_ 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 #[cfg(fuzzing)]
  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);
  61 }
  62
  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"));
  70         }
  71         if flags & 0b0111_1010_0000_0111 != 0 {
  72                 return Err(Error::new(ErrorKind::Other, "Server indicated error or provided bunk flags"));
  73         }
  74         if flags & 0b10_0000 == 0 {
  75                 return Err(Error::new(ErrorKind::Other, "Server indicated data could not be authenticated"));
  76         }
  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))?;
  83
  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
  88         }
  89
  90         // Only read the answers (skip authorities and additional) as that's all we care about.
  91         let mut min_ttl = u32::MAX;
  92         for _ in 0..answers {
  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); }
  97         }
  98         Ok(min_ttl)
  99 }
 100
 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)
 107 }
 108
 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)
 116 }
 117
 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;
 144                                         queries_made += 1;
 145                                         dnskeys_requested.push(key_name.clone());
 146
 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;
 151                                                 queries_made += 1;
 152                                         }
 153                                 }
 154                         }
 155                 }
 156
 157                 if queries_made > MAX_REQUESTS {
 158                         Err(Error::new(ErrorKind::Other, "Too many requests required"))
 159                 } else {
 160                         Ok((res, min_ttl))
 161                 }
 162         } }
 163 }
 164
 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)
 169 }
 170
 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>(()) })
 176 }
 177
 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 ///
 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)
 185 }
 186
 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.
 189 ///
 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)
 194 }
 195
 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.
 198 ///
 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)
 203 }
 204
 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.
 207 ///
 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)
 212 }
 213
 214
 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.
 217 ///
 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
 223 }
 224
 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.
 227 ///
 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
 233 }
 234
 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.
 237 ///
 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
 243 }
 244
 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.
 247 ///
 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
 253 }
 254
 255 #[cfg(all(feature = "validation", test))]
 256 mod tests {
 257         use super::*;
 258         use crate::validation::*;
 259
 260         use rand::seq::SliceRandom;
 261
 262         use std::net::ToSocketAddrs;
 263         use std::time::SystemTime;
 264
 265
 266         #[test]
 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();
 271
 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);
 276
 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);
 280         }
 281
 282         #[test]
 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();
 287
 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);
 292
 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);
 296         }
 297
 298         #[test]
 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();
 303
 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);
 308
 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);
 312         }
 313
 314         #[test]
 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();
 320
 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);
 325
 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);
 329
 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");
 335                         } else { panic!(); }
 336                 }
 337         }
 338
 339         #[cfg(feature = "tokio")]
 340         use tokio_crate as tokio;
 341
 342         #[cfg(feature = "tokio")]
 343         #[tokio::test]
 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();
 348
 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);
 353
 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);
 357         }
 358
 359         #[cfg(feature = "tokio")]
 360         #[tokio::test]
 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();
 366
 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);
 371
 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);
 375
 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:"));
 381                         } else { panic!(); }
 382                 }
 383         }
 384 }