[PATCH v3 09/14] KEYS: Retry asym key search with partial ID in restrict_link_by_signature()

Roberto Sassu
2024-09-11T12:30:38Z

From: Roberto Sassu <roberto.sassu@huawei.com>

Retry asymmetric key search in restrict_link_by_signature() to support the
case of partial IDs, provided by PGP signatures (only the last 8 bytes).

Although RFC 9580 supports the signature subpacket type 33, which contains
the full issuer fingerprint, we cannot rely on existing signatures to
support it.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
crypto/asymmetric_keys/restrict.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/crypto/asymmetric_keys/restrict.c b/crypto/asymmetric_keys/restrict.c
index afcd4d101ac5..dd3d4b3405f7 100644
--- a/crypto/asymmetric_keys/restrict.c
+++ b/crypto/asymmetric_keys/restrict.c
@@ -97,8 +97,14 @@ int restrict_link_by_signature(struct key *dest_keyring,
key = find_asymmetric_key(trust_keyring,
sig->auth_ids[0], sig->auth_ids[1],
sig->auth_ids[2], false);
- if (IS_ERR(key))
- return -ENOKEY;
+ if (IS_ERR(key)) {
+ /* Retry with a partial ID. */
+ key = find_asymmetric_key(trust_keyring,
+ sig->auth_ids[0], sig->auth_ids[1],
+ sig->auth_ids[2], true);
+ if (IS_ERR(key))
+ return -ENOKEY;
+ }

if (use_builtin_keys && !test_bit(KEY_FLAG_BUILTIN, &key->flags))
ret = -ENOKEY;
--
2.34.1