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x86/kprobes: Update kcb status flag after singlestepping

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Fix kprobes to update kcb (kprobes control block) status flag to
KPROBE_HIT_SSDONE even if the kp->post_handler is not set.

This bug may cause a kernel panic if another INT3 user runs right
after kprobes because kprobe_int3_handler() misunderstands the
INT3 is kprobe's single stepping INT3.

Fixes: 6256e668b7 ("x86/kprobes: Use int3 instead of debug trap for single-step")
Reported-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Daniel Müller <deso@posteo.net>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20220727210136.jjgc3lpqeq42yr3m@muellerd-fedora-PC2BDTX9
Link: https://lore.kernel.org/r/165942025658.342061.12452378391879093249.stgit@devnote2
This commit is contained in:
Masami Hiramatsu (Google) 2022-08-02 15:04:16 +09:00 • committed by Ingo Molnar
parent 28f6c37a29
commit dec8784c90
1 changed files with 11 additions and 7 deletions
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18
arch/x86/kernel/kprobes/core.c
View file

@ -814,16 +814,20 @@ set_current_kprobe(struct kprobe *p, struct pt_regs *regs,
static void kprobe_post_process(struct kprobe *cur, struct pt_regs *regs,
struct kprobe_ctlblk *kcb)
{
if ((kcb->kprobe_status != KPROBE_REENTER) && cur->post_handler) {
kcb->kprobe_status = KPROBE_HIT_SSDONE;
cur->post_handler(cur, regs, 0);
}
/* Restore back the original saved kprobes variables and continue. */
if (kcb->kprobe_status == KPROBE_REENTER)
if (kcb->kprobe_status == KPROBE_REENTER) {
/* This will restore both kcb and current_kprobe */
restore_previous_kprobe(kcb);
else
} else {
/*
* Always update the kcb status because
* reset_curent_kprobe() doesn't update kcb.
*/
kcb->kprobe_status = KPROBE_HIT_SSDONE;
if (cur->post_handler)
cur->post_handler(cur, regs, 0);
reset_current_kprobe();
}
}
NOKPROBE_SYMBOL(kprobe_post_process);