); err != nil {
return nil, fmt.Errorf("A lookup for %s: %w", domain, err)
} else if a != nil {
server.A = a
}
if aaaa, err := lookupAAAA(resolver, fqdn); err != nil {
return nil, fmt.Errorf("AAAA lookup for %s: %w", domain, err)
} else if aaaa != nil {
server.AAAA = aaaa
}
if server.A == nil && server.AAAA == nil {
return nil, fmt.Errorf("no A/AAAA records found for %s", domain)
}
if sshfp, err := lookupSSHFP(resolver, fqdn); err != nil {
return nil, fmt.Errorf("SSHFP lookup for %s: %w", domain, err)
} else {
server.SSHFP = sshfp
}
svcBody, err := json.Marshal(server)
if err != nil {
return nil, fmt.Errorf("marshal abstract.Server: %w", err)
}
opts := sdk.CheckerOptions{
OptionService: happydns.ServiceMessage{
ServiceMeta: happydns.ServiceMeta{
Type: "abstract.Server",
Domain: domain,
},
Service: svcBody,
},
}
if ports := strings.TrimSpace(r.FormValue(OptionPorts)); ports != "" {
opts[OptionPorts] = ports
}
if raw := strings.TrimSpace(r.FormValue(OptionProbeTimeoutMs)); raw != "" {
v, err := strconv.ParseFloat(raw, 64)
if err != nil {
return nil, errors.New("timeout must be a number")
}
opts[OptionProbeTimeoutMs] = v
}
opts[OptionIncludeAuthProbe] = parseInteractiveBool(r, OptionIncludeAuthProbe, true)
return opts, nil
}
// parseInteractiveBool reads a checkbox-style field. HTML forms omit
// unchecked checkboxes entirely, so a missing key means false if the
// form was submitted (detected via the required "domain" field).
func parseInteractiveBool(r *http.Request, key string, def bool) bool {
if _, ok := r.Form[key]; !ok {
if _, submitted := r.Form["domain"]; submitted {
return false
}
return def
}
v := strings.ToLower(strings.TrimSpace(r.FormValue(key)))
switch v {
case "", "0", "false", "off", "no":
return false
default:
return true
}
}
// systemResolver picks a DNS server to send explicit SSHFP/A/AAAA
// queries to. Resolution order:
// 1. CHECKER_DNS_RESOLVER env var (host or host:port)
// 2. The OS resolver config when one exists (resolvConfPath)
// 3. 1.1.1.1:53 as a last-resort public fallback
func systemResolver() (string, error) {
if env := strings.TrimSpace(os.Getenv("CHECKER_DNS_RESOLVER")); env != "" {
if _, _, err := net.SplitHostPort(env); err != nil {
env = net.JoinHostPort(env, "53")
}
return env, nil
}
if path := resolvConfPath(); path != "" {
if cfg, err := dns.ClientConfigFromFile(path); err == nil && len(cfg.Servers) > 0 {
return net.JoinHostPort(cfg.Servers[0], cfg.Port), nil
}
}
return net.JoinHostPort("1.1.1.1", "53"), nil
}
// resolvConfPath returns the platform-specific resolver config file, or
// "" if none is expected on this OS (e.g. Windows).
func resolvConfPath() string {
for _, p := range []string{"/etc/resolv.conf"} {
if _, err := os.Stat(p); err == nil {
return p
}
}
return ""
}
func dnsExchange(resolver, name string, qtype uint16) (*dns.Msg, error) {
msg := new(dns.Msg)
msg.SetQuestion(name, qtype)
msg.RecursionDesired = true
c := new(dns.Client)
in, _, err := c.Exchange(msg, resolver)
if err != nil {
return nil, err
}
if in.Rcode != dns.RcodeSuccess && in.Rcode != dns.RcodeNameError {
return nil, fmt.Errorf("rcode %s", dns.RcodeToString[in.Rcode])
}
return in, nil
}
func lookupA(resolver, fqdn string) (*dns.A, error) {
in, err := dnsExchange(resolver, fqdn, dns.TypeA)
if err != nil {
return nil, err
}
for _, rr := range in.Answer {
if a, ok := rr.(*dns.A); ok {
return a, nil
}
}
return nil, nil
}
func lookupAAAA(resolver, fqdn string) (*dns.AAAA, error) {
in, err := dnsExchange(resolver, fqdn, dns.TypeAAAA)
if err != nil {
return nil, err
}
for _, rr := range in.Answer {
if aaaa, ok := rr.(*dns.AAAA); ok {
return aaaa, nil
}
}
return nil, nil
}
func lookupSSHFP(resolver, fqdn string) ([]*dns.SSHFP, error) {
in, err := dnsExchange(resolver, fqdn, dns.TypeSSHFP)
if err != nil {
return nil, err
}
var out []*dns.SSHFP
for _, rr := range in.Answer {
if s, ok := rr.(*dns.SSHFP); ok {
out = append(out, s)
}
}
return out, nil
}

378
checker/kexinit.go Normal file
View file

@ -0,0 +1,378 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"bufio"
"crypto/rand"
"encoding/binary"
"fmt"
"io"
"strings"
)
// The SSH transport protocol is fully specified in RFC 4253. For the
// security audit we only need the pre-authentication handshake:
//
// 1. exchange of protocol version strings (ASCII banners, CRLF-terminated)
// 2. exchange of SSH_MSG_KEXINIT packets, which carry the full algorithm
// preference lists in one go.
//
// We deliberately avoid going beyond KEXINIT: a shallow probe is cheap,
// works against every RFC-compliant SSH server without depending on any
// particular algorithm family being supported, and sidesteps the risk of
// running actual KEX math with untrusted peers.
const (
// sshClientBanner is the version string we advertise. ssh-audit and
// nmap publish a recognisable banner so operators can tell an audit
// probe apart from a real client in their logs.
sshClientBanner = "SSH-2.0-happyDomain-checker_1.0"
msgKexInit = 20
// maxPacketSize caps the largest packet we will read. RFC 4253 allows
// up to 32768 bytes of payload, so 65k is a safe ceiling that also
// protects us from a rogue server trying to exhaust memory.
maxPacketSize = 65535
// maxBannerSize limits how much we read before we give up on the
// peer's version string. RFC 4253 mandates at most 255 bytes.
maxBannerSize = 4096
)
// kexInitPayload is the parsed contents of a KEXINIT packet. The field
// names match RFC 4253 §7.1 verbatim to make audits easy.
type kexInitPayload struct {
Cookie [16]byte
KexAlgorithms []string
ServerHostKeyAlgorithms []string
EncryptionAlgorithmsClientToSvr []string
EncryptionAlgorithmsSvrToClient []string
MACAlgorithmsClientToSvr []string
MACAlgorithmsSvrToClient []string
CompressionAlgorithmsClientToSv []string
CompressionAlgorithmsSvrToClt []string
LanguagesClientToSvr []string
LanguagesSvrToClient []string
FirstKexPacketFollows bool
}
// readBanner reads the peer's SSH identification string. Servers may
// send several CRLF-terminated lines of free-text before the actual
// "SSH-2.0-..." line (RFC 4253 §4.2); we skip those and return the first
// line that looks like a version exchange.
func readBanner(r *bufio.Reader) (string, error) {
for i := 0; i < 16; i++ {
line, err := readLine(r, maxBannerSize)
if err != nil {
return "", err
}
if strings.HasPrefix(line, "SSH-") {
return line, nil
}
}
return "", fmt.Errorf("no SSH version string received")
}
// readLine reads a single CRLF-terminated line (or LF-terminated, as
// some servers omit the CR) and returns it without the terminator.
func readLine(r *bufio.Reader, max int) (string, error) {
var buf []byte
for {
b, err := r.ReadByte()
if err != nil {
return "", err
}
if b == '\n' {
if n := len(buf); n > 0 && buf[n-1] == '\r' {
buf = buf[:n-1]
}
return string(buf), nil
}
buf = append(buf, b)
if len(buf) > max {
return "", fmt.Errorf("line too long")
}
}
}
// writeBanner sends our client identification string.
func writeBanner(w io.Writer) error {
_, err := io.WriteString(w, sshClientBanner+"\r\n")
return err
}
// readPacket reads a single SSH binary packet (RFC 4253 §6) from r. The
// handshake is still in cleartext at this point, so we don't worry
// about MAC or cipher state: packet_length + padding_length + payload +
// random padding, no MAC.
func readPacket(r io.Reader) (payload []byte, err error) {
var lenBuf [4]byte
if _, err = io.ReadFull(r, lenBuf[:]); err != nil {
return nil, err
}
packetLen := binary.BigEndian.Uint32(lenBuf[:])
if packetLen < 5 || packetLen > maxPacketSize {
return nil, fmt.Errorf("invalid packet length %d", packetLen)
}
body := make([]byte, packetLen)
if _, err = io.ReadFull(r, body); err != nil {
return nil, err
}
padLen := int(body[0])
if padLen >= len(body) {
return nil, fmt.Errorf("invalid padding length %d vs packet %d", padLen, len(body))
}
return body[1 : len(body)-padLen], nil
}
// writePacket frames payload into an RFC 4253 binary packet and sends it.
func writePacket(w io.Writer, payload []byte) error {
// packet_length covers padding_length + payload + random_padding,
// but not itself. The total (4 + packet_length) must be a multiple
// of 8 (the block size used in unencrypted mode), and padding must
// be at least 4 bytes.
const blockSize = 8
padLen := blockSize - ((5 + len(payload)) % blockSize)
if padLen < 4 {
padLen += blockSize
}
packetLen := 1 + len(payload) + padLen
buf := make([]byte, 4+packetLen)
binary.BigEndian.PutUint32(buf[:4], uint32(packetLen))
buf[4] = byte(padLen)
copy(buf[5:], payload)
if _, err := rand.Read(buf[5+len(payload):]); err != nil {
return fmt.Errorf("padding rand: %w", err)
}
_, err := w.Write(buf)
return err
}
// buildKexInit crafts a client KEXINIT payload that advertises every
// algorithm family the Go SSH stack knows, plus the typical OpenSSH
// names we aren't implementing. We are never going to actually perform
// key exchange over this connection: the server only needs to accept
// our KEXINIT as well-formed and echo its own.
func buildKexInit() []byte {
var cookie [16]byte
_ = mustRand(cookie[:])
kex := strings.Join([]string{
"curve25519-sha256",
"curve25519-sha256@libssh.org",
"ecdh-sha2-nistp256",
"ecdh-sha2-nistp384",
"ecdh-sha2-nistp521",
"diffie-hellman-group-exchange-sha256",
"diffie-hellman-group16-sha512",
"diffie-hellman-group14-sha256",
"diffie-hellman-group14-sha1",
"diffie-hellman-group1-sha1",
"sntrup761x25519-sha512@openssh.com",
"mlkem768x25519-sha256",
}, ",")
hostKey := strings.Join([]string{
"ssh-ed25519",
"ssh-ed25519-cert-v01@openssh.com",
"rsa-sha2-512",
"rsa-sha2-256",
"ssh-rsa",
"ecdsa-sha2-nistp256",
"ecdsa-sha2-nistp384",
"ecdsa-sha2-nistp521",
"ssh-dss",
}, ",")
ciphers := strings.Join([]string{
"chacha20-poly1305@openssh.com",
"aes256-gcm@openssh.com",
"aes128-gcm@openssh.com",
"aes256-ctr",
"aes192-ctr",
"aes128-ctr",
"aes256-cbc",
"aes128-cbc",
"3des-cbc",
}, ",")
macs := strings.Join([]string{
"hmac-sha2-512-etm@openssh.com",
"hmac-sha2-256-etm@openssh.com",
"umac-128-etm@openssh.com",
"hmac-sha2-512",
"hmac-sha2-256",
"hmac-sha1",
"hmac-sha1-96",
"hmac-md5",
}, ",")
comp := "none,zlib@openssh.com,zlib"
w := newPayloadWriter()
w.writeByte(msgKexInit)
w.writeBytes(cookie[:])
w.writeString(kex)
w.writeString(hostKey)
w.writeString(ciphers)
w.writeString(ciphers)
w.writeString(macs)
w.writeString(macs)
w.writeString(comp)
w.writeString(comp)
w.writeString("") // languages c2s
w.writeString("") // languages s2c
w.writeByte(0) // first_kex_packet_follows
w.writeUint32(0) // reserved
return w.bytes()
}
func mustRand(b []byte) error {
_, err := rand.Read(b)
return err
}
// parseKexInit parses a server KEXINIT payload. Validation is minimal:
// we do not reject over-long algorithm lists, we just trim them at the
// RFC ceiling so a hostile server can't make us allocate unbounded
// amounts of memory.
func parseKexInit(payload []byte) (*kexInitPayload, error) {
if len(payload) < 1 || payload[0] != msgKexInit {
return nil, fmt.Errorf("not a KEXINIT packet (first byte = %d)", func() byte {
if len(payload) == 0 {
return 0
}
return payload[0]
}())
}
r := newPayloadReader(payload[1:])
out := &kexInitPayload{}
if err := r.readBytes(out.Cookie[:]); err != nil {
return nil, err
}
var err error
if out.KexAlgorithms, err = r.readNameList(); err != nil {
return nil, err
}
if out.ServerHostKeyAlgorithms, err = r.readNameList(); err != nil {
return nil, err
}
if out.EncryptionAlgorithmsClientToSvr, err = r.readNameList(); err != nil {
return nil, err
}
if out.EncryptionAlgorithmsSvrToClient, err = r.readNameList(); err != nil {
return nil, err
}
if out.MACAlgorithmsClientToSvr, err = r.readNameList(); err != nil {
return nil, err
}
if out.MACAlgorithmsSvrToClient, err = r.readNameList(); err != nil {
return nil, err
}
if out.CompressionAlgorithmsClientToSv, err = r.readNameList(); err != nil {
return nil, err
}
if out.CompressionAlgorithmsSvrToClt, err = r.readNameList(); err != nil {
return nil, err
}
if out.LanguagesClientToSvr, err = r.readNameList(); err != nil {
return nil, err
}
if out.LanguagesSvrToClient, err = r.readNameList(); err != nil {
return nil, err
}
b, err := r.readByte()
if err != nil {
return nil, err
}
out.FirstKexPacketFollows = b != 0
return out, nil
}
// payloadWriter/Reader are tiny helpers for SSH wire encoding. We only
// ever use uint32-prefixed strings and comma-separated name-lists.
type payloadWriter struct{ buf []byte }
func newPayloadWriter() *payloadWriter { return &payloadWriter{} }
func (w *payloadWriter) bytes() []byte { return w.buf }
func (w *payloadWriter) writeByte(b byte) { w.buf = append(w.buf, b) }
func (w *payloadWriter) writeBytes(b []byte) { w.buf = append(w.buf, b...) }
func (w *payloadWriter) writeUint32(v uint32) {
var b [4]byte
binary.BigEndian.PutUint32(b[:], v)
w.buf = append(w.buf, b[:]...)
}
func (w *payloadWriter) writeString(s string) {
w.writeUint32(uint32(len(s)))
w.buf = append(w.buf, s...)
}
type payloadReader struct {
buf []byte
pos int
}
func newPayloadReader(b []byte) *payloadReader { return &payloadReader{buf: b} }
func (r *payloadReader) readByte() (byte, error) {
if r.pos >= len(r.buf) {
return 0, io.ErrUnexpectedEOF
}
b := r.buf[r.pos]
r.pos++
return b, nil
}
func (r *payloadReader) readBytes(dst []byte) error {
if r.pos+len(dst) > len(r.buf) {
return io.ErrUnexpectedEOF
}
copy(dst, r.buf[r.pos:r.pos+len(dst)])
r.pos += len(dst)
return nil
}
func (r *payloadReader) readUint32() (uint32, error) {
if r.pos+4 > len(r.buf) {
return 0, io.ErrUnexpectedEOF
}
v := binary.BigEndian.Uint32(r.buf[r.pos : r.pos+4])
r.pos += 4
return v, nil
}
func (r *payloadReader) readNameList() ([]string, error) {
n, err := r.readUint32()
if err != nil {
return nil, err
}
if int(n) > len(r.buf)-r.pos {
return nil, io.ErrUnexpectedEOF
}
s := string(r.buf[r.pos : r.pos+int(n)])
r.pos += int(n)
if s == "" {
return nil, nil
}
return strings.Split(s, ","), nil
}

