diff options
| author | Masami Hiramatsu <mhiramat@redhat.com> | 2007-12-18 18:05:58 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-12-18 18:05:58 +0100 |
| commit | 0b0122faf4833548072d23f3c3063c23bc289746 (patch) | |
| tree | 4c5183e0b92142bdfb0f5abf2cab58329e997cbc /arch | |
| parent | 29b6cd794e73eea7600541d06288a09861ffecb0 (diff) | |
x86: kprobes bugfix
Kprobes for x86-64 may cause a kernel crash if it inserted on "iret"
instruction. "call absolute" is invalid on x86-64, so we don't need
treat it.
- Change the processing order as same as x86-32.
- Add "iret"(0xcf) case.
- Remove next_rip local variable.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/kprobes_64.c | 41 |
1 files changed, 18 insertions, 23 deletions
diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c index a575059fb42..5df19a9f923 100644 --- a/arch/x86/kernel/kprobes_64.c +++ b/arch/x86/kernel/kprobes_64.c @@ -485,7 +485,6 @@ static void __kprobes resume_execution(struct kprobe *p, struct pt_regs *regs, struct kprobe_ctlblk *kcb) { unsigned long *tos = (unsigned long *)regs->rsp; - unsigned long next_rip = 0; unsigned long copy_rip = (unsigned long)p->ainsn.insn; unsigned long orig_rip = (unsigned long)p->addr; kprobe_opcode_t *insn = p->ainsn.insn; @@ -494,46 +493,42 @@ static void __kprobes resume_execution(struct kprobe *p, if (*insn >= 0x40 && *insn <= 0x4f) insn++; + regs->eflags &= ~TF_MASK; switch (*insn) { - case 0x9c: /* pushfl */ + case 0x9c: /* pushfl */ *tos &= ~(TF_MASK | IF_MASK); *tos |= kcb->kprobe_old_rflags; break; - case 0xc3: /* ret/lret */ - case 0xcb: - case 0xc2: + case 0xc2: /* iret/ret/lret */ + case 0xc3: case 0xca: - regs->eflags &= ~TF_MASK; - /* rip is already adjusted, no more changes required*/ - return; - case 0xe8: /* call relative - Fix return addr */ + case 0xcb: + case 0xcf: + case 0xea: /* jmp absolute -- ip is correct */ + /* ip is already adjusted, no more changes required */ + goto no_change; + case 0xe8: /* call relative - Fix return addr */ *tos = orig_rip + (*tos - copy_rip); break; case 0xff: if ((insn[1] & 0x30) == 0x10) { /* call absolute, indirect */ - /* Fix return addr; rip is correct. */ - next_rip = regs->rip; + /* Fix return addr; ip is correct. */ *tos = orig_rip + (*tos - copy_rip); + goto no_change; } else if (((insn[1] & 0x31) == 0x20) || /* jmp near, absolute indirect */ ((insn[1] & 0x31) == 0x21)) { /* jmp far, absolute indirect */ - /* rip is correct. */ - next_rip = regs->rip; + /* ip is correct. */ + goto no_change; } - break; - case 0xea: /* jmp absolute -- rip is correct */ - next_rip = regs->rip; - break; default: break; } - regs->eflags &= ~TF_MASK; - if (next_rip) { - regs->rip = next_rip; - } else { - regs->rip = orig_rip + (regs->rip - copy_rip); - } + regs->rip = orig_rip + (regs->rip - copy_rip); +no_change: + + return; } int __kprobes post_kprobe_handler(struct pt_regs *regs) |