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>, rrsig_key_names: &mut Vec<Name>) -> Result<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 min_ttl = u32::MAX;
86 let (rr, ttl) = emap(parse_wire_packet_rr(&mut read, &resp))?;
87 write_rr(&rr, ttl, proof);
88 min_ttl = cmp::min(min_ttl, ttl);
89 if let RR::RRSig(rrsig) = rr { rrsig_key_names.push(rrsig.key_name); }
94 fn read_response(stream: &mut TcpStream, proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, Error> {
96 stream.read_exact(&mut len)?;
97 let mut resp = vec![0; u16::from_be_bytes(len) as usize];
98 stream.read_exact(&mut resp)?;
99 handle_response(&resp, proof, rrsig_key_names)
102 #[cfg(feature = "tokio")]
103 async fn read_response_async(stream: &mut TokioTcpStream, proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, Error> {
104 let mut len = [0; 2];
105 stream.read_exact(&mut len).await?;
106 let mut resp = vec![0; u16::from_be_bytes(len) as usize];
107 stream.read_exact(&mut resp).await?;
108 handle_response(&resp, proof, rrsig_key_names)
111 macro_rules! build_proof_impl {
112 ($stream: ident, $send_query: ident, $read_response: ident $(, $async_ok: tt)?) => { {
113 // We require the initial query to have already gone out, and assume our resolver will
114 // return any CNAMEs all the way to the final record in the response. From there, we just
115 // have to take any RRSIGs in the response and walk them up to the root. We do so
116 // iteratively, sending DNSKEY and DS lookups after every response, deduplicating requests
117 // using `dnskeys_requested`.
118 let mut res = Vec::new(); // The actual proof stream
119 let mut min_ttl = u32::MAX; // Min TTL of any answer record
120 const MAX_REQUESTS: usize = 20;
121 let mut rrsig_key_names = Vec::with_capacity(4); // Last response's RRSIG key_names
122 let mut dnskeys_requested = Vec::with_capacity(MAX_REQUESTS);
123 let mut pending_queries = 1;
124 let mut queries_made = 1;
125 while pending_queries != 0 && queries_made <= MAX_REQUESTS {
126 let response_min_ttl = $read_response(&mut $stream, &mut res, &mut rrsig_key_names)
127 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
128 pending_queries -= 1;
129 min_ttl = cmp::min(min_ttl, response_min_ttl);
130 rrsig_key_names.sort_unstable();
131 rrsig_key_names.dedup();
132 for key_name in rrsig_key_names.drain(..) {
133 if !dnskeys_requested.contains(&key_name) {
134 $send_query(&mut $stream, &key_name, DnsKey::TYPE)
135 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
136 pending_queries += 1;
138 dnskeys_requested.push(key_name.clone());
140 if key_name.as_str() != "." {
141 $send_query(&mut $stream, &key_name, DS::TYPE)
142 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
143 pending_queries += 1;
150 if queries_made > MAX_REQUESTS {
151 Err(Error::new(ErrorKind::Other, "Too many requests required"))
158 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
159 let mut stream = TcpStream::connect(resolver)?;
160 send_query(&mut stream, domain, ty)?;
161 build_proof_impl!(stream, send_query, read_response)
164 #[cfg(feature = "tokio")]
165 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
166 let mut stream = TokioTcpStream::connect(resolver).await?;
167 send_query_async(&mut stream, domain, ty).await?;
168 build_proof_impl!(stream, send_query_async, read_response_async, { Ok::<(), Error>(()) })
171 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
172 /// well as the TTL for the proof provided by the recursive resolver.
173 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
174 build_proof(resolver, domain, A::TYPE)
177 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
178 /// as well as the TTL for the proof provided by the recursive resolver.
179 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
180 build_proof(resolver, domain, AAAA::TYPE)
183 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
184 /// as well as the TTL for the proof provided by the recursive resolver.
185 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
186 build_proof(resolver, domain, Txt::TYPE)
189 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
190 /// as well as the TTL for the proof provided by the recursive resolver.
191 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
192 build_proof(resolver, domain, TLSA::TYPE)
196 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
197 /// well as the TTL for the proof provided by the recursive resolver.
198 #[cfg(feature = "tokio")]
199 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
200 build_proof_async(resolver, domain, A::TYPE).await
203 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
204 /// as well as the TTL for the proof provided by the recursive resolver.
205 #[cfg(feature = "tokio")]
206 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
207 build_proof_async(resolver, domain, AAAA::TYPE).await
210 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
211 /// as well as the TTL for the proof provided by the recursive resolver.
