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authorMasami Hiramatsu <mhiramat@redhat.com>2007-12-18 18:05:58 +0100
committerIngo Molnar <mingo@elte.hu>2007-12-18 18:05:58 +0100
commit0b0122faf4833548072d23f3c3063c23bc289746 (patch)
tree4c5183e0b92142bdfb0f5abf2cab58329e997cbc /arch
parent29b6cd794e73eea7600541d06288a09861ffecb0 (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.c41
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)