kprobes: Forbid probing on trampoline and BPF code areas

[ Upstream commit 31d5759ce06e6a7fb9a9f6eb353d6e3f44d21f65 ]

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: bf6a01b7b2ab ("kprobes, extable: Identify kprobes trampolines as kernel text area")
Fixes: 487a429673a4 ("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
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index c93340bae3ac2590e8d67e966c5212b17f68408c..671b51782182bd43e7d910284819584719e29ff9 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1594,7 +1594,8 @@ 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)) {