Linux Kernel exFAT File System Infinite Loop Vulnerability in Directory Read Function

An infinite loop vulnerability has been identified in the Linux kernel's exFAT file system implementation, specifically within the 'exfat_readdir()' function. This issue arises when a corrupted file system creates a cluster that links to itself, leaving an unused directory entry. In such cases, the 'dentry' variable fails to increment, allowing the condition 'dentry < max_dentries' to bypass the loop, leading to an infinite iteration. Consequently, the 's_lock' is not released, causing other tasks, like 'exfat_sync_fs()', to hang. The vulnerability affects several versions of the Linux kernel that include the flawed exFAT implementation.

Impact

Exploitation of this vulnerability leads to a deadlock, where the file system lock is not released, causing tasks that depend on the file system synchronization to hang indefinitely.