In the Linux kernel, the following vulnerability has been resolved: Squashfs: check metadata...

In the Linux kernel, the following vulnerability has been resolved:

Squashfs: check metadata block offset is within range

Syzkaller reports a "general protection fault in squashfs_copy_data"

This is ultimately caused by a corrupted index look-up table, which produces a negative metadata block offset.

This is subsequently passed to squashfs_copy_data (via squashfs_read_metadata) where the negative offset causes an out of bounds access.

The fix is to check that the offset is within range in squashfs_read_metadata. This will trap this and other cases.