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fix(netxlite): reject replies with wrong queryID (#732)

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This diff has been extracted from c2f7ccab0e

See https://github.com/ooni/probe/issues/2096

While there, export DecodeReply to decode a raw reply without
interpreting the Rcode or parsing the results, which seems a
nice extra feature to have to more flexibly parse DNS replies
in other parts of the codebase.
This commit is contained in:
Simone Basso 2022-05-14 19:38:46 +02:00 • committed by GitHub
commit 9d2301cae2
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18 changed files with 261 additions and 128 deletions
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27
internal/netxlite/dnsdecoder.go
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@ -1,6 +1,8 @@
package netxlite
import (
"errors"
"github.com/miekg/dns"
"github.com/ooni/probe-cli/v3/internal/model"
)
@ -8,11 +10,26 @@ import (
// DNSDecoderMiekg uses github.com/miekg/dns to implement the Decoder.
type DNSDecoderMiekg struct{}
func (d *DNSDecoderMiekg) parseReply(data []byte) (*dns.Msg, error) {
// ErrDNSReplyWithWrongQueryID indicates we have got a DNS reply with the wrong queryID.
var ErrDNSReplyWithWrongQueryID = errors.New(FailureDNSReplyWithWrongQueryID)
// DecodeReply implements model.DNSDecoder.DecodeReply
func (d *DNSDecoderMiekg) DecodeReply(data []byte) (*dns.Msg, error) {
reply := new(dns.Msg)
if err := reply.Unpack(data); err != nil {
return nil, err
}
return reply, nil
}
func (d *DNSDecoderMiekg) parseReply(data []byte, queryID uint16) (*dns.Msg, error) {
reply, err := d.DecodeReply(data)
if err != nil {
return nil, err
}
if reply.Id != queryID {
return nil, ErrDNSReplyWithWrongQueryID
}
// TODO(bassosimone): map more errors to net.DNSError names
// TODO(bassosimone): add support for lame referral.
switch reply.Rcode {
@ -29,8 +46,8 @@ func (d *DNSDecoderMiekg) parseReply(data []byte) (*dns.Msg, error) {
}
}
func (d *DNSDecoderMiekg) DecodeHTTPS(data []byte) (*model.HTTPSSvc, error) {
reply, err := d.parseReply(data)
func (d *DNSDecoderMiekg) DecodeHTTPS(data []byte, queryID uint16) (*model.HTTPSSvc, error) {
reply, err := d.parseReply(data, queryID)
if err != nil {
return nil, err
}
@ -64,8 +81,8 @@ func (d *DNSDecoderMiekg) DecodeHTTPS(data []byte) (*model.HTTPSSvc, error) {
return out, nil
}
func (d *DNSDecoderMiekg) DecodeLookupHost(qtype uint16, data []byte) ([]string, error) {
reply, err := d.parseReply(data)
func (d *DNSDecoderMiekg) DecodeLookupHost(qtype uint16, data []byte, queryID uint16) ([]string, error) {
reply, err := d.parseReply(data, queryID)
if err != nil {
return nil, err
}