395
checker/prober.go Normal file
View file

@ -0,0 +1,395 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"bufio"
"context"
"crypto/sha1"
"crypto/sha256"
"encoding/hex"
"errors"
"net"
"strconv"
"strings"
"time"
"golang.org/x/crypto/ssh"
)
// probeEndpoint runs the full probe flow on a single (host, ip, port)
// triple. It never returns a Go error: every failure mode is recorded
// as a raw field on SSHProbe (Stage + Error). Severity / pass/fail
// classification is performed later by CheckRule.Evaluate, never here.
func probeEndpoint(ctx context.Context, host, ip string, port uint16, timeout time.Duration, includeAuthProbe bool, sshfp SSHFPSummary) SSHProbe {
start := time.Now()
addr := net.JoinHostPort(ip, strconv.Itoa(int(port)))
p := SSHProbe{
Host: host,
Port: port,
Address: addr,
IP: ip,
IsIPv6: strings.Contains(ip, ":"),
Stage: "dial",
}
dialCtx, cancel := context.WithTimeout(ctx, timeout)
defer cancel()
d := &net.Dialer{}
conn, err := d.DialContext(dialCtx, "tcp", addr)
if err != nil {
p.Error = "dial: " + err.Error()
p.ElapsedMS = time.Since(start).Milliseconds()
return p
}
defer conn.Close()
p.TCPConnected = true
p.Stage = "banner"
if deadline, ok := dialCtx.Deadline(); ok {
_ = conn.SetDeadline(deadline)
}
// Phase 1: protocol banner exchange.
br := bufio.NewReader(conn)
banner, err := readBanner(br)
if err != nil {
p.Error = "banner: " + err.Error()
p.ElapsedMS = time.Since(start).Milliseconds()
return p
}
p.Banner = banner
p.ProtoVer, p.SoftVer, p.Vendor = parseBanner(banner)
p.Stage = "banner_write"
if err := writeBanner(conn); err != nil {
p.Error = "write-banner: " + err.Error()
p.ElapsedMS = time.Since(start).Milliseconds()
return p
}
// Phase 2: exchange KEXINIT.
p.Stage = "kexinit_read"
srvPayload, err := readPacket(br)
if err != nil {
p.Error = "kexinit-read: " + err.Error()
p.ElapsedMS = time.Since(start).Milliseconds()
return p
}
p.Stage = "kexinit_parse"
srvKex, err := parseKexInit(srvPayload)
if err != nil {
p.Error = "kexinit-parse: " + err.Error()
p.ElapsedMS = time.Since(start).Milliseconds()
return p
}
p.KEX = srvKex.KexAlgorithms
p.HostKey = srvKex.ServerHostKeyAlgorithms
p.CiphersC2S = srvKex.EncryptionAlgorithmsClientToSvr
p.CiphersS2C = srvKex.EncryptionAlgorithmsSvrToClient
p.MACsC2S = srvKex.MACAlgorithmsClientToSvr
p.MACsS2C = srvKex.MACAlgorithmsSvrToClient
p.CompC2S = srvKex.CompressionAlgorithmsClientToSv
p.CompS2C = srvKex.CompressionAlgorithmsSvrToClt
p.Stage = "kexinit_ok"
// We intentionally don't proceed with KEX here: algorithm posture is
// already captured. Closing now is friendlier than triggering a full
// exchange that might never terminate.
_ = conn.Close()
// We hand off to Go's ssh package for the full handshake. HostKeyCallback lets us
// capture each presented key without reimplementing DH/curve25519/kyber ourselves.
p.HostKeys = probeHostKeys(ctx, addr, host, srvKex.ServerHostKeyAlgorithms, timeout)
for i := range p.HostKeys {
p.HostKeys[i].applySSHFP(sshfp)
}
if len(p.HostKeys) > 0 {
p.Stage = "handshake_ok"
}
if includeAuthProbe {
p.AuthProbeAttempted = true
methods, err := probeAuthMethods(ctx, addr, timeout)
if err == nil {
p.AuthMethods = methods
for _, m := range methods {
switch m {
case "password":
p.PasswordAuth = true
case "keyboard-interactive":
p.KeyboardInteractive = true
case "publickey":
p.PublicKeyAuth = true
}
}
}
}
p.ElapsedMS = time.Since(start).Milliseconds()
return p
}
// Most deployments expose at most two or three key families (ed25519, rsa, ecdsa),
// so connecting once per family stays cheap.
func probeHostKeys(ctx context.Context, addr, host string, algos []string, timeout time.Duration) []HostKeyInfo {
wantFamilies := pickHostKeyFamilies(algos)
seen := map[string]bool{} // by sha256 hex, dedupe across families
var out []HostKeyInfo
for _, algo := range wantFamilies {
key, err := fetchHostKey(ctx, addr, host, algo, timeout)
if err != nil || key == nil {
continue
}
info := describeHostKey(key)
if seen[info.SHA256] {
continue
}
seen[info.SHA256] = true
out = append(out, info)
}
return out
}
// rsa-sha2-512 and rsa-sha2-256 both return the same RSA key, so we collapse by family.
func pickHostKeyFamilies(algos []string) []string {
var out []string
families := map[string]bool{}
add := func(family, algo string) {
if families[family] {
return
}
families[family] = true
out = append(out, algo)
}
for _, a := range algos {
switch a {
case "ssh-ed25519", "ssh-ed25519-cert-v01@openssh.com":
add("ed25519", "ssh-ed25519")
case "rsa-sha2-512", "rsa-sha2-256", "ssh-rsa":
add("rsa", a)
case "ecdsa-sha2-nistp256", "ecdsa-sha2-nistp384", "ecdsa-sha2-nistp521":
add("ecdsa", a)
case "ssh-dss":
add("dsa", "ssh-dss")
}
}
return out
}
// Offering no auth methods aborts the handshake at the auth step, which is enough
// to capture the host key without completing a full session.
func fetchHostKey(ctx context.Context, addr, host, algo string, timeout time.Duration) (ssh.PublicKey, error) {
var captured ssh.PublicKey
cfg := &ssh.ClientConfig{
User: "happydomain-checker",
Auth: nil,
HostKeyCallback: func(_ string, _ net.Addr, key ssh.PublicKey) error {
captured = key
return nil
},
HostKeyAlgorithms: []string{algo},
Timeout: timeout,
ClientVersion: sshClientBanner,
}
dialCtx, cancel := context.WithTimeout(ctx, timeout)
defer cancel()
d := &net.Dialer{}
conn, err := d.DialContext(dialCtx, "tcp", addr)
if err != nil {
return nil, err
}
defer conn.Close()
if deadline, ok := dialCtx.Deadline(); ok {
_ = conn.SetDeadline(deadline)
}
_, _, _, err = ssh.NewClientConn(conn, host, cfg)
if err != nil && captured == nil {
return nil, err
}
return captured, nil
}
// probeAuthMethods opens a fresh connection, completes the KEX, and
// then sends a "none" authentication request (RFC 4252 §5.2). The
// server's failure response carries the list of methods it would
// actually accept: exactly what we need.
func probeAuthMethods(ctx context.Context, addr string, timeout time.Duration) ([]string, error) {
cfg := &ssh.ClientConfig{
User: "happydomain-checker",
Auth: []ssh.AuthMethod{}, // forces a "none" attempt
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
Timeout: timeout,
ClientVersion: sshClientBanner,
}
dialCtx, cancel := context.WithTimeout(ctx, timeout)
defer cancel()
d := &net.Dialer{}
conn, err := d.DialContext(dialCtx, "tcp", addr)
if err != nil {
return nil, err
}
defer conn.Close()
if deadline, ok := dialCtx.Deadline(); ok {
_ = conn.SetDeadline(deadline)
}
_, _, _, err = ssh.NewClientConn(conn, addr, cfg)
if err == nil {
// A server that lets us through "none" is unusual but possible
// (anonymous SSH for git-serve-style deployments); report that
// upstream by returning an empty list.
return nil, nil
}
return extractMethodsFromAuthError(err), nil
}
// x/crypto/ssh does not expose offered auth methods via a typed accessor; string
// parsing is the officially documented path.
func extractMethodsFromAuthError(err error) []string {
if err == nil {
return nil
}
msg := err.Error()
start := strings.Index(msg, "attempted methods [")
if start < 0 {
return nil
}
start += len("attempted methods [")
end := strings.Index(msg[start:], "]")
if end < 0 {
return nil
}
raw := strings.Fields(msg[start : start+end])
var out []string
for _, m := range raw {
if m == "none" {
continue
}
out = append(out, m)
}
return out
}
func describeHostKey(key ssh.PublicKey) HostKeyInfo {
marshaled := key.Marshal()
sha2 := sha256.Sum256(marshaled)
sha1sum := sha1.Sum(marshaled)
info := HostKeyInfo{
Type: key.Type(),
SHA256: hex.EncodeToString(sha2[:]),
SHA1: hex.EncodeToString(sha1sum[:]),
}
info.SSHFPAlgo = sshfpAlgoForKeyType(info.Type)
info.Bits = keyBits(key)
return info
}
// keyBits returns a key-family-specific size estimate. It is advisory:
// we only use it in the report, and a server that ships an RSA key
// smaller than 2048 bits is the sort of red flag we want to show.
func keyBits(key ssh.PublicKey) int {
switch k := key.(type) {
case ssh.CryptoPublicKey:
type bitSizer interface{ Size() int }
switch p := k.CryptoPublicKey().(type) {
case bitSizer:
return p.Size() * 8
default:
_ = p
}
}
return 0
}
// sshfpAlgoForKeyType maps an SSH host-key type string to the SSHFP
// algorithm number defined in RFC 4255 / RFC 6594 / RFC 7479.
func sshfpAlgoForKeyType(t string) uint8 {
switch t {
case "ssh-rsa", "rsa-sha2-256", "rsa-sha2-512":
return 1
case "ssh-dss":
return 2
case "ecdsa-sha2-nistp256", "ecdsa-sha2-nistp384", "ecdsa-sha2-nistp521":
return 3
case "ssh-ed25519":
return 4
}
return 0
}
// parseBanner splits an "SSH-2.0-OpenSSH_9.3p1 Debian-1" banner into
// (protocolVersion, softwareVersion, vendorComment). The grammar is
// RFC 4253 §4.2: "SSH-<protoversion>-<softwareversion> <comments>".
func parseBanner(b string) (proto, soft, vendor string) {
// SSH- prefix is guaranteed by readBanner.
rest := strings.TrimPrefix(b, "SSH-")
dash := strings.IndexByte(rest, '-')
if dash < 0 {
return rest, "", ""
}
proto = rest[:dash]
rest = rest[dash+1:]
if sp := strings.IndexByte(rest, ' '); sp >= 0 {
soft = rest[:sp]
vendor = strings.TrimSpace(rest[sp+1:])
} else {
soft = rest
}
return
}
// applySSHFP fills in the SSHFPMatchSHA* flags based on the declared
// SSHFP records for this key's algorithm family. These are raw
// observations (the record matched this key fingerprint); any
// severity verdict about coverage lives in the SSHFP rule.
func (h *HostKeyInfo) applySSHFP(s SSHFPSummary) {
for _, rr := range s.Records {
if rr.Algorithm != h.SSHFPAlgo {
continue
}
want := strings.ToLower(rr.Fingerprint)
switch rr.Type {
case 1:
if want == h.SHA1 {
h.SSHFPMatchSHA1 = true
}
case 2:
if want == h.SHA256 {
h.SSHFPMatchSHA256 = true
}
}
}
}
// errNoHostKey is returned by fetchHostKey when the callback never
// fired (e.g. transport-level error before the host key was received).
// Currently only used internally for readability.
var errNoHostKey = errors.New("no host key observed")

