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=1793316343; b=mmLeTa5WUGz3y+6+zv6p3OkNbPn/m4esBKvDk8Hd6K03/XDnedfeH+oss53y3ATRwC5x c4oD34e2tlCs41nPWwAexZMvaWhxvXSFOcwHVCbxMvrSb7xB4U6wMLbd/MielRMLVamSh qm/63gU0Qv3rYRboepaSuhCxvPs53aRfkwCjMqsiL975vCUTqOkSNQsoxeTBNT0rGsvuJ FxFhHtxmMqBXG+2exP9/V1knAfr9tUnL9fKmPExfU/n6uCVX1ANs9jwCzv+as/EkDYBf/ 9h/QzQdUnNchiL4zES9Dgh7D58zFs3Z5TIM7jUExPQ5UmVvKTvQ6bSHPG5FF8GFPzLA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793316343; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=uy/FZh24B32RYF0ZgiKoGJHXlBRYP7HqQOuRiOOjXeE=; b=LS6MDKGgtsAODh/0Ih6bmsdgV0HF4eRNJzShiFPdmHsuHvVDCrKs6/dThW4wYoJsOCm1 zgc6nz/8WHcuXQb9oAsMxNL4oIVTu0Co9zUm5LIEIhQwN5RAq1pxrbvebWCDMmhxaMVHs 766bzLtlbrmU9GJYGP9A0fIlMD1gNhskfvOTKZWgZWhY1RmII0QN6XOQm8atU7kpeySD2 MEJE0JOI9VWYQRKvwdyPVaUVafdQ/k0JNKa/M+p4Ipg93OU4973X/eTaGdaivp3wk1LTR Mo9rnVifEtUxM5i7tap4Zg60FlzuyBaYOmSdCSm/8P/Sr4nxo0xyfZHgMom9XpxZvJg== 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="n/UfjZG4"; 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 D93EA606A31A; Thu, 29 Oct 2026 23:25:42 +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=n/UfjZG4 Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id A7A761F00A22; Thu, 29 Oct 2026 23:25:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793316342; bh=uy/FZh24B32RYF0ZgiKoGJHXlBRYP7HqQOuRiOOjXeE=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=n/UfjZG4Xre6CtdKbTCQPofGneqZlZHEt/PF/tXrPp/zphplFkx0MAcItFQeicMWW zUpED7Jle7zZ4V/nsPgVEFr8TofdfoK1fk3ZKLuC+7hWk/OCl/e/fIP2hnYoRTviZi hWVdzNIbN4JKVWQZn34gJM7dL9kPxLR2UU20xjUOM2OItlo4pTLUhCnXMGUpL+YiF2 uh5N+dtNYyzCmhxVUxFKFtchSQ5ds0unIwm2uGKTr8FGYRDhqV7r0z7xD9m1y3heSO VcM16OMo1CXD4Q8ODXLxqMYnLxy66ib0QiYT4HJ1g71PJ0VL88NezJVsWlS2m2CWDk ZnrNnganPBxfA== From: Jarkko Sakkinen To: David Howells Cc: keyrings@vger.kernel.org, Eric Biggers , Jarkko Sakkinen , Lukas Wunner , Ignat Korchagin , Herbert Xu , "David S. Miller" , Alasdair Kergon , Mike Snitzer , Mikulas Patocka , Benjamin Marzinski , "Theodore Y. Ts'o" , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Martin KaFai Lau , Song Liu , Yonghong Song , Jiri Olsa , Emil Tsalapatis , Ihor Solodrai , Paul Moore , James Morris , "Serge E. Hallyn" , Shuah Khan , Christian Brauner , linux-crypto@vger.kernel.org (open list:ASYMMETRIC KEYS), linux-kernel@vger.kernel.org (open list), dm-devel@lists.linux.dev (open list:DEVICE-MAPPER (LVM)), fsverity@lists.linux.dev (open list:FSVERITY: READ-ONLY FILE-BASED AUTHENTICITY PRO...), bpf@vger.kernel.org (open list:BPF [GENERAL] (Safe Dynamic Programs and Tools)), linux-security-module@vger.kernel.org (open list:SECURITY SUBSYSTEM), linux-kselftest@vger.kernel.org (open list:KERNEL SELFTEST FRAMEWORK) Subject: [PATCH v4 1/3] KEYS: Introduce keyring_is_empty() Date: Fri, 30 Oct 2026 01:24:09 +0200 Message-ID: <20261029232437.2581640-2-jarkko@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261029232437.2581640-1-jarkko@kernel.org> References: <20261029232437.2581640-1-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. 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 aadcf5e4a47c..cad21e9144ed 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 c4486e938a06..20ca43f5eab1 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