kernel/linux.git/fs/verity, branch v6.18.48

fsverity: Fix silent truncation in bpf_get_fsverity_digest()

2026-08-19T16:18:20+00:00

commit 7c68ed5c5ad4c185ea9654f5d8ee36560277b7dd upstream. bpf_get_fsverity_digest() silently truncates the digest if the provided buffer is too small. This is a footgun, and it doesn't match the semantics of the equivalent UAPI (FS_IOC_MEASURE_VERITY). Change it to return -EOVERFLOW instead, matching FS_IOC_MEASURE_VERITY. Fixes: 67814c00de31 ("bpf, fsverity: Add kfunc bpf_get_fsverity_digest") Signed-off-by: Eric Biggers Acked-by: Song Liu Cc: stable@vger.kernel.org Link: https://lore.kernel.org/bpf/20260803181232.14743-3-ebiggers@kernel.org Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Greg Kroah-Hartman

fsverity: Fix bpf_get_fsverity_digest() dynptr assumptions

2026-08-19T16:18:20+00:00

commit 3e8ec7c0387273329374f5c7bd61f5f38af71fe1 upstream. The BPF verifier and the dynptr abstraction ensure that the memory space referenced by a dynptr remains valid. They do not, however, provide any guarantee that the contents of the memory are stable. kfuncs are expected to remain memory-safe even if concurrent modifications occur. bpf_get_fsverity_digest() didn't follow that: it could crash if arg->digest_size was concurrently modified. Fix that by using the known-good value hash_alg->digest_size instead. Also widen 'dynptr_sz' and 'out_digest_sz' to u64 to match the return type of __bpf_dynptr_size(). It doesn't appear that it can actually be more than INT_MAX currently (since __bpf_dynptr_data_rw() excludes file-based pointers), but the correct type might as well be used. Fixes: 67814c00de31 ("bpf, fsverity: Add kfunc bpf_get_fsverity_digest") Signed-off-by: Eric Biggers Acked-by: Kumar Kartikeya Dwivedi Acked-by: Song Liu Cc: stable@vger.kernel.org Link: https://lore.kernel.org/bpf/20260803181232.14743-2-ebiggers@kernel.org Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Greg Kroah-Hartman

Merge tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux

2025-09-29T22:55:20+00:00

Pull interleaved SHA-256 hashing support from Eric Biggers: "Optimize fsverity with 2-way interleaved hashing Add support for 2-way interleaved SHA-256 hashing to lib/crypto/, and make fsverity use it for faster file data verification. This improves fsverity performance on many x86_64 and arm64 processors. Later, I plan to make dm-verity use this too" * tag 'fsverity-for-linus' of git://git.kernel.org/pub/scm/fs/fsverity/linux: fsverity: Use 2-way interleaved SHA-256 hashing when supported fsverity: Remove inode parameter from fsverity_hash_block() lib/crypto: tests: Add tests and benchmark for sha256_finup_2x() lib/crypto: x86/sha256: Add support for 2-way interleaved hashing lib/crypto: arm64/sha256: Add support for 2-way interleaved hashing lib/crypto: sha256: Add support for 2-way interleaved hashing

Merge tag 'vfs-6.18-rc1.workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-09-29T17:27:17+00:00

Pull vfs workqueue updates from Christian Brauner: "This contains various workqueue changes affecting the filesystem layer. Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This replaces the use of system_wq and system_unbound_wq. system_wq is a per-CPU workqueue which isn't very obvious from the name and system_unbound_wq is to be used when locality is not required. So this renames system_wq to system_percpu_wq, and system_unbound_wq to system_dfl_wq. This also adds a new WQ_PERCPU flag to allow the fs subsystem users to explicitly request the use of per-CPU behavior. Both WQ_UNBOUND and WQ_PERCPU flags coexist for one release cycle to allow callers to transition their calls. WQ_UNBOUND will be removed in a next release cycle" * tag 'vfs-6.18-rc1.workqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: fs: WQ_PERCPU added to alloc_workqueue users fs: replace use of system_wq with system_percpu_wq fs: replace use of system_unbound_wq with system_dfl_wq