49
checker/provider.go Normal file
View file

@ -0,0 +1,49 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"encoding/json"
"fmt"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// Provider returns a new SSH observation provider.
func Provider() sdk.ObservationProvider {
return &sshProvider{}
}
type sshProvider struct{}
func (p *sshProvider) Key() sdk.ObservationKey {
return ObservationKeySSH
}
// GetHTMLReport implements sdk.CheckerHTMLReporter.
func (p *sshProvider) GetHTMLReport(rctx sdk.ReportContext) (string, error) {
var d SSHData
if err := json.Unmarshal(rctx.Data(), &d); err != nil {
return "", fmt.Errorf("unmarshal ssh observation: %w", err)
}
return renderReport(&d, rctx)
}

679
checker/report.go Normal file
View file

@ -0,0 +1,679 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"fmt"
"html/template"
"sort"
"strings"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// renderReport builds the HTML iframe contents displayed in the
// happyDomain UI. The layout is deliberately close to the XMPP/TLS
// reports so operators get a consistent experience across checkers.
//
// Structure:
// 1. Header with overall status badge + SSHFP verdict chips.
// 2. "What to fix" list (the most common / highest-severity issues
// with inline copy-pasteable sshd_config or DNS snippets).
// 3. Per-endpoint details (banner, host keys, algorithm tables,
// auth methods).
//
// We render the algorithm tables with per-row severity classes so the
// weak/broken entries light up visually.
func renderReport(d *SSHData, rctx sdk.ReportContext) (string, error) {
var states []sdk.CheckState
if rctx != nil {
states = rctx.States()
}
view := buildReportData(d, states)
var buf strings.Builder
if err := reportTpl.Execute(&buf, view); err != nil {
return "", fmt.Errorf("render ssh report: %w", err)
}
return buf.String(), nil
}
type reportView struct {
Domain string
RunAt string
StatusLabel string
StatusClass string
HasIssues bool
TopFixes []reportFix
SSHFPPresent bool
SSHFPMatched bool
SSHFPRecords []reportSSHFPRecord
Endpoints []reportEndpoint
HasAuthProbe bool
AnyIPv4, AnyIPv6 bool
}
type reportFix struct {
Severity string
Code string
Message string
Fix string
Endpoint string
}
type reportSSHFPRecord struct {
Algorithm uint8
AlgoName string
Type uint8
TypeName string
Fingerprint string
Matched bool
}
type reportEndpoint struct {
Address string
Host string
Port uint16
IsIPv6 bool
TCPConnected bool
Banner string
SoftwareVer string
Vendor string
ElapsedMS int64
Error string
StatusLabel string
StatusClass string
AnyFail bool
HostKeys []reportHostKey
AlgoTables []reportAlgoTable
AuthMethods []reportAuthMethod
Issues []reportFix
}
type reportHostKey struct {
Type string
Bits int
SHA256 string
SHA1 string
SSHFPMatched bool
SSHFPFamily string
SSHFPSnippet string
}
type reportAlgoTable struct {
Title string
Rows []reportAlgoRow
}
type reportAlgoRow struct {
Name string
Severity string // "", "warn", "crit", "info"
Note string
}
type reportAuthMethod struct {
Name string
Severity string // "ok", "warn"
Note string
}
func buildReportData(d *SSHData, states []sdk.CheckState) reportView {
v := reportView{
Domain: d.Domain,
RunAt: d.CollectedAt.Format("2006-01-02 15:04 MST"),
SSHFPPresent: d.SSHFP.Present,
}
// Deduplicate: the same weak cipher reported by two endpoints merges into one row.
// When no states are available, fall back to data-only rendering with no hints.
type fix struct {
severity string
code string
message string
fixText string
endpoint string
}
stateFix := func(s sdk.CheckState) (fix, bool) {
sev := statusToSeverity(s.Status)
if sev == "" {
return fix{}, false
}
var fixText string
if s.Meta != nil {
if raw, ok := s.Meta["fix"]; ok {
if str, ok := raw.(string); ok {
fixText = str
}
}
}
return fix{
severity: sev,
code: s.Code,
message: s.Message,
fixText: fixText,
endpoint: s.Subject,
}, true
}
// Per-endpoint grouping by Subject (endpoint Address).
perEp := map[string][]fix{}
var allFixes []fix
seen := map[string]bool{}
for _, s := range states {
f, ok := stateFix(s)
if !ok {
continue
}
if f.endpoint != "" {
perEp[f.endpoint] = append(perEp[f.endpoint], f)
}
key := f.code + "|" + f.message
if seen[key] {
continue
}
seen[key] = true
allFixes = append(allFixes, f)
}
sort.SliceStable(allFixes, func(i, j int) bool {
return sevRank(allFixes[i].severity) < sevRank(allFixes[j].severity)
})
for _, f := range allFixes {
if f.severity == SeverityInfo && !strings.Contains(f.code, "sshfp") {
continue // informational clutter, keep in per-endpoint only
}
v.TopFixes = append(v.TopFixes, reportFix{
Severity: f.severity,
Code: f.code,
Message: f.message,
Fix: f.fixText,
Endpoint: f.endpoint,
})
}
v.HasIssues = len(v.TopFixes) > 0
worst := SeverityOK
for _, f := range allFixes {
if f.severity == SeverityCrit {
worst = SeverityCrit
break
}
if f.severity == SeverityWarn && worst != SeverityCrit {
worst = SeverityWarn
}
}
switch worst {
case SeverityCrit:
v.StatusLabel = "FAIL"
v.StatusClass = "fail"
case SeverityWarn:
v.StatusLabel = "WARN"
v.StatusClass = "warn"
default:
v.StatusLabel = "OK"
v.StatusClass = "ok"
}
// SSHFP records table.
for _, rr := range d.SSHFP.Records {
matched := false
for _, ep := range d.Endpoints {
for _, k := range ep.HostKeys {
if k.SSHFPAlgo == rr.Algorithm {
if rr.Type == 2 && strings.EqualFold(rr.Fingerprint, k.SHA256) {
matched = true
}
if rr.Type == 1 && strings.EqualFold(rr.Fingerprint, k.SHA1) {
matched = true
}
}
}
}
if matched {
v.SSHFPMatched = true
}
v.SSHFPRecords = append(v.SSHFPRecords, reportSSHFPRecord{
Algorithm: rr.Algorithm,
AlgoName: sshfpAlgoName(rr.Algorithm),
Type: rr.Type,
TypeName: sshfpHashName(rr.Type),
Fingerprint: rr.Fingerprint,
Matched: matched,
})
}
for _, ep := range d.Endpoints {
re := reportEndpoint{
Address: ep.Address,
Host: ep.Host,
Port: ep.Port,
IsIPv6: ep.IsIPv6,
TCPConnected: ep.TCPConnected,
Banner: ep.Banner,
SoftwareVer: ep.SoftVer,
Vendor: ep.Vendor,
ElapsedMS: ep.ElapsedMS,
Error: ep.Error,
}
if ep.IsIPv6 {
v.AnyIPv6 = true
} else {
v.AnyIPv4 = true
}
perEpIssues := perEp[ep.Address]
// Per-endpoint status label.
epWorst := SeverityOK
for _, f := range perEpIssues {
if f.severity == SeverityCrit {
epWorst = SeverityCrit
break
}
if f.severity == SeverityWarn && epWorst != SeverityCrit {
epWorst = SeverityWarn
}
}
switch epWorst {
case SeverityCrit:
re.StatusLabel = "FAIL"
re.StatusClass = "fail"
re.AnyFail = true
case SeverityWarn:
re.StatusLabel = "WARN"
re.StatusClass = "warn"
default:
re.StatusLabel = "OK"
re.StatusClass = "ok"
}
for _, k := range ep.HostKeys {
rh := reportHostKey{
Type: k.Type,
Bits: k.Bits,
SHA256: k.SHA256,
SHA1: k.SHA1,
}
rh.SSHFPMatched = k.SSHFPMatchSHA256 || k.SSHFPMatchSHA1
rh.SSHFPFamily = sshfpAlgoName(k.SSHFPAlgo)
rh.SSHFPSnippet = fmt.Sprintf("%d 2 %s", k.SSHFPAlgo, k.SHA256)
re.HostKeys = append(re.HostKeys, rh)
}
re.AlgoTables = []reportAlgoTable{
{Title: "Key exchange (KEX)", Rows: algoRows(ep.KEX, kexAlgos)},
{Title: "Server host keys", Rows: algoRows(ep.HostKey, hostKeyAlgos)},
{Title: "Ciphers", Rows: algoRows(uniqueMerge(ep.CiphersC2S, ep.CiphersS2C), cipherAlgos)},
{Title: "MACs", Rows: algoRows(uniqueMerge(ep.MACsC2S, ep.MACsS2C), macAlgos)},
}
if ep.AuthMethods != nil || ep.PasswordAuth || ep.PublicKeyAuth || ep.KeyboardInteractive {
v.HasAuthProbe = true
for _, m := range ep.AuthMethods {
sev := SeverityOK
note := ""
switch m {
case "password":
sev = SeverityWarn
note = "password auth over the internet is the #1 brute-force target"
case "keyboard-interactive":
note = "often used for 2FA, otherwise equivalent to password"
case "publickey":
note = "preferred method"
}
re.AuthMethods = append(re.AuthMethods, reportAuthMethod{
Name: m,
Severity: sev,
Note: note,
})
}
}
for _, f := range perEpIssues {
re.Issues = append(re.Issues, reportFix{
Severity: f.severity,
Code: f.code,
Message: f.message,
Fix: f.fixText,
})
}
v.Endpoints = append(v.Endpoints, re)
}
return v
}
// Non-finding statuses return "" so callers skip them in fix listings.
func statusToSeverity(s sdk.Status) string {
switch s {
case sdk.StatusCrit:
return SeverityCrit
case sdk.StatusWarn:
return SeverityWarn
case sdk.StatusInfo:
return SeverityInfo
}
return ""
}
func algoRows(list []string, table map[string]algoVerdict) []reportAlgoRow {
out := make([]reportAlgoRow, 0, len(list))
for _, name := range list {
v := verdictFor(table, name)
out = append(out, reportAlgoRow{
Name: name,
Severity: v.severity,
Note: v.reason,
})
}
return out
}
func sevRank(s string) int {
switch s {
case SeverityCrit:
return 0
case SeverityWarn:
return 1
case SeverityInfo:
return 2
}
return 3
}
func sshfpAlgoName(a uint8) string {
switch a {
case 1:
return "RSA"
case 2:
return "DSA"
case 3:
return "ECDSA"
case 4:
return "Ed25519"
case 6:
return "Ed448"
}
return fmt.Sprintf("algo %d", a)
}
func sshfpHashName(t uint8) string {
switch t {
case 1:
return "SHA-1"
case 2:
return "SHA-256"
}
return fmt.Sprintf("hash %d", t)
}
var reportTpl = template.Must(template.New("ssh").Funcs(template.FuncMap{
"sevClass": func(s string) string {
switch s {
case SeverityCrit:
return "fail"
case SeverityWarn:
return "warn"
case SeverityInfo:
return "muted"
case SeverityOK:
return "ok"
}
return ""
},
}).Parse(`<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>SSH Report: {{.Domain}}</title>
<style>
*, *::before, *::after { box-sizing: border-box; }
:root {
font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
font-size: 14px;
line-height: 1.5;
color: #1f2937;
background: #f3f4f6;
}
body { margin: 0; padding: 1rem; }
code { font-family: ui-monospace, monospace; font-size: .9em; }
pre { font-family: ui-monospace, monospace; font-size: .78rem; background: #111827; color: #e5e7eb; padding: .6rem .8rem; border-radius: 6px; overflow-x: auto; margin: .35rem 0 0; }
h1 { margin: 0 0 .4rem; font-size: 1.15rem; font-weight: 700; }
h2 { font-size: 1rem; font-weight: 700; margin: 0 0 .6rem; }
h3 { font-size: .9rem; font-weight: 600; margin: .5rem 0 .3rem; }
.hd, .section, details {
background: #fff;
box-shadow: 0 1px 3px rgba(0,0,0,.08);
}
.hd { border-radius: 10px; padding: 1rem 1.25rem; margin-bottom: .75rem; }
.section { border-radius: 8px; padding: .85rem 1rem; margin-bottom: .6rem; }
details { border-radius: 8px; margin-bottom: .45rem; overflow: hidden; }
.badge {
display: inline-flex; align-items: center;
padding: .2em .65em; border-radius: 9999px;
font-size: .78rem; font-weight: 700; letter-spacing: .02em;
}
.ok { background: #d1fae5; color: #065f46; }
.warn { background: #fef3c7; color: #92400e; }
.fail { background: #fee2e2; color: #991b1b; }
.muted { background: #e5e7eb; color: #374151; }
.meta { color: #6b7280; font-size: .82rem; margin-top: .35rem; }
summary {
display: flex; align-items: center; gap: .5rem;
padding: .65rem 1rem; cursor: pointer; user-select: none; list-style: none;
}
summary::-webkit-details-marker { display: none; }
summary::before { content: "▶"; font-size: .65rem; color: #9ca3af; transition: transform .15s; flex-shrink: 0; }
details[open] > summary::before { transform: rotate(90deg); }
.conn-addr { font-weight: 600; flex: 1; font-size: .9rem; font-family: ui-monospace, monospace; }
.details-body { padding: .6rem 1rem .85rem; border-top: 1px solid #f3f4f6; }
table { border-collapse: collapse; width: 100%; font-size: .85rem; margin-top: .25rem; }
th, td { text-align: left; padding: .25rem .5rem; border-bottom: 1px solid #f3f4f6; vertical-align: top; }
th { font-weight: 600; color: #6b7280; }
tr.crit td:first-child { border-left: 3px solid #dc2626; }
tr.warn td:first-child { border-left: 3px solid #f59e0b; }
tr.info td:first-child { border-left: 3px solid #3b82f6; }
.fix {
border-left: 3px solid #dc2626;
padding: .5rem .75rem; margin-bottom: .5rem;
background: #fef2f2; border-radius: 0 6px 6px 0;
}
.fix.warn { border-color: #f59e0b; background: #fffbeb; }
.fix.info { border-color: #3b82f6; background: #eff6ff; }
.fix.muted { border-color: #9ca3af; background: #f9fafb; }
.fix .code { font-family: ui-monospace, monospace; font-size: .75rem; color: #6b7280; }
.fix .msg { font-weight: 600; margin: .1rem 0 .2rem; }
.fix .how { font-size: .88rem; }
.fix .ep { font-size: .78rem; color: #6b7280; font-family: ui-monospace, monospace; }
.chiprow { display: flex; flex-wrap: wrap; gap: .25rem; }
.chip {
display: inline-block; padding: .12em .5em;
background: #e0e7ff; color: #3730a3;
border-radius: 4px; font-size: .78rem; font-family: ui-monospace, monospace;
}
.chip.fail { background: #fee2e2; color: #991b1b; }
.chip.warn { background: #fef3c7; color: #92400e; }
.chip.ok { background: #d1fae5; color: #065f46; }
.kv { display: grid; grid-template-columns: auto 1fr; gap: .3rem 1rem; font-size: .86rem; }
.kv dt { color: #6b7280; }
.kv dd { margin: 0; }
.note { color: #6b7280; font-size: .85rem; }
.footer { color: #6b7280; font-size: .78rem; text-align: center; margin-top: 1rem; padding-bottom: 2rem; }
.check-ok { color: #059669; }
.check-fail { color: #dc2626; }
.fp {
font-family: ui-monospace, monospace; font-size: .72rem;
word-break: break-all;
}
</style>
</head>
<body>
<div class="hd">
<h1>SSH: <code>{{.Domain}}</code></h1>
<span class="badge {{.StatusClass}}">{{.StatusLabel}}</span>
<div class="meta">
{{if .SSHFPPresent}}
{{if .SSHFPMatched}}<span class="badge ok">SSHFP verified</span>
{{else}}<span class="badge fail">SSHFP mismatch</span>{{end}}
{{else}}<span class="badge muted">no SSHFP</span>{{end}}
{{if .AnyIPv4}}<span class="badge muted">IPv4</span>{{end}}
{{if .AnyIPv6}}<span class="badge muted">IPv6</span>{{end}}
</div>
<div class="meta">Checked {{.RunAt}}</div>
</div>
{{if .HasIssues}}
<div class="section">
<h2>What to fix</h2>
{{range .TopFixes}}
<div class="fix {{sevClass .Severity}}">
<div class="code">{{.Code}}{{if .Endpoint}} · {{.Endpoint}}{{end}}</div>
<div class="msg">{{.Message}}</div>
{{if .Fix}}<div class="how">&rarr; {{.Fix}}</div>{{end}}
</div>
{{end}}
</div>
{{end}}
{{if .SSHFPPresent}}
<div class="section">
<h2>SSHFP records</h2>
<table>
<tr><th>Algorithm</th><th>Hash</th><th>Fingerprint</th><th>Status</th></tr>
{{range .SSHFPRecords}}
<tr>
<td>{{.AlgoName}} ({{.Algorithm}})</td>
<td>{{.TypeName}} ({{.Type}})</td>
<td class="fp">{{.Fingerprint}}</td>
<td>{{if .Matched}}<span class="badge ok">match</span>{{else}}<span class="badge warn">no match</span>{{end}}</td>
</tr>
{{end}}
</table>
</div>
{{else}}
<div class="section">
<h2>SSHFP records</h2>
<p class="note">No SSHFP records are published for this service. Clients trust the host key the first time they connect (TOFU). Publishing SSHFP records (with DNSSEC) lets clients verify the server automatically.</p>
</div>
{{end}}
{{if .Endpoints}}
<div class="section">
<h2>Endpoints ({{len .Endpoints}})</h2>
{{range .Endpoints}}
<details{{if .AnyFail}} open{{end}}>
<summary>
<span class="conn-addr">{{.Address}}{{if .Banner}} · {{.Banner}}{{end}}</span>
<span class="badge {{.StatusClass}}">{{.StatusLabel}}</span>
</summary>
<div class="details-body">
<dl class="kv">
<dt>Host</dt><dd>{{.Host}}</dd>
<dt>IP</dt><dd><code>{{.Address}}</code>{{if .IsIPv6}} (IPv6){{end}}</dd>
<dt>TCP</dt><dd>{{if .TCPConnected}}<span class="check-ok">&#10003; connected</span>{{else}}<span class="check-fail">&#10007; failed</span>{{end}}</dd>
{{if .SoftwareVer}}<dt>Version</dt><dd><code>{{.SoftwareVer}}</code>{{if .Vendor}} · <span class="note">{{.Vendor}}</span>{{end}}</dd>{{end}}
<dt>Duration</dt><dd>{{.ElapsedMS}} ms</dd>
{{if .Error}}<dt>Error</dt><dd><span class="check-fail">{{.Error}}</span></dd>{{end}}
</dl>
{{if .HostKeys}}
<h3>Host keys</h3>
<table>
<tr><th>Type</th><th>Bits</th><th>SHA-256 fingerprint</th><th>SSHFP</th></tr>
{{range .HostKeys}}
<tr>
<td>{{.Type}}</td>
<td>{{if .Bits}}{{.Bits}}{{else}}-{{end}}</td>
<td class="fp">{{.SHA256}}</td>
<td>
{{if .SSHFPMatched}}<span class="badge ok">verified</span>
{{else}}<span class="badge warn">no match</span>
<div class="note">Add: <code>IN SSHFP {{.SSHFPSnippet}}</code></div>
{{end}}
</td>
</tr>
{{end}}
</table>
{{end}}
{{range .AlgoTables}}
{{if .Rows}}
<h3>{{.Title}}</h3>
<table>
<tr><th>Algorithm</th><th>Verdict</th></tr>
{{range .Rows}}
<tr class="{{.Severity}}">
<td><code>{{.Name}}</code></td>
<td>
{{if eq .Severity "crit"}}<span class="badge fail">broken</span>
{{else if eq .Severity "warn"}}<span class="badge warn">weak</span>
{{else if eq .Severity "info"}}<span class="badge muted">info</span>
{{else if eq .Severity "ok"}}<span class="badge ok">good</span>
{{else}}<span class="badge ok">OK</span>{{end}}
{{if .Note}} <span class="note">{{.Note}}</span>{{end}}
</td>
</tr>
{{end}}
</table>
{{end}}
{{end}}
{{if .AuthMethods}}
<h3>Authentication methods</h3>
<div class="chiprow">
{{range .AuthMethods}}<span class="chip {{sevClass .Severity}}">{{.Name}}</span>{{end}}
</div>
{{end}}
{{if .Issues}}
<h3>Findings</h3>
{{range .Issues}}
<div class="fix {{sevClass .Severity}}">
<div class="code">{{.Code}}</div>
<div class="msg">{{.Message}}</div>
{{if .Fix}}<div class="how">&rarr; {{.Fix}}</div>{{end}}
</div>
{{end}}
{{end}}
</div>
</details>
{{end}}
</div>
{{end}}
<p class="footer">SSH checker: algorithm posture inspired by <a href="https://github.com/jtesta/ssh-audit">ssh-audit</a>. For client-side audits, run that tool locally.</p>
</body>
</html>`))

