_ Git - dnssec-prover/blob - 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 }