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Publish certificate chain data for DANE consumers

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Add Chain []CertInfo to TLSProbe, carrying per-cert DER and precomputed
TLSA hashes (Cert/SPKI, SHA-256/SHA-512) plus the raw SPKI DER. This
lets downstream checkers (checker-dane) perform TLSA matching against
the observed chain without re-running a TLS handshake.
This commit is contained in:
nemunaire 2026-04-23 19:05:25 +07:00
commit 17ecf3beb5
2 changed files with 67 additions and 0 deletions
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30
checker/prober.go
View file

@ -2,8 +2,11 @@ package checker
import (
"context"
"crypto/sha256"
"crypto/sha512"
"crypto/tls"
"crypto/x509"
"encoding/base64"
"encoding/hex"
"errors"
"fmt"
@ -15,6 +18,32 @@ import (
"git.happydns.org/checker-tls/contract"
)
// buildChain returns CertInfo for each cert presented by the server, in the
// order the server sent them (leaf first). SPKI is extracted from the parsed
// certificate's RawSubjectPublicKeyInfo so we hash exactly the DER bytes
// DANE selector 1 refers to (RFC 6698 §1.1.3).
func buildChain(certs []*x509.Certificate) []CertInfo {
out := make([]CertInfo, len(certs))
for i, c := range certs {
certSum256 := sha256.Sum256(c.Raw)
certSum512 := sha512.Sum512(c.Raw)
spkiSum256 := sha256.Sum256(c.RawSubjectPublicKeyInfo)
spkiSum512 := sha512.Sum512(c.RawSubjectPublicKeyInfo)
out[i] = CertInfo{
DERBase64: base64.StdEncoding.EncodeToString(c.Raw),
Subject: c.Subject.String(),
Issuer: c.Issuer.String(),
NotAfter: c.NotAfter,
CertSHA256: hex.EncodeToString(certSum256[:]),
CertSHA512: hex.EncodeToString(certSum512[:]),
SPKISHA256: hex.EncodeToString(spkiSum256[:]),
SPKISHA512: hex.EncodeToString(spkiSum512[:]),
SPKIDERBase64: base64.StdEncoding.EncodeToString(c.RawSubjectPublicKeyInfo),
}
}
return out
}
// probeTypeString renders the TLSProbe.Type string from a TLSEndpoint.
// Observation consumers already parse this field in its "tls" /
// "starttls-<proto>" shape; the contract-level split of direct vs.
@ -102,6 +131,7 @@ func probe(ctx context.Context, ep contract.TLSEndpoint, timeout time.Duration)
}
p.Subject = leaf.Subject.CommonName
p.DNSNames = append(p.DNSNames, leaf.DNSNames...)
p.Chain = buildChain(state.PeerCertificates)
hostnameMatch := leaf.VerifyHostname(sni) == nil
p.HostnameMatch = &hostnameMatch

37
checker/types.go
View file

@ -59,11 +59,48 @@ type TLSProbe struct {
IssuerAKI string `json:"issuer_aki,omitempty"`
Subject string `json:"subject,omitempty"`
DNSNames []string `json:"dns_names,omitempty"`
// Chain carries one entry per certificate presented by the server
// (leaf first, then intermediates in order). Each entry precomputes
// the four TLSA selector×matching_type hashes plus the raw DER so
// DANE consumers can match without re-handshaking or re-parsing.
Chain []CertInfo `json:"chain,omitempty"`
ElapsedMS int64 `json:"elapsed_ms,omitempty"`
Error string `json:"error,omitempty"`
Issues []Issue `json:"issues,omitempty"`
}
// CertInfo describes one certificate in the presented chain together with
// pre-hashed forms suitable for DANE/TLSA matching (RFC 6698 §2.1).
//
// Hex fields are lowercase, matching the representation emitted by
// miekg/dns for TLSA RR Certificate fields.
type CertInfo struct {
// DERBase64 is the standard base64 encoding of the certificate's DER
// form. Carried so consumers can do matching-type 0 (Full) without
// requiring a precomputed "full" hash and for fallback inspection.
DERBase64 string `json:"der_base64,omitempty"`
// Subject / Issuer are short human-readable DNs for the HTML report.
Subject string `json:"subject,omitempty"`
Issuer string `json:"issuer,omitempty"`
// NotAfter is the certificate's expiry. Carried so editors can show
// "expires on …" without re-parsing the DER.
NotAfter time.Time `json:"not_after,omitempty"`
// Selector 0 = full certificate.
CertSHA256 string `json:"cert_sha256,omitempty"`
CertSHA512 string `json:"cert_sha512,omitempty"`
// Selector 1 = SubjectPublicKeyInfo.
SPKISHA256 string `json:"spki_sha256,omitempty"`
SPKISHA512 string `json:"spki_sha512,omitempty"`
// SPKIDERBase64 lets consumers handle (selector=1, matching=0) without
// re-parsing the certificate.
SPKIDERBase64 string `json:"spki_der_base64,omitempty"`
}
// Issue is a single TLS finding surfaced to the consumer.
type Issue struct {
Code string `json:"code"`