diff options
| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2022-08-02 15:04:16 +0900 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2022-08-02 12:35:04 +0200 |
| commit | dec8784c9088b131a1523f582c2194cfc8107dc0 (patch) | |
| tree | bc17e45a99172dc9dbd541538d41b7f0924a8288 /arch/x86/kernel/kprobes | |
| parent | 28f6c37a2910f565b4f5960df52b2eccae28c891 (diff) | |
x86/kprobes: Update kcb status flag after singlestepping
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: 6256e668b7af ("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
Diffstat (limited to 'arch/x86/kernel/kprobes')
| -rw-r--r-- | arch/x86/kernel/kprobes/core.c | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 7c4ab8870da4..74167dc5f55e 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -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); |