do_wait: return security_task_wait() error code in place of -ECHILD

[linux-2.6-omap-h63xx.git] / kernel / exit.c

diff --git a/kernel/exit.c b/kernel/exit.c
index 1e909826a80483a7acf6d52a8cee8b2bcc6d7522..a2af6cac823c2fd42744e4d2e20e667a71b876f2 100644 (file)
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1199,14 +1199,10 @@ static int eligible_child(enum pid_type type, struct pid *pid, int options,
                return 0;
 
        err = security_task_wait(p);
-       if (likely(!err))
-               return 1;
+       if (err)
+               return err;
 
-       if (type != PIDTYPE_PID)
-               return 0;
-       /* This child was explicitly requested, abort */
-       read_unlock(&tasklist_lock);
-       return err;
+       return 1;
 }
 
 static int wait_noreap_copyout(struct task_struct *p, pid_t pid, uid_t uid,
@@ -1536,7 +1532,8 @@ static int wait_task_continued(struct task_struct *p, int options,
  * -ECHILD should be in *@notask_error before the first call.
  * Returns nonzero for a final return, when we have unlocked tasklist_lock.
  * Returns zero if the search for a child should continue;
- * then *@notask_error is 0 if @p is an eligible child, or still -ECHILD.
+ * then *@notask_error is 0 if @p is an eligible child,
+ * or another error from security_task_wait(), or still -ECHILD.
  */
 static int wait_consider_task(struct task_struct *parent, int ptrace,
                              struct task_struct *p, int *notask_error,
@@ -1545,9 +1542,21 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
                              int __user *stat_addr, struct rusage __user *ru)
 {
        int ret = eligible_child(type, pid, options, p);
-       if (ret <= 0)
+       if (!ret)
                return ret;
 
+       if (unlikely(ret < 0)) {
+               /*
+                * If we have not yet seen any eligible child,
+                * then let this error code replace -ECHILD.
+                * A permission error will give the user a clue
+                * to look for security policy problems, rather
+                * than for mysterious wait bugs.
+                */
+               if (*notask_error)
+                       *notask_error = ret;
+       }
+
        if (likely(!ptrace) && unlikely(p->ptrace)) {
                /*
                 * This child is hidden by ptrace.
@@ -1585,7 +1594,8 @@ static int wait_consider_task(struct task_struct *parent, int ptrace,
  * -ECHILD should be in *@notask_error before the first call.
  * Returns nonzero for a final return, when we have unlocked tasklist_lock.
  * Returns zero if the search for a child should continue; then
- * *@notask_error is 0 if there were any eligible children, or still -ECHILD.
+ * *@notask_error is 0 if there were any eligible children,
+ * or another error from security_task_wait(), or still -ECHILD.
  */
 static int do_wait_thread(struct task_struct *tsk, int *notask_error,
                          enum pid_type type, struct pid *pid, int options,