fs: WQ_PERCPU added to alloc_workqueue users

2025-09-19T14:15:07+00:00

Currently if a user enqueue a work item using schedule_delayed_work() the used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to schedule_work() that is using system_wq and queue_work(), that makes use again of WORK_CPU_UNBOUND. This lack of consistentcy cannot be addressed without refactoring the API. alloc_workqueue() treats all queues as per-CPU by default, while unbound workqueues must opt-in via WQ_UNBOUND. This default is suboptimal: most workloads benefit from unbound queues, allowing the scheduler to place worker threads where they’re needed and reducing noise when CPUs are isolated. This patch adds a new WQ_PERCPU flag to all the fs subsystem users to explicitly request the use of the per-CPU behavior. Both flags coexist for one release cycle to allow callers to transition their calls. Once migration is complete, WQ_UNBOUND can be removed and unbound will become the implicit default. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. All existing users have been updated accordingly. Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Link: https://lore.kernel.org/20250916082906.77439-4-marco.crivellari@suse.com Signed-off-by: Christian Brauner

fsverity: Use 2-way interleaved SHA-256 hashing when supported

2025-09-17T18:10:04+00:00

When the crypto library provides an optimized implementation of sha256_finup_2x(), use it to interleave the hashing of pairs of data blocks. On some CPUs this nearly doubles hashing performance. The increase in overall throughput of cold-cache fsverity reads that I'm seeing on arm64 and x86_64 is roughly 35% (though this metric is hard to measure as it jumps around a lot). For now this is only done on the verification path, and only for data blocks, not Merkle tree blocks. We could use sha256_finup_2x() on Merkle tree blocks too, but that is less important as there aren't as many Merkle tree blocks as data blocks, and that would require some additional code restructuring. We could also use sha256_finup_2x() to accelerate building the Merkle tree, but verification performance is more important. Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20250915160819.140019-7-ebiggers@kernel.org Signed-off-by: Eric Biggers

fsverity: Remove inode parameter from fsverity_hash_block()

2025-09-17T18:09:40+00:00

Due to the conversion from crypto_shash to the library API, fsverity_hash_block() can no longer fail. Therefore, the inode parameter, which was used only to print an error message in the case of a failure, is no longer necessary. Remove it. Reviewed-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20250915160819.140019-6-ebiggers@kernel.org Signed-off-by: Eric Biggers

fsverity: add support for info in fs-specific part of inode

2025-08-21T11:58:07+00:00

Add an inode_info_offs field to struct fsverity_operations, and update fs/verity/ to support it. When set to a nonzero value, it specifies the offset to the fsverity_info pointer within the filesystem-specific part of the inode structure, to be used instead of inode::i_verity_info. Since this makes inode::i_verity_info no longer necessarily used, update comments that mentioned it. This is a prerequisite for a later commit that removes inode::i_verity_info, saving memory and improving cache efficiency on filesystems that don't support fsverity. Co-developed-by: Christian Brauner Signed-off-by: Eric Biggers Link: https://lore.kernel.org/20250810075706.172910-9-ebiggers@kernel.org Signed-off-by: Christian Brauner

fsverity: Switch from crypto_shash to SHA-2 library

2025-07-14T18:29:32+00:00

fsverity supports two hash algorithms: SHA-256 and SHA-512. Since both of these have a library API now, just use the library API instead of crypto_shash. Even with multiple algorithms, the library-based code still ends up being quite a bit simpler, due to how clumsy the old-school crypto API is. The library-based code is also more efficient, since it avoids overheads such as indirect calls. Acked-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20250630172224.46909-3-ebiggers@kernel.org Signed-off-by: Eric Biggers

fsverity: Explicitly include

2025-07-14T18:29:32+00:00

Fix build warnings with W=1 that started appearing after commit a934a57a42f6 ("scripts/misc-check: check missing #include when W=1"). Link: https://lore.kernel.org/r/20250614221723.131827-1-ebiggers@kernel.org Signed-off-by: Eric Biggers