CVE-2024-56619 Information

Description

In the Linux kernel the following vulnerability has been resolved:

nilfs2: fix potential out-of-bounds memory access in nilfs_find_entry()

Syzbot reported that when searching for records in a directory where the inode’s i_size is corrupted and has a large value memory access outside the folio/page range may occur or a use-after-free bug may be detected if KASAN is enabled.

This is because nilfs_last_byte() which is called by nilfs_find_entry() and others to calculate the number of valid bytes of directory data in a page from i_size and the page index loses the upper 32 bits of the 64-bit size information due to an inappropriate type of local variable to which the i_size value is assigned.

This caused a large byte offset value due to underflow in the end address calculation in the calling nilfs_find_entry() resulting in memory access that exceeds the folio/page size.

Fix this issue by changing the type of the local variable causing the bit loss from �nsigned int\ to d. The return value of nilfs_last_byte() is also of type �nsigned int\ but it is truncated so as not to exceed PAGE_SIZE and no bit loss occurs so no change is required.

Reference

https://git.kernel.org/stable/c/09d6d05579fd46e61abf6e457bb100ff11f3a9d3 https://git.kernel.org/stable/c/31f7b57a77d4c82a34ddcb6ff35b5aa577ef153e https://git.kernel.org/stable/c/48eb6e7404948032bbe811c5affbe39f6b316951 https://git.kernel.org/stable/c/5af8366625182f01f6d8465c9a3210574673af57 https://git.kernel.org/stable/c/985ebec4ab0a28bb5910c3b1481a40fbf7f9e61d https://git.kernel.org/stable/c/c3afea07477baccdbdec4483f8d5e59d42a3f67f https://git.kernel.org/stable/c/e3732102a9d638d8627d14fdf7b208462f0520e0