CVE-2026-53320

Summary

In the Linux kernel, the following vulnerability has been resolved:

nilfs2: reject zero bd_oblocknr in nilfs_ioctl_mark_blocks_dirty()

nilfs_ioctl_mark_blocks_dirty() uses bd_oblocknr to detect dead blocks by comparing it with the current block number bd_blocknr. If they differ, the block is considered dead and skipped.

However, bd_oblocknr should never be 0 since block 0 typically stores the primary superblock and is never a valid GC target block. A corrupted ioctl request with bd_oblocknr set to 0 causes the comparison to incorrectly match when the lookup returns -ENOENT and sets bd_blocknr to 0, bypassing the dead block check and calling nilfs_bmap_mark() on a non-existent block. This causes nilfs_btree_do_lookup() to return -ENOENT, triggering the WARN_ON(ret == -ENOENT).

Fix this by rejecting ioctl requests with bd_oblocknr set to 0 at the beginning of each iteration.

[ryusuke: slightly modified the commit message and comments for accuracy]

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/e0a0c4903cbba351f0f5b5d104960d3a5b23202f
• https://git.kernel.org/stable/c/9472d37799a0b9ff9b99639f35961ac2f0b3c9be
• https://git.kernel.org/stable/c/65e07964b4b2daf9a54e686cf0fa72d74a9648a8
• https://git.kernel.org/stable/c/b88f905d4449b70da6bda547be546e365e44352e
• https://git.kernel.org/stable/c/4525658002be3ad310b16bf8db48c8adb6a55d32
• https://git.kernel.org/stable/c/e5ff0ba4b6983cdbcc826efc201e7179ece5d46f
• https://git.kernel.org/stable/c/94094e70fe292c9566502772d4d4d6d6a99204b1
• https://git.kernel.org/stable/c/be3e5d10643d3be1cbac9d9939f220a99253f980

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