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kprobes: Forbid probing on trampoline and BPF code areas

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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: 5b485629ba ("kprobes, extable: Identify kprobes trampolines as kernel text area")
Fixes: 74451e66d5 ("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
This commit is contained in:
Chen Zhongjin 2022-08-01 11:37:19 +08:00 committed by Ingo Molnar
parent 9de1f9c8ca
commit 28f6c37a29
1 changed files with 2 additions and 1 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

3
kernel/kprobes.c
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@ -1560,7 +1560,8 @@ static int check_kprobe_address_safe(struct kprobe *p,
preempt_disable(); preempt_disable();
/* Ensure it is not in reserved area nor out of text */ /* 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) || within_kprobe_blacklist((unsigned long) p->addr) ||
jump_label_text_reserved(p->addr, p->addr) || jump_label_text_reserved(p->addr, p->addr) ||
static_call_text_reserved(p->addr, p->addr) || static_call_text_reserved(p->addr, p->addr) ||