Linux Kernel iomap Truncation Vulnerability Leading to Infinite Loop on xfs Filesystem

A vulnerability in the Linux kernel's iomap implementation could cause an infinite loop when writing to an xfs filesystem on 32-bit kernels. This issue arises because iomap_write_delalloc_scan() incorrectly uses a 32-bit position, leading to the truncation of 64-bit offsets. The problem is caused by folio_next_index() returning an unsigned long, which on 32-bit systems, is effectively a 32-bit value. The vulnerability has been addressed in the Linux kernel.

Impact

Exploitation of this vulnerability could result in an infinite loop, causing a denial of service by hanging the writing process.