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>
95 lines
2.7 KiB
Go
95 lines
2.7 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"
|
|
|
|
"codeberg.org/miekg/dns"
|
|
)
|
|
|
|
type (
|
|
// Client performs DNS lookups used to verify domain ownership and
|
|
// certificate prerequisites.
|
|
Client struct {
|
|
ResolverAddr string
|
|
exchange exchangeFunc
|
|
}
|
|
|
|
exchangeFunc func(ctx context.Context, msg *dns.Msg, network string) (*dns.Msg, error)
|
|
)
|
|
|
|
// NewClient returns a client that resolves names through resolverAddr.
|
|
func NewClient(resolverAddr string) *Client {
|
|
return &Client{ResolverAddr: resolverAddr}
|
|
}
|
|
|
|
func (c *Client) exchangeUDP(ctx context.Context, msg *dns.Msg) (*dns.Msg, error) {
|
|
if c.exchange != nil {
|
|
return c.exchange(ctx, msg, "udp")
|
|
}
|
|
|
|
client := dns.NewClient()
|
|
|
|
resp, _, err := client.Exchange(ctx, msg, "udp", c.ResolverAddr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return resp, nil
|
|
}
|
|
|
|
func (c *Client) exchangeTCP(ctx context.Context, msg *dns.Msg) (*dns.Msg, error) {
|
|
if c.exchange != nil {
|
|
return c.exchange(ctx, msg, "tcp")
|
|
}
|
|
|
|
client := dns.NewClient()
|
|
|
|
resp, _, err := client.Exchange(ctx, msg, "tcp", c.ResolverAddr)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return resp, nil
|
|
}
|
|
|
|
func (c *Client) query(ctx context.Context, msg *dns.Msg) (*dns.Msg, error) {
|
|
resp, err := c.exchangeUDP(ctx, msg)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("cannot exchange dns message: %w", err)
|
|
}
|
|
|
|
if resp.Truncated {
|
|
resp, err = c.exchangeTCP(ctx, msg)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("cannot exchange dns message over TCP: %w", err)
|
|
}
|
|
}
|
|
|
|
if resp.Truncated {
|
|
return nil, fmt.Errorf("cannot exchange dns message: truncated response")
|
|
}
|
|
|
|
return resp, nil
|
|
}
|