]> git.itanic.dy.fi Git - linux-stable/commit
kprobes: Fix possible use-after-free issue on kprobe registration
authorZheng Yejian <zhengyejian1@huawei.com>
Wed, 10 Apr 2024 01:58:02 +0000 (09:58 +0800)
committerMasami Hiramatsu (Google) <mhiramat@kernel.org>
Wed, 10 Apr 2024 14:35:51 +0000 (23:35 +0900)
commit325f3fb551f8cd672dbbfc4cf58b14f9ee3fc9e8
tree8b8acb50b22c50f4be100883e4c31b7505968292
parentfec50db7033ea478773b159e0e2efb135270e3b7
kprobes: Fix possible use-after-free issue on kprobe registration

When unloading a module, its state is changing MODULE_STATE_LIVE ->
 MODULE_STATE_GOING -> MODULE_STATE_UNFORMED. Each change will take
a time. `is_module_text_address()` and `__module_text_address()`
works with MODULE_STATE_LIVE and MODULE_STATE_GOING.
If we use `is_module_text_address()` and `__module_text_address()`
separately, there is a chance that the first one is succeeded but the
next one is failed because module->state becomes MODULE_STATE_UNFORMED
between those operations.

In `check_kprobe_address_safe()`, if the second `__module_text_address()`
is failed, that is ignored because it expected a kernel_text address.
But it may have failed simply because module->state has been changed
to MODULE_STATE_UNFORMED. In this case, arm_kprobe() will try to modify
non-exist module text address (use-after-free).

To fix this problem, we should not use separated `is_module_text_address()`
and `__module_text_address()`, but use only `__module_text_address()`
once and do `try_module_get(module)` which is only available with
MODULE_STATE_LIVE.

Link: https://lore.kernel.org/all/20240410015802.265220-1-zhengyejian1@huawei.com/
Fixes: 28f6c37a2910 ("kprobes: Forbid probing on trampoline and BPF code areas")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
kernel/kprobes.c