In the Linux kernel, the following vulnerability has been resolved:
ocfs2: reject FITRIM ranges shorter than a cluster
ocfs2_trim_mainbm() trims the global bitmap in cluster units, but its too-short range validation only checks sb->s_blocksize.
On filesystems with a cluster size larger than the block size, a FITRIM range that is at least one block but shorter than one cluster is accepted and shifted down to len == 0. The later start + len - 1 and len -= … arithmetic then underflows and can drive trimming past the requested range.
Reject ranges shorter than s_clustersize instead. That preserves the existing -EINVAL behavior for requests that cannot discard even one allocation unit and keeps zero-cluster trims out of the group walk.
References
- https://git.kernel.org/stable/c/06c0a0431b9856506fcd9b2c1b0c6136567d756d
- https://git.kernel.org/stable/c/2c13e02592b918be7725ab5965e01ef4e46c4b57
- https://git.kernel.org/stable/c/346314bb0cc2fc52b50b73d6ecc62e0217455c2e
- https://git.kernel.org/stable/c/3fa7139b5f42731a61f78c42433adae13f9adc21
- https://git.kernel.org/stable/c/441abb77222f155e8d931dbabb465466db01cfd7
- https://git.kernel.org/stable/c/ca1afd88f5eaaff9168e1466e5401385edf59543
- https://git.kernel.org/stable/c/d903d59c0315f59bdf0214b4f13d71c9feb2c45c
- https://git.kernel.org/stable/c/e652d0f5108e447b22da4249bcd23dd1b63c73dd