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?;
57 /// Read some input and parse it as if it came from a server, for fuzzing.
58 pub fn fuzz_response(response: &[u8]) {
59 let (mut proof, mut names) = (Vec::new(), Vec::new());
60 let _ = handle_response(response, &mut proof, &mut names);
63 fn handle_response(resp: &[u8], proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, Error> {
64 let mut read: &[u8] = resp;
65 if emap(read_u16(&mut read))? != TXID { return Err(Error::new(ErrorKind::Other, "bad txid")); }
66 // 2 byte transaction ID
67 let flags = emap(read_u16(&mut read))?;
68 if flags & 0b1000_0000_0000_0000 == 0 {
69 return Err(Error::new(ErrorKind::Other, "Missing response flag"));
71 if flags & 0b0111_1010_0000_0111 != 0 {
72 return Err(Error::new(ErrorKind::Other, "Server indicated error or provided bunk flags"));
74 if flags & 0b10_0000 == 0 {
75 return Err(Error::new(ErrorKind::Other, "Server indicated data could not be authenticated"));
77 let questions = emap(read_u16(&mut read))?;
78 if questions != 1 { return Err(Error::new(ErrorKind::Other, "server responded to multiple Qs")); }
79 let answers = emap(read_u16(&mut read))?;
80 if answers == 0 { return Err(Error::new(ErrorKind::Other, "No answers")); }
81 let _authorities = emap(read_u16(&mut read))?;
82 let _additional = emap(read_u16(&mut read))?;
84 for _ in 0..questions {
85 emap(read_wire_packet_name(&mut read, resp))?;
86 emap(read_u16(&mut read))?; // type
87 emap(read_u16(&mut read))?; // class
90 // Only read the answers (skip authorities and additional) as that's all we care about.
91 let mut min_ttl = u32::MAX;
93 let (rr, ttl) = emap(parse_wire_packet_rr(&mut read, &resp))?;
94 write_rr(&rr, ttl, proof);
95 min_ttl = cmp::min(min_ttl, ttl);
96 if let RR::RRSig(rrsig) = rr { rrsig_key_names.push(rrsig.key_name); }
101 fn read_response(stream: &mut TcpStream, proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, Error> {
102 let mut len = [0; 2];
103 stream.read_exact(&mut len)?;
104 let mut resp = vec![0; u16::from_be_bytes(len) as usize];
105 stream.read_exact(&mut resp)?;
106 handle_response(&resp, proof, rrsig_key_names)
109 #[cfg(feature = "tokio")]
110 async fn read_response_async(stream: &mut TokioTcpStream, proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, Error> {
111 let mut len = [0; 2];
112 stream.read_exact(&mut len).await?;
113 let mut resp = vec![0; u16::from_be_bytes(len) as usize];
114 stream.read_exact(&mut resp).await?;
115 handle_response(&resp, proof, rrsig_key_names)
118 macro_rules! build_proof_impl {
119 ($stream: ident, $send_query: ident, $read_response: ident $(, $async_ok: tt)?) => { {
120 // We require the initial query to have already gone out, and assume our resolver will
121 // return any CNAMEs all the way to the final record in the response. From there, we just
122 // have to take any RRSIGs in the response and walk them up to the root. We do so
123 // iteratively, sending DNSKEY and DS lookups after every response, deduplicating requests
124 // using `dnskeys_requested`.
125 let mut res = Vec::new(); // The actual proof stream
126 let mut min_ttl = u32::MAX; // Min TTL of any answer record
127 const MAX_REQUESTS: usize = 20;
128 let mut rrsig_key_names = Vec::with_capacity(4); // Last response's RRSIG key_names
129 let mut dnskeys_requested = Vec::with_capacity(MAX_REQUESTS);
130 let mut pending_queries = 1;
131 let mut queries_made = 1;
132 while pending_queries != 0 && queries_made <= MAX_REQUESTS {
133 let response_min_ttl = $read_response(&mut $stream, &mut res, &mut rrsig_key_names)
134 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
135 pending_queries -= 1;
136 min_ttl = cmp::min(min_ttl, response_min_ttl);
137 rrsig_key_names.sort_unstable();
138 rrsig_key_names.dedup();
139 for key_name in rrsig_key_names.drain(..) {
140 if !dnskeys_requested.contains(&key_name) {
141 $send_query(&mut $stream, &key_name, DnsKey::TYPE)
142 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
143 pending_queries += 1;
145 dnskeys_requested.push(key_name.clone());
147 if key_name.as_str() != "." {
148 $send_query(&mut $stream, &key_name, DS::TYPE)
149 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
150 pending_queries += 1;
157 if queries_made > MAX_REQUESTS {
158 Err(Error::new(ErrorKind::Other, "Too many requests required"))
165 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
166 let mut stream = TcpStream::connect(resolver)?;
167 send_query(&mut stream, domain, ty)?;
168 build_proof_impl!(stream, send_query, read_response)
171 #[cfg(feature = "tokio")]
172 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<(Vec<u8>, u32), Error> {
173 let mut stream = TokioTcpStream::connect(resolver).await?;
174 send_query_async(&mut stream, domain, ty).await?;
175 build_proof_impl!(stream, send_query_async, read_response_async, { Ok::<(), Error>(()) })
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.
181 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
182 /// module to validate the records contained.
183 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
184 build_proof(resolver, domain, A::TYPE)
187 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
188 /// as well as the TTL for the proof provided by the recursive resolver.
190 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
191 /// module to validate the records contained.
192 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
193 build_proof(resolver, domain, AAAA::TYPE)
196 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
197 /// as well as the TTL for the proof provided by the recursive resolver.
