1 files changed, 73 insertions, 31 deletions

diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 9178d5cc0b01..800f113bea66 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -47,6 +47,13 @@
 #define PTRACE_GETREGSET        0x4204
 #define PTRACE_SETREGSET        0x4205
 
+#define PTRACE_SEIZE            0x4206
+#define PTRACE_INTERRUPT        0x4207
+#define PTRACE_LISTEN           0x4208
+
+/* 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 +72,7 @@
 #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>
 
@@ -77,16 +85,22 @@
  * 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
 #define PT_PTRACE_CAP   0x00000008      /* ptracer can follow suid-exec */
-#define PT_TRACE_FORK   0x00000010
-#define PT_TRACE_VFORK  0x00000020
-#define PT_TRACE_CLONE  0x00000040
-#define PT_TRACE_EXEC   0x00000080
-#define PT_TRACE_VFORK_DONE     0x00000100
-#define PT_TRACE_EXIT   0x00000200
+
+/* PT_TRACE_* event enable flags */
+#define PT_EVENT_FLAG_SHIFT     4
+#define PT_EVENT_FLAG(event)    (1 << (PT_EVENT_FLAG_SHIFT + (event) - 1))
+
+#define PT_TRACE_FORK           PT_EVENT_FLAG(PTRACE_EVENT_FORK)
+#define PT_TRACE_VFORK          PT_EVENT_FLAG(PTRACE_EVENT_VFORK)
+#define PT_TRACE_CLONE          PT_EVENT_FLAG(PTRACE_EVENT_CLONE)
+#define PT_TRACE_EXEC           PT_EVENT_FLAG(PTRACE_EVENT_EXEC)
+#define PT_TRACE_VFORK_DONE     PT_EVENT_FLAG(PTRACE_EVENT_VFORK_DONE)
+#define PT_TRACE_EXIT           PT_EVENT_FLAG(PTRACE_EVENT_EXIT)
 
 #define PT_TRACE_MASK   0x000003f4
 
@@ -105,7 +119,7 @@ extern long arch_ptrace(struct task_struct *child, long request,
 extern int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len);
 extern int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len);
 extern void ptrace_disable(struct task_struct *);
-extern int ptrace_check_attach(struct task_struct *task, int kill);
+extern int ptrace_check_attach(struct task_struct *task, bool ignore_state);
 extern int ptrace_request(struct task_struct *child, long request,
                           unsigned long addr, unsigned long data);
 extern void ptrace_notify(int exit_code);
@@ -122,7 +136,7 @@ extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
 
 static inline int ptrace_reparented(struct task_struct *child)
 {
-        return child->real_parent != child->parent;
+        return !same_thread_group(child->real_parent, child->parent);
 }
 
 static inline void ptrace_unlink(struct task_struct *child)
@@ -137,36 +151,56 @@ int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
                             unsigned long data);
 
 /**
- * task_ptrace - return %PT_* flags that apply to a task
- * @task:       pointer to &task_struct in question
+ * ptrace_parent - return the task that is tracing the given task
+ * @task: task to consider
  *
- * Returns the %PT_* flags that apply to @task.
+ * Returns %NULL if no one is tracing @task, or the &struct task_struct
+ * pointer to its tracer.
+ *
+ * Must called under rcu_read_lock().  The pointer returned might be kept
+ * live only by RCU.  During exec, this may be called with task_lock() held
+ * on @task, still held from when check_unsafe_exec() was called.
  */
-static inline int task_ptrace(struct task_struct *task)
+static inline struct task_struct *ptrace_parent(struct task_struct *task)
 {
-        return task->ptrace;
+        if (unlikely(task->ptrace))
+                return rcu_dereference(task->parent);
+        return NULL;
+}
+
+/**
+ * ptrace_event_enabled - test whether a ptrace event is enabled
+ * @task: ptracee of interest
+ * @event: %PTRACE_EVENT_* to test
+ *
+ * Test whether @event is enabled for ptracee @task.
+ *
+ * Returns %true if @event is enabled, %false otherwise.
+ */
+static inline bool ptrace_event_enabled(struct task_struct *task, int event)
+{
+        return task->ptrace & PT_EVENT_FLAG(event);
 }
 
 /**
  * ptrace_event - possibly stop for a ptrace event notification
- * @mask:       %PT_* bit to check in @current->ptrace
- * @event:      %PTRACE_EVENT_* value to report if @mask is set
+ * @event:      %PTRACE_EVENT_* value to report
  * @message:    value for %PTRACE_GETEVENTMSG to return
  *
- * This checks the @mask bit to see if ptrace wants stops for this event.
- * If so we stop, reporting @event and @message to the ptrace parent.
- *
- * Returns nonzero if we did a ptrace notification, zero if not.
+ * Check whether @event is enabled and, if so, report @event and @message
+ * to the ptrace parent.
  *
  * Called without locks.
  */
-static inline int ptrace_event(int mask, int event, unsigned long message)
+static inline void ptrace_event(int event, unsigned long message)
 {
-        if (mask && likely(!(current->ptrace & mask)))
-                return 0;
-        current->ptrace_message = message;
-        ptrace_notify((event << 8) | SIGTRAP);
-        return 1;
+        if (unlikely(ptrace_event_enabled(current, event))) {
+                current->ptrace_message = message;
+                ptrace_notify((event << 8) | SIGTRAP);
+        } else if (event == PTRACE_EVENT_EXEC && unlikely(current->ptrace)) {
+                /* legacy EXEC report via SIGTRAP */
+                send_sig(SIGTRAP, current, 0);
+        }
 }
 
 /**
@@ -183,16 +217,24 @@ static inline void ptrace_init_task(struct task_struct *child, bool ptrace)
 {
         INIT_LIST_HEAD(&child->ptrace_entry);
         INIT_LIST_HEAD(&child->ptraced);
-        child->parent = child->real_parent;
+#ifdef CONFIG_HAVE_HW_BREAKPOINT
+        atomic_set(&child->ptrace_bp_refcnt, 1);
+#endif
+        child->jobctl = 0;
         child->ptrace = 0;
-        if (unlikely(ptrace) && (current->ptrace & PT_PTRACED)) {
+        child->parent = child->real_parent;
+
+        if (unlikely(ptrace) && current->ptrace) {
                 child->ptrace = current->ptrace;
                 __ptrace_link(child, current->parent);
-        }
 
-#ifdef CONFIG_HAVE_HW_BREAKPOINT
-        atomic_set(&child->ptrace_bp_refcnt, 1);
-#endif
+                if (child->ptrace & PT_SEIZED)
+                        task_set_jobctl_pending(child, JOBCTL_TRAP_STOP);
+                else
+                        sigaddset(&child->pending.signal, SIGSTOP);
+
+                set_tsk_thread_flag(child, TIF_SIGPENDING);
+        }
 }
 
 /**