212 #[cfg(feature = "tokio")]
213 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
214 build_proof_async(resolver, domain, Txt::TYPE).await
217 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
218 /// as well as the TTL for the proof provided by the recursive resolver.
219 #[cfg(feature = "tokio")]
220 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
221 build_proof_async(resolver, domain, TLSA::TYPE).await
224 #[cfg(all(feature = "validation", test))]
227 use crate::validation::*;
229 use rand::seq::SliceRandom;
231 use std::net::ToSocketAddrs;
232 use std::time::SystemTime;
236 fn test_cloudflare_txt_query() {
237 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
238 let query_name = "cloudflare.com.".try_into().unwrap();
239 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
241 let mut rrs = parse_rr_stream(&proof).unwrap();
242 rrs.shuffle(&mut rand::rngs::OsRng);
243 let verified_rrs = verify_rr_stream(&rrs).unwrap();
244 assert!(verified_rrs.verified_rrs.len() > 1);
246 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
247 assert!(verified_rrs.valid_from < now);
248 assert!(verified_rrs.expires > now);
252 fn test_sha1_query() {
253 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
254 let query_name = "benthecarman.com.".try_into().unwrap();
255 let (proof, _) = build_a_proof(sockaddr, &query_name).unwrap();
257 let mut rrs = parse_rr_stream(&proof).unwrap();
258 rrs.shuffle(&mut rand::rngs::OsRng);
259 let verified_rrs = verify_rr_stream(&rrs).unwrap();
260 assert!(verified_rrs.verified_rrs.len() >= 1);
262 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
263 assert!(verified_rrs.valid_from < now);
264 assert!(verified_rrs.expires > now);
268 fn test_txt_query() {
269 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
270 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
271 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
273 let mut rrs = parse_rr_stream(&proof).unwrap();
274 rrs.shuffle(&mut rand::rngs::OsRng);
275 let verified_rrs = verify_rr_stream(&rrs).unwrap();
276 assert_eq!(verified_rrs.verified_rrs.len(), 1);
278 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
279 assert!(verified_rrs.valid_from < now);
280 assert!(verified_rrs.expires > now);
284 fn test_cname_query() {
285 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
286 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
287 let query_name = "cname_test.matcorallo.com.".try_into().unwrap();
288 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
290 let mut rrs = parse_rr_stream(&proof).unwrap();
291 rrs.shuffle(&mut rand::rngs::OsRng);
292 let verified_rrs = verify_rr_stream(&rrs).unwrap();
293 assert_eq!(verified_rrs.verified_rrs.len(), 2);
295 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
296 assert!(verified_rrs.valid_from < now);
297 assert!(verified_rrs.expires > now);
299 let resolved_rrs = verified_rrs.resolve_name(&query_name);
300 assert_eq!(resolved_rrs.len(), 1);
301 if let RR::Txt(txt) = &resolved_rrs[0] {
302 assert_eq!(txt.name.as_str(), "txt_test.matcorallo.com.");
303 assert_eq!(txt.data, b"dnssec_prover_test");
308 #[cfg(feature = "tokio")]
309 use tokio_crate as tokio;
311 #[cfg(feature = "tokio")]
313 async fn test_txt_query_async() {
314 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
315 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
316 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
318 let mut rrs = parse_rr_stream(&proof).unwrap();
319 rrs.shuffle(&mut rand::rngs::OsRng);
320 let verified_rrs = verify_rr_stream(&rrs).unwrap();
321 assert_eq!(verified_rrs.verified_rrs.len(), 1);
323 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
324 assert!(verified_rrs.valid_from < now);
325 assert!(verified_rrs.expires > now);
328 #[cfg(feature = "tokio")]
330 async fn test_cross_domain_cname_query_async() {
331 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
332 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
333 let query_name = "wildcard.x_domain_cname_wild.matcorallo.com.".try_into().unwrap();
334 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
336 let mut rrs = parse_rr_stream(&proof).unwrap();
337 rrs.shuffle(&mut rand::rngs::OsRng);
338 let verified_rrs = verify_rr_stream(&rrs).unwrap();
339 assert_eq!(verified_rrs.verified_rrs.len(), 2);
341 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
342 assert!(verified_rrs.valid_from < now);
343 assert!(verified_rrs.expires > now);
345 let resolved_rrs = verified_rrs.resolve_name(&query_name);
346 assert_eq!(resolved_rrs.len(), 1);
347 if let RR::Txt(txt) = &resolved_rrs[0] {
348 assert_eq!(txt.name.as_str(), "matt.user._bitcoin-payment.mattcorallo.com.");
349 assert!(txt.data.starts_with(b"bitcoin:"));