Subject: CVE-2023-52848: f2fs: fix to drop meta_inode's page cache in f2fs_put_super()

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

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

f2fs: fix to drop meta_inode's page cache in f2fs_put_super()

syzbot reports a kernel bug as below:

F2FS-fs (loop1): detect filesystem reference count leak during umount, type: 10, count: 1
kernel BUG at fs/f2fs/super.c:1639!
CPU: 0 PID: 15451 Comm: syz-executor.1 Not tainted 6.5.0-syzkaller-09338-ge0152e7481c6 #0
RIP: 0010:f2fs_put_super+0xce1/0xed0 fs/f2fs/super.c:1639
Call Trace:
 generic_shutdown_super+0x161/0x3c0 fs/super.c:693
 kill_block_super+0x3b/0x70 fs/super.c:1646
 kill_f2fs_super+0x2b7/0x3d0 fs/f2fs/super.c:4879
 deactivate_locked_super+0x9a/0x170 fs/super.c:481
 deactivate_super+0xde/0x100 fs/super.c:514
 cleanup_mnt+0x222/0x3d0 fs/namespace.c:1254
 task_work_run+0x14d/0x240 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:171 [inline]
 exit_to_user_mode_prepare+0x210/0x240 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x1d/0x60 kernel/entry/common.c:296
 do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

In f2fs_put_super(), it tries to do sanity check on dirty and IO
reference count of f2fs, once there is any reference count leak,
it will trigger panic.

The root case is, during f2fs_put_super(), if there is any IO error
in f2fs_wait_on_all_pages(), we missed to truncate meta_inode's page
cache later, result in panic, fix this case.

The Linux kernel CVE team has assigned CVE-2023-52848 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.5 with commit 20872584b8c0 and fixed in 6.5.12 with commit eb42e1862aa7
	Issue introduced in 6.5 with commit 20872584b8c0 and fixed in 6.6.2 with commit 10b2a6c0dade
	Issue introduced in 6.5 with commit 20872584b8c0 and fixed in 6.7 with commit a4639380bbe6
	Issue introduced in 6.4.16 with commit 0e2577074b45

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2023-52848
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	fs/f2fs/super.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/eb42e1862aa7934c2c21890097ce4993c5e0d192
	https://git.kernel.org/stable/c/10b2a6c0dade67b5a2b2d17fb75c457ea1985fad
	https://git.kernel.org/stable/c/a4639380bbe66172df329f8b54aa7d2e943f0f64