diff options
Diffstat (limited to 'arch/x86_64/kernel/ptrace.c')
| -rw-r--r-- | arch/x86_64/kernel/ptrace.c | 29 |
1 files changed, 17 insertions, 12 deletions
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c index 2d50024c9f3..addc14af0c5 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; |