diff options
author | Justus Winter <justus@sequoia-pgp.org> | 2024-05-14 19:21:44 +0200 |
---|---|---|
committer | Justus Winter <justus@sequoia-pgp.org> | 2024-05-29 12:17:24 +0200 |
commit | 426ecd605cb52039ece5e2872086889489fc015c (patch) | |
tree | 110bb7979ed14ee421fe641c3bc17ad7ab45ce18 /openpgp | |
parent | 1b38fd1a464a855adfdb0a2b3b6395d765bd9aa2 (diff) |
openpgp: Consider signature type when hashing 3rd party sigs.
- Previously, when the third-party key is not
available (i.e. always), we only hashed the signature and did not
check whether the signature has the right type. This has the
potential (1 in 2^16 chance) of not recognizing that a signature
is misplaced (also happens when using Cert::insert_packets).
- Fix this by also checking the signature type when using the hash
heuristic.
- See also #1107.
Diffstat (limited to 'openpgp')
-rw-r--r-- | openpgp/src/cert.rs | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/openpgp/src/cert.rs b/openpgp/src/cert.rs index a484a88e..0dbdd896 100644 --- a/openpgp/src/cert.rs +++ b/openpgp/src/cert.rs @@ -1489,6 +1489,7 @@ impl Cert { fn canonicalize(mut self) -> Self { tracer!(TRACE, "canonicalize", 0); + use SignatureType::*; // Before we do anything, we'll order and deduplicate the // components. If two components are the same, they will be @@ -1558,6 +1559,7 @@ impl Cert { $lookup_fn:expr, // a function to lookup keys $verify_method:ident, // the method to call to verify it $hash_method:ident, // the method to call to compute the hash + $sig_type_pat:pat, // pattern to test signature types against $($verify_args:expr),* // additional arguments to pass to the above ) => ({ t!("check_3rd_party!({}, {}, {:?}, {}, {}, ...)", @@ -1567,8 +1569,12 @@ impl Cert { // Use hash prefix as heuristic. let key = self.primary.key(); match sig.hash_algo().context().and_then(|mut ctx| { - sig.$hash_method(&mut ctx, key, $($verify_args),*); - ctx.into_digest() + if matches!(sig.typ(), $sig_type_pat) { + sig.$hash_method(&mut ctx, key, $($verify_args),*); + ctx.into_digest() + } else { + Err(Error::UnsupportedSignatureType(sig.typ()).into()) + } }) { Ok(hash) => { if &sig.digest_prefix()[..] == &hash[..2] { @@ -1617,9 +1623,9 @@ impl Cert { } }); ($desc:expr, $binding:expr, $sigs:ident, $lookup_fn:expr, - $verify_method:ident, $hash_method:ident) => ({ + $verify_method:ident, $hash_method:ident, $sig_type_pat:pat) => ({ check_3rd_party!($desc, $binding, $sigs, $lookup_fn, - $verify_method, $hash_method, ) + $verify_method, $hash_method, $sig_type_pat, ) }); } @@ -1635,10 +1641,11 @@ impl Cert { self.primary, self_revocations, verify_primary_key_revocation); check_3rd_party!("primary key", self.primary, certifications, lookup_fn, - verify_direct_key, hash_direct_key); + verify_direct_key, hash_direct_key, DirectKey); check_3rd_party!("primary key", self.primary, other_revocations, lookup_fn, - verify_primary_key_revocation, hash_direct_key); + verify_primary_key_revocation, hash_direct_key, + KeyRevocation); for ua in self.userids.iter_mut() { check!(format!("userid \"{}\"", @@ -1658,12 +1665,15 @@ impl Cert { String::from_utf8_lossy(ua.userid().value())), ua, certifications, lookup_fn, verify_userid_binding, hash_userid_binding, + GenericCertification | PersonaCertification + | CasualCertification | PositiveCertification, ua.userid()); check_3rd_party!( format!("userid \"{}\"", String::from_utf8_lossy(ua.userid().value())), ua, other_revocations, lookup_fn, verify_userid_revocation, hash_userid_binding, + CertificationRevocation, ua.userid()); } @@ -1681,11 +1691,14 @@ impl Cert { "user attribute", binding, certifications, lookup_fn, verify_user_attribute_binding, hash_user_attribute_binding, + GenericCertification | PersonaCertification + | CasualCertification | PositiveCertification, binding.user_attribute()); check_3rd_party!( "user attribute", binding, other_revocations, lookup_fn, verify_user_attribute_revocation, hash_user_attribute_binding, + CertificationRevocation, binding.user_attribute()); } @@ -1700,11 +1713,13 @@ impl Cert { format!("subkey {}", binding.key().keyid()), binding, certifications, lookup_fn, verify_subkey_binding, hash_subkey_binding, + SubkeyBinding, binding.key()); check_3rd_party!( format!("subkey {}", binding.key().keyid()), binding, other_revocations, lookup_fn, verify_subkey_revocation, hash_subkey_binding, + SubkeyRevocation, binding.key()); } @@ -1879,7 +1894,6 @@ impl Cert { }); } - use SignatureType::*; match sig.typ() { DirectKey => { check_one!("primary key", self.primary.self_signatures, |