137
checker/rules.go Normal file
View file

@ -0,0 +1,137 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
"fmt"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// Each concern is its own rule so results surface independently in the UI
// rather than being squashed under a single aggregated verdict.
func Rules() []sdk.CheckRule {
return []sdk.CheckRule{
&reachabilityRule{},
&handshakeRule{},
&protocolVersionRule{},
&bannerSoftwareRule{},
&knownVulnsRule{},
newKexAlgorithmsRule(),
newHostKeyAlgorithmsRule(),
newCipherAlgorithmsRule(),
newMacAlgorithmsRule(),
&strictKexRule{},
&preauthCompressionRule{},
&hostKeyStrengthRule{},
&sshfpAlignmentRule{},
&sshfpHashRule{},
&authMethodsRule{},
}
}
// On failure, returns a single error state the caller should emit to short-circuit its rule.
func loadSSHData(ctx context.Context, obs sdk.ObservationGetter) (*SSHData, *sdk.CheckState) {
var data SSHData
if err := obs.Get(ctx, ObservationKeySSH, &data); err != nil {
return nil, &sdk.CheckState{
Status: sdk.StatusError,
Message: fmt.Sprintf("failed to load SSH observation: %v", err),
Code: "ssh.observation_error",
}
}
return &data, nil
}
// reachableEndpoints returns the subset of endpoints that completed
// enough of the handshake to expose algorithm data.
func reachableEndpoints(eps []SSHProbe) []SSHProbe {
var out []SSHProbe
for _, ep := range eps {
if len(ep.KEX) > 0 {
out = append(out, ep)
}
}
return out
}
// severityToStatus maps an Issue severity to the SDK Status enum.
func severityToStatus(sev string) sdk.Status {
switch sev {
case SeverityCrit:
return sdk.StatusCrit
case SeverityWarn:
return sdk.StatusWarn
case SeverityInfo:
return sdk.StatusInfo
default:
return sdk.StatusOK
}
}
func issueToState(is Issue) sdk.CheckState {
st := sdk.CheckState{
Status: severityToStatus(is.Severity),
Message: is.Message,
Code: is.Code,
Subject: is.Endpoint,
}
if is.Fix != "" {
st.Meta = map[string]any{"fix": is.Fix}
}
return st
}
func statesFromIssues(issues []Issue) []sdk.CheckState {
out := make([]sdk.CheckState, 0, len(issues))
for _, is := range issues {
out = append(out, issueToState(is))
}
return out
}
func passState(code, message string) sdk.CheckState {
return sdk.CheckState{
Status: sdk.StatusOK,
Message: message,
Code: code,
}
}
func notTestedState(code, message string) sdk.CheckState {
return sdk.CheckState{
Status: sdk.StatusUnknown,
Message: message,
Code: code,
}
}
// noEndpointsState is returned by rules that need probe output but got
// nothing (no endpoints collected at all).
func noEndpointsState(code string) sdk.CheckState {
return sdk.CheckState{
Status: sdk.StatusUnknown,
Message: "No SSH endpoints were probed.",
Code: code,
}
}

