kprobes: Forbid probing on trampoline and BPF code areas

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

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f214f8c..80697e5 100644 (file)
--- 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) ||
            static_call_text_reserved(p->addr, p->addr) ||