Linux Kernel EROFS Incorrect Offset Calculation Vulnerability Leading to Warning Trigger

A vulnerability in the Linux kernel's EROFS file system was introduced by an incorrect calculation of the offset in the zmap component. This miscalculation caused the I/O map length to be set to zero, which in turn triggered a warning in the I/O map iteration process. The issue was reported as a crash by syzbot, although it was not directly related to the EROFS file system.

Impact

The vulnerability could lead to a kernel crash by triggering a warning in the I/O map iteration process, indicating that the I/O map handling was not completed correctly.

Reproduction

The vulnerability can be reproduced using a syzkaller fuzzing campaign, which identified the issue by sending crafted inputs that exploited the incorrect offset calculation in the EROFS file system.

Remediation

Users should upgrade to the latest version of the Linux kernel where this vulnerability has been addressed.