174
checker/rules_algorithms.go Normal file
View file

@ -0,0 +1,174 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// algorithmFamilyRule is the shared implementation for the four
// algorithm posture rules (KEX, host key, cipher, MAC). Each one
// inspects a different field on SSHProbe and uses a different catalog.
type algorithmFamilyRule struct {
ruleName string
description string
passCode string
passMsg string
family string
extract func(p *SSHProbe) []string
table map[string]algoVerdict
}
func (r *algorithmFamilyRule) Name() string { return r.ruleName }
func (r *algorithmFamilyRule) Description() string { return r.description }
func (r *algorithmFamilyRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
eps := reachableEndpoints(data.Endpoints)
if len(eps) == 0 {
return []sdk.CheckState{notTestedState(r.ruleName+".skipped", "No endpoint produced an algorithm listing.")}
}
var issues []Issue
for _, ep := range eps {
issues = append(issues, analyseWeakAlgos(ep.Address, r.family, r.extract(&ep), r.table)...)
}
if len(issues) == 0 {
return []sdk.CheckState{passState(r.passCode, r.passMsg)}
}
return statesFromIssues(issues)
}
type kexAlgorithmsRule struct{ algorithmFamilyRule }
func newKexAlgorithmsRule() *kexAlgorithmsRule {
return &kexAlgorithmsRule{algorithmFamilyRule{
ruleName: "ssh.kex_algorithms",
description: "Flags key-exchange algorithms advertised by the server that are weak or broken.",
passCode: "ssh.kex_algorithms.ok",
passMsg: "Every advertised KEX algorithm is modern.",
family: "kex",
extract: func(p *SSHProbe) []string { return p.KEX },
table: kexAlgos,
}}
}
type hostKeyAlgorithmsRule struct{ algorithmFamilyRule }
func newHostKeyAlgorithmsRule() *hostKeyAlgorithmsRule {
return &hostKeyAlgorithmsRule{algorithmFamilyRule{
ruleName: "ssh.host_key_algorithms",
description: "Flags server host-key algorithms that are weak or deprecated (ssh-rsa/SHA-1, ssh-dss, …).",
passCode: "ssh.host_key_algorithms.ok",
passMsg: "Every advertised host-key algorithm is modern.",
family: "hostkey_alg",
extract: func(p *SSHProbe) []string { return p.HostKey },
table: hostKeyAlgos,
}}
}
type cipherAlgorithmsRule struct{ algorithmFamilyRule }
func newCipherAlgorithmsRule() *cipherAlgorithmsRule {
return &cipherAlgorithmsRule{algorithmFamilyRule{
ruleName: "ssh.cipher_algorithms",
description: "Flags symmetric ciphers advertised by the server that are weak or broken (CBC, 3DES, RC4, …).",
passCode: "ssh.cipher_algorithms.ok",
passMsg: "Every advertised cipher is modern.",
family: "cipher",
extract: func(p *SSHProbe) []string { return uniqueMerge(p.CiphersC2S, p.CiphersS2C) },
table: cipherAlgos,
}}
}
type macAlgorithmsRule struct{ algorithmFamilyRule }
func newMacAlgorithmsRule() *macAlgorithmsRule {
return &macAlgorithmsRule{algorithmFamilyRule{
ruleName: "ssh.mac_algorithms",
description: "Flags MAC algorithms advertised by the server that are weak (SHA-1, non-ETM, …).",
passCode: "ssh.mac_algorithms.ok",
passMsg: "Every advertised MAC algorithm is modern.",
family: "mac",
extract: func(p *SSHProbe) []string { return uniqueMerge(p.MACsC2S, p.MACsS2C) },
table: macAlgos,
}}
}
// strictKexRule flags the absence of the Terrapin mitigation marker.
type strictKexRule struct{}
func (r *strictKexRule) Name() string { return "ssh.strict_kex" }
func (r *strictKexRule) Description() string {
return "Verifies the server advertises the strict-KEX marker (CVE-2023-48795 Terrapin mitigation)."
}
func (r *strictKexRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
eps := reachableEndpoints(data.Endpoints)
if len(eps) == 0 {
return []sdk.CheckState{notTestedState("ssh.strict_kex.skipped", "No endpoint produced an algorithm listing.")}
}
var issues []Issue
for _, ep := range eps {
issues = append(issues, analyseStrictKex(ep.Address, ep.KEX)...)
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.strict_kex.ok", "Every endpoint advertises the Terrapin mitigation marker.")}
}
return statesFromIssues(issues)
}
// preauthCompressionRule flags servers offering "zlib" (pre-auth)
// compression alongside / instead of zlib@openssh.com (post-auth).
type preauthCompressionRule struct{}
func (r *preauthCompressionRule) Name() string { return "ssh.preauth_compression" }
func (r *preauthCompressionRule) Description() string {
return "Flags servers that offer pre-authentication zlib compression (prefer zlib@openssh.com)."
}
func (r *preauthCompressionRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
eps := reachableEndpoints(data.Endpoints)
if len(eps) == 0 {
return []sdk.CheckState{notTestedState("ssh.preauth_compression.skipped", "No endpoint produced compression data.")}
}
var issues []Issue
for _, ep := range eps {
issues = append(issues, analysePreauthCompression(ep.Address, ep.CompC2S)...)
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.preauth_compression.ok", "No endpoint offers pre-authentication zlib compression.")}
}
return statesFromIssues(issues)
}

61
checker/rules_auth.go Normal file
View file

@ -0,0 +1,61 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// authMethodsRule reports on the authentication methods advertised by
// the server (password exposure, missing public-key support). Only
// active when the auth probe ran.
type authMethodsRule struct{}
func (r *authMethodsRule) Name() string { return "ssh.auth_methods" }
func (r *authMethodsRule) Description() string {
return "Reviews the advertised authentication methods (password exposure, public-key availability)."
}
func (r *authMethodsRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
var probed bool
var issues []Issue
for _, ep := range data.Endpoints {
if !ep.AuthProbeAttempted {
continue
}
probed = true
issues = append(issues, analyseAuthMethods(ep.Address, &ep)...)
}
if !probed {
return []sdk.CheckState{notTestedState("ssh.auth_methods.skipped", "Authentication-method enumeration disabled or not performed.")}
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.auth_methods.ok", "Authentication method posture looks sound.")}
}
return statesFromIssues(issues)
}

122
checker/rules_banner.go Normal file
View file

@ -0,0 +1,122 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
"fmt"
"strings"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// protocolVersionRule flags servers advertising SSH-1.x, which has
// not been safe for decades.
type protocolVersionRule struct{}
func (r *protocolVersionRule) Name() string { return "ssh.protocol_version" }
func (r *protocolVersionRule) Description() string {
return "Verifies every endpoint advertises SSH-2 and rejects the legacy SSH-1 protocol."
}
func (r *protocolVersionRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
if len(data.Endpoints) == 0 {
return []sdk.CheckState{noEndpointsState("ssh.protocol_version.no_endpoints")}
}
var states []sdk.CheckState
for _, ep := range data.Endpoints {
if ep.Banner == "" {
continue
}
if !strings.HasPrefix(ep.ProtoVer, "2.") && ep.ProtoVer != "2" {
states = append(states, sdk.CheckState{
Status: sdk.StatusCrit,
Code: "ssh_legacy_protocol",
Subject: ep.Address,
Message: fmt.Sprintf("Server advertises SSH protocol %q (banner %q). SSH-1 is obsolete and insecure.", ep.ProtoVer, ep.Banner),
Meta: map[string]any{"fix": "Disable SSH-1 support; run an sshd that only speaks SSH-2."},
})
}
}
if len(states) == 0 {
return []sdk.CheckState{passState("ssh.protocol_version.ok", "Every endpoint advertises SSH-2.")}
}
return states
}
// bannerSoftwareRule reports when a server's software identifier does
// not look like a recognised OpenSSH build.
type bannerSoftwareRule struct{}
func (r *bannerSoftwareRule) Name() string { return "ssh.banner_software" }
func (r *bannerSoftwareRule) Description() string {
return "Flags servers whose banner is not a recognised OpenSSH build (so their maintenance status cannot be inferred)."
}
func (r *bannerSoftwareRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
if len(data.Endpoints) == 0 {
return []sdk.CheckState{noEndpointsState("ssh.banner_software.no_endpoints")}
}
var issues []Issue
for _, ep := range data.Endpoints {
issues = append(issues, analyseBannerSoftware(ep.Address, ep.Banner, ep.SoftVer)...)
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.banner_software.ok", "All probed servers advertise a recognised OpenSSH build.")}
}
return statesFromIssues(issues)
}
// knownVulnsRule maps the observed banner against an OpenSSH CVE
// catalog and emits one state per matched vulnerability.
type knownVulnsRule struct{}
func (r *knownVulnsRule) Name() string { return "ssh.known_vulnerabilities" }
func (r *knownVulnsRule) Description() string {
return "Matches the advertised OpenSSH version against a curated catalog of remotely-observable CVEs."
}
func (r *knownVulnsRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
if len(data.Endpoints) == 0 {
return []sdk.CheckState{noEndpointsState("ssh.known_vulnerabilities.no_endpoints")}
}
var issues []Issue
for _, ep := range data.Endpoints {
issues = append(issues, analyseBannerVulns(ep.Address, ep.Banner, ep.SoftVer)...)
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.known_vulnerabilities.ok", "No known CVE match against the advertised OpenSSH versions.")}
}
return statesFromIssues(issues)
}

64
checker/rules_hostkey.go Normal file
View file

@ -0,0 +1,64 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// hostKeyStrengthRule flags host keys whose size is below what modern
// OpenSSH requires (currently < 2048-bit RSA).
type hostKeyStrengthRule struct{}
func (r *hostKeyStrengthRule) Name() string { return "ssh.host_key_strength" }
func (r *hostKeyStrengthRule) Description() string {
return "Flags SSH host keys whose size is below the currently accepted minimum (e.g. RSA < 2048 bits)."
}
func (r *hostKeyStrengthRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
var anyKey bool
var issues []Issue
for _, ep := range data.Endpoints {
if len(ep.HostKeys) > 0 {
anyKey = true
}
// Also flag endpoints that reached KEXINIT but failed to
// produce any host key: the handshake didn't complete.
if len(ep.KEX) > 0 {
issues = append(issues, analyseHandshakeHostKey(ep.Address, true, ep.HostKeys)...)
}
issues = append(issues, analyseHostKeyStrength(ep.Address, ep.HostKeys)...)
}
if !anyKey && len(issues) == 0 {
return []sdk.CheckState{notTestedState("ssh.host_key_strength.skipped", "No host key observed on any reachable endpoint.")}
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.host_key_strength.ok", "Every observed host key meets the minimum accepted size.")}
}
return statesFromIssues(issues)
}

134
checker/rules_reachability.go Normal file
View file

@ -0,0 +1,134 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
"fmt"
"strconv"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// reachabilityRule reports per-endpoint TCP reachability. One state
// per probed (ip, port) pair so the UI distinguishes individual
// firewall / routing issues.
type reachabilityRule struct{}
func (r *reachabilityRule) Name() string { return "ssh.tcp_reachable" }
func (r *reachabilityRule) Description() string {
return "Verifies that every probed (address, port) pair accepts a TCP connection."
}
func (r *reachabilityRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
if len(data.Endpoints) == 0 {
return []sdk.CheckState{noEndpointsState("ssh.tcp_reachable.no_endpoints")}
}
var states []sdk.CheckState
for _, ep := range data.Endpoints {
if ep.TCPConnected {
continue
}
msg := "Cannot open TCP connection to " + ep.Address
if ep.Error != "" {
msg += ": " + ep.Error
}
states = append(states, sdk.CheckState{
Status: sdk.StatusCrit,
Message: msg,
Code: "tcp_unreachable",
Subject: ep.Address,
Meta: map[string]any{
"fix": "Check DNS, firewall (allow tcp/" + strconv.Itoa(int(ep.Port)) + " from the internet), and that sshd is running.",
},
})
}
if len(states) == 0 {
return []sdk.CheckState{passState("ssh.tcp_reachable.ok", "All probed endpoints accept TCP connections.")}
}
return states
}
// handshakeRule reports per-endpoint SSH handshake progress: whether
// banner exchange and KEXINIT parsing completed. Endpoints that are
// TCP-unreachable are skipped (covered by reachabilityRule).
type handshakeRule struct{}
func (r *handshakeRule) Name() string { return "ssh.handshake" }
func (r *handshakeRule) Description() string {
return "Verifies that the SSH banner exchange and KEXINIT parse succeed on every reachable endpoint."
}
func (r *handshakeRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
if len(data.Endpoints) == 0 {
return []sdk.CheckState{noEndpointsState("ssh.handshake.no_endpoints")}
}
var states []sdk.CheckState
for _, ep := range data.Endpoints {
if !ep.TCPConnected {
continue
}
switch ep.Stage {
case "banner":
states = append(states, sdk.CheckState{
Status: sdk.StatusCrit,
Code: "no_ssh_banner",
Subject: ep.Address,
Message: fmt.Sprintf("Server on %s did not send an SSH-2.0 banner: %s", ep.Address, ep.Error),
Meta: map[string]any{"fix": "Check that an SSH daemon (not HTTP, mail, ...) listens on this port."},
})
case "banner_write":
states = append(states, sdk.CheckState{
Status: sdk.StatusCrit,
Code: "banner_write_failed",
Subject: ep.Address,
Message: "Failed to send our client banner: " + ep.Error,
})
case "kexinit_read":
states = append(states, sdk.CheckState{
Status: sdk.StatusCrit,
Code: "kexinit_read_failed",
Subject: ep.Address,
Message: "Server did not send KEXINIT after banner: " + ep.Error,
})
case "kexinit_parse":
states = append(states, sdk.CheckState{
Status: sdk.StatusCrit,
Code: "kexinit_parse_failed",
Subject: ep.Address,
Message: "Malformed KEXINIT packet: " + ep.Error,
})
}
}
if len(states) == 0 {
return []sdk.CheckState{passState("ssh.handshake.ok", "All reachable endpoints completed the SSH handshake.")}
}
return states
}

