use alloc::borrow::ToOwned;
use alloc::vec::Vec;
use alloc::vec;
-use core::cmp;
+use core::cmp::{self, Ordering};
use ring::signature;
+use crate::base32;
use crate::crypto;
use crate::rr::*;
use crate::ser::write_name;
for record in records.iter() {
let record_labels = record.name().labels() as usize;
let labels = sig.labels.into();
- if record_labels != labels {
+ // For NSec types, the name should already match the wildcard, so we don't do any
+ // filtering here. This is relied upon in `verify_rr_stream` to check whether an
+ // NSec record is matching via wildcard (as otherwise we'd allow a resolver to
+ // change the name out from under us and change the wildcard to something else).
+ if record.ty() != NSec::TYPE && record_labels != labels {
if record_labels < labels { return Err(ValidationError::Invalid); }
let signed_name = record.name().trailing_n_labels(sig.labels);
debug_assert!(signed_name.is_some());
}
}
+fn nsec_ord(a: &str, b: &str) -> Ordering {
+ let mut a_label_iter = a.rsplit(".");
+ let mut b_label_iter = b.rsplit(".");
+ loop {
+ match (a_label_iter.next(), b_label_iter.next()) {
+ (Some(_), None) => return Ordering::Greater,
+ (None, Some(_)) => return Ordering::Less,
+ (Some(a_label), Some(b_label)) => {
+ let mut a_bytes = a_label.bytes();
+ let mut b_bytes = b_label.bytes();
+ loop {
+ match (a_bytes.next(), b_bytes.next()) {
+ (Some(_), None) => return Ordering::Greater,
+ (None, Some(_)) => return Ordering::Less,
+ (Some(mut a), Some(mut b)) => {
+ if a >= 'A' as u8 && a <= 'Z' as u8 {
+ a += 'a' as u8 - 'A' as u8;
+ }
+ if b >= 'A' as u8 && b <= 'Z' as u8 {
+ b += 'a' as u8 - 'A' as u8;
+ }
+ if a != b { return a.cmp(&b); }
+ },
+ (None, None) => break,
+ }
+ }
+ },
+ (None, None) => return Ordering::Equal,
+ }
+ }
+}
+fn nsec_ord_extra<T, U>(a: &(&str, T, U), b: &(&str, T, U)) -> Ordering {
+ nsec_ord(a.0, b.0)
+}
+
+#[cfg(test)]
+#[test]
+fn rfc4034_sort_test() {
+ // Test nsec_ord based on RFC 4034 section 6.1's example
+ // Note that we replace the \200 example with \7f as I have no idea what \200 is
+ let v = vec!["example.", "a.example.", "yljkjljk.a.example.", "Z.a.example.",
+ "zABC.a.EXAMPLE.", "z.example.", "\001.z.example.", "*.z.example.", "\x7f.z.example."];
+ let mut sorted = v.clone();
+ sorted.sort_unstable_by(|a, b| nsec_ord(*a, *b));
+ assert_eq!(sorted, v);
+}
+
/// Verifies the given set of resource records.
///
/// Given a set of arbitrary records, this attempts to validate DNSSEC data from the [`root_hints`]
pub fn verify_rr_stream<'a>(inp: &'a [RR]) -> Result<VerifiedRRStream<'a>, ValidationError> {
let mut zone = ".";
let mut res = Vec::new();
+ let mut rrs_needing_non_existence_proofs = Vec::new();
let mut pending_ds_sets = Vec::with_capacity(1);
let mut latest_inception = 0;
let mut earliest_expiry = u64::MAX;
}
},
_ => {
+ if rrsig.labels != rrsig.name.labels() && rrsig.ty != NSec::TYPE {
+ if rrsig.ty == NSec3::TYPE {
+ // NSEC3 records should never appear on wildcards, so treat the
+ // whole proof as invalid
+ return Err(ValidationError::Invalid);
+ }
+ // If the RR used a wildcard, we need an NSEC/NSEC3 proof, which we
+ // check for at the end. Note that the proof should be for the
+ // "next closest" name, i.e. if the name here is a.b.c and it was
+ // signed as *.c, we want a proof for nothing being in b.c.
+ // Alternatively, if it was signed as *.b.c, we'd want a proof for
+ // a.b.c.
+ let proof_name = rrsig.name.trailing_n_labels(rrsig.labels + 1)
+ .ok_or(ValidationError::Invalid)?;
+ rrs_needing_non_existence_proofs.push((proof_name, &rrsig.key_name, rrsig.ty));
+ }
for record in signed_records {
if !res.contains(&record) { res.push(record); }
}
return Err(ValidationError::Invalid);
}
}
- if res.is_empty() { Err(ValidationError::Invalid) }
- else if latest_inception >= earliest_expiry { Err(ValidationError::Invalid) }
- else {
- Ok(VerifiedRRStream {
- verified_rrs: res, valid_from: latest_inception, expires: earliest_expiry,
- max_cache_ttl: min_ttl,
- })
+ if res.is_empty() { return Err(ValidationError::Invalid) }
+ if latest_inception >= earliest_expiry { return Err(ValidationError::Invalid) }
+
+ // First sort the proofs we're looking for so that the retains below avoid shifting.
