Pierre-Olivier Mercier
7953dfc3ed
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Wrap user-facing lookup errors through a new formatDNSError helper that clears net.DNSError.Server so the " on <addr>" suffix no longer leaks the upstream resolver (e.g. "on 127.0.0.11:53") to end users. Closes: https://framagit.org/happyDomain/happydeliver/-/work_items/2
93 lines
3.4 KiB
Go
93 lines
3.4 KiB
Go
// This file is part of the happyDeliver (R) project.
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// Copyright (c) 2025 happyDomain
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// Authors: Pierre-Olivier Mercier, et al.
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//
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// This program is offered under a commercial and under the AGPL license.
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// For commercial licensing, contact us at <contact@happydomain.org>.
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//
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// For AGPL licensing:
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <https://www.gnu.org/licenses/>.
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package analyzer
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import (
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"context"
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"errors"
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"net"
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)
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// formatDNSError renders a resolution error without exposing the upstream
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// resolver address that net.DNSError.Error() normally appends as " on <addr>".
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func formatDNSError(err error) string {
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var dnsErr *net.DNSError
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if errors.As(err, &dnsErr) {
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sanitized := *dnsErr
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sanitized.Server = ""
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return sanitized.Error()
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}
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return err.Error()
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}
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// DNSResolver defines the interface for DNS resolution operations.
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// This interface abstracts DNS lookups to allow for custom implementations,
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// such as mock resolvers for testing or caching resolvers for performance.
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type DNSResolver interface {
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// LookupMX returns the DNS MX records for the given domain.
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LookupMX(ctx context.Context, name string) ([]*net.MX, error)
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// LookupTXT returns the DNS TXT records for the given domain.
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LookupTXT(ctx context.Context, name string) ([]string, error)
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// LookupAddr performs a reverse lookup for the given IP address,
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// returning a list of hostnames mapping to that address.
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LookupAddr(ctx context.Context, addr string) ([]string, error)
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// LookupHost looks up the given hostname using the local resolver.
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// It returns a slice of that host's addresses (IPv4 and IPv6).
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LookupHost(ctx context.Context, host string) ([]string, error)
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}
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// StandardDNSResolver is the default DNS resolver implementation that uses net.Resolver.
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type StandardDNSResolver struct {
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resolver *net.Resolver
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}
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// NewStandardDNSResolver creates a new StandardDNSResolver with default settings.
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func NewStandardDNSResolver() DNSResolver {
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return &StandardDNSResolver{
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resolver: &net.Resolver{
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PreferGo: true,
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},
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}
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}
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// LookupMX implements DNSResolver.LookupMX using net.Resolver.
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func (r *StandardDNSResolver) LookupMX(ctx context.Context, name string) ([]*net.MX, error) {
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return r.resolver.LookupMX(ctx, name)
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}
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// LookupTXT implements DNSResolver.LookupTXT using net.Resolver.
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func (r *StandardDNSResolver) LookupTXT(ctx context.Context, name string) ([]string, error) {
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return r.resolver.LookupTXT(ctx, name)
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}
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// LookupAddr implements DNSResolver.LookupAddr using net.Resolver.
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func (r *StandardDNSResolver) LookupAddr(ctx context.Context, addr string) ([]string, error) {
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return r.resolver.LookupAddr(ctx, addr)
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}
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// LookupHost implements DNSResolver.LookupHost using net.Resolver.
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func (r *StandardDNSResolver) LookupHost(ctx context.Context, host string) ([]string, error) {
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return r.resolver.LookupHost(ctx, host)
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}
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