linux-cve-announce - CVE-2022-50654: bpf: Fix panic due to wrong pageattr of im->image

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Message-ID: <2025120938-CVE-2022-50654-a5d9@gregkh>
Date: Tue,  9 Dec 2025 09:01:55 +0900
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2022-50654: bpf: Fix panic due to wrong pageattr of im->image

From: Greg Kroah-Hartman <gregkh@...nel.org>

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

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

bpf: Fix panic due to wrong pageattr of im->image

In the scenario where livepatch and kretfunc coexist, the pageattr of
im->image is rox after arch_prepare_bpf_trampoline in
bpf_trampoline_update, and then modify_fentry or register_fentry returns
-EAGAIN from bpf_tramp_ftrace_ops_func, the BPF_TRAMP_F_ORIG_STACK flag
will be configured, and arch_prepare_bpf_trampoline will be re-executed.

At this time, because the pageattr of im->image is rox,
arch_prepare_bpf_trampoline will read and write im->image, which causes
a fault. as follows:

  insmod livepatch-sample.ko    # samples/livepatch/livepatch-sample.c
  bpftrace -e 'kretfunc:cmdline_proc_show {}'

BUG: unable to handle page fault for address: ffffffffa0206000
PGD 322d067 P4D 322d067 PUD 322e063 PMD 1297e067 PTE d428061
Oops: 0003 [#1] PREEMPT SMP PTI
CPU: 2 PID: 270 Comm: bpftrace Tainted: G            E K    6.1.0 #5
RIP: 0010:arch_prepare_bpf_trampoline+0xed/0x8c0
RSP: 0018:ffffc90001083ad8 EFLAGS: 00010202
RAX: ffffffffa0206000 RBX: 0000000000000020 RCX: 0000000000000000
RDX: ffffffffa0206001 RSI: ffffffffa0206000 RDI: 0000000000000030
RBP: ffffc90001083b70 R08: 0000000000000066 R09: ffff88800f51b400
R10: 000000002e72c6e5 R11: 00000000d0a15080 R12: ffff8880110a68c8
R13: 0000000000000000 R14: ffff88800f51b400 R15: ffffffff814fec10
FS:  00007f87bc0dc780(0000) GS:ffff88803e600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffa0206000 CR3: 0000000010b70000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
 bpf_trampoline_update+0x25a/0x6b0
 __bpf_trampoline_link_prog+0x101/0x240
 bpf_trampoline_link_prog+0x2d/0x50
 bpf_tracing_prog_attach+0x24c/0x530
 bpf_raw_tp_link_attach+0x73/0x1d0
 __sys_bpf+0x100e/0x2570
 __x64_sys_bpf+0x1c/0x30
 do_syscall_64+0x5b/0x80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

With this patch, when modify_fentry or register_fentry returns -EAGAIN
from bpf_tramp_ftrace_ops_func, the pageattr of im->image will be reset
to nx+rw.

The Linux kernel CVE team has assigned CVE-2022-50654 to this issue.


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

	Issue introduced in 6.0 with commit 00963a2e75a872e5fce4d0115ac2786ec86b57a6 and fixed in 6.0.19 with commit d9d383cbf812a3b4094c089aa5f5d41a3bb4531d
	Issue introduced in 6.0 with commit 00963a2e75a872e5fce4d0115ac2786ec86b57a6 and fixed in 6.1.5 with commit 7f656fff955ccb216c40fa188a24c05fa40985a5
	Issue introduced in 6.0 with commit 00963a2e75a872e5fce4d0115ac2786ec86b57a6 and fixed in 6.2 with commit 9ed1d9aeef5842ecacb660fce933613b58af1e00

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-2022-50654
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:
	kernel/bpf/trampoline.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/d9d383cbf812a3b4094c089aa5f5d41a3bb4531d
	https://git.kernel.org/stable/c/7f656fff955ccb216c40fa188a24c05fa40985a5
	https://git.kernel.org/stable/c/9ed1d9aeef5842ecacb660fce933613b58af1e00