_ 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::net::{SocketAddr, TcpStream};
   5 use std::io::{Read, Write, Error, ErrorKind};
   6
   7 #[cfg(feature = "tokio")]
   8 use tokio_crate::net::TcpStream as TokioTcpStream;
   9 #[cfg(feature = "tokio")]
  10 use tokio_crate::io::{AsyncReadExt, AsyncWriteExt};
  11
  12 use crate::rr::*;
  13 use crate::ser::*;
  14
  15 // We don't care about transaction IDs as we're only going to accept signed data. Thus, we use
  16 // this constant instead of a random value.
  17 const TXID: u16 = 0x4242;
  18
  19 fn emap<V>(v: Result<V, ()>) -> Result<V, Error> {
  20         v.map_err(|_| Error::new(ErrorKind::Other, "Bad Response"))
  21 }
  22
  23 fn build_query(domain: &Name, ty: u16) -> Vec<u8> {
  24         // TODO: Move to not allocating for the query
  25         let mut query = Vec::with_capacity(1024);
  26         let query_msg_len: u16 = 2 + 2 + 8 + 2 + 2 + name_len(domain) + 11;
  27         query.extend_from_slice(&query_msg_len.to_be_bytes());
  28         query.extend_from_slice(&TXID.to_be_bytes());
  29         query.extend_from_slice(&[0x01, 0x20]); // Flags: Recursive, Authenticated Data
  30         query.extend_from_slice(&[0, 1, 0, 0, 0, 0, 0, 1]); // One question, One additional
  31         write_name(&mut query, domain);
  32         query.extend_from_slice(&ty.to_be_bytes());
  33         query.extend_from_slice(&1u16.to_be_bytes()); // INternet class
  34         query.extend_from_slice(&[0, 0, 0x29]); // . OPT
  35         query.extend_from_slice(&0u16.to_be_bytes()); // 0 UDP payload size
  36         query.extend_from_slice(&[0, 0]); // EDNS version 0
  37         query.extend_from_slice(&0x8000u16.to_be_bytes()); // Accept DNSSEC RRs
  38         query.extend_from_slice(&0u16.to_be_bytes()); // No additional data
  39         query
  40 }
  41
  42 fn send_query(stream: &mut TcpStream, domain: &Name, ty: u16) -> Result<(), Error> {
  43         let query = build_query(domain, ty);
  44         stream.write_all(&query)?;
  45         Ok(())
  46 }
  47
  48 #[cfg(feature = "tokio")]
  49 async fn send_query_async(stream: &mut TokioTcpStream, domain: &Name, ty: u16) -> Result<(), Error> {
  50         let query = build_query(domain, ty);
  51         stream.write_all(&query).await?;
  52         Ok(())
  53 }
  54
  55 fn handle_response(resp: &[u8], proof: &mut Vec<u8>) -> Result<Option<RRSig>, Error> {
  56         let mut read: &[u8] = resp;
  57         if emap(read_u16(&mut read))? != TXID { return Err(Error::new(ErrorKind::Other, "bad txid")); }
  58         // 2 byte transaction ID
  59         let flags = emap(read_u16(&mut read))?;
  60         if flags & 0b1000_0000_0000_0000 == 0 {
  61                 return Err(Error::new(ErrorKind::Other, "Missing response flag"));
  62         }
  63         if flags & 0b0111_1010_0000_0111 != 0 {
  64                 return Err(Error::new(ErrorKind::Other, "Server indicated error or provided bunk flags"));
  65         }
  66         if flags & 0b10_0000 == 0 {
  67                 return Err(Error::new(ErrorKind::Other, "Server indicated data could not be authenticated"));
  68         }
  69         let questions = emap(read_u16(&mut read))?;
  70         if questions != 1 { return Err(Error::new(ErrorKind::Other, "server responded to multiple Qs")); }
  71         let answers = emap(read_u16(&mut read))?;
  72         if answers == 0 { return Err(Error::new(ErrorKind::Other, "No answers")); }
  73         let _authorities = emap(read_u16(&mut read))?;
  74         let _additional = emap(read_u16(&mut read))?;
  75
  76         for _ in 0..questions {
  77                 emap(read_wire_packet_name(&mut read, resp))?;
  78                 emap(read_u16(&mut read))?; // type
  79                 emap(read_u16(&mut read))?; // class
  80         }
  81
  82         // Only read the answers (skip authorities and additional) as that's all we care about.
