kernel/linux.git/fs/crypto, branch v6.18.21

fscrypt: fix left shift underflow when inode->i_blkbits > PAGE_SHIFT

2025-11-05T00:37:38+00:00

When simulating an nvme device on qemu with both logical_block_size and physical_block_size set to 8 KiB, an error trace appears during partition table reading at boot time. The issue is caused by inode->i_blkbits being larger than PAGE_SHIFT, which leads to a left shift of -1 and triggering a UBSAN warning. [ 2.697306] ------------[ cut here ]------------ [ 2.697309] UBSAN: shift-out-of-bounds in fs/crypto/inline_crypt.c:336:37 [ 2.697311] shift exponent -1 is negative [ 2.697315] CPU: 3 UID: 0 PID: 274 Comm: (udev-worker) Not tainted 6.18.0-rc2+ #34 PREEMPT(voluntary) [ 2.697317] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 2.697320] Call Trace: [ 2.697324] [ 2.697325] dump_stack_lvl+0x76/0xa0 [ 2.697340] dump_stack+0x10/0x20 [ 2.697342] __ubsan_handle_shift_out_of_bounds+0x1e3/0x390 [ 2.697351] bh_get_inode_and_lblk_num.cold+0x12/0x94 [ 2.697359] fscrypt_set_bio_crypt_ctx_bh+0x44/0x90 [ 2.697365] submit_bh_wbc+0xb6/0x190 [ 2.697370] block_read_full_folio+0x194/0x270 [ 2.697371] ? __pfx_blkdev_get_block+0x10/0x10 [ 2.697375] ? __pfx_blkdev_read_folio+0x10/0x10 [ 2.697377] blkdev_read_folio+0x18/0x30 [ 2.697379] filemap_read_folio+0x40/0xe0 [ 2.697382] filemap_get_pages+0x5ef/0x7a0 [ 2.697385] ? mmap_region+0x63/0xd0 [ 2.697389] filemap_read+0x11d/0x520 [ 2.697392] blkdev_read_iter+0x7c/0x180 [ 2.697393] vfs_read+0x261/0x390 [ 2.697397] ksys_read+0x71/0xf0 [ 2.697398] __x64_sys_read+0x19/0x30 [ 2.697399] x64_sys_call+0x1e88/0x26a0 [ 2.697405] do_syscall_64+0x80/0x670 [ 2.697410] ? __x64_sys_newfstat+0x15/0x20 [ 2.697414] ? x64_sys_call+0x204a/0x26a0 [ 2.697415] ? do_syscall_64+0xb8/0x670 [ 2.697417] ? irqentry_exit_to_user_mode+0x2e/0x2a0 [ 2.697420] ? irqentry_exit+0x43/0x50 [ 2.697421] ? exc_page_fault+0x90/0x1b0 [ 2.697422] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 2.697425] RIP: 0033:0x75054cba4a06 [ 2.697426] Code: 5d e8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 75 19 83 e2 39 83 fa 08 75 11 e8 26 ff ff ff 66 0f 1f 44 00 00 48 8b 45 10 0f 05 <48> 8b 5d f8 c9 c3 0f 1f 40 00 f3 0f 1e fa 55 48 89 e5 48 83 ec 08 [ 2.697427] RSP: 002b:00007fff973723a0 EFLAGS: 00000202 ORIG_RAX: 0000000000000000 [ 2.697430] RAX: ffffffffffffffda RBX: 00005ea9a2c02760 RCX: 000075054cba4a06 [ 2.697432] RDX: 0000000000002000 RSI: 000075054c190000 RDI: 000000000000001b [ 2.697433] RBP: 00007fff973723c0 R08: 0000000000000000 R09: 0000000000000000 [ 2.697434] R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 [ 2.697434] R13: 00005ea9a2c027c0 R14: 00005ea9a2be5608 R15: 00005ea9a2be55f0 [ 2.697436] [ 2.697436] ---[ end trace ]--- This situation can happen for block devices because when CONFIG_TRANSPARENT_HUGEPAGE is enabled, the maximum logical_block_size is 64 KiB. set_init_blocksize() then sets the block device inode->i_blkbits to 13, which is within this limit. File I/O does not trigger this problem because for filesystems that do not support the FS_LBS feature, sb_set_blocksize() prevents sb->s_blocksize_bits from being larger than PAGE_SHIFT. During inode allocation, alloc_inode()->inode_init_always() assigns inode->i_blkbits from sb->s_blocksize_bits. Currently, only xfs_fs_type has the FS_LBS flag, and since xfs I/O paths do not reach submit_bh_wbc(), it does not hit the left-shift underflow issue. Signed-off-by: Yongpeng Yang Fixes: 47dd67532303 ("block/bdev: lift block size restrictions to 64k") Cc: stable@vger.kernel.org [EB: use folio_pos() and consolidate the two shifts by i_blkbits] Link: https://lore.kernel.org/r/20251105003642.42796-1-ebiggers@kernel.org Signed-off-by: Eric Biggers

