_ 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         let _authorities = emap(read_u16(&mut read))?;
  73         let _additional = emap(read_u16(&mut read))?;
  74
  75         for _ in 0..questions {
  76                 emap(read_wire_packet_name(&mut read, resp))?;
  77                 emap(read_u16(&mut read))?; // type
  78                 emap(read_u16(&mut read))?; // class
  79         }
  80
  81         // Only read the answers (skip authorities and additional) as that's all we care about.
  82         let mut rrsig_opt = None;
  83         for _ in 0..answers {
  84                 let (rr, ttl) = emap(parse_wire_packet_rr(&mut read, &resp))?;
  85                 write_rr(&rr, ttl, proof);
  86                 if let RR::RRSig(rrsig) = rr { rrsig_opt = Some(rrsig); }
  87         }
  88         Ok(rrsig_opt)
  89 }
  90
  91 fn read_response(stream: &mut TcpStream, proof: &mut Vec<u8>) -> Result<Option<RRSig>, Error> {
  92         let mut len = [0; 2];
  93         stream.read_exact(&mut len)?;
  94         let mut resp = vec![0; u16::from_be_bytes(len) as usize];
  95         stream.read_exact(&mut resp)?;
  96         handle_response(&resp, proof)
  97 }
  98
  99 #[cfg(feature = "tokio")]
 100 async fn read_response_async(stream: &mut TokioTcpStream, proof: &mut Vec<u8>) -> Result<Option<RRSig>, Error> {
 101         let mut len = [0; 2];
 102         stream.read_exact(&mut len).await?;
 103         let mut resp = vec![0; u16::from_be_bytes(len) as usize];
 104         stream.read_exact(&mut resp).await?;
 105         handle_response(&resp, proof)
 106 }
 107
 108 macro_rules! build_proof_impl {
 109         ($stream: ident, $send_query: ident, $read_response: ident $(, $async_ok: tt)?) => { {
 110                 let mut res = Vec::new();
 111                 let mut reached_root = false;
 112                 for i in 0..10 {
 113                         let rrsig_opt = $read_response(&mut $stream, &mut res)
 114                                 $(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 115                         if let Some(rrsig) = rrsig_opt {
 116                                 if rrsig.name.as_str() == "." {
 117                                         reached_root = true;
 118                                 } else {
 119                                         if i != 0 && rrsig.name == rrsig.key_name {
 120                                                 $send_query(&mut $stream, &rrsig.key_name, DS::TYPE)
 121                                         } else {
 122                                                 $send_query(&mut $stream, &rrsig.key_name, DnsKey::TYPE)
 123                                         }$(.await?; $async_ok)??; // Either await?; Ok(())?, or just ?
 124                                 }
 125                         }
 126                         if reached_root { break; }
 127                 }
 128
 129                 if !reached_root { Err(Error::new(ErrorKind::Other, "Too many requests required")) }
 130                 else { Ok(res) }
 131         } }
 132 }
 133
 134 fn build_proof(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<Vec<u8>, Error> {
 135         let mut stream = TcpStream::connect(resolver)?;
 136         send_query(&mut stream, domain, ty)?;
 137         build_proof_impl!(stream, send_query, read_response)
 138 }
 139
 140 #[cfg(feature = "tokio")]
 141 async fn build_proof_async(resolver: SocketAddr, domain: &Name, ty: u16) -> Result<Vec<u8>, Error> {
 142         let mut stream = TokioTcpStream::connect(resolver).await?;
 143         send_query_async(&mut stream, domain, ty).await?;
 144         build_proof_impl!(stream, send_query_async, read_response_async, { Ok::<(), Error>(()) })
 145 }
 146
 147 /// Builds a DNSSEC proof for an A record by querying a recursive resolver
 148 pub fn build_a_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 149         build_proof(resolver, domain, A::TYPE)
 150 }
 151
 152 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver
 153 pub fn build_aaaa_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 154         build_proof(resolver, domain, AAAA::TYPE)
 155 }
 156
 157 /// Builds a DNSSEC proof for a TXT record by querying a recursive resolver
