kernel/git/stable/linux.git/fs/crypto, branch linux-6.18.y

fscrypt: Replace mk_users keyring with simple list

2026-07-18T14:53:06+00:00

[ Upstream commit 696c030e1e3438955aba443b308ee8b6faa3983e ] Change mk_users (the set of user claims to an fscrypt master key) from a 'struct key' keyring to a simple linked list. It's still a collection of 'struct key' for quota tracking. It was originally thought to be natural that a collection of 'struct key' should be held in a 'struct key' keyring. In reality, it's just been causing problems, similar to how using 'struct key' for the filesystem keyring caused problems and was removed in commit d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key"). Commit d3a7bd420076 ("fscrypt: clear keyring before calling key_put()") fixed mk_users cleanup to be synchronous. But that apparently wasn't enough: the keyring subsystem's redundant locking is still generating lockdep false positives due to the interaction with filesystem reclaim. With the simple list, the redundant locking and lockdep issue goes away. Of course, searching a linked list is linear-time whereas the 'struct key' keyring used a fancy constant-time associative array. But that's fine here, since in practice there's just one entry in the list. In fact the new code is much faster in practice, since it's much smaller and doesn't have to convert the kuid_t into a string to search for it. Reported-by: syzbot+f55b043dacf43776b50c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=f55b043dacf43776b50c Reported-by: Mohammed EL Kadiri Closes: https://lore.kernel.org/keyrings/20260614150041.21172-1-med08elkadiri@gmail.com/ Fixes: 23c688b54016 ("fscrypt: allow unprivileged users to add/remove keys for v2 policies") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260618221921.87896-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

fscrypt: Fix key setup in edge case with multiple data unit sizes

2026-07-18T14:53:06+00:00

[ Upstream commit dd015b566d505d698386103e9c80b739c7336eb8 ] The addition of support for customizable data unit sizes introduced an edge case where a file's contents can be en/decrypted with the wrong data unit size. It occurs when there are multiple v2 policies that: - Have *different* data unit sizes, via the log2_data_unit_size field - Share the same master_key_identifier, contents_encryption_mode, and either FSCRYPT_POLICY_FLAG_DIRECT_KEY, FSCRYPT_POLICY_FLAG_IV_INO_LBLK_32, or FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64 - Are being used on the same filesystem, which also must be mounted with the "inlinecrypt" mount option. Fortunately this edge case doesn't actually occur in practice. I just found it via code review. But it needs to be fixed regardless. The bug is caused by the data unit size not being fully considered when blk_crypto_keys are cached in mk_direct_keys, mk_iv_ino_lblk_32_keys, and mk_iv_ino_lblk_64_keys. They're differentiated only by master key, encryption mode, and flag. However, each one actually has a data unit size too. Only the first data unit size that is cached is used. To fix this, start using the data unit size to differentiate the cached keys. For several reasons, including avoiding increasing the size of struct fscrypt_master_key, just replace all three arrays with a single linked list instead of changing them into two-dimensional arrays. This works well when considering that in practice at most 2 entries are used across all three arrays, so it was already mostly wasted space. For simplicity, make the list also take over the publish/subscribe of the prepared key itself. That is, create separate list nodes for blk_crypto_keys vs crypto_skciphers, and add nodes to the list only when their key is actually prepared. (Note that the legacy fscrypt_direct_keys table in fs/crypto/keysetup_v1.c already works this way.) This eliminates the need for the additional memory barriers when reading and writing the fields of struct fscrypt_prepared_key. Note that I technically should have included the data unit size in the HKDF info string as well. But it's too late to change that. Fixes: 5b1188847180 ("fscrypt: support crypto data unit size less than filesystem block size") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260618180652.52742-1-ebiggers@kernel.org Signed-off-by: Eric Biggers Signed-off-by: Sasha Levin

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