Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux...

[cascardo/linux.git] / kernel / fork.c

diff --git a/kernel/fork.c b/kernel/fork.c
index 6a13c46..fbd3497 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -315,6 +315,15 @@ static struct task_struct *dup_task_struct(struct task_struct *orig)
                goto free_ti;
 
        tsk->stack = ti;
+#ifdef CONFIG_SECCOMP
+       /*
+        * We must handle setting up seccomp filters once we're under
+        * the sighand lock in case orig has changed between now and
+        * then. Until then, filter must be NULL to avoid messing up
+        * the usage counts on the error path calling free_task.
+        */
+       tsk->seccomp.filter = NULL;
+#endif
 
        setup_thread_stack(tsk, orig);
        clear_user_return_notifier(tsk);
@@ -1081,6 +1090,39 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
        return 0;
 }
 
+static void copy_seccomp(struct task_struct *p)
+{
+#ifdef CONFIG_SECCOMP
+       /*
+        * Must be called with sighand->lock held, which is common to
+        * all threads in the group. Holding cred_guard_mutex is not
+        * needed because this new task is not yet running and cannot
+        * be racing exec.
+        */
+       BUG_ON(!spin_is_locked(&current->sighand->siglock));
+
+       /* Ref-count the new filter user, and assign it. */
+       get_seccomp_filter(current);
+       p->seccomp = current->seccomp;
+
+       /*
+        * Explicitly enable no_new_privs here in case it got set
+        * between the task_struct being duplicated and holding the
+        * sighand lock. The seccomp state and nnp must be in sync.
+        */
+       if (task_no_new_privs(current))
+               task_set_no_new_privs(p);
+
+       /*
+        * If the parent gained a seccomp mode after copying thread
+        * flags and between before we held the sighand lock, we have
+        * to manually enable the seccomp thread flag here.
+        */
+       if (p->seccomp.mode != SECCOMP_MODE_DISABLED)
+               set_tsk_thread_flag(p, TIF_SECCOMP);
+#endif
+}
+
 SYSCALL_DEFINE1(set_tid_address, int __user *, tidptr)
 {
        current->clear_child_tid = tidptr;
@@ -1095,7 +1137,6 @@ static void rt_mutex_init_task(struct task_struct *p)
        p->pi_waiters = RB_ROOT;
        p->pi_waiters_leftmost = NULL;
        p->pi_blocked_on = NULL;
-       p->pi_top_task = NULL;
 #endif
 }
 
@@ -1196,7 +1237,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
                goto fork_out;
 
        ftrace_graph_init_task(p);
-       get_seccomp_filter(p);
 
        rt_mutex_init_task(p);
 
@@ -1262,9 +1302,8 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
        posix_cpu_timers_init(p);
 
-       do_posix_clock_monotonic_gettime(&p->start_time);
-       p->real_start_time = p->start_time;
-       monotonic_to_bootbased(&p->real_start_time);
+       p->start_time = ktime_get_ns();
+       p->real_start_time = ktime_get_boot_ns();
        p->io_context = NULL;
        p->audit_context = NULL;
        if (clone_flags & CLONE_THREAD)
@@ -1436,6 +1475,12 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
        spin_lock(&current->sighand->siglock);
 
+       /*
+        * Copy seccomp details explicitly here, in case they were changed
+        * before holding sighand lock.
+        */
+       copy_seccomp(p);
+
        /*
         * Process group and session signals need to be delivered to just the
         * parent before the fork or both the parent and the child after the