CVE-2022-49769
In the Linux kernel, the following vulnerability has been resolved: gfs2: Check sb_bsize_shift after reading superblock Fuzzers like to scribble over sb_bsize_shift but in reality it's very unlikely that this field would be corrupted on its own.
Does this matter?
Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: gfs2: Check sb_bsize_shift after reading superblock Fuzzers like to scribble over sb_bsize_shift but in reality it's very unlikely that this field would be corrupted on its own. Nevertheless it should be checked to avoid the possibility of messy mount errors due to bad calculations. It's always a fixed value based on the block size so we can just check that it's the expected value. Tested with: mkfs.gfs2 -O -p lock_nolock /dev/vdb for i in 0 -1 64 65 32 33; do gfs2_edit -p sb field sb_bsize_shift $i /dev/vdb mount /dev/vdb /mnt/test && umount /mnt/test done Before this patch we get a withdraw after [ 76.413681] gfs2: fsid=loop0.0: fatal: invalid metadata block [ 76.413681] bh = 19 (type: exp=5, found=4) [ 76.413681] function = gfs2_meta_buffer, file = fs/gfs2/meta_io.c, line = 492 and with UBSAN configured we also get complaints like [ 76.373395] UBSAN: shift-out-of-bounds in fs/gfs2/ops_fstype.c:295:19 [ 76.373815] shift exponent 4294967287 is too large for 64-bit type 'long unsigned int' After the patch, these complaints don't appear, mount fails immediately and we get an explanation in dmesg.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.21% probability · 12th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/15c83fa0fd659dd9fbdc940a560b61236e876a80Patch
- https://git.kernel.org/stable/c/16670534c7cff1acd918a6a5ec751b14e7436b76Patch
- https://git.kernel.org/stable/c/1ad197097343568066a8ffaa27ee7d0ae6d9f476Patch
- https://git.kernel.org/stable/c/28275a7c84d21c55ab3282d897f284d8d527173cPatch
- https://git.kernel.org/stable/c/5fa30be7ba81191b0a0c7239a89befc0c94286d5Patch
- https://git.kernel.org/stable/c/670f8ce56dd0632dc29a0322e188cc73ce3c6b92Patch
- https://git.kernel.org/stable/c/8b6534c9ae9dba5489703a19d8ba6c8f2cfa33c2Patch
- https://git.kernel.org/stable/c/d6b1e8ea6f3418c3b461ad5a35cdc93c996b2c87Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.