This patch cleans up and fixes bugs in resume_execution on x86-64.
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 <[EMAIL PROTECTED]>
---
arch/x86/kernel/kprobes_64.c | 37 ++++++++++++++++---------------------
1 file changed, 16 insertions(+), 21 deletions(-)
Index: 2.6.24-rc4-mm1/arch/x86/kernel/kprobes_64.c
===================================================================
--- 2.6.24-rc4-mm1.orig/arch/x86/kernel/kprobes_64.c
+++ 2.6.24-rc4-mm1/arch/x86/kernel/kprobes_64.c
@@ -498,7 +498,6 @@ static void __kprobes resume_execution(s
struct pt_regs *regs, struct kprobe_ctlblk *kcb)
{
unsigned long *tos = (unsigned long *)regs->sp;
- 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;
@@ -507,48 +506,44 @@ static void __kprobes resume_execution(s
if (*insn >= 0x40 && *insn <= 0x4f)
insn++;
+ regs->flags &= ~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->flags &= ~TF_MASK;
- /* ip 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; ip is correct. */
- next_rip = regs->ip;
*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 */
/* ip is correct. */
- next_rip = regs->ip;
+ goto no_change;
}
- break;
- case 0xea: /* jmp absolute -- ip is correct */
- next_rip = regs->ip;
- break;
default:
break;
}
- regs->flags &= ~TF_MASK;
- if (next_rip) {
- regs->ip = next_rip;
- } else {
- regs->ip = orig_rip + (regs->ip - copy_rip);
- }
+ regs->ip = orig_rip + (regs->ip - copy_rip);
+no_change:
restore_btf();
+
+ return;
}
int __kprobes post_kprobe_handler(struct pt_regs *regs)
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: [EMAIL PROTECTED], [EMAIL PROTECTED]
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