From: Chen Zhongjin <chenzhongjin@huawei.com>
Date: Mon, 1 Aug 2022 11:37:19 +0800
Subject: kprobes: Forbid probing on trampoline and BPF code areas
Git-commit: 28f6c37a2910f565b4f5960df52b2eccae28c891
Patch-mainline: v6.0-rc1
References: git-fixes
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@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20220801033719.228248-1-chenzhongjin@huawei.com
Acked-by: Petr Pavlu <petr.pavlu@suse.com>
---
kernel/kprobes.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f214f8c088ed..80697e5e03e4 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1560,7 +1560,8 @@ 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)) {