From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793848454; b=Hd7ceMW04HfPhRGl7NGL0SLveu/oMOMJUe7YVJEpzR7SMZDyVe1YBMo65+8AzQ6M1coY 5GQReNSICIJBn4hqET7KC+fOUGxAxnaMruSxTb41iaFd/vd4iJZ8v9xjaT0w36Up7zGmG 37zNNhOUKOZTFcqO8zBGYSKIODE2oYMXrD+m7r9ICct4PF65T6VwKoIsL5zssWf+eIOUO LZVpCS/CKrzExoj2eOUz1rjPMQ+ZP4kH+RpY1vq9hUU1OGDxuRYuvm8K3ttNhh8lveIkr xuQ3Gv70OmQm499QKNZGDhCHWd4eWw6fa9ScswPgGqeenNpaRi8Zba0oi9j+LhJ+ntA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793848454; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=d57Xwxdq7ggCiZHh4PGNXJufaWf8Hx04l8Vo55VakVk=; b=PNALdDJkv6X1Lwsq1NqV01RMVivLHn9yxkPOaudkeLdRJPVnUQp4CIcQW1/k6LVhi5cy 6Ub0wQLVArxK5zUxBm4jDIjdFr801SO0uzs9QQ6aWoxrKk7qCMPLoOE4y1+SWT8zZXaIP 1zNrDPEyoJnP/OAMEcvVHUgIb5t5FMGOBRS/MPdH3HB855+KBFaI6FM8TrIciOPPGaP0N GA1U8Ac5X6YEcwP6IG1oNz5fJ2AwfCv2rOXUs68UJa3EhkBnIGrFHyaZ1MZKleVaYWtjD j28G+/f89EfJvkcvpaV0Kdfec01K4TwWVJKfnTorQJn0+i5H8Ch/18Wn/CWuA4UD0Uw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=VgdQBmAF; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with UTF8SMTPS id 6EA03606A334; Thu, 5 Nov 2026 03:14:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=VgdQBmAF Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 6A2C11F00A15; Thu, 5 Nov 2026 03:14:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793848454; bh=d57Xwxdq7ggCiZHh4PGNXJufaWf8Hx04l8Vo55VakVk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=VgdQBmAFZs7l45kySOt1KaURQxQBpI2W7uJgqVFaQwbaaNBsyaOCNcAh/9wOhyKAe OIlClBLYE4vwVfPsOkEfp628ND79LS1HjHHuIqEIy4EDzNE+6pZsLzXidmBbPSKqUg ila5gkcd4EXi4u7OJghEIiyPf1HfmcrFxfd01TdSO/Weo3IP4x//Ezi6njHCNtEMmK wIESO/hyhzH4UbRVvc1Dvj84es71LNee33JVW2YUoMOUnNkyVDBc1jS+h4c15wT6u8 1LzvYeIwlR0nOTVl7TR2KaRxZx/oYCw/Qlojbs2FERLNLzmqr84oZREBGlzOYy7k1+ YsGnaBS8WblHA== From: Jarkko Sakkinen To: David Howells Cc: Jarkko Sakkinen , bpf@vger.kernel.org, dm-devel@lists.linux.dev, fsverity@lists.linux.dev, keyrings@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-security-module@vger.kernel.org, Alasdair Kergon , Alexei Starovoitov , Alex Shi , Andrew Morton , Andrii Nakryiko , Benjamin Marzinski , Daniel Borkmann , Dongliang Mu , Eduard Zingerman , Emil Tsalapatis , Eric Biggers , Ihor Solodrai , James Morris , Jiri Olsa , Jonathan Corbet , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Mike Snitzer , Mikulas Patocka , Paul Moore , Randy Dunlap , "Serge E. Hallyn" , Shuah Khan , Song Liu , "Theodore Y. Ts'o" , Yanteng Si , Yonghong Song Subject: [PATCH v5 1/3] KEYS: Introduce keyring_is_empty() Date: Thu, 5 Nov 2026 05:13:59 +0200 Message-ID: <20261105031401.956609-2-jarkko@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261105031401.956609-1-jarkko@kernel.org> References: <20261105031401.956609-1-jarkko@kernel.org> X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Introduce keyring_is_empty() in order to decouple for BPF, dm-verity and fs-verity how keyring internally manages the keys. Reviewed-by: Eric Biggers Signed-off-by: Jarkko Sakkinen --- drivers/md/dm-verity-verify-sig.c | 2 +- fs/verity/signature.c | 2 +- include/linux/key.h | 1 + kernel/bpf/keys.c | 2 +- security/keys/keyring.c | 10 ++++++++++ .../selftests/dm-verity/test-dm-verity-keyring.sh | 2 +- 6 files changed, 15 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-verity-verify-sig.c b/drivers/md/dm-verity-verify-sig.c index 0c65c7a31da8..bd5143aae4fa 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 2f49c5d9d987..b45b39b829b2 100644 --- a/fs/verity/signature.c +++ b/fs/verity/signature.c @@ -70,7 +70,7 @@ 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 420412aab926..9ff10b780865 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -439,6 +439,7 @@ 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/kernel/bpf/keys.c b/kernel/bpf/keys.c index bffc356839ac..24e0416abc99 100644 --- a/kernel/bpf/keys.c +++ b/kernel/bpf/keys.c @@ -29,7 +29,7 @@ struct bpf_key *bpf_lookup_keyring(void) if (!bpf_keyring) return NULL; - if (!READ_ONCE(bpf_keyring->keys.nr_leaves_on_tree) || + if (keyring_is_empty(bpf_keyring) || !READ_ONCE(bpf_keyring->restrict_link)) return NULL; diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 5281da9d5bf7..ac48d6204915 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 is empty + * @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