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

2025-09-29T22:33:50+00:00

Pull fscrypt updates from Eric Biggers: "Make fs/crypto/ use the HMAC-SHA512 library functions instead of crypto_shash. This is simpler, faster, and more reliable" * tag 'fscrypt-for-linus' of git://git.kernel.org/pub/scm/fs/fscrypt/linux: fscrypt: use HMAC-SHA512 library for HKDF fscrypt: Remove redundant __GFP_NOWARN

fscrypt: use HMAC-SHA512 library for HKDF

2025-09-06T04:01:51+00:00

For the HKDF-SHA512 key derivation needed by fscrypt, just use the HMAC-SHA512 library functions directly. These functions were introduced in v6.17, and they provide simple and efficient direct support for HMAC-SHA512. This ends up being quite a bit simpler and more efficient than using crypto/hkdf.c, as it avoids the generic crypto layer: - The HMAC library can't fail, so callers don't need to handle errors - No inefficient indirect calls - No inefficient and error-prone dynamic allocations - No inefficient and error-prone loading of algorithm by name - Less stack usage Benchmarks on x86_64 show that deriving a per-file key gets about 30% faster, and FS_IOC_ADD_ENCRYPTION_KEY gets nearly twice as fast. The only small downside is the HKDF-Expand logic gets duplicated again. Then again, even considering that, the new fscrypt_hkdf_expand() is only 7 lines longer than the version that called hkdf_expand(). Later we could add HKDF support to lib/crypto/, but for now let's just do this. Link: https://lore.kernel.org/r/20250906035913.1141532-1-ebiggers@kernel.org Signed-off-by: Eric Biggers

fscrypt: 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 fscrypt_operations, and update fs/crypto/ to support it. When set to a nonzero value, it specifies the offset to the fscrypt_inode_info pointer within the filesystem-specific part of the inode structure, to be used instead of inode::i_crypt_info. Since this makes inode::i_crypt_info no longer necessarily used, update comments that mentioned it. This is a prerequisite for a later commit that removes inode::i_crypt_info, saving memory and improving cache efficiency with filesystems that don't support fscrypt. Co-developed-by: Christian Brauner Signed-off-by: Eric Biggers Link: https://lore.kernel.org/20250810075706.172910-3-ebiggers@kernel.org Signed-off-by: Christian Brauner

fscrypt: replace raw loads of info pointer with helper function

2025-08-21T11:58:06+00:00

Add and use a helper function fscrypt_get_inode_info_raw(). It loads an inode's fscrypt info pointer using a raw dereference, which is appropriate when the caller knows the key setup already happened. This eliminates most occurrences of inode::i_crypt_info in the source, in preparation for replacing that with a filesystem-specific field. Co-developed-by: Christian Brauner Signed-off-by: Eric Biggers Link: https://lore.kernel.org/20250810075706.172910-2-ebiggers@kernel.org Signed-off-by: Christian Brauner

fscrypt: Remove redundant __GFP_NOWARN

2025-08-11T17:27:32+00:00

GFP_NOWAIT already includes __GFP_NOWARN, so let's remove the redundant __GFP_NOWARN. Signed-off-by: Qianfeng Rong Link: https://lore.kernel.org/r/20250803102243.623705-3-rongqianfeng@vivo.com Signed-off-by: Eric Biggers

fscrypt: Remove gfp_t argument from fscrypt_encrypt_block_inplace()

2025-07-10T19:33:13+00:00

This argument is no longer used, so remove it. Reviewed-by: Alex Markuze Link: https://lore.kernel.org/r/20250710060754.637098-6-ebiggers@kernel.org Signed-off-by: Eric Biggers

fscrypt: Remove gfp_t argument from fscrypt_crypt_data_unit()

2025-07-10T19:33:08+00:00

This argument is no longer used, so remove it. Link: https://lore.kernel.org/r/20250710060754.637098-5-ebiggers@kernel.org Signed-off-by: Eric Biggers

fscrypt: Switch to sync_skcipher and on-stack requests

2025-07-10T19:33:08+00:00

Now that fscrypt uses only synchronous skciphers, switch to the actual sync_skcipher API and the corresponding on-stack requests. This eliminates a heap allocation per en/decryption operation. Link: https://lore.kernel.org/r/20250710060754.637098-4-ebiggers@kernel.org Signed-off-by: Eric Biggers

fscrypt: Drop FORBID_WEAK_KEYS flag for AES-ECB

2025-07-10T19:33:08+00:00

This flag only has an effect for DES, 3DES, and XTS mode. It does nothing for AES-ECB, as there is no concept of weak keys for AES. Link: https://lore.kernel.org/r/20250710060754.637098-3-ebiggers@kernel.org Signed-off-by: Eric Biggers