This is a note to let you know that I've just added the patch titled
kprobes: Forbid probing on trampoline and BPF code areas
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kprobes-forbid-probing-on-trampoline-and-bpf-code-ar.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cdc4f9341442913f18916902ffe78bc578d5de3f
Author: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
Date: Mon Aug 1 11:37:19 2022 +0800
kprobes: Forbid probing on trampoline and BPF code areas
[ Upstream commit 28f6c37a2910f565b4f5960df52b2eccae28c891 ]
kernel_text_address() treats ftrace_trampoline, kprobe_insn_slot
and bpf_text_address as valid kprobe addresses - which is not ideal.
These text areas are removable and changeable without any notification
to kprobes, and probing on them can trigger unexpected behavior:
https://lkml.org/lkml/2022/7/26/1148
Considering that jump_label and static_call text are already
forbiden to probe, kernel_text_address() should be replaced with
core_kernel_text() and is_module_text_address() to check other text
areas which are unsafe to kprobe.
[ mingo: Rewrote the changelog. ]
Fixes: 5b485629ba0d ("kprobes, extable: Identify kprobes trampolines as kernel text area")
Fixes: 74451e66d516 ("bpf: make jited programs visible in traces")
Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220801033719.228248-1-chenzhongjin@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 4f918dd28fb7..b8e14aa6d496 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1551,7 +1551,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
preempt_disable();
/* Ensure it is not in reserved area nor out of text */
- if (!kernel_text_address((unsigned long) p->addr) ||
+ if (!(core_kernel_text((unsigned long) p->addr) ||
+ is_module_text_address((unsigned long) p->addr)) ||
within_kprobe_blacklist((unsigned long) p->addr) ||
jump_label_text_reserved(p->addr, p->addr) ||
find_bug((unsigned long)p->addr)) {
