TLDRVuln - Cybersecurity Vulnerabilities Made Simple

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

fs/ntfs3: Fix NULL deref in ntfs_update_mftmirr

If ntfs_fill_super() wasn't called then sbi->sb will be equal to NULL.

Code should check this ptr before dereferencing. Syzbot hit this issue

via passing wrong mount param as can be seen from log below

Fail log:

ntfs3: Unknown parameter 'iochvrset'

general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN

KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]

CPU: 1 PID: 3589 Comm: syz-executor210 Not tainted 5.18.0-rc3-syzkaller-00016-gb253435746d9 #0

...

Call Trace:

<TASK>

put_ntfs+0x1ed/0x2a0 fs/ntfs3/super.c:463

ntfs_fs_free+0x6a/0xe0 fs/ntfs3/super.c:1363

put_fs_context+0x119/0x7a0 fs/fs_context.c:469

do_new_mount+0x2b4/0xad0 fs/namespace.c:3044

do_mount fs/namespace.c:3383 [inline]

__do_sys_mount fs/namespace.c:3591 [inline]