From 41325dbd0bad5c9eccf6008ca8924fb28e2f8c57 Mon Sep 17 00:00:00 2001 From: Chen Zhongjin Date: Mon, 1 Aug 2022 11:37:19 +0800 Subject: [PATCH] kprobes: Forbid probing on trampoline and BPF code areas [ Upstream commit f10812102a0d296d72036cd82456386ce6db09f0 ] 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: 83b8b035c5dc ("kprobes, extable: Identify kprobes trampolines as kernel text area") Fixes: c2d5f4374f26 ("bpf: make jited programs visible in traces") Signed-off-by: Chen Zhongjin Signed-off-by: Ingo Molnar Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20220801033719.228248-1-chenzhongjin@huawei.com Signed-off-by: Sasha Levin --- kernel/kprobes.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 2ef90d15699fb..3a3c0166bd1f3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1559,7 +1559,8 @@ 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) || -- 2.39.5