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Commit 6a119c1a authored by Chen Zhongjin's avatar Chen Zhongjin Committed by Greg Kroah-Hartman
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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: 5b485629 ("kprobes, extable: Identify kprobes trampolines as kernel text area")
Fixes: 74451e66 ("bpf: make jited programs visible in traces")
Signed-off-by: default avatarChen Zhongjin <chenzhongjin@huawei.com>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20220801033719.228248-1-chenzhongjin@huawei.com


Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent cc53477d

kernel/kprobes.c

+2 −1
Original line number Diff line number Diff line
@@ -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)) {