  83         let mut rrsig_opt = None;
  84         for _ in 0..answers {
  85                 let (rr, ttl) = emap(parse_wire_packet_rr(&mut read, &resp))?;
  86                 write_rr(&rr, ttl, proof);
  87                 if let RR::RRSig(rrsig) = rr { rrsig_opt = Some(rrsig); }
  88         }
  89         Ok(rrsig_opt)
  90 }
  91
  92 fn read_response(stream: &mut TcpStream, proof: &mut Vec<u8>) -> Result<Option<RRSig>, Error> {
  93         let mut len = [0; 2];
  94         stream.read_exact(&mut len)?;
  95         let mut resp = vec![0; u16::from_be_bytes(len) as usize];
  96         stream.read_exact(&mut resp)?;
  97         handle_response(&resp, proof)
  98 }
  99
 100 #[cfg(feature = "tokio")]
 101 async fn read_response_async(stream: &mut TokioTcpStream, proof: &mut Vec<u8>) -> Result<Option<RRSig>, Error> {
 102         let mut len = [0; 2];
 103         stream.read_exact(&mut len).await?;
 104         let mut resp = vec![0; u16::from_be_bytes(len) as usize];
 105         stream.read_exact(&mut resp).await?;
 106         handle_response(&resp, proof)
 107 }
 108
 109 macro_rules! build_proof_impl {
 110         ($stream: ident, $send_query: ident, $read_response: ident $(, $async_ok: tt)?) => { {
 111                 let mut res = Vec::new();
 112                 let mut reached_root = false;
 113                 for i in 0..10 {
 114                         let rrsig_opt = $read_response(&mut $stream, &mut res)
 115                                 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 116                         if let Some(rrsig) = rrsig_opt {
 117                                 if rrsig.name.as_str() == "." {
 118                                         reached_root = true;
 119                                 } else {
 120                                         if i != 0 && rrsig.name == rrsig.key_name {
 121                                                 $send_query(&mut $stream, &rrsig.key_name, DS::TYPE)
 122                                         } else {
 123                                                 $send_query(&mut $stream, &rrsig.key_name, DnsKey::TYPE)
 124                                         }$(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 125                                 }
 126                         }
 127                         if reached_root { break; }
 128                 }
 129
 130                 if !reached_root { Err(Error::new(ErrorKind::Other, "Too many requests required")) }
 131                 else { Ok(res) }
 132         } }
 133 }
 134
 135 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<Vec<u8>, Error> {
 136         let mut stream = TcpStream::connect(resolver)?;
 137         send_query(&mut stream, domain, ty)?;
 138         build_proof_impl!(stream, send_query, read_response)
 139 }
 140
 141 #[cfg(feature = "tokio")]
 142 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<Vec<u8>, Error> {
 143         let mut stream = TokioTcpStream::connect(resolver).await?;
 144         send_query_async(&mut stream, domain, ty).await?;
 145         build_proof_impl!(stream, send_query_async, read_response_async, { Ok::<(), Error>(()) })
 146 }
 147
 148 /// Builds a DNSSEC proof for an A record by querying a recursive resolver
 149 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 150         build_proof(resolver, domain, A::TYPE)
 151 }
 152
 153 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver
 154 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 155         build_proof(resolver, domain, AAAA::TYPE)
 156 }
 157
 158 /// Builds a DNSSEC proof for a TXT record by querying a recursive resolver
 159 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 160         build_proof(resolver, domain, Txt::TYPE)
 161 }
 162
 163 /// Builds a DNSSEC proof for a TLSA record by querying a recursive resolver
 164 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 165         build_proof(resolver, domain, TLSA::TYPE)
 166 }
 167
 168
 169 /// Builds a DNSSEC proof for an A record by querying a recursive resolver
 170 #[cfg(feature = "tokio")]
 171 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 172         build_proof_async(resolver, domain, A::TYPE).await
 173 }
 174
 175 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver
 176 #[cfg(feature = "tokio")]
 177 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 178         build_proof_async(resolver, domain, AAAA::TYPE).await
 179 }
 180
 181 /// Builds a DNSSEC proof for a TXT record by querying a recursive resolver
 182 #[cfg(feature = "tokio")]
 183 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 184         build_proof_async(resolver, domain, Txt::TYPE).await
 185 }
 186
 187 /// Builds a DNSSEC proof for a TLSA record by querying a recursive resolver
 188 #[cfg(feature = "tokio")]
 189 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 190         build_proof_async(resolver, domain, TLSA::TYPE).await
 191 }
 192
 193 #[cfg(all(feature = "validation", test))]
 194 mod tests {
 195         use super::*;
 196         use crate::validation::*;
 197
 198         use rand::seq::SliceRandom;
 199
 200         use std::net::ToSocketAddrs;
 201         use std::time::SystemTime;
 202
 203
 204         #[test]
 205         fn test_cloudflare_txt_query() {
 206                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 207                 let query_name = "cloudflare.com.".try_into().unwrap();
 208                 let proof = build_txt_proof(sockaddr, &query_name).unwrap();
 209
 210                 let mut rrs = parse_rr_stream(&proof).unwrap();
 211                 rrs.shuffle(&mut rand::rngs::OsRng);
 212                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 213                 assert!(verified_rrs.verified_rrs.len() > 1);
 214
 215                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 216                 assert!(verified_rrs.valid_from < now);
 217                 assert!(verified_rrs.expires > now);
 218         }
 219
 220         #[test]
 221         fn test_txt_query() {
 222                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 223                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
 224                 let proof = build_txt_proof(sockaddr, &query_name).unwrap();
 225
 226                 let mut rrs = parse_rr_stream(&proof).unwrap();
 227                 rrs.shuffle(&mut rand::rngs::OsRng);
 228                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 229                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
 230
 231                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 232                 assert!(verified_rrs.valid_from < now);
 233                 assert!(verified_rrs.expires > now);
 234         }
 235
 236         #[cfg(feature = "tokio")]
 237         use tokio_crate as tokio;
 238
 239         #[cfg(feature = "tokio")]
 240         #[tokio::test]
 241         async fn test_txt_query_async() {
 242                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 243                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
 244                 let proof = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
 245
 246                 let mut rrs = parse_rr_stream(&proof).unwrap();
 247                 rrs.shuffle(&mut rand::rngs::OsRng);
 248                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 249                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
 250
 251                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 252                 assert!(verified_rrs.valid_from < now);
 253                 assert!(verified_rrs.expires > now);
 254         }
 255 }