199 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
200 /// module to validate the records contained.
201 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
202 build_proof(resolver, domain, Txt::TYPE)
205 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
206 /// as well as the TTL for the proof provided by the recursive resolver.
208 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
209 /// module to validate the records contained.
210 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
211 build_proof(resolver, domain, TLSA::TYPE)
215 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
216 /// well as the TTL for the proof provided by the recursive resolver.
218 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
219 /// module to validate the records contained.
220 #[cfg(feature = "tokio")]
221 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
222 build_proof_async(resolver, domain, A::TYPE).await
225 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
226 /// as well as the TTL for the proof provided by the recursive resolver.
228 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
229 /// module to validate the records contained.
230 #[cfg(feature = "tokio")]
231 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
232 build_proof_async(resolver, domain, AAAA::TYPE).await
235 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
236 /// as well as the TTL for the proof provided by the recursive resolver.
238 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
239 /// module to validate the records contained.
240 #[cfg(feature = "tokio")]
241 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
242 build_proof_async(resolver, domain, Txt::TYPE).await
245 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
246 /// as well as the TTL for the proof provided by the recursive resolver.
248 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
249 /// module to validate the records contained.
250 #[cfg(feature = "tokio")]
251 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
252 build_proof_async(resolver, domain, TLSA::TYPE).await
255 #[cfg(all(feature = "validation", test))]
258 use crate::validation::*;
260 use rand::seq::SliceRandom;
262 use std::net::ToSocketAddrs;
263 use std::time::SystemTime;
267 fn test_cloudflare_txt_query() {
268 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
269 let query_name = "cloudflare.com.".try_into().unwrap();
270 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
272 let mut rrs = parse_rr_stream(&proof).unwrap();
273 rrs.shuffle(&mut rand::rngs::OsRng);
274 let verified_rrs = verify_rr_stream(&rrs).unwrap();
275 assert!(verified_rrs.verified_rrs.len() > 1);
277 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
278 assert!(verified_rrs.valid_from < now);
279 assert!(verified_rrs.expires > now);
283 fn test_sha1_query() {
284 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
285 let query_name = "benthecarman.com.".try_into().unwrap();
286 let (proof, _) = build_a_proof(sockaddr, &query_name).unwrap();
288 let mut rrs = parse_rr_stream(&proof).unwrap();
289 rrs.shuffle(&mut rand::rngs::OsRng);
290 let verified_rrs = verify_rr_stream(&rrs).unwrap();
291 assert!(verified_rrs.verified_rrs.len() >= 1);
293 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
294 assert!(verified_rrs.valid_from < now);
295 assert!(verified_rrs.expires > now);
299 fn test_txt_query() {
300 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
301 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
302 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
304 let mut rrs = parse_rr_stream(&proof).unwrap();
305 rrs.shuffle(&mut rand::rngs::OsRng);
306 let verified_rrs = verify_rr_stream(&rrs).unwrap();
307 assert_eq!(verified_rrs.verified_rrs.len(), 1);
309 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
310 assert!(verified_rrs.valid_from < now);
311 assert!(verified_rrs.expires > now);
315 fn test_cname_query() {
316 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
317 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
318 let query_name = "cname_test.matcorallo.com.".try_into().unwrap();
319 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
321 let mut rrs = parse_rr_stream(&proof).unwrap();
322 rrs.shuffle(&mut rand::rngs::OsRng);
323 let verified_rrs = verify_rr_stream(&rrs).unwrap();
324 assert_eq!(verified_rrs.verified_rrs.len(), 2);
326 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
327 assert!(verified_rrs.valid_from < now);
328 assert!(verified_rrs.expires > now);
330 let resolved_rrs = verified_rrs.resolve_name(&query_name);
331 assert_eq!(resolved_rrs.len(), 1);
332 if let RR::Txt(txt) = &resolved_rrs[0] {
333 assert_eq!(txt.name.as_str(), "txt_test.matcorallo.com.");
334 assert_eq!(txt.data, b"dnssec_prover_test");
339 #[cfg(feature = "tokio")]
340 use tokio_crate as tokio;
342 #[cfg(feature = "tokio")]
344 async fn test_txt_query_async() {
345 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
346 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
347 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
349 let mut rrs = parse_rr_stream(&proof).unwrap();
350 rrs.shuffle(&mut rand::rngs::OsRng);
351 let verified_rrs = verify_rr_stream(&rrs).unwrap();
352 assert_eq!(verified_rrs.verified_rrs.len(), 1);
354 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
355 assert!(verified_rrs.valid_from < now);
356 assert!(verified_rrs.expires > now);
359 #[cfg(feature = "tokio")]
361 async fn test_cross_domain_cname_query_async() {
362 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
363 let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
364 let query_name = "wildcard.x_domain_cname_wild.matcorallo.com.".try_into().unwrap();
365 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
367 let mut rrs = parse_rr_stream(&proof).unwrap();
368 rrs.shuffle(&mut rand::rngs::OsRng);
369 let verified_rrs = verify_rr_stream(&rrs).unwrap();
370 assert_eq!(verified_rrs.verified_rrs.len(), 2);
372 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
373 assert!(verified_rrs.valid_from < now);
374 assert!(verified_rrs.expires > now);
376 let resolved_rrs = verified_rrs.resolve_name(&query_name);
377 assert_eq!(resolved_rrs.len(), 1);
378 if let RR::Txt(txt) = &resolved_rrs[0] {
379 assert_eq!(txt.name.as_str(), "matt.user._bitcoin-payment.mattcorallo.com.");
380 assert!(txt.data.starts_with(b"bitcoin:"));