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19cac7902a
vol->lcn_empty_bits_per_page is sized from vol->nr_clusters at mount, but
ntfs_cluster_alloc() bounds its scan of that array by the size of $Bitmap.
Those are independent on-disk quantities and the mount-time check only
rejects a $Bitmap that is too small, so an image whose $Bitmap covers more
clusters than the volume has lets the scan index past the array. A run
whose LCN lies in that gap takes the allocator straight there, since the
caller passes the file's own last LCN as its locality hint. KASAN reports
a slab out-of-bounds read when a file on such a volume is extended.
Clamp the scan to what that array covers, mirroring the max_index
calculation the mount-time scan already uses, and reject a decoded LCN
at or beyond nr_clusters in the mapping pairs decoder. Conforming
volumes are unaffected.
Fixes: 11ccc9107d ("ntfs: update runlist handling and cluster allocator")
Cc: stable@vger.kernel.org
Signed-off-by: Bryam Vargas <hexlabsecurity@proton.me>
Reviewed-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
1054 lines
33 KiB
1054 lines
33 KiB