Messages in this thread | | | Date | Tue, 2 Aug 2022 20:28:39 +0800 | Subject | Re: [PATCH v3] kprobes: Forbid probing on trampoline and bpf prog | From | Chen Zhongjin <> |
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On 2022/8/2 17:06, Jiri Olsa wrote: > On Mon, Aug 01, 2022 at 04:51:46PM -0400, Steven Rostedt wrote: >> On Mon, 1 Aug 2022 22:41:19 +0200 >> Jiri Olsa <olsajiri@gmail.com> wrote: >> >>> LGTM cc-ing Steven because it affects ftrace as well >> Thanks for the Cc, but I don't quite see how it affects ftrace. >> >> Unless you are just saying how it can affect kprobe_events? > nope, I just saw the 'ftrace' in changelog ;-) > > anyway the patch makes check_kprobe_address_safe to fail > on ftrace trampoline address.. but not sure you could make > kprobe on ftrace trampoline before, probably not > > jirka
In fact with CONFIG_KPROBE_EVENTS_ON_NOTRACE=y it can happen.
But I think ftrace has no responsibility to promise the address safety when this option open.
Best,
Chen
>> -- Steve >> >> >>> jirka >>> >>>> v1 -> v2: >>>> Check core_kernel_text and is_module_text_address rather than >>>> only kprobe_insn. >>>> Also fix title and commit message for this. See old patch at [1]. >>>> --- >>>> 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) || >>>> static_call_text_reserved(p->addr, p->addr) || >>>> -- >>>> 2.17.1 >>>>
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