CVE-2024-53143 Information

Description

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.

Reference

https://git.kernel.org/stable/c/21d1b618b6b9da46c5116c640ac4b1cc8d40d63a https://git.kernel.org/stable/c/45a8f8232a495221ed058191629f5c628f21601a https://git.kernel.org/stable/c/83af1cfa10d9aafdabd06b3655e07727f373b434