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-rw-r--r--include/linux/ptrace.h7
-rw-r--r--kernel/ptrace.c35
-rw-r--r--kernel/signal.c39
3 files changed, 66 insertions, 15 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index e93ef1a54fc7..67ad3f152329 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -47,6 +47,11 @@
#define PTRACE_GETREGSET 0x4204
#define PTRACE_SETREGSET 0x4205
+#define PTRACE_SEIZE 0x4206
+
+/* flags in @data for PTRACE_SEIZE */
+#define PTRACE_SEIZE_DEVEL 0x80000000 /* temp flag for development */
+
/* options set using PTRACE_SETOPTIONS */
#define PTRACE_O_TRACESYSGOOD 0x00000001
#define PTRACE_O_TRACEFORK 0x00000002
@@ -65,6 +70,7 @@
#define PTRACE_EVENT_EXEC 4
#define PTRACE_EVENT_VFORK_DONE 5
#define PTRACE_EVENT_EXIT 6
+#define PTRACE_EVENT_STOP 7
#include <asm/ptrace.h>
@@ -77,6 +83,7 @@
* flags. When the a task is stopped the ptracer owns task->ptrace.
*/
+#define PT_SEIZED 0x00010000 /* SEIZE used, enable new behavior */
#define PT_PTRACED 0x00000001
#define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
#define PT_TRACESYSGOOD 0x00000004
diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 45a8a4c5d8b2..dcf9f974198c 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -209,10 +209,28 @@ bool ptrace_may_access(struct task_struct *task, unsigned int mode)
return !err;
}
-static int ptrace_attach(struct task_struct *task)
+static int ptrace_attach(struct task_struct *task, long request,
+ unsigned long flags)
{
+ bool seize = (request == PTRACE_SEIZE);
int retval;
+ /*
+ * SEIZE will enable new ptrace behaviors which will be implemented
+ * gradually. SEIZE_DEVEL is used to prevent applications
+ * expecting full SEIZE behaviors trapping on kernel commits which
+ * are still in the process of implementing them.
+ *
+ * Only test programs for new ptrace behaviors being implemented
+ * should set SEIZE_DEVEL. If unset, SEIZE will fail with -EIO.
+ *
+ * Once SEIZE behaviors are completely implemented, this flag and
+ * the following test will be removed.
+ */
+ retval = -EIO;
+ if (seize && !(flags & PTRACE_SEIZE_DEVEL))
+ goto out;
+
audit_ptrace(task);
retval = -EPERM;
@@ -244,11 +262,16 @@ static int ptrace_attach(struct task_struct *task)
goto unlock_tasklist;
task->ptrace = PT_PTRACED;
+ if (seize)
+ task->ptrace |= PT_SEIZED;
if (task_ns_capable(task, CAP_SYS_PTRACE))
task->ptrace |= PT_PTRACE_CAP;
__ptrace_link(task, current);
- send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
+
+ /* SEIZE doesn't trap tracee on attach */
+ if (!seize)
+ send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
spin_lock(&task->sighand->siglock);
@@ -785,8 +808,8 @@ SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
goto out;
}
- if (request == PTRACE_ATTACH) {
- ret = ptrace_attach(child);
+ if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+ ret = ptrace_attach(child, request, data);
/*
* Some architectures need to do book-keeping after
* a ptrace attach.
@@ -927,8 +950,8 @@ asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
goto out;
}
- if (request == PTRACE_ATTACH) {
- ret = ptrace_attach(child);
+ if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
+ ret = ptrace_attach(child, request, data);
/*
* Some architectures need to do book-keeping after
* a ptrace attach.
diff --git a/kernel/signal.c b/kernel/signal.c
index b5f55ca1f43f..589292f38530 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -1873,21 +1873,26 @@ static void ptrace_stop(int exit_code, int why, int clear_code, siginfo_t *info)
recalc_sigpending_tsk(current);
}
-void ptrace_notify(int exit_code)
+static void ptrace_do_notify(int signr, int exit_code, int why)
{
siginfo_t info;
- BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
-
memset(&info, 0, sizeof info);
- info.si_signo = SIGTRAP;
+ info.si_signo = signr;
info.si_code = exit_code;
info.si_pid = task_pid_vnr(current);
info.si_uid = current_uid();
/* Let the debugger run. */
+ ptrace_stop(exit_code, why, 1, &info);
+}
+
+void ptrace_notify(int exit_code)
+{
+ BUG_ON((exit_code & (0x7f | ~0xffff)) != SIGTRAP);
+
spin_lock_irq(&current->sighand->siglock);
- ptrace_stop(exit_code, CLD_TRAPPED, 1, &info);
+ ptrace_do_notify(SIGTRAP, exit_code, CLD_TRAPPED);
spin_unlock_irq(&current->sighand->siglock);
}
@@ -2017,7 +2022,13 @@ static bool do_signal_stop(int signr)
/**
* do_jobctl_trap - take care of ptrace jobctl traps
*
- * It is currently used only to trap for group stop while ptraced.
+ * When PT_SEIZED, it's used for both group stop and explicit
+ * SEIZE/INTERRUPT traps. Both generate PTRACE_EVENT_STOP trap with
+ * accompanying siginfo. If stopped, lower eight bits of exit_code contain
+ * the stop signal; otherwise, %SIGTRAP.
+ *
+ * When !PT_SEIZED, it's used only for group stop trap with stop signal
+ * number as exit_code and no siginfo.
*
* CONTEXT:
* Must be called with @current->sighand->siglock held, which may be
@@ -2025,11 +2036,21 @@ static bool do_signal_stop(int signr)
*/
static void do_jobctl_trap(void)
{
+ struct signal_struct *signal = current->signal;
int signr = current->jobctl & JOBCTL_STOP_SIGMASK;
- WARN_ON_ONCE(!signr);
- ptrace_stop(signr, CLD_STOPPED, 0, NULL);
- current->exit_code = 0;
+ if (current->ptrace & PT_SEIZED) {
+ if (!signal->group_stop_count &&
+ !(signal->flags & SIGNAL_STOP_STOPPED))
+ signr = SIGTRAP;
+ WARN_ON_ONCE(!signr);
+ ptrace_do_notify(signr, signr | (PTRACE_EVENT_STOP << 8),
+ CLD_STOPPED);
+ } else {
+ WARN_ON_ONCE(!signr);
+ ptrace_stop(signr, CLD_STOPPED, 0, NULL);
+ current->exit_code = 0;
+ }
}
static int ptrace_signal(int signr, siginfo_t *info,