+ rrs_needing_non_existence_proofs.sort_unstable_by(nsec_ord_extra);
+ 'proof_search_loop: while let Some((name, zone, ty)) = rrs_needing_non_existence_proofs.pop() {
+ let nsec_search = res.iter()
+ .filter_map(|rr| if let RR::NSec(nsec) = rr { Some(nsec) } else { None })
+ .filter(|nsec| nsec.name.ends_with(zone.as_str()));
+ for nsec in nsec_search {
+ let name_matches = nsec.name.as_str() == name;
+ let name_contained = nsec_ord(&nsec.name, &name) != Ordering::Greater &&
+ nsec_ord(&nsec.next_name, name) == Ordering::Greater;
+ if (name_matches && !nsec.types.contains_type(ty)) || name_contained {
+ rrs_needing_non_existence_proofs
+ .retain(|(n, _, t)| *n != name || (name_matches && nsec.types.contains_type(*t)));
+ continue 'proof_search_loop;
+ }
+ }
+ let nsec3_search = res.iter()
+ .filter_map(|rr| if let RR::NSec3(nsec3) = rr { Some(nsec3) } else { None })
+ .filter(|nsec3| nsec3.name.ends_with(zone.as_str()));
+
+ // Because we will only ever have two entries, a Vec is simpler than a map here.
+ let mut nsec3params_to_name_hash = Vec::new();
+ for nsec3 in nsec3_search.clone() {
+ if nsec3.hash_iterations > 2500 {
+ // RFC 5115 places different limits on the iterations based on the signature key
+ // length, but we just use 2500 for all key types
+ continue;
+ }
+ if nsec3.hash_algo != 1 { continue; }
+ if nsec3params_to_name_hash.iter()
+ .any(|(iterations, salt, _)| *iterations == nsec3.hash_iterations && *salt == &nsec3.salt)
+ { continue; }
+
+ let mut hasher = crypto::hash::Hasher::sha1();
+ write_name(&mut hasher, &name);
+ hasher.update(&nsec3.salt);
+ for _ in 0..nsec3.hash_iterations {
+ let res = hasher.finish();
+ hasher = crypto::hash::Hasher::sha1();
+ hasher.update(res.as_ref());
+ hasher.update(&nsec3.salt);
+ }
+ nsec3params_to_name_hash.push((nsec3.hash_iterations, &nsec3.salt, hasher.finish()));
+
+ if nsec3params_to_name_hash.len() >= 2 {
+ // We only allow for up to two sets of hash_iterations/salt per zone. Beyond that
+ // we assume this is a malicious DoSing proof and give up.
+ break;
+ }
+ }
+ for nsec3 in nsec3_search {
+ if nsec3.flags != 0 {
+ // This is an opt-out NSEC3 (or has unknown flags set). Thus, we shouldn't rely on
+ // it as proof that some record doesn't exist.
+ continue;
+ }
+ if nsec3.hash_algo != 1 { continue; }
+ let name_hash = if let Some((_, _, hash)) =
+ nsec3params_to_name_hash.iter()
+ .find(|(iterations, salt, _)| *iterations == nsec3.hash_iterations && *salt == &nsec3.salt)
+ {
+ hash
+ } else { continue };
+
+ let (start_hash_base32, _) = nsec3.name.split_once(".")
+ .unwrap_or_else(|| { debug_assert!(false); ("", "")});
+ let start_hash = if let Ok(start_hash) = base32::decode(start_hash_base32) {
+ start_hash
+ } else { continue };
+ if start_hash.len() != 20 || nsec3.next_name_hash.len() != 20 { continue; }
+
+ let hash_matches = &start_hash[..] == name_hash.as_ref();
+ let hash_contained =
+ &start_hash[..] <= name_hash.as_ref() && &nsec3.next_name_hash[..] > name_hash.as_ref();
+ if (hash_matches && !nsec3.types.contains_type(ty)) || hash_contained {
+ rrs_needing_non_existence_proofs
+ .retain(|(n, _, t)| *n != name || (hash_matches && nsec3.types.contains_type(*t)));
+ continue 'proof_search_loop;
+ }
+ }
+ return Err(ValidationError::Invalid);
}
+
+ Ok(VerifiedRRStream {
+ verified_rrs: res, valid_from: latest_inception, expires: earliest_expiry,
+ max_cache_ttl: min_ttl,
+ })
}
impl<'a> VerifiedRRStream<'a> {
projects / dnssec-prover / commitdiff