Linux Kernel exFAT File System Infinite Loop Vulnerability Due to Cluster Chain Corruption

A denial-of-service vulnerability has been identified in the Linux kernel's exFAT file system implementation. This issue arises from an infinite loop that can occur when the cluster chain of a directory is corrupted, creating a loop without any unused entries to break the cycle. Several functions, including 'exfat_count_dir_entries', 'exfat_create_upcase_table', 'exfat_load_bitmap', 'exfat_find_dir_entry', and 'exfat_check_dir_empty', can enter this infinite loop under specific conditions related to the cluster chain's integrity.

Impact

Exploitation of this vulnerability leads to an infinite loop, causing a denial-of-service condition by hanging the process indefinitely.

Reproduction

The vulnerability can be reproduced by creating a corrupted exFAT file system where the cluster chain of a directory includes a loop, and there are no unused entries available to terminate the loop. This corrupted file system can then be mounted by the Linux kernel, triggering the infinite loop in the affected exFAT functions.

Remediation

Users can upgrade to the latest version of the Linux kernel, where this vulnerability has been addressed. Instructions for upgrading the Linux kernel can be found in the official Linux documentation.