_ 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 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<(Vec<u8>, u32), Error> {
 174         build_proof(resolver, domain, A::TYPE)
 175 }
 176
 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)
 181 }
 182
 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)
 187 }
 188
 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)
 193 }
 194
 195
 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
 201 }
 202
 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
 208 }
 209
 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
 215 }
 216
 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
 222 }
 223
 224 #[cfg(all(feature = "validation", test))]
 225 mod tests {
 226         use super::*;
 227         use crate::validation::*;
 228
 229         use rand::seq::SliceRandom;
 230
 231         use std::net::ToSocketAddrs;
 232         use std::time::SystemTime;
 233
 234
 235         #[test]
 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();
 240
 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);
 245
 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);
 249         }
 250
 251         #[test]
 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();
 256
 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);
 261
 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);
 265         }
 266
 267         #[test]
 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();
 272
 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);
 277
 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);
 281         }
 282
 283         #[test]
 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();
 289
 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);
 294
 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);
 298
 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");
 304                         } else { panic!(); }
 305                 }
 306         }
 307
 308         #[cfg(feature = "tokio")]
 309         use tokio_crate as tokio;
 310
 311         #[cfg(feature = "tokio")]
 312         #[tokio::test]
 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();
 317
 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);
 322
 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);
 326         }
 327
 328         #[cfg(feature = "tokio")]
 329         #[tokio::test]
 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();
 335
 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);
 340
 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);
 344
 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:"));
 350                         } else { panic!(); }
 351                 }
 352         }
 353 }