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Diffstat (limited to 'arch/x86_64/kernel/ptrace.c')
-rw-r--r--arch/x86_64/kernel/ptrace.c29
1 files changed, 17 insertions, 12 deletions
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c
index 2d50024..addc14a 100644
--- a/arch/x86_64/kernel/ptrace.c
+++ b/arch/x86_64/kernel/ptrace.c
@@ -116,17 +116,17 @@ unsigned long convert_rip_to_linear(struct task_struct *child, struct pt_regs *r
return addr;
}
-static int is_at_popf(struct task_struct *child, struct pt_regs *regs)
+static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
{
int i, copied;
- unsigned char opcode[16];
+ unsigned char opcode[15];
unsigned long addr = convert_rip_to_linear(child, regs);
copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
for (i = 0; i < copied; i++) {
switch (opcode[i]) {
- /* popf */
- case 0x9d:
+ /* popf and iret */
+ case 0x9d: case 0xcf:
return 1;
/* CHECKME: 64 65 */
@@ -138,14 +138,17 @@ static int is_at_popf(struct task_struct *child, struct pt_regs *regs)
case 0x26: case 0x2e:
case 0x36: case 0x3e:
case 0x64: case 0x65:
- case 0xf0: case 0xf2: case 0xf3:
+ case 0xf2: case 0xf3:
continue;
- /* REX prefixes */
case 0x40 ... 0x4f:
+ if (regs->cs != __USER_CS)
+ /* 32-bit mode: register increment */
+ return 0;
+ /* 64-bit mode: REX prefix */
continue;
- /* CHECKME: f0, f2, f3 */
+ /* CHECKME: f2, f3 */
/*
* pushf: NOTE! We should probably not let
@@ -186,10 +189,8 @@ static void set_singlestep(struct task_struct *child)
* ..but if TF is changed by the instruction we will trace,
* don't mark it as being "us" that set it, so that we
* won't clear it by hand later.
- *
- * AK: this is not enough, LAHF and IRET can change TF in user space too.
*/
- if (is_at_popf(child, regs))
+ if (is_setting_trap_flag(child, regs))
return;
child->ptrace |= PT_DTRACE;
@@ -420,9 +421,13 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
if ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
break;
if (i == 4) {
- child->thread.debugreg7 = data;
+ child->thread.debugreg7 = data;
+ if (data)
+ set_tsk_thread_flag(child, TIF_DEBUG);
+ else
+ clear_tsk_thread_flag(child, TIF_DEBUG);
ret = 0;
- }
+ }
break;
}
break;
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