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Note lack of proof verification in query method docs
[dnssec-prover] / src / query.rs
1 //! This module exposes utilities for building DNSSEC proofs by directly querying a recursive
2 //! resolver.
3
4 use std::cmp;
5 use std::net::{SocketAddr, TcpStream};
6 use std::io::{Read, Write, Error, ErrorKind};
7
8 #[cfg(feature = "tokio")]
9 use tokio_crate::net::TcpStream as TokioTcpStream;
10 #[cfg(feature = "tokio")]
11 use tokio_crate::io::{AsyncReadExt, AsyncWriteExt};
12
13 use crate::rr::*;
14 use crate::ser::*;
15
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;
19
20 fn emap<V>(v: Result<V, ()>) -> Result<V, Error> {
21         v.map_err(|_| Error::new(ErrorKind::Other, "Bad Response"))
22 }
23
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
40         query
41 }
42
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)?;
46         Ok(())
47 }
48
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?;
53         Ok(())
54 }
55
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"));
63         }
64         if flags & 0b0111_1010_0000_0111 != 0 {
65                 return Err(Error::new(ErrorKind::Other, "Server indicated error or provided bunk flags"));
66         }
67         if flags & 0b10_0000 == 0 {
68                 return Err(Error::new(ErrorKind::Other, "Server indicated data could not be authenticated"));
69         }
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))?;
76
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
81         }
82
83         // Only read the answers (skip authorities and additional) as that's all we care about.
84         let mut min_ttl = u32::MAX;
85         for _ in 0..answers {
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); }
90         }
91         Ok(min_ttl)
92 }
93
94 fn read_response(stream: &mut TcpStream, proof: &mut Vec<u8>, rrsig_key_names: &mut Vec<Name>) -> Result<u32, Error> {
95         let mut len = [0; 2];
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)
100 }
101
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)
109 }
110
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;
137                                         queries_made += 1;
138                                         dnskeys_requested.push(key_name.clone());
139
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;
144                                                 queries_made += 1;
145                                         }
146                                 }
147                         }
148                 }
149
150                 if queries_made > MAX_REQUESTS {
151                         Err(Error::new(ErrorKind::Other, "Too many requests required"))
152                 } else {
153                         Ok((res, min_ttl))
154                 }
155         } }
156 }
157
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)
162 }
163
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>(()) })
169 }
170
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 ///
174 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
175 /// module to validate the records contained.
176 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
177         build_proof(resolver, domain, A::TYPE)
178 }
179
180 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
181 /// as well as the TTL for the proof provided by the recursive resolver.
182 ///
183 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
184 /// module to validate the records contained.
185 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
186         build_proof(resolver, domain, AAAA::TYPE)
187 }
188
189 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
190 /// as well as the TTL for the proof provided by the recursive resolver.
191 ///
192 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
193 /// module to validate the records contained.
194 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
195         build_proof(resolver, domain, Txt::TYPE)
196 }
197
198 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
199 /// as well as the TTL for the proof provided by the recursive resolver.
200 ///
201 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
202 /// module to validate the records contained.
203 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
204         build_proof(resolver, domain, TLSA::TYPE)
205 }
206
207
208 /// Builds a DNSSEC proof for an A record by querying a recursive resolver, returning the proof as
209 /// well as the TTL for the proof provided by the recursive resolver.
210 ///
211 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
212 /// module to validate the records contained.
213 #[cfg(feature = "tokio")]
214 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
215         build_proof_async(resolver, domain, A::TYPE).await
216 }
217
218 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver, returning the proof
219 /// as well as the TTL for the proof provided by the recursive resolver.
220 ///
221 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
222 /// module to validate the records contained.
223 #[cfg(feature = "tokio")]
224 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
225         build_proof_async(resolver, domain, AAAA::TYPE).await
226 }
227
228 /// Builds a DNSSEC proof for an TXT record by querying a recursive resolver, returning the proof
229 /// as well as the TTL for the proof provided by the recursive resolver.
230 ///
231 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
232 /// module to validate the records contained.
233 #[cfg(feature = "tokio")]
234 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
235         build_proof_async(resolver, domain, Txt::TYPE).await
236 }
237
238 /// Builds a DNSSEC proof for an TLSA record by querying a recursive resolver, returning the proof
239 /// as well as the TTL for the proof provided by the recursive resolver.
240 ///
241 /// Note that this proof is NOT verified in any way, you need to use the [`crate::validation`]
242 /// module to validate the records contained.
