CVE-2021-47114
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the…
Does this matter?
Lower severity and a low EPSS score (0.23%). Track it; it rarely justifies an emergency change on its own.
Description
In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix data corruption by fallocate When fallocate punches holes out of inode size, if original isize is in the middle of last cluster, then the part from isize to the end of the cluster will be zeroed with buffer write, at that time isize is not yet updated to match the new size, if writeback is kicked in, it will invoke ocfs2_writepage()->block_write_full_page() where the pages out of inode size will be dropped. That will cause file corruption. Fix this by zero out eof blocks when extending the inode size. Running the following command with qemu-image 4.2.1 can get a corrupted coverted image file easily. qemu-img convert -p -t none -T none -f qcow2 $qcow_image \ -O qcow2 -o compat=1.1 $qcow_image.conv The usage of fallocate in qemu is like this, it first punches holes out of inode size, then extend the inode size. fallocate(11, FALLOC_FL_KEEP_SIZE|FALLOC_FL_PUNCH_HOLE, 2276196352, 65536) = 0 fallocate(11, 0, 2276196352, 65536) = 0 v1: https://www.spinics.net/lists/linux-fsdevel/msg193999.html v2: https://lore.kernel.org/linux-fsdevel/20210525093034.GB4112@quack2.suse.cz/T/
- 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
- 0.23% probability · 13th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0a31dd6fd2f4e7db538fb6eb1f06973d81f8dd3bPatch
- https://git.kernel.org/stable/c/33e03adafb29eedae1bae9cdb50c1385279fcf65Patch
- https://git.kernel.org/stable/c/624fa7baa3788dc9e57840ba5b94bc22b03cda57Patch
- https://git.kernel.org/stable/c/6bba4471f0cc1296fe3c2089b9e52442d3074b2ePatch
- https://git.kernel.org/stable/c/a1700479524bb9cb5e8ae720236a6fabd003acaePatch
- https://git.kernel.org/stable/c/c8d5faee46242c3f33b8a71a4d7d52214785bfccPatch
- https://git.kernel.org/stable/c/cc2edb99ea606a45182b5ea38cc8f4e583aa0774Patch
- https://git.kernel.org/stable/c/cec4e857ffaa8c447f51cd8ab4e72350077b6770Patch
- https://git.kernel.org/stable/c/0a31dd6fd2f4e7db538fb6eb1f06973d81f8dd3bPatch
- https://git.kernel.org/stable/c/33e03adafb29eedae1bae9cdb50c1385279fcf65Patch
- https://git.kernel.org/stable/c/624fa7baa3788dc9e57840ba5b94bc22b03cda57Patch
- https://git.kernel.org/stable/c/6bba4471f0cc1296fe3c2089b9e52442d3074b2ePatch
- https://git.kernel.org/stable/c/a1700479524bb9cb5e8ae720236a6fabd003acaePatch
- https://git.kernel.org/stable/c/c8d5faee46242c3f33b8a71a4d7d52214785bfccPatch
- https://git.kernel.org/stable/c/cc2edb99ea606a45182b5ea38cc8f4e583aa0774Patch
- https://git.kernel.org/stable/c/cec4e857ffaa8c447f51cd8ab4e72350077b6770Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.