64ef051d18
Extract shared DNS checks into dnsclient and fail closed on truncated or non-success CAA responses. Climb past eTLD+1, validate RFC 8659 issue-value syntax, and map NXDOMAIN TXT lookups to the pending-verification path. Signed-off-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: Bryan FRIMIN <bryan@frimin.fr>
70 lines
2.2 KiB
Go
70 lines
2.2 KiB
Go
// Copyright (c) 2026 Probo Inc <hello@probo.com>.
|
|
//
|
|
// Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
// of this software and associated documentation files (the "Software"), to deal
|
|
// in the Software without restriction, including without limitation the rights
|
|
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
// copies of the Software, and to permit persons to whom the Software is
|
|
// furnished to do so, subject to the following conditions:
|
|
//
|
|
// The above copyright notice and this permission notice shall be included in
|
|
// all copies or substantial portions of the Software.
|
|
//
|
|
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
|
|
// SOFTWARE.
|
|
|
|
package dnsclient
|
|
|
|
import (
|
|
"context"
|
|
"fmt"
|
|
"strings"
|
|
|
|
"codeberg.org/miekg/dns"
|
|
)
|
|
|
|
// CheckTXT verifies that domain has a TXT record owned by that exact name whose
|
|
// value equals expectedValue. Parent apex records are ignored.
|
|
func (c *Client) CheckTXT(ctx context.Context, domain, expectedValue string) error {
|
|
msg := dns.NewMsg(domain, dns.TypeTXT)
|
|
|
|
resp, err := c.query(ctx, msg)
|
|
if err != nil {
|
|
return fmt.Errorf("cannot query TXT record for %q: %w", domain, err)
|
|
}
|
|
|
|
if resp.Rcode == dns.RcodeNameError {
|
|
return fmt.Errorf("%w for %q", ErrTXTNotFound, domain)
|
|
}
|
|
|
|
if resp.Rcode != dns.RcodeSuccess {
|
|
return fmt.Errorf(
|
|
"cannot query TXT record for %q: %s",
|
|
domain,
|
|
dns.RcodeToString[resp.Rcode],
|
|
)
|
|
}
|
|
|
|
if len(resp.Answer) == 0 {
|
|
return fmt.Errorf("%w for %q", ErrTXTNotFound, domain)
|
|
}
|
|
|
|
for _, answer := range resp.Answer {
|
|
txt, ok := answer.(*dns.TXT)
|
|
if !ok || !EqualNames(txt.Hdr.Name, domain) {
|
|
continue
|
|
}
|
|
|
|
if strings.Join(txt.Txt, "") == expectedValue {
|
|
return nil
|
|
}
|
|
}
|
|
|
|
return fmt.Errorf("%w for %q", ErrTXTMismatch, domain)
|
|
}
|