 158 pub fn build_txt_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 159         build_proof(resolver, domain, Txt::TYPE)
 160 }
 161
 162 /// Builds a DNSSEC proof for a TLSA record by querying a recursive resolver
 163 pub fn build_tlsa_proof(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 164         build_proof(resolver, domain, TLSA::TYPE)
 165 }
 166
 167
 168 /// Builds a DNSSEC proof for an A record by querying a recursive resolver
 169 #[cfg(feature = "tokio")]
 170 pub async fn build_a_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 171         build_proof_async(resolver, domain, A::TYPE).await
 172 }
 173
 174 /// Builds a DNSSEC proof for an AAAA record by querying a recursive resolver
 175 #[cfg(feature = "tokio")]
 176 pub async fn build_aaaa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 177         build_proof_async(resolver, domain, AAAA::TYPE).await
 178 }
 179
 180 /// Builds a DNSSEC proof for a TXT record by querying a recursive resolver
 181 #[cfg(feature = "tokio")]
 182 pub async fn build_txt_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 183         build_proof_async(resolver, domain, Txt::TYPE).await
 184 }
 185
 186 /// Builds a DNSSEC proof for a TLSA record by querying a recursive resolver
 187 #[cfg(feature = "tokio")]
 188 pub async fn build_tlsa_proof_async(resolver: SocketAddr, domain: &Name) -> Result<Vec<u8>, Error> {
 189         build_proof_async(resolver, domain, TLSA::TYPE).await
 190 }
 191
 192 #[cfg(all(feature = "validation", test))]
 193 mod tests {
 194         use super::*;
 195         use crate::validation::*;
 196
 197         use rand::seq::SliceRandom;
 198
 199         use std::net::ToSocketAddrs;
 200         use std::time::SystemTime;
 201
 202
 203         #[test]
 204         fn test_cloudflare_txt_query() {
 205                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 206                 let query_name = "cloudflare.com.".try_into().unwrap();
 207                 let proof = build_txt_proof(sockaddr, &query_name).unwrap();
 208
 209                 let mut rrs = parse_rr_stream(&proof).unwrap();
 210                 rrs.shuffle(&mut rand::rngs::OsRng);
 211                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 212                 assert!(verified_rrs.verified_rrs.len() > 1);
 213
 214                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 215                 assert!(verified_rrs.valid_from < now);
 216                 assert!(verified_rrs.expires > now);
 217         }
 218
 219         #[test]
 220         fn test_txt_query() {
 221                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 222                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
 223                 let proof = build_txt_proof(sockaddr, &query_name).unwrap();
 224
 225                 let mut rrs = parse_rr_stream(&proof).unwrap();
 226                 rrs.shuffle(&mut rand::rngs::OsRng);
 227                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 228                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
 229
 230                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 231                 assert!(verified_rrs.valid_from < now);
 232                 assert!(verified_rrs.expires > now);
 233         }
 234
 235         #[cfg(feature = "tokio")]
 236         use tokio_crate as tokio;
 237
 238         #[cfg(feature = "tokio")]
 239         #[tokio::test]
 240         async fn test_txt_query_async() {
 241                 let sockaddr = "8.8.8.8:53".to_socket_addrs().unwrap().next().unwrap();
 242                 let query_name = "matt.user._bitcoin-payment.mattcorallo.com.".try_into().unwrap();
 243                 let proof = build_txt_proof_async(sockaddr, &query_name).await.unwrap();
 244
 245                 let mut rrs = parse_rr_stream(&proof).unwrap();
 246                 rrs.shuffle(&mut rand::rngs::OsRng);
 247                 let verified_rrs = verify_rr_stream(&rrs).unwrap();
 248                 assert_eq!(verified_rrs.verified_rrs.len(), 1);
 249
 250                 let now = SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).unwrap().as_secs();
 251                 assert!(verified_rrs.valid_from < now);
 252                 assert!(verified_rrs.expires > now);
 253         }
 254 }