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CVE PROGRAM SOURCE RECORDUnscored

CVE-2025-38709

loop: Avoid updating block size under exclusive owner

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: loop: Avoid updating block size under exclusive owner Syzbot came up with a reproducer where a loop device block size is changed underneath a mounted filesystem. This causes a mismatch between the block device block size and the block size stored in the superblock causing confusion in various places such as fs/buffer.c. The particular issue triggered by syzbot was a warning in __getblk_slow() due to requested buffer size not matching block device block size. Fix the problem by getting exclusive hold of the loop device to change its block size. This fails if somebody (such as filesystem) has already an exclusive ownership of the block device and thus prevents modifying the loop device under some exclusive owner which doesn't expect it.

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

  • 89e4fdecb51cf5535867026274bc97de9480ade5 to < 457d2c5e112fd08dc1039b1ae39a83ec1782360daffected
  • 89e4fdecb51cf5535867026274bc97de9480ade5 to < 139a000d20f2f38ce34296feddd641d730fe1c08affected
  • 89e4fdecb51cf5535867026274bc97de9480ade5 to < b928438cc87c0bf7ae078e4b7b6e14261e84c5c5affected
  • 89e4fdecb51cf5535867026274bc97de9480ade5 to < 5d67b30aefeb7a949040bbb1b4e3b84c5d29a624affected
  • 89e4fdecb51cf5535867026274bc97de9480ade5 to < 7e49538288e523427beedd26993d446afef1a6fbaffected

Linux Linux

Default version status: affected

  • 4.14affected
  • 0 to < 4.14unaffected
  • 6.6.109 to ≤ 6.6.*unaffected
  • 6.12.43 to ≤ 6.12.*unaffected
  • 6.15.11 to ≤ 6.15.*unaffected
  • 6.16.2 to ≤ 6.16.*unaffected
  • 6.17 to ≤ *unaffected

References