87
checker/rules_sshfp.go Normal file
View file

@ -0,0 +1,87 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"context"
sdk "git.happydns.org/checker-sdk-go/checker"
)
// sshfpAlignmentRule compares the published SSHFP records with the
// observed host keys (match, missing, mismatch, uncovered family).
type sshfpAlignmentRule struct{}
func (r *sshfpAlignmentRule) Name() string { return "ssh.sshfp_alignment" }
func (r *sshfpAlignmentRule) Description() string {
return "Compares published SSHFP records against the observed host keys (match, missing, mismatch)."
}
func (r *sshfpAlignmentRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
var issues []Issue
sawKey := false
for _, ep := range data.Endpoints {
if len(ep.HostKeys) == 0 {
continue
}
sawKey = true
issues = append(issues, analyseSSHFPAlignment(ep.Address, ep.HostKeys, data.SSHFP)...)
}
if !sawKey {
return []sdk.CheckState{notTestedState("ssh.sshfp_alignment.skipped", "No host key observed; SSHFP alignment cannot be assessed.")}
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.sshfp_alignment.ok", "Published SSHFP records match the observed host keys.")}
}
return statesFromIssues(issues)
}
// sshfpHashRule flags an SSHFP set that uses only the deprecated SHA-1
// (type 1) hash variant.
type sshfpHashRule struct{}
func (r *sshfpHashRule) Name() string { return "ssh.sshfp_hash" }
func (r *sshfpHashRule) Description() string {
return "Flags SSHFP record sets that only publish SHA-1 (type 1) fingerprints instead of SHA-256."
}
func (r *sshfpHashRule) Evaluate(ctx context.Context, obs sdk.ObservationGetter, _ sdk.CheckerOptions) []sdk.CheckState {
data, errSt := loadSSHData(ctx, obs)
if errSt != nil {
return []sdk.CheckState{*errSt}
}
if !data.SSHFP.Present {
return []sdk.CheckState{notTestedState("ssh.sshfp_hash.skipped", "No SSHFP records published.")}
}
var issues []Issue
for _, ep := range data.Endpoints {
issues = append(issues, analyseSSHFPHashes(ep.Address, ep.HostKeys, data.SSHFP)...)
}
if len(issues) == 0 {
return []sdk.CheckState{passState("ssh.sshfp_hash.ok", "SSHFP records include a SHA-256 (type 2) fingerprint.")}
}
return statesFromIssues(issues)
}

47
checker/service.go Normal file
View file

@ -0,0 +1,47 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"encoding/json"
"github.com/miekg/dns"
)
// serviceMessage mirrors happydns.ServiceMessage for the tiny subset
// of fields this checker reads or produces. Keeping a local copy lets
// us drop the happyDomain module dependency while preserving the
// on-the-wire JSON shape that the host emits when AutoFillService
// hands us an abstract.Server payload.
type serviceMessage struct {
Type string `json:"_svctype"`
Domain string `json:"_domain"`
Service json.RawMessage `json:"Service"`
}
// abstractServer mirrors services/abstract.Server: the A/AAAA/SSHFP
// records associated to a host in a zone.
type abstractServer struct {
A *dns.A `json:"A,omitempty"`
AAAA *dns.AAAA `json:"AAAA,omitempty"`
SSHFP []*dns.SSHFP `json:"SSHFP,omitempty"`
}

174
checker/sshfp.go Normal file
View file

@ -0,0 +1,174 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"fmt"
"strings"
)
// analyseHandshakeHostKey flags an endpoint where the full handshake
// never yielded any host key.
func analyseHandshakeHostKey(addr string, reached bool, keys []HostKeyInfo) []Issue {
if !reached || len(keys) > 0 {
return nil
}
return []Issue{{
Code: "no_host_key",
Severity: SeverityCrit,
Message: "Could not retrieve any SSH host key; the full handshake failed.",
Fix: "Check that the server accepts curve25519-sha256 or a similarly modern KEX, and that firewalls don't terminate the TLS-less SSH transport mid-flight.",
Endpoint: addr,
}}
}
// analyseHostKeyStrength flags host keys whose size is below the
// minimum accepted by modern OpenSSH.
func analyseHostKeyStrength(addr string, keys []HostKeyInfo) []Issue {
var issues []Issue
for _, k := range keys {
if k.SSHFPAlgo == 1 && k.Bits > 0 && k.Bits < 2048 {
issues = append(issues, Issue{
Code: "short_rsa_host_key",
Severity: SeverityCrit,
Message: fmt.Sprintf("RSA host key is %d bits; OpenSSH has rejected < 2048 bits since 8.2.", k.Bits),
Fix: "Regenerate the host key: rm /etc/ssh/ssh_host_rsa_key && ssh-keygen -t rsa -b 4096 -f /etc/ssh/ssh_host_rsa_key -N ''",
Endpoint: addr,
})
}
}
return issues
}
// analyseSSHFPAlignment returns per-key alignment issues: match,
// no coverage for a key family, or mismatch between DNS and server.
func analyseSSHFPAlignment(addr string, keys []HostKeyInfo, s SSHFPSummary) []Issue {
if len(keys) == 0 {
return nil
}
if !s.Present {
return []Issue{{
Code: "sshfp_missing",
Severity: SeverityInfo,
Message: "No SSHFP records published. Clients currently trust-on-first-use this server's host key.",
Fix: fmt.Sprintf("Publish SSHFP records under this service. Example for the ed25519 key: `IN SSHFP 4 2 %s`.", firstSHA256(keys)),
Endpoint: addr,
}}
}
var issues []Issue
coveredFamily := map[uint8]bool{}
for _, rr := range s.Records {
coveredFamily[rr.Algorithm] = true
}
for _, k := range keys {
if k.SSHFPMatchSHA256 || k.SSHFPMatchSHA1 {
issues = append(issues, Issue{
Code: "sshfp_verified",
Severity: SeverityInfo,
Message: fmt.Sprintf("Host key %s (%s) matches the published SSHFP record.", k.Type, shortFP(k.SHA256)),
Endpoint: addr,
})
continue
}
if !coveredFamily[k.SSHFPAlgo] {
issues = append(issues, Issue{
Code: "sshfp_not_covered",
Severity: SeverityWarn,
Message: fmt.Sprintf("No SSHFP record covers host-key algorithm %s.", k.Type),
Fix: fmt.Sprintf("Add `IN SSHFP %d 2 %s` to the zone.", k.SSHFPAlgo, k.SHA256),
Endpoint: addr,
})
continue
}
issues = append(issues, Issue{
Code: "sshfp_mismatch",
Severity: SeverityCrit,
Message: fmt.Sprintf("Published SSHFP record does not match the %s host key presented by %s. Either the server key was rotated without updating DNS, or the server is impersonated.", k.Type, addr),
Fix: fmt.Sprintf("Update the SSHFP record to the current fingerprint: `IN SSHFP %d 2 %s`, and investigate why DNS and the server disagree.", k.SSHFPAlgo, k.SHA256),
Endpoint: addr,
})
}
return issues
}
// analyseSSHFPHashes flags a server whose published SSHFP records only
// use the deprecated SHA-1 (type 1) hash variant and where at least
// one of those records matched an observed key.
func analyseSSHFPHashes(addr string, keys []HostKeyInfo, s SSHFPSummary) []Issue {
if !s.Present {
return nil
}
matchedAny := false
for _, k := range keys {
if k.SSHFPMatchSHA256 || k.SSHFPMatchSHA1 {
matchedAny = true
break
}
}
if !matchedAny {
return nil
}
for _, rr := range s.Records {
if rr.Type == 2 {
return nil
}
}
return []Issue{{
Code: "sshfp_only_sha1",
Severity: SeverityWarn,
Message: "SSHFP records use only SHA-1 (type 1) fingerprints. SHA-1 is deprecated for this use.",
Fix: "Add SHA-256 (type 2) SSHFP records alongside (or instead of) the existing SHA-1 ones.",
Endpoint: addr,
}}
}
// analyseHostKeys is a convenience wrapper used by the HTML report.
// reachedKexInit signals whether the handshake made it far enough for
// the absence of host keys to be meaningful (i.e. the server accepted
// our KEXINIT).
func analyseHostKeys(addr string, keys []HostKeyInfo, s SSHFPSummary, reachedKexInit bool) []Issue {
var issues []Issue
issues = append(issues, analyseHandshakeHostKey(addr, reachedKexInit, keys)...)
issues = append(issues, analyseHostKeyStrength(addr, keys)...)
issues = append(issues, analyseSSHFPAlignment(addr, keys, s)...)
issues = append(issues, analyseSSHFPHashes(addr, keys, s)...)
return issues
}
func firstSHA256(keys []HostKeyInfo) string {
for _, k := range keys {
if k.Type == "ssh-ed25519" {
return k.SHA256
}
}
if len(keys) > 0 {
return keys[0].SHA256
}
return ""
}
func shortFP(hexFP string) string {
if len(hexFP) < 16 {
return hexFP
}
return strings.ToUpper(hexFP[:8] + ":" + hexFP[8:16] + "…")
}

147
checker/types.go Normal file
View file

@ -0,0 +1,147 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
// Package checker implements an SSH server security checker for
// happyDomain. It probes each SSH endpoint associated with an
// abstract.Server service and produces a structured report covering
// reachability, banner/version posture, algorithm negotiation
// (KEX/HostKey/Cipher/MAC/Compression), authentication method exposure
// and SSHFP host-key fingerprint validation.
package checker
import "time"
// ObservationKeySSH is the observation key this checker writes.
const ObservationKeySSH = "ssh"
// Option ids on CheckerOptions.
const (
OptionService = "service"
OptionPorts = "ports"
OptionProbeTimeoutMs = "probeTimeoutMs"
OptionIncludeAuthProbe = "includeAuthProbe"
)
// Defaults.
const (
DefaultSSHPort = 22
DefaultProbeTimeoutMs = 10000
MaxConcurrentProbes = 16
)
// Severity levels used in Issue.Severity.
const (
SeverityCrit = "crit"
SeverityWarn = "warn"
SeverityInfo = "info"
SeverityOK = "ok"
)
// SSHData is the full collected payload written under ObservationKeySSH.
type SSHData struct {
Domain string `json:"domain,omitempty"`
Endpoints []SSHProbe `json:"endpoints"`
SSHFP SSHFPSummary `json:"sshfp"`
CollectedAt time.Time `json:"collected_at"`
}
// SSHFPSummary captures the SSHFP records declared for the service and
// whether a usable chain (DNSSEC) is available.
type SSHFPSummary struct {
Records []SSHFPRecord `json:"records,omitempty"`
// Present indicates whether the service carries at least one SSHFP RR.
Present bool `json:"present"`
}
// SSHFPRecord is a single SSHFP record as declared in the zone.
type SSHFPRecord struct {
Algorithm uint8 `json:"algorithm"` // 1=RSA, 2=DSA, 3=ECDSA, 4=Ed25519
Type uint8 `json:"type"` // 1=SHA-1, 2=SHA-256
Fingerprint string `json:"fingerprint"` // hex, lowercase
}
// SSHProbe is the outcome of probing a single SSH endpoint.
type SSHProbe struct {
Host string `json:"host"`
Port uint16 `json:"port"`
Address string `json:"address"`
IP string `json:"ip,omitempty"`
IsIPv6 bool `json:"ipv6,omitempty"`
TCPConnected bool `json:"tcp_connected"`
// Banner is the SSH protocol banner (e.g. "SSH-2.0-OpenSSH_9.3p1").
Banner string `json:"banner,omitempty"`
SoftVer string `json:"software_version,omitempty"`
ProtoVer string `json:"protocol_version,omitempty"`
Vendor string `json:"vendor,omitempty"`
ElapsedMS int64 `json:"elapsed_ms,omitempty"`
Error string `json:"error,omitempty"`
// Algorithms negotiated by the server.
KEX []string `json:"kex_algorithms,omitempty"`
HostKey []string `json:"host_key_algorithms,omitempty"`
CiphersC2S []string `json:"ciphers_c2s,omitempty"`
CiphersS2C []string `json:"ciphers_s2c,omitempty"`
MACsC2S []string `json:"macs_c2s,omitempty"`
MACsS2C []string `json:"macs_s2c,omitempty"`
CompC2S []string `json:"compression_c2s,omitempty"`
CompS2C []string `json:"compression_s2c,omitempty"`
// Host keys observed during KEX. Multiple entries can appear if the
// server advertises several host-key types and we probe each in a
// second pass.
HostKeys []HostKeyInfo `json:"host_keys,omitempty"`
// Authentication methods advertised for a dummy "none" auth attempt.
AuthMethods []string `json:"auth_methods,omitempty"`
PasswordAuth bool `json:"password_auth,omitempty"`
KeyboardInteractive bool `json:"keyboard_interactive,omitempty"`
PublicKeyAuth bool `json:"public_key_auth,omitempty"`
AuthProbeAttempted bool `json:"auth_probe_attempted,omitempty"`
// Stage is the furthest probe stage the connection reached. One of
// "dial", "banner", "banner_write", "kexinit_read", "kexinit_parse",
// "kexinit_ok", "handshake_ok". Empty means the dial failed before
// even being attempted.
Stage string `json:"stage,omitempty"`
}
// HostKeyInfo captures an observed host key and its computed fingerprints.
type HostKeyInfo struct {
Type string `json:"type"` // e.g. "ssh-ed25519"
Bits int `json:"bits,omitempty"` // key size (bits)
SHA256 string `json:"sha256"` // hex fingerprint (lowercase, no colons)
SHA1 string `json:"sha1"` // hex fingerprint (lowercase, no colons)
SSHFPAlgo uint8 `json:"sshfp_algorithm"` // the SSHFP algorithm number matching this key type
SSHFPMatchSHA256 bool `json:"sshfp_match_sha256"`
SSHFPMatchSHA1 bool `json:"sshfp_match_sha1"`
}
// Issue is a single SSH finding surfaced to consumers.
type Issue struct {
Code string `json:"code"`
Severity string `json:"severity"`
Message string `json:"message,omitempty"`
Fix string `json:"fix,omitempty"`
// Endpoint is the "host:port" this issue applies to (empty for
// service-level issues such as missing SSHFP).
Endpoint string `json:"endpoint,omitempty"`
}

