Subject: CVE-2024-49887: f2fs: fix to don't panic system for no free segment fault injection

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

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

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

f2fs: fix to don't panic system for no free segment fault injection

f2fs: fix to don't panic system for no free segment fault injection

syzbot reports a f2fs bug as below:

F2FS-fs (loop0): inject no free segment in get_new_segment of __allocate_new_segment+0x1ce/0x940 fs/f2fs/segment.c:3167
F2FS-fs (loop0): Stopped filesystem due to reason: 7
------------[ cut here ]------------
kernel BUG at fs/f2fs/segment.c:2748!
CPU: 0 UID: 0 PID: 5109 Comm: syz-executor304 Not tainted 6.11.0-rc6-syzkaller-00363-g89f5e14d05b4 #0
RIP: 0010:get_new_segment fs/f2fs/segment.c:2748 [inline]
RIP: 0010:new_curseg+0x1f61/0x1f70 fs/f2fs/segment.c:2836
Call Trace:
 __allocate_new_segment+0x1ce/0x940 fs/f2fs/segment.c:3167
 f2fs_allocate_new_section fs/f2fs/segment.c:3181 [inline]
 f2fs_allocate_pinning_section+0xfa/0x4e0 fs/f2fs/segment.c:3195
 f2fs_expand_inode_data+0x5d6/0xbb0 fs/f2fs/file.c:1799
 f2fs_fallocate+0x448/0x960 fs/f2fs/file.c:1903
 vfs_fallocate+0x553/0x6c0 fs/open.c:334
 do_vfs_ioctl+0x2592/0x2e50 fs/ioctl.c:886
 __do_sys_ioctl fs/ioctl.c:905 [inline]
 __se_sys_ioctl+0x81/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0010:get_new_segment fs/f2fs/segment.c:2748 [inline]
RIP: 0010:new_curseg+0x1f61/0x1f70 fs/f2fs/segment.c:2836

The root cause is when we inject no free segment fault into f2fs,
we should not panic system, fix it.

The Linux kernel CVE team has assigned CVE-2024-49887 to this issue.

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

	Issue introduced in 6.9 with commit 8b10d3653735 and fixed in 6.10.14 with commit 9f6e7a0512a5
	Issue introduced in 6.9 with commit 8b10d3653735 and fixed in 6.11.3 with commit 645ec43760e8
	Issue introduced in 6.9 with commit 8b10d3653735 and fixed in 6.12-rc1 with commit 65a6ce4726c2

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-2024-49887
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/segment.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/9f6e7a0512a57387d36f5e9e9635d6668cac13dd
	https://git.kernel.org/stable/c/645ec43760e86d3079fee2e8b51fde7060a540d0
	https://git.kernel.org/stable/c/65a6ce4726c27b45600303f06496fef46d00b57f