CVE-2024-50015: ext4: dax: fix overflowing extents beyond inode size when partially writing
First published: Mon Oct 21 2024(Updated: )
In the Linux kernel, the following vulnerability has been resolved: ext4: dax: fix overflowing extents beyond inode size when partially writing The dax_iomap_rw() does two things in each iteration: map written blocks and copy user data to blocks. If the process is killed by user(See signal handling in dax_iomap_iter()), the copied data will be returned and added on inode size, which means that the length of written extents may exceed the inode size, then fsck will fail. An example is given as: dd if=/dev/urandom of=file bs=4M count=1 dax_iomap_rw iomap_iter // round 1 ext4_iomap_begin ext4_iomap_alloc // allocate 0~2M extents(written flag) dax_iomap_iter // copy 2M data iomap_iter // round 2 iomap_iter_advance iter->pos += iter->processed // iter->pos = 2M ext4_iomap_begin ext4_iomap_alloc // allocate 2~4M extents(written flag) dax_iomap_iter fatal_signal_pending done = iter->pos - iocb->ki_pos // done = 2M ext4_handle_inode_extension ext4_update_inode_size // inode size = 2M fsck reports: Inode 13, i_size is 2097152, should be 4194304. Fix? Fix the problem by truncating extents if the written length is smaller than expected.
Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 416baaa9-dc9f-4396-8d5f-8c081fb06d67
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Kernel | >=4.10<5.10.227 | |
| Linux Kernel | >=5.11<5.15.168 | |
| Linux Kernel | >=5.16<6.1.113 | |
| Linux Kernel | >=6.2<6.6.55 | |
| Linux Kernel | >=6.7<6.10.14 | |
| Linux Kernel | >=6.11<6.11.3 | |
| debian/linux | <=5.10.223-1<=5.10.226-1 | 6.1.123-1 6.1.128-1 6.12.12-1 6.12.15-1 |
| debian/linux-6.1 | 6.1.119-1~deb11u1 |
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Reference Links
- https://git.kernel.org/stable/c/5efccdee4a7d507a483f20f880b809cc4eaef14d
- https://git.kernel.org/stable/c/8c30a9a8610c314554997f86370140746aa35661
- https://git.kernel.org/stable/c/a9f331f51515bdb3ebc8d0963131af367ef468f6
- https://git.kernel.org/stable/c/abfaa876b948baaea4d14f21a1963789845c8b4c
- https://git.kernel.org/stable/c/dda898d7ffe85931f9cca6d702a51f33717c501e
- https://git.kernel.org/stable/c/ec0dd451e236c46e4858d53e9e82bae7797a7af5
- https://git.kernel.org/stable/c/f8a7c342326f6ad1dfdb30a18dd013c70f5e9669
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2024-50015
- https://nvd.nist.gov/vuln/detail/CVE-2024-50015
- https://launchpad.net/bugs/cve/CVE-2024-50015
- https://security-tracker.debian.org/tracker/CVE-2024-50015
- https://ubuntu.com/security/CVE-2024-50015
- https://git.kernel.org/linus/dda898d7ffe85931f9cca6d702a51f33717c501e
Frequently Asked Questions
What is the severity of CVE-2024-50015?
CVE-2024-50015 has been assigned a severity rating of medium.
How do I fix CVE-2024-50015?
To fix CVE-2024-50015, ensure that your Linux kernel is updated to a version that is not affected, specifically versions 6.1.123-1, 6.1.119-1, 6.12.11-1, or 6.12.12-1.
Which versions of the Linux kernel are affected by CVE-2024-50015?
CVE-2024-50015 affects Linux kernel versions from 4.10 up to 6.11.2 and includes several versions in between.
Is CVE-2024-50015 a zero-day vulnerability?
CVE-2024-50015 is not classified as a zero-day vulnerability since a fix is already available.
What types of attacks could exploit CVE-2024-50015?
CVE-2024-50015 could be exploited to cause denial of service conditions or data corruption during data writes.
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