249
checker/vulns.go Normal file
View file

@ -0,0 +1,249 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package checker
import (
"fmt"
"regexp"
"strconv"
"strings"
)
// OpenSSH CVE database. The entries here are a curated subset of the
// ssh-audit vulnerability list focused on issues that are both
// remotely observable from a banner and serious enough to warrant
// surfacing in a periodic check.
//
// Versions are expressed using a semver-ish triple plus an optional
// "p" patch suffix, which mirrors OpenSSH's own numbering
// (e.g. 9.3p1 < 9.3p2 < 9.4p1). The matcher is conservative: when a
// banner can't be parsed into a version, we skip the match rather
// than over-flag.
type opensshVuln struct {
Code string
CVE string
Severity string
Title string
Description string
Fix string
AffectedRanges []opensshRange
}
type opensshRange struct {
MinInclusive string // "" means open-ended below
MaxExclusive string // "" means open-ended above
}
var opensshVulns = []opensshVuln{
{
Code: "cve_2024_6387_regreSSHion",
CVE: "CVE-2024-6387",
Severity: SeverityCrit,
Title: "regreSSHion (CVE-2024-6387)",
Description: "Signal-handler race in OpenSSH's sshd allows unauthenticated remote code execution as root on glibc-based systems.",
Fix: "Upgrade OpenSSH to 9.8p1 or later. If upgrading is not possible, set LoginGraceTime 0 in sshd_config as a mitigation (denial-of-service trade-off).",
AffectedRanges: []opensshRange{
// Regression reintroduced in 8.5p1; fixed in 9.8p1.
{MinInclusive: "8.5p1", MaxExclusive: "9.8p1"},
// The race also existed in < 4.4p1 (CVE-2006-5051 variant).
{MaxExclusive: "4.4p1"},
},
},
{
Code: "cve_2023_38408_agent",
CVE: "CVE-2023-38408",
Severity: SeverityCrit,
Title: "ssh-agent PKCS#11 provider RCE",
Description: "OpenSSH's forwarded ssh-agent in 5.5 through 9.3p1 can load and execute arbitrary shared libraries, enabling RCE if an attacker controls the forwarded agent.",
Fix: "Upgrade OpenSSH to 9.3p2 or later.",
AffectedRanges: []opensshRange{
{MinInclusive: "5.5", MaxExclusive: "9.3p2"},
},
},
{
Code: "cve_2023_48795_terrapin",
CVE: "CVE-2023-48795",
Severity: SeverityWarn,
Title: "Terrapin prefix truncation (CVE-2023-48795)",
Description: "A MITM can silently drop the first messages after KEX completes, potentially downgrading security features. Affects any SSH server supporting ChaCha20-Poly1305 or CBC-EtM without strict-KEX.",
Fix: "Upgrade OpenSSH to 9.6p1 or later (advertises kex-strict-s-v00@openssh.com).",
AffectedRanges: []opensshRange{
{MaxExclusive: "9.6p1"},
},
},
{
Code: "cve_2021_41617_agent_forward",
CVE: "CVE-2021-41617",
Severity: SeverityWarn,
Title: "sshd AuthorizedKeysCommand / AuthorizedPrincipalsCommand privilege drop flaw",
Description: "sshd from 6.2 to 8.8 fails to correctly drop supplementary groups when executing the AuthorizedKeysCommand/AuthorizedPrincipalsCommand helpers.",
Fix: "Upgrade OpenSSH to 8.8p1 or later.",
AffectedRanges: []opensshRange{
{MinInclusive: "6.2", MaxExclusive: "8.8p1"},
},
},
{
Code: "cve_2020_15778_scp",
CVE: "CVE-2020-15778",
Severity: SeverityWarn,
Title: "scp command-injection via shell quoting",
Description: "scp in OpenSSH through 8.3p1 does not sanitise filenames when copying files, enabling command injection on the destination via crafted names.",
Fix: "Upgrade OpenSSH to 8.4p1 or later; prefer sftp/rsync over scp.",
AffectedRanges: []opensshRange{
{MaxExclusive: "8.4p1"},
},
},
{
Code: "cve_2018_15473_user_enum",
CVE: "CVE-2018-15473",
Severity: SeverityWarn,
Title: "Username enumeration via timing",
Description: "OpenSSH through 7.7p1 allows remote username enumeration by timing the response to malformed authentication packets.",
Fix: "Upgrade OpenSSH to 7.8p1 or later.",
AffectedRanges: []opensshRange{
{MaxExclusive: "7.8p1"},
},
},
}
// analyseBannerSoftware flags a non-OpenSSH banner for operator
// awareness. No CVE match is attempted on unrecognised software.
func analyseBannerSoftware(addr, banner, software string) []Issue {
if banner == "" {
return nil
}
if parseOpenSSHVersion(software) != nil {
return nil
}
if looksLikeOpenSSH(software) {
return nil
}
return []Issue{{
Code: "non_openssh",
Severity: SeverityInfo,
Message: fmt.Sprintf("Server reports %q, not a recognised OpenSSH build. Verify the deployed software is maintained.", software),
Endpoint: addr,
}}
}
// analyseBannerVulns runs the banner through the OpenSSH CVE database
// and returns the matched issues. The banner parser is deliberately
// loose: a server running a vendor-patched OpenSSH (e.g.
// "OpenSSH_9.2p1 Debian-2+deb12u2") will still match the upstream
// version numbers, because distribution maintainers tend to backport
// fixes without changing the version string. Operators get to
// override these false positives at the UI layer, same as other
// checkers.
func analyseBannerVulns(addr, banner, software string) []Issue {
if banner == "" {
return nil
}
ver := parseOpenSSHVersion(software)
if ver == nil {
return nil
}
var issues []Issue
for _, v := range opensshVulns {
if rangesMatch(ver, v.AffectedRanges) {
issues = append(issues, Issue{
Code: v.Code,
Severity: v.Severity,
Message: fmt.Sprintf("%s: %s", v.Title, v.Description),
Fix: v.Fix,
Endpoint: addr,
})
}
}
return issues
}
// analyseBanner combines software-awareness and vulnerability matches.
// Retained as a convenience for the HTML report, which surfaces both
// concerns in a single "What to fix" list.
func analyseBanner(addr, banner, software string) []Issue {
out := analyseBannerSoftware(addr, banner, software)
out = append(out, analyseBannerVulns(addr, banner, software)...)
return out
}
func looksLikeOpenSSH(s string) bool {
return strings.HasPrefix(s, "OpenSSH_")
}
// opensshVersion captures a (major, minor, portable) tuple. Portable
// is 0 when the banner lists only a vanilla upstream version (which
// is rare). OpenSSH_9.3p1 → {9, 3, 1}.
type opensshVersion struct{ Major, Minor, Portable int }
var opensshBannerRe = regexp.MustCompile(`^OpenSSH_(\d+)\.(\d+)(?:p(\d+))?`)
func parseOpenSSHVersion(software string) *opensshVersion {
m := opensshBannerRe.FindStringSubmatch(software)
if m == nil {
return nil
}
v := &opensshVersion{}
v.Major, _ = strconv.Atoi(m[1])
v.Minor, _ = strconv.Atoi(m[2])
if m[3] != "" {
v.Portable, _ = strconv.Atoi(m[3])
}
return v
}
func less(a, b opensshVersion) bool {
if a.Major != b.Major {
return a.Major < b.Major
}
if a.Minor != b.Minor {
return a.Minor < b.Minor
}
return a.Portable < b.Portable
}
func rangesMatch(v *opensshVersion, ranges []opensshRange) bool {
for _, r := range ranges {
min, okMin := parseVersionString(r.MinInclusive)
max, okMax := parseVersionString(r.MaxExclusive)
if okMin && less(*v, min) {
continue
}
if okMax && !less(*v, max) {
continue
}
return true
}
return false
}
func parseVersionString(s string) (opensshVersion, bool) {
if s == "" {
return opensshVersion{}, false
}
// Reuse the banner regex by pretending we have a "OpenSSH_" prefix.
v := parseOpenSSHVersion("OpenSSH_" + s)
if v == nil {
return opensshVersion{}, false
}
return *v, true
}

45
go.mod Normal file
View file

@ -0,0 +1,45 @@
module git.happydns.org/checker-ssh
go 1.25.0
require (
git.happydns.org/checker-sdk-go v1.5.0
git.happydns.org/happyDomain v0.7.0
github.com/miekg/dns v1.1.72
golang.org/x/crypto v0.49.0
)
require (
github.com/bytedance/gopkg v0.1.3 // indirect
github.com/bytedance/sonic v1.15.0 // indirect
github.com/bytedance/sonic/loader v0.5.0 // indirect
github.com/cloudwego/base64x v0.1.6 // indirect
github.com/gabriel-vasile/mimetype v1.4.13 // indirect
github.com/gin-contrib/sse v1.1.0 // indirect
github.com/gin-gonic/gin v1.12.0 // indirect
github.com/go-playground/locales v0.14.1 // indirect
github.com/go-playground/universal-translator v0.18.1 // indirect
github.com/go-playground/validator/v10 v10.30.1 // indirect
github.com/goccy/go-json v0.10.5 // indirect
github.com/goccy/go-yaml v1.19.2 // indirect
github.com/json-iterator/go v1.1.13-0.20220915233716-71ac16282d12 // indirect
github.com/klauspost/cpuid/v2 v2.3.0 // indirect
github.com/leodido/go-urn v1.4.0 // indirect
github.com/mattn/go-isatty v0.0.20 // indirect
github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd // indirect
github.com/modern-go/reflect2 v1.0.2 // indirect
github.com/pelletier/go-toml/v2 v2.2.4 // indirect
github.com/quic-go/qpack v0.6.0 // indirect
github.com/quic-go/quic-go v0.59.0 // indirect
github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
github.com/ugorji/go/codec v1.3.1 // indirect
go.mongodb.org/mongo-driver/v2 v2.5.0 // indirect
golang.org/x/arch v0.24.0 // indirect
golang.org/x/mod v0.33.0 // indirect
golang.org/x/net v0.51.0 // indirect
golang.org/x/sync v0.20.0 // indirect
golang.org/x/sys v0.42.0 // indirect
golang.org/x/text v0.35.0 // indirect
golang.org/x/tools v0.42.0 // indirect
google.golang.org/protobuf v1.36.11 // indirect
)

