CVE-2025-38709 (GCVE-0-2025-38709)
Vulnerability from cvelistv5
Published
2025-09-04 15:32
Modified
2025-09-04 15:32
Severity ?
Summary
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/139a000d20f2f38ce34296feddd641d730fe1c08
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5d67b30aefeb7a949040bbb1b4e3b84c5d29a624
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/7e49538288e523427beedd26993d446afef1a6fb
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b928438cc87c0bf7ae078e4b7b6e14261e84c5c5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ce8da5d13d8c2a7b30b2fb376a22e8eb1a70b8bb
Impacted products
Vendor Product Version
Linux Linux Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
Version: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2
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