CVE-2021-47114
Last modified
CVE-2021-47114 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. 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. EPSS estimates a 0.23% chance of exploitation in the next 30 days.
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/
Metrics
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected Software
| Vendor | Product | Versions | Update |
|---|---|---|---|
| Linux | Linux Kernel | < 4.4.272 | — |
| Linux | Linux Kernel | >= 4.5, < 4.9.272 | — |
| Linux | Linux Kernel | >= 4.10, < 4.14.236 | — |
| Linux | Linux Kernel | >= 4.15, < 4.19.194 | — |
| Linux | Linux Kernel | >= 4.20, < 5.4.125 | — |
| Linux | Linux Kernel | >= 5.5, < 5.10.43 | — |
| Linux | Linux Kernel | >= 5.11, < 5.12.10 | — |
| Linux | Linux Kernel | 5.13 | Rc1 |
References
Timeline
- Published
- Last Modified
- Status
- Analyzed
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Related CVEs from 2021
- CVE-2021-47108In the Linux kernel, the following vulnerability has been re…5.5
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- CVE-2021-47110In the Linux kernel, the following vulnerability has been re…7.1
- CVE-2021-47111In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2021-47112In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47113In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47115Rejected reason: This CVE ID has been rejected or withdrawn …
- CVE-2021-47116In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47117In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47118In the Linux kernel, the following vulnerability has been re…7.8
- CVE-2021-47119In the Linux kernel, the following vulnerability has been re…5.5
- CVE-2021-47120In the Linux kernel, the following vulnerability has been re…5.5
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