243 #[cfg(feature = "tokio")]
244 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
245         build_proof_async(resolver, domain, TLSA::TYPE).await
246 }
247
248 #[cfg(all(feature = "validation", test))]
249 mod tests {
250         use super::*;
251         use crate::validation::*;
252
253         use rand::seq::SliceRandom;
254
255         use std::net::ToSocketAddrs;
256         use std::time::SystemTime;
257
258
259         #[test]
260         fn test_cloudflare_txt_query() {
261                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
262                 let query_name = "cloudflare.com.".try_into().unwrap();
263                 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
264
265                 let mut rrs = parse_rr_stream(&proof).unwrap();
266                 rrs.shuffle(&mut rand::rngs::OsRng);
267                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
268                 assert!(verified_rrs.verified_rrs.len() > 1);
269
270                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
271                 assert!(verified_rrs.valid_from < now);
272                 assert!(verified_rrs.expires > now);
273         }
274
275         #[test]
276         fn test_sha1_query() {
277                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
278                 let query_name = "benthecarman.com.".try_into().unwrap();
279                 let (proof, _) = build_a_proof(sockaddr, &query_name).unwrap();
280
281                 let mut rrs = parse_rr_stream(&proof).unwrap();
282                 rrs.shuffle(&mut rand::rngs::OsRng);
283                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
284                 assert!(verified_rrs.verified_rrs.len() >= 1);
285
286                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
287                 assert!(verified_rrs.valid_from < now);
288                 assert!(verified_rrs.expires > now);
289         }
290
291         #[test]
292         fn test_txt_query() {
293                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
294                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
295                 let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
296
297                 let mut rrs = parse_rr_stream(&proof).unwrap();
298                 rrs.shuffle(&mut rand::rngs::OsRng);
299                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
300                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
301
302                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
303                 assert!(verified_rrs.valid_from < now);
304                 assert!(verified_rrs.expires > now);
305         }
306
307         #[test]
308         fn test_cname_query() {
309                 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
310                         let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
311                         let query_name = "cname_test.matcorallo.com.".try_into().unwrap();
312                         let (proof, _) = build_txt_proof(sockaddr, &query_name).unwrap();
313
314                         let mut rrs = parse_rr_stream(&proof).unwrap();
315                         rrs.shuffle(&mut rand::rngs::OsRng);
316                         let verified_rrs = verify_rr_stream(&rrs).unwrap();
317                         assert_eq!(verified_rrs.verified_rrs.len(), 2);
318
319                         let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
320                         assert!(verified_rrs.valid_from < now);
321                         assert!(verified_rrs.expires > now);
322
323                         let resolved_rrs = verified_rrs.resolve_name(&query_name);
324                         assert_eq!(resolved_rrs.len(), 1);
325                         if let RR::Txt(txt) = &resolved_rrs[0] {
326                                 assert_eq!(txt.name.as_str(), "txt_test.matcorallo.com.");
327                                 assert_eq!(txt.data, b"dnssec_prover_test");
328                         } else { panic!(); }
329                 }
330         }
331
332         #[cfg(feature = "tokio")]
333         use tokio_crate as tokio;
334
335         #[cfg(feature = "tokio")]
336         #[tokio::test]
337         async fn test_txt_query_async() {
338                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
339                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
340                 let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
341
342                 let mut rrs = parse_rr_stream(&proof).unwrap();
343                 rrs.shuffle(&mut rand::rngs::OsRng);
344                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
345                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
346
347                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
348                 assert!(verified_rrs.valid_from < now);
349                 assert!(verified_rrs.expires > now);
350         }
351
352         #[cfg(feature = "tokio")]
353         #[tokio::test]
354         async fn test_cross_domain_cname_query_async() {
355                 for resolver in ["1.1.1.1:53", "8.8.8.8:53", "9.9.9.9:53"] {
356                         let sockaddr = resolver.to_socket_addrs().unwrap().next().unwrap();
357                         let query_name = "wildcard.x_domain_cname_wild.matcorallo.com.".try_into().unwrap();
358                         let (proof, _) = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
359
360                         let mut rrs = parse_rr_stream(&proof).unwrap();
361                         rrs.shuffle(&mut rand::rngs::OsRng);
362                         let verified_rrs = verify_rr_stream(&rrs).unwrap();
363                         assert_eq!(verified_rrs.verified_rrs.len(), 2);
364
365                         let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
366                         assert!(verified_rrs.valid_from < now);
367                         assert!(verified_rrs.expires > now);
368
369                         let resolved_rrs = verified_rrs.resolve_name(&query_name);
370                         assert_eq!(resolved_rrs.len(), 1);
371                         if let RR::Txt(txt) = &resolved_rrs[0] {
372                                 assert_eq!(txt.name.as_str(), "matt.user._bitcoin-payment.mattcorallo.com.");
373                                 assert!(txt.data.starts_with(b"bitcoin:"));
374                         } else { panic!(); }
375                 }
376         }
377 }