fs-verity and dm-verity read assoc_array's nr_leaves_on_tree directly to check whether a keyring is empty.
Add keyring_is_empty() and use it in the both callers. Signed-off-by: Jarkko Sakkinen <[email protected]> --- drivers/md/dm-verity-verify-sig.c | 2 +- fs/verity/signature.c | 2 +- include/linux/key.h | 1 + security/keys/keyring.c | 10 ++++++++++ .../selftests/dm-verity/test-dm-verity-keyring.sh | 2 +- 5 files changed, 14 insertions(+), 3 deletions(-) diff --git a/drivers/md/dm-verity-verify-sig.c b/drivers/md/dm-verity-verify-sig.c index b2b55c41e2cb..2ccb71bfb3ca 100644 --- a/drivers/md/dm-verity-verify-sig.c +++ b/drivers/md/dm-verity-verify-sig.c @@ -153,7 +153,7 @@ int verity_verify_root_hash(const void *root_hash, size_t root_hash_len, if (ret != -ENOKEY && ret != -EKEYREJECTED) return ret; - if (dm_verity_keyring->keys.nr_leaves_on_tree && + if (!keyring_is_empty(dm_verity_keyring) && dm_verity_keyring->restrict_link) ret = verify_pkcs7_signature(root_hash, root_hash_len, sig_data, sig_len, diff --git a/fs/verity/signature.c b/fs/verity/signature.c index 0302a4e506ec..890d33b9d812 100644 --- a/fs/verity/signature.c +++ b/fs/verity/signature.c @@ -67,7 +67,7 @@ int fsverity_verify_signature(const struct fsverity_info *vi, return 0; } - if (fsverity_keyring->keys.nr_leaves_on_tree == 0) { + if (keyring_is_empty(fsverity_keyring)) { /* * The ".fs-verity" keyring is empty, due to builtin signatures * being supported by the kernel but not actually being used. diff --git a/include/linux/key.h b/include/linux/key.h index 26139c3adf62..d82253b06c54 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -436,6 +436,7 @@ extern int restrict_link_reject(struct key *keyring, struct key *restriction_key); extern int keyring_clear(struct key *keyring); +bool keyring_is_empty(const struct key *keyring); extern key_ref_t keyring_search(key_ref_t keyring, struct key_type *type, diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 9ccce0db0665..613d1db41611 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -443,6 +443,16 @@ static void keyring_destroy(struct key *keyring) assoc_array_destroy(&keyring->keys, &keyring_assoc_array_ops); } +/** + * keyring_is_empty - Check whether a keyring contains any links + * @keyring: The keyring to check. + */ +bool keyring_is_empty(const struct key *keyring) +{ + return READ_ONCE(keyring->keys.nr_leaves_on_tree) == 0; +} +EXPORT_SYMBOL(keyring_is_empty); + /* * Describe a keyring for /proc. */ diff --git a/tools/testing/selftests/dm-verity/test-dm-verity-keyring.sh b/tools/testing/selftests/dm-verity/test-dm-verity-keyring.sh index 1f9601ef22f8..792449d356cf 100755 --- a/tools/testing/selftests/dm-verity/test-dm-verity-keyring.sh +++ b/tools/testing/selftests/dm-verity/test-dm-verity-keyring.sh @@ -746,7 +746,7 @@ test_keyring_inactive_when_empty() { log_info "TEST: Verify dm-verity keyring is inactive when sealed empty" # When keyring_unsealed=0, the keyring is sealed immediately while empty - # This means it should NOT be used for verification (nr_leaves_on_tree=0) + # An empty keyring should NOT be used for verification. log_info "Keyring state (should be empty and sealed):" list_keyring_keys -- 2.47.3
