vulnerability
Debian: CVE-2022-49779: linux -- security update
| Severity | CVSS | Published | Added | Modified |
|---|---|---|---|---|
| 7 | (AV:L/AC:L/Au:S/C:C/I:C/A:C) | May 1, 2025 | May 5, 2025 | Mar 30, 2026 |
Description
In the Linux kernel, the following vulnerability has been resolved:
kprobes: Skip clearing aggrprobe's post_handler in kprobe-on-ftrace case
In __unregister_kprobe_top(), if the currently unregistered probe has
post_handler but other child probes of the aggrprobe do not have
post_handler, the post_handler of the aggrprobe is cleared. If this is
a ftrace-based probe, there is a problem. In later calls to
disarm_kprobe(), we will use kprobe_ftrace_ops because post_handler is
NULL. But we're armed with kprobe_ipmodify_ops. This triggers a WARN in
__disarm_kprobe_ftrace() and may even cause use-after-free:
Failed to disarm kprobe-ftrace at kernel_clone+0x0/0x3c0 (error -2)
WARNING: CPU: 5 PID: 137 at kernel/kprobes.c:1135 __disarm_kprobe_ftrace.isra.21+0xcf/0xe0
Modules linked in: testKprobe_007(-)
CPU: 5 PID: 137 Comm: rmmod Not tainted 6.1.0-rc4-dirty #18
[...]
Call Trace:
<TASK>
__disable_kprobe+0xcd/0xe0
__unregister_kprobe_top+0x12/0x150
? mutex_lock+0xe/0x30
unregister_kprobes.part.23+0x31/0xa0
unregister_kprobe+0x32/0x40
__x64_sys_delete_module+0x15e/0x260
? do_user_addr_fault+0x2cd/0x6b0
do_syscall_64+0x3a/0x90
entry_SYSCALL_64_after_hwframe+0x63/0xcd
[...]
For the kprobe-on-ftrace case, we keep the post_handler setting to
identify this aggrprobe armed with kprobe_ipmodify_ops. This way we
can disarm it correctly.
Solution
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