104
go.sum Normal file
View file

@ -0,0 +1,104 @@
git.happydns.org/checker-sdk-go v1.5.0 h1:5uD5Cm6xJ+lwnhbJ09iCXGHbYS9zRh+Yh0NeBHkAPBY=
git.happydns.org/checker-sdk-go v1.5.0/go.mod h1:aNAcfYFfbhvH9kJhE0Njp5GX0dQbxdRB0rJ0KvSC5nI=
git.happydns.org/happyDomain v0.7.0 h1:NV82/NbcSeRm0+IUZqaK3Vu9Ovl5+vv4AigUJZMdwws=
git.happydns.org/happyDomain v0.7.0/go.mod h1:5tgkmqFE65kK359rY49V++49wgZ0gco+Gh9X6tbL+bY=
github.com/bytedance/gopkg v0.1.3 h1:TPBSwH8RsouGCBcMBktLt1AymVo2TVsBVCY4b6TnZ/M=
github.com/bytedance/gopkg v0.1.3/go.mod h1:576VvJ+eJgyCzdjS+c4+77QF3p7ubbtiKARP3TxducM=
github.com/bytedance/sonic v1.15.0 h1:/PXeWFaR5ElNcVE84U0dOHjiMHQOwNIx3K4ymzh/uSE=
github.com/bytedance/sonic v1.15.0/go.mod h1:tFkWrPz0/CUCLEF4ri4UkHekCIcdnkqXw9VduqpJh0k=
github.com/bytedance/sonic/loader v0.5.0 h1:gXH3KVnatgY7loH5/TkeVyXPfESoqSBSBEiDd5VjlgE=
github.com/bytedance/sonic/loader v0.5.0/go.mod h1:AR4NYCk5DdzZizZ5djGqQ92eEhCCcdf5x77udYiSJRo=
github.com/cloudwego/base64x v0.1.6 h1:t11wG9AECkCDk5fMSoxmufanudBtJ+/HemLstXDLI2M=
github.com/cloudwego/base64x v0.1.6/go.mod h1:OFcloc187FXDaYHvrNIjxSe8ncn0OOM8gEHfghB2IPU=
github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc h1:U9qPSI2PIWSS1VwoXQT9A3Wy9MM3WgvqSxFWenqJduM=
github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
github.com/gabriel-vasile/mimetype v1.4.13 h1:46nXokslUBsAJE/wMsp5gtO500a4F3Nkz9Ufpk2AcUM=
github.com/gabriel-vasile/mimetype v1.4.13/go.mod h1:d+9Oxyo1wTzWdyVUPMmXFvp4F9tea18J8ufA774AB3s=
github.com/gin-contrib/sse v1.1.0 h1:n0w2GMuUpWDVp7qSpvze6fAu9iRxJY4Hmj6AmBOU05w=
github.com/gin-contrib/sse v1.1.0/go.mod h1:hxRZ5gVpWMT7Z0B0gSNYqqsSCNIJMjzvm6fqCz9vjwM=
github.com/gin-gonic/gin v1.12.0 h1:b3YAbrZtnf8N//yjKeU2+MQsh2mY5htkZidOM7O0wG8=
github.com/gin-gonic/gin v1.12.0/go.mod h1:VxccKfsSllpKshkBWgVgRniFFAzFb9csfngsqANjnLc=
github.com/go-playground/assert/v2 v2.2.0 h1:JvknZsQTYeFEAhQwI4qEt9cyV5ONwRHC+lYKSsYSR8s=
github.com/go-playground/assert/v2 v2.2.0/go.mod h1:VDjEfimB/XKnb+ZQfWdccd7VUvScMdVu0Titje2rxJ4=
github.com/go-playground/locales v0.14.1 h1:EWaQ/wswjilfKLTECiXz7Rh+3BjFhfDFKv/oXslEjJA=
github.com/go-playground/locales v0.14.1/go.mod h1:hxrqLVvrK65+Rwrd5Fc6F2O76J/NuW9t0sjnWqG1slY=
github.com/go-playground/universal-translator v0.18.1 h1:Bcnm0ZwsGyWbCzImXv+pAJnYK9S473LQFuzCbDbfSFY=
github.com/go-playground/universal-translator v0.18.1/go.mod h1:xekY+UJKNuX9WP91TpwSH2VMlDf28Uj24BCp08ZFTUY=
github.com/go-playground/validator/v10 v10.30.1 h1:f3zDSN/zOma+w6+1Wswgd9fLkdwy06ntQJp0BBvFG0w=
github.com/go-playground/validator/v10 v10.30.1/go.mod h1:oSuBIQzuJxL//3MelwSLD5hc2Tu889bF0Idm9Dg26cM=
github.com/goccy/go-json v0.10.5 h1:Fq85nIqj+gXn/S5ahsiTlK3TmC85qgirsdTP/+DeaC4=
github.com/goccy/go-json v0.10.5/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
github.com/goccy/go-yaml v1.19.2 h1:PmFC1S6h8ljIz6gMRBopkjP1TVT7xuwrButHID66PoM=
github.com/goccy/go-yaml v1.19.2/go.mod h1:XBurs7gK8ATbW4ZPGKgcbrY1Br56PdM69F7LkFRi1kA=
github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
github.com/google/gofuzz v1.0.0/go.mod h1:dBl0BpW6vV/+mYPU4Po3pmUjxk6FQPldtuIdl/M65Eg=
github.com/json-iterator/go v1.1.13-0.20220915233716-71ac16282d12 h1:9Nu54bhS/H/Kgo2/7xNSUuC5G28VR8ljfrLKU2G4IjU=
github.com/json-iterator/go v1.1.13-0.20220915233716-71ac16282d12/go.mod h1:TBzl5BIHNXfS9+C35ZyJaklL7mLDbgUkcgXzSLa8Tk0=
github.com/klauspost/cpuid/v2 v2.3.0 h1:S4CRMLnYUhGeDFDqkGriYKdfoFlDnMtqTiI/sFzhA9Y=
github.com/klauspost/cpuid/v2 v2.3.0/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
github.com/leodido/go-urn v1.4.0 h1:WT9HwE9SGECu3lg4d/dIA+jxlljEa1/ffXKmRjqdmIQ=
github.com/leodido/go-urn v1.4.0/go.mod h1:bvxc+MVxLKB4z00jd1z+Dvzr47oO32F/QSNjSBOlFxI=
github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
github.com/miekg/dns v1.1.72 h1:vhmr+TF2A3tuoGNkLDFK9zi36F2LS+hKTRW0Uf8kbzI=
github.com/miekg/dns v1.1.72/go.mod h1:+EuEPhdHOsfk6Wk5TT2CzssZdqkmFhf8r+aVyDEToIs=
github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
github.com/modern-go/reflect2 v1.0.2 h1:xBagoLtFs94CBntxluKeaWgTMpvLxC4ur3nMaC9Gz0M=
github.com/modern-go/reflect2 v1.0.2/go.mod h1:yWuevngMOJpCy52FWWMvUC8ws7m/LJsjYzDa0/r8luk=
github.com/pelletier/go-toml/v2 v2.2.4 h1:mye9XuhQ6gvn5h28+VilKrrPoQVanw5PMw/TB0t5Ec4=
github.com/pelletier/go-toml/v2 v2.2.4/go.mod h1:2gIqNv+qfxSVS7cM2xJQKtLSTLUE9V8t9Stt+h56mCY=
github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 h1:Jamvg5psRIccs7FGNTlIRMkT8wgtp5eCXdBlqhYGL6U=
github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
github.com/quic-go/qpack v0.6.0 h1:g7W+BMYynC1LbYLSqRt8PBg5Tgwxn214ZZR34VIOjz8=
github.com/quic-go/qpack v0.6.0/go.mod h1:lUpLKChi8njB4ty2bFLX2x4gzDqXwUpaO1DP9qMDZII=
github.com/quic-go/quic-go v0.59.0 h1:OLJkp1Mlm/aS7dpKgTc6cnpynnD2Xg7C1pwL6vy/SAw=
github.com/quic-go/quic-go v0.59.0/go.mod h1:upnsH4Ju1YkqpLXC305eW3yDZ4NfnNbmQRCMWS58IKU=
github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
github.com/stretchr/objx v0.5.2/go.mod h1:FRsXN1f5AsAjCGJKqEizvkpNtU+EGNCLh3NxZ/8L+MA=
github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu7U=
github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
github.com/twitchyliquid64/golang-asm v0.15.1 h1:SU5vSMR7hnwNxj24w34ZyCi/FmDZTkS4MhqMhdFk5YI=
github.com/twitchyliquid64/golang-asm v0.15.1/go.mod h1:a1lVb/DtPvCB8fslRZhAngC2+aY1QWCk3Cedj/Gdt08=
github.com/ugorji/go/codec v1.3.1 h1:waO7eEiFDwidsBN6agj1vJQ4AG7lh2yqXyOXqhgQuyY=
github.com/ugorji/go/codec v1.3.1/go.mod h1:pRBVtBSKl77K30Bv8R2P+cLSGaTtex6fsA2Wjqmfxj4=
go.mongodb.org/mongo-driver/v2 v2.5.0 h1:yXUhImUjjAInNcpTcAlPHiT7bIXhshCTL3jVBkF3xaE=
go.mongodb.org/mongo-driver/v2 v2.5.0/go.mod h1:yOI9kBsufol30iFsl1slpdq1I0eHPzybRWdyYUs8K/0=
go.uber.org/mock v0.6.0 h1:hyF9dfmbgIX5EfOdasqLsWD6xqpNZlXblLB/Dbnwv3Y=
go.uber.org/mock v0.6.0/go.mod h1:KiVJ4BqZJaMj4svdfmHM0AUx4NJYO8ZNpPnZn1Z+BBU=
golang.org/x/arch v0.24.0 h1:qlJ3M9upxvFfwRM51tTg3Yl+8CP9vCC1E7vlFpgv99Y=
golang.org/x/arch v0.24.0/go.mod h1:dNHoOeKiyja7GTvF9NJS1l3Z2yntpQNzgrjh1cU103A=
golang.org/x/crypto v0.49.0 h1:+Ng2ULVvLHnJ/ZFEq4KdcDd/cfjrrjjNSXNzxg0Y4U4=
golang.org/x/crypto v0.49.0/go.mod h1:ErX4dUh2UM+CFYiXZRTcMpEcN8b/1gxEuv3nODoYtCA=
golang.org/x/mod v0.33.0 h1:tHFzIWbBifEmbwtGz65eaWyGiGZatSrT9prnU8DbVL8=
golang.org/x/mod v0.33.0/go.mod h1:swjeQEj+6r7fODbD2cqrnje9PnziFuw4bmLbBZFrQ5w=
golang.org/x/net v0.51.0 h1:94R/GTO7mt3/4wIKpcR5gkGmRLOuE/2hNGeWq/GBIFo=
golang.org/x/net v0.51.0/go.mod h1:aamm+2QF5ogm02fjy5Bb7CQ0WMt1/WVM7FtyaTLlA9Y=
golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
golang.org/x/term v0.41.0 h1:QCgPso/Q3RTJx2Th4bDLqML4W6iJiaXFq2/ftQF13YU=
golang.org/x/term v0.41.0/go.mod h1:3pfBgksrReYfZ5lvYM0kSO0LIkAl4Yl2bXOkKP7Ec2A=
golang.org/x/text v0.35.0 h1:JOVx6vVDFokkpaq1AEptVzLTpDe9KGpj5tR4/X+ybL8=
golang.org/x/text v0.35.0/go.mod h1:khi/HExzZJ2pGnjenulevKNX1W67CUy0AsXcNubPGCA=
golang.org/x/tools v0.42.0 h1:uNgphsn75Tdz5Ji2q36v/nsFSfR/9BRFvqhGBaJGd5k=
golang.org/x/tools v0.42.0/go.mod h1:Ma6lCIwGZvHK6XtgbswSoWroEkhugApmsXyrUmBhfr0=
google.golang.org/protobuf v1.36.11 h1:fV6ZwhNocDyBLK0dj+fg8ektcVegBBuEolpbTQyBNVE=
google.golang.org/protobuf v1.36.11/go.mod h1:HTf+CrKn2C3g5S8VImy6tdcUvCska2kB7j23XfzDpco=
gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

48
main.go Normal file
View file

@ -0,0 +1,48 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
package main
import (
"flag"
"log"
"git.happydns.org/checker-sdk-go/checker/server"
ssh "git.happydns.org/checker-ssh/checker"
)
// Version is the standalone binary's version. It defaults to
// "custom-build" and is meant to be overridden by the CI at link time:
//
// go build -ldflags "-X main.Version=1.2.3" .
var Version = "custom-build"
var listenAddr = flag.String("listen", ":8080", "HTTP listen address")
func main() {
flag.Parse()
ssh.Version = Version
srv := server.New(ssh.Provider())
if err := srv.ListenAndServe(*listenAddr); err != nil {
log.Fatalf("server error: %v", err)
}
}

42
plugin/plugin.go Normal file
View file

@ -0,0 +1,42 @@
// This file is part of the happyDomain (R) project.
// Copyright (c) 2020-2026 happyDomain
// Authors: Pierre-Olivier Mercier, et al.
//
// This program is offered under a commercial and under the AGPL license.
// For commercial licensing, contact us at <contact@happydomain.org>.
//
// For AGPL licensing:
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.
// Command plugin is the happyDomain plugin entrypoint for the SSH
// checker. It is built as a Go plugin (`go build -buildmode=plugin`)
// and loaded at runtime by happyDomain.
package main
import (
sdk "git.happydns.org/checker-sdk-go/checker"
ssh "git.happydns.org/checker-ssh/checker"
)
// Version is the plugin's version. Override at link time with
// -ldflags "-X main.Version=1.2.3".
var Version = "custom-build"
// NewCheckerPlugin is the symbol resolved by happyDomain when loading
// the .so file.
func NewCheckerPlugin() (*sdk.CheckerDefinition, sdk.ObservationProvider, error) {
ssh.Version = Version
prvd := ssh.Provider()
return prvd.(sdk.CheckerDefinitionProvider).Definition(), prvd, nil
}