aboutsummaryrefslogtreecommitdiff
path: root/arch/i386/kernel/ptrace.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/i386/kernel/ptrace.c')
-rw-r--r--arch/i386/kernel/ptrace.c63
1 files changed, 55 insertions, 8 deletions
diff --git a/arch/i386/kernel/ptrace.c b/arch/i386/kernel/ptrace.c
index 0da59b42843..340980203b0 100644
--- a/arch/i386/kernel/ptrace.c
+++ b/arch/i386/kernel/ptrace.c
@@ -271,6 +271,8 @@ static void clear_singlestep(struct task_struct *child)
void ptrace_disable(struct task_struct *child)
{
clear_singlestep(child);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
}
/*
@@ -509,15 +511,20 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
}
break;
+ case PTRACE_SYSEMU: /* continue and stop at next syscall, which will not be executed */
case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
case PTRACE_CONT: /* restart after signal. */
ret = -EIO;
if (!valid_signal(data))
break;
- if (request == PTRACE_SYSCALL) {
+ if (request == PTRACE_SYSEMU) {
+ set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+ clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+ } else if (request == PTRACE_SYSCALL) {
set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
- }
- else {
+ clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+ } else {
+ clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}
child->exit_code = data;
@@ -542,10 +549,17 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
wake_up_process(child);
break;
+ case PTRACE_SYSEMU_SINGLESTEP: /* Same as SYSEMU, but singlestep if not syscall */
case PTRACE_SINGLESTEP: /* set the trap flag. */
ret = -EIO;
if (!valid_signal(data))
break;
+
+ if (request == PTRACE_SYSEMU_SINGLESTEP)
+ set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+ else
+ clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
+
clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
set_singlestep(child);
child->exit_code = data;
@@ -678,26 +692,52 @@ void send_sigtrap(struct task_struct *tsk, struct pt_regs *regs, int error_code)
* - triggered by current->work.syscall_trace
*/
__attribute__((regparm(3)))
-void do_syscall_trace(struct pt_regs *regs, int entryexit)
+int do_syscall_trace(struct pt_regs *regs, int entryexit)
{
+ int is_sysemu = test_thread_flag(TIF_SYSCALL_EMU), ret = 0;
+ /* With TIF_SYSCALL_EMU set we want to ignore TIF_SINGLESTEP for syscall
+ * interception. */
+ int is_singlestep = !is_sysemu && test_thread_flag(TIF_SINGLESTEP);
+
/* do the secure computing check first */
secure_computing(regs->orig_eax);
- if (unlikely(current->audit_context) && entryexit)
- audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
+ if (unlikely(current->audit_context)) {
+ if (entryexit)
+ audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
+ /* Debug traps, when using PTRACE_SINGLESTEP, must be sent only
+ * on the syscall exit path. Normally, when TIF_SYSCALL_AUDIT is
+ * not used, entry.S will call us only on syscall exit, not
+ * entry; so when TIF_SYSCALL_AUDIT is used we must avoid
+ * calling send_sigtrap() on syscall entry.
+ *
+ * Note that when PTRACE_SYSEMU_SINGLESTEP is used,
+ * is_singlestep is false, despite his name, so we will still do
+ * the correct thing.
+ */
+ else if (is_singlestep)
+ goto out;
+ }
if (!(current->ptrace & PT_PTRACED))
goto out;
+ /* If a process stops on the 1st tracepoint with SYSCALL_TRACE
+ * and then is resumed with SYSEMU_SINGLESTEP, it will come in
+ * here. We have to check this and return */
+ if (is_sysemu && entryexit)
+ return 0;
+
/* Fake a debug trap */
- if (test_thread_flag(TIF_SINGLESTEP))
+ if (is_singlestep)
send_sigtrap(current, regs, 0);
- if (!test_thread_flag(TIF_SYSCALL_TRACE))
+ if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_sysemu)
goto out;
/* the 0x80 provides a way for the tracing parent to distinguish
between a syscall stop and SIGTRAP delivery */
+ /* Note that the debugger could change the result of test_thread_flag!*/
ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
/*
@@ -709,9 +749,16 @@ void do_syscall_trace(struct pt_regs *regs, int entryexit)
send_sig(current->exit_code, current, 1);
current->exit_code = 0;
}
+ ret = is_sysemu;
out:
if (unlikely(current->audit_context) && !entryexit)
audit_syscall_entry(current, AUDIT_ARCH_I386, regs->orig_eax,
regs->ebx, regs->ecx, regs->edx, regs->esi);
+ if (ret == 0)
+ return 0;
+ regs->orig_eax = -1; /* force skip of syscall restarting */
+ if (unlikely(current->audit_context))
+ audit_syscall_exit(current, AUDITSC_RESULT(regs->eax), regs->eax);
+ return 1;
}