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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2026-68147

fscrypt: Avoid dynamic allocation in fscrypt_get_devices()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: fscrypt: Avoid dynamic allocation in fscrypt_get_devices() When a blk_crypto_key starts being used or is evicted, fs/crypto/ calls fscrypt_get_devices() to get the filesystem's list of block devices, then iterates over them and calls blk_crypto_config_supported(), blk_crypto_start_using_key(), or blk_crypto_evict_key() on each one. Currently, the block device pointers are placed in a dynamically allocated array. This dynamic allocation is problematic because: - It can fail, especially at the fscrypt_destroy_inline_crypt_key() call site when it's invoked for inode eviction under direct reclaim. - fscrypt_destroy_inline_crypt_key() doesn't handle the failure. It just zeroizes and frees the blk_crypto_key without calling blk_crypto_evict_key(). That causes a use-after-free. For now, let's fix this in the straightforward and easily-backportable way by switching to an on-stack array. Currently the fscrypt multi-device functionality is used only by f2fs, which has a hardcoded limit of 8 block devices. An on-stack array works fine for that. (Of course, this solution won't scale up to large number of block devices. For that we'd need a different solution, like moving the block device iteration into the filesystem. Or in the case of btrfs, which will only support blk-crypto-fallback, we should make it just call blk-crypto-fallback directly, so the block devices won't be needed.)

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 22e9947a4b2ba255888541bd0111cf00b9b16586 to < bab016bb80d74a9d1f7d4121a7fc1cb529b470e0affected
  • 22e9947a4b2ba255888541bd0111cf00b9b16586 to < 4462ac3d90e897dda52ce4b6af2d526ddae835a8affected
  • 22e9947a4b2ba255888541bd0111cf00b9b16586 to < 97a688563be71ec6fefc071aff69a66c69dbe244affected
  • 22e9947a4b2ba255888541bd0111cf00b9b16586 to < 81ea8e8221853950c47dac7164f27c63a96f8f86affected
  • 22e9947a4b2ba255888541bd0111cf00b9b16586 to < bc2d630296e0e049210ec05ff08459a6893ae749affected
  • 22e9947a4b2ba255888541bd0111cf00b9b16586 to < 6fe4e4b8259e1330945b5f3c9476e08473b8e0e8affected

Linux Linux

Default version status: affected

  • 6.1affected
  • 0 to < 6.1unaffected
  • 6.1.183 to ≤ 6.1.*unaffected
  • 6.6.148 to ≤ 6.6.*unaffected
  • 6.12.101 to ≤ 6.12.*unaffected
  • 6.18.42 to ≤ 6.18.*unaffected
  • 7.1.6 to ≤ 7.1.*unaffected
  • 7.2 to ≤ *unaffected

References