1 //! This module exposes utilities for building DNSSEC proofs by directly querying a recursive
5 use std::net::{SocketAddr, TcpStream};
6 use std::io::{Read, Write, Error, ErrorKind};
8 #[cfg(feature = "tokio")]
9 use tokio_crate::net::TcpStream as TokioTcpStream;
10 #[cfg(feature = "tokio")]
11 use tokio_crate::io::{AsyncReadExt, AsyncWriteExt};
16 // We don't care about transaction IDs as we're only going to accept signed data. Thus, we use
17 // this constant instead of a random value.
18 const TXID: u16 = 0x4242;
20 fn emap<V>(v: Result<V, ()>) -> Result<V, Error> {
21 v.map_err(|_| Error::new(ErrorKind::Other, "Bad Response"))
24 fn build_query(domain: &Name, ty: u16) -> Vec<u8> {
25 // TODO: Move to not allocating for the query
26 let mut query = Vec::with_capacity(1024);
27 let query_msg_len: u16 = 2 + 2 + 8 + 2 + 2 + name_len(domain) + 11;
28 query.extend_from_slice(&query_msg_len.to_be_bytes());
29 query.extend_from_slice(&TXID.to_be_bytes());
30 query.extend_from_slice(&[0x01, 0x20]); // Flags: Recursive, Authenticated Data
31 query.extend_from_slice(&[0, 1, 0, 0, 0, 0, 0, 1]); // One question, One additional
32 write_name(&mut query, domain);
33 query.extend_from_slice(&ty.to_be_bytes());
34 query.extend_from_slice(&1u16.to_be_bytes()); // INternet class
35 query.extend_from_slice(&[0, 0, 0x29]); // . OPT
36 query.extend_from_slice(&0u16.to_be_bytes()); // 0 UDP payload size
37 query.extend_from_slice(&[0, 0]); // EDNS version 0
38 query.extend_from_slice(&0x8000u16.to_be_bytes()); // Accept DNSSEC RRs
39 query.extend_from_slice(&0u16.to_be_bytes()); // No additional data
43 fn send_query(stream: &mut TcpStream, domain: &Name, ty: u16) -> Result<(), Error> {
44 let query = build_query(domain, ty);
45 stream.write_all(&query)?;
49 #[cfg(feature = "tokio")]
50 async fn send_query_async(stream: &mut TokioTcpStream, domain: &Name, ty: u16) -> Result<(), Error> {
51 let query = build_query(domain, ty);
52 stream.write_all(&query).await?;
56 fn handle_response(resp: &[u8], proof: &mut Vec<u8>) -> Result<Option<(RRSig, u32)>, Error> {
57 let mut read: &[u8] = resp;
58 if emap(read_u16(&mut read))? != TXID { return Err(Error::new(ErrorKind::Other, "bad txid")); }
59 // 2 byte transaction ID
60 let flags = emap(read_u16(&mut read))?;
61 if flags & 0b1000_0000_0000_0000 == 0 {
62 return Err(Error::new(ErrorKind::Other, "Missing response flag"));
64 if flags & 0b0111_1010_0000_0111 != 0 {
65 return Err(Error::new(ErrorKind::Other, "Server indicated error or provided bunk flags"));
67 if flags & 0b10_0000 == 0 {
68 return Err(Error::new(ErrorKind::Other, "Server indicated data could not be authenticated"));
70 let questions = emap(read_u16(&mut read))?;
71 if questions != 1 { return Err(Error::new(ErrorKind::Other, "server responded to multiple Qs")); }
72 let answers = emap(read_u16(&mut read))?;
73 if answers == 0 { return Err(Error::new(ErrorKind::Other, "No answers")); }
74 let _authorities = emap(read_u16(&mut read))?;
75 let _additional = emap(read_u16(&mut read))?;
77 for _ in 0..questions {
78 emap(read_wire_packet_name(&mut read, resp))?;
79 emap(read_u16(&mut read))?; // type
80 emap(read_u16(&mut read))?; // class
83 // Only read the answers (skip authorities and additional) as that's all we care about.
