UBUNTU-CVE-2024-53143
In the Linux kernel, the following vulnerability has been resolved: fsnotify: Fix ordering of iput() and watched_objects decrement Ensure the superblock is kept alive until we're done with iput(). Holding a reference to an inode is not allowed unless we ensure the superblock stays alive, which fsnotify does by keeping the watched_objects count elevated, so iput() must happen before the watched_objects decrement. This can lead to a UAF of something like sb->s_fs_info in tmpfs, but the UAF is hard to hit because race orderings that oops are more likely, thanks to the CHECK_DATA_CORRUPTION() block in generic_shutdown_super(). Also, ensure that fsnotify_put_sb_watched_objects() doesn't call fsnotify_sb_watched_objects() on a superblock that may have already been freed, which would cause a UAF read of sb->s_fsnotify_info.
02 / AFFECTED SOFTWARE
Affected packages
29 explicit affected versions
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10 explicit affected versions
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26 explicit affected versions
23 explicit affected versions
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26 explicit affected versions
12 explicit affected versions
44 explicit affected versions
4 explicit affected versions
4 explicit affected versions
16 explicit affected versions
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13 explicit affected versions
7 explicit affected versions
13 explicit affected versions
7 explicit affected versions
10 explicit affected versions
11 explicit affected versions
14 explicit affected versions
18 explicit affected versions
3 explicit affected versions
16 explicit affected versions
43 explicit affected versions
35 explicit affected versions
12 explicit affected versions
13 explicit affected versions
6 explicit affected versions
12 explicit affected versions
50 explicit affected versions
11 explicit affected versions
12 explicit affected versions
27 explicit affected versions
12 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: fsnotify: Fix ordering of iput() and watched_objects decrement Ensure the superblock is kept alive until we're done with iput(). Holding a reference to an inode is not allowed unless we ensure the superblock stays alive, which fsnotify does by keeping the watched_objects count elevated, so iput() must happen before the watched_objects decrement. This can lead to a UAF of something like sb->s_fs_info in tmpfs, but the UAF is hard to hit because race orderings that oops are more likely, thanks to the CHECK_DATA_CORRUPTION() block in generic_shutdown_super(). Also, ensure that fsnotify_put_sb_watched_objects() doesn't call fsnotify_sb_watched_objects() on a superblock that may have already been freed, which would cause a UAF read of sb->s_fsnotify_info.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/21d1b618b6b9da46c5116c640ac4b1cc8d40d63a
- https://git.kernel.org/stable/c/21d1b618b6b9da46c5116c640ac4b1cc8d40d63a
- https://git.kernel.org/stable/c/45a8f8232a495221ed058191629f5c628f21601a
- https://git.kernel.org/stable/c/83af1cfa10d9aafdabd06b3655e07727f373b434
- https://ubuntu.com/security/CVE-2024-53143
- https://ubuntu.com/security/notices/USN-7276-1
- https://ubuntu.com/security/notices/USN-7277-1
- https://ubuntu.com/security/notices/USN-7310-1
- https://www.cve.org/CVERecord?id=CVE-2024-53143