84 let mut rrsig_opt = None;
85 let mut min_ttl = u32::MAX;
87 let (rr, ttl) = emap(parse_wire_packet_rr(&mut read, &resp))?;
88 write_rr(&rr, ttl, proof);
89 min_ttl = cmp::min(min_ttl, ttl);
90 if let RR::RRSig(rrsig) = rr { rrsig_opt = Some(rrsig); }
92 Ok(rrsig_opt.map(|rr| (rr, min_ttl)))
95 fn read_response(stream: &mut TcpStream, proof: &mut Vec<u8>) -> Result<Option<(RRSig, u32)>, Error> {
97 stream.read_exact(&mut len)?;
98 let mut resp = vec![0; u16::from_be_bytes(len) as usize];
99 stream.read_exact(&mut resp)?;
100 handle_response(&resp, proof)
103 #[cfg(feature = "tokio")]
104 async fn read_response_async(stream: &mut TokioTcpStream, proof: &mut Vec<u8>) -> Result<Option<(RRSig, u32)>, Error> {
105 let mut len = [0; 2];
106 stream.read_exact(&mut len).await?;
107 let mut resp = vec![0; u16::from_be_bytes(len) as usize];
108 stream.read_exact(&mut resp).await?;
109 handle_response(&resp, proof)
112 macro_rules! build_proof_impl {
113 ($stream: ident, $send_query: ident, $read_response: ident $(, $async_ok: tt)?) => { {
114 let mut res = Vec::new();
115 let mut reached_root = false;
116 let mut min_ttl = u32::MAX;
118 let resp_opt = $read_response(&mut $stream, &mut res)
119 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
120 if let Some((rrsig, rrsig_min_ttl)) = resp_opt {
121 min_ttl = cmp::min(min_ttl, rrsig_min_ttl);
122 if rrsig.name.as_str() == "." {
125 if i != 0 && rrsig.name == rrsig.key_name {
126 $send_query(&mut $stream, &rrsig.key_name, DS::TYPE)
128 $send_query(&mut $stream, &rrsig.key_name, DnsKey::TYPE)
129 }$(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
132 if reached_root { break; }
135 if !reached_root { Err(Error::new(ErrorKind::Other, "Too many requests required")) }
136 else { Ok((res, min_ttl)) }
140 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
141 let mut stream = TcpStream::connect(resolver)?;
142 send_query(&mut stream, domain, ty)?;
143 build_proof_impl!(stream, send_query, read_response)
146 #[cfg(feature = "tokio")]
147 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
148 let mut stream = TokioTcpStream::connect(resolver).await?;
149 send_query_async(&mut stream, domain, ty).await?;
150 build_proof_impl!(stream, send_query_async, read_response_async, { Ok::<(), Error>(()) })
153 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
154 /// well as the TTL for the proof provided by the recursive resolver.
155 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
156 build_proof(resolver, domain, A::TYPE)
159 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
160 /// as well as the TTL for the proof provided by the recursive resolver.
161 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
162 build_proof(resolver, domain, AAAA::TYPE)
165 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
166 /// as well as the TTL for the proof provided by the recursive resolver.
167 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
168 build_proof(resolver, domain, Txt::TYPE)
171 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
172 /// as well as the TTL for the proof provided by the recursive resolver.
173 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
174 build_proof(resolver, domain, TLSA::TYPE)
178 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
179 /// well as the TTL for the proof provided by the recursive resolver.
180 #[cfg(feature = "tokio")]
181 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
182 build_proof_async(resolver, domain, A::TYPE).await
185 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
186 /// as well as the TTL for the proof provided by the recursive resolver.
187 #[cfg(feature = "tokio")]
188 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
189 build_proof_async(resolver, domain, AAAA::TYPE).await
192 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
193 /// as well as the TTL for the proof provided by the recursive resolver.
194 #[cfg(feature = "tokio")]
195 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
196 build_proof_async(resolver, domain, Txt::TYPE).await
199 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
200 /// as well as the TTL for the proof provided by the recursive resolver.
201 #[cfg(feature = "tokio")]
202 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
203 build_proof_async(resolver, domain, TLSA::TYPE).await
206 #[cfg(all(feature = "validation", test))]
209 use crate::validation::*;
211 use rand::seq::SliceRandom;
213 use std::net::ToSocketAddrs;
214 use std::time::SystemTime;
218 fn test_cloudflare_txt_query() {
219 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
220 let query_name = "cloudflare.com.".try_into().unwrap();
221 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
223 let mut rrs = parse_rr_stream(&proof).unwrap();
224 rrs.shuffle(&mut rand::rngs::OsRng);
225 let verified_rrs = verify_rr_stream(&rrs).unwrap();
226 assert!(verified_rrs.verified_rrs.len() > 1);
228 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
229 assert!(verified_rrs.valid_from < now);
230 assert!(verified_rrs.expires > now);
234 fn test_sha1_query() {
235 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
236 let query_name = "benthecarman.com.".try_into().unwrap();
237 let (proof, _) = build_a_proof(sockaddr, &query_name).unwrap();
239 let mut rrs = parse_rr_stream(&proof).unwrap();
240 rrs.shuffle(&mut rand::rngs::OsRng);
241 let verified_rrs = verify_rr_stream(&rrs).unwrap();
242 assert!(verified_rrs.verified_rrs.len() >= 1);
244 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
245 assert!(verified_rrs.valid_from < now);
246 assert!(verified_rrs.expires > now);
250 fn test_txt_query() {
251 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
252 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
253 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
255 let mut rrs = parse_rr_stream(&proof).unwrap();
256 rrs.shuffle(&mut rand::rngs::OsRng);
257 let verified_rrs = verify_rr_stream(&rrs).unwrap();
258 assert_eq!(verified_rrs.verified_rrs.len(), 1);
260 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
261 assert!(verified_rrs.valid_from < now);
262 assert!(verified_rrs.expires > now);
265 #[cfg(feature = "tokio")]
266 use tokio_crate as tokio;
268 #[cfg(feature = "tokio")]
270 async fn test_txt_query_async() {
271 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
272 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
273 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
275 let mut rrs = parse_rr_stream(&proof).unwrap();
276 rrs.shuffle(&mut rand::rngs::OsRng);
277 let verified_rrs = verify_rr_stream(&rrs).unwrap();
278 assert_eq!(verified_rrs.verified_rrs.len(), 1);
280 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
281 assert!(verified_rrs.valid_from < now);
282 assert!(verified_rrs.expires > now);