__send_signal: pass q->info, not info, to userns_fixup_signal_uid (v2)

[karo-tx-linux.git] / kernel / signal.c

diff --git a/kernel/signal.c b/kernel/signal.c
index b3f78d09a1053b67f62719a8879f6619ae12253b..2daed3188118d43470500be91248b6414b3caf80 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -28,6 +28,7 @@
 #include <linux/freezer.h>
 #include <linux/pid_namespace.h>
 #include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
 #define CREATE_TRACE_POINTS
 #include <trace/events/signal.h>
 
@@ -1019,6 +1020,34 @@ static inline int legacy_queue(struct sigpending *signals, int sig)
        return (sig < SIGRTMIN) && sigismember(&signals->signal, sig);
 }
 
+/*
+ * map the uid in struct cred into user namespace *ns
+ */
+static inline uid_t map_cred_ns(const struct cred *cred,
+                               struct user_namespace *ns)
+{
+       return user_ns_map_uid(ns, cred, cred->uid);
+}
+
+#ifdef CONFIG_USER_NS
+static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+{
+       if (current_user_ns() == task_cred_xxx(t, user_ns))
+               return;
+
+       if (SI_FROMKERNEL(info))
+               return;
+
+       info->si_uid = user_ns_map_uid(task_cred_xxx(t, user_ns),
+                                       current_cred(), info->si_uid);
+}
+#else
+static inline void userns_fixup_signal_uid(struct siginfo *info, struct task_struct *t)
+{
+       return;
+}
+#endif
+
 static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
                        int group, int from_ancestor_ns)
 {
@@ -1088,6 +1117,9 @@ static int __send_signal(int sig, struct siginfo *info, struct task_struct *t,
                                q->info.si_pid = 0;
                        break;
                }
+
+               userns_fixup_signal_uid(&q->info, t);
+
        } else if (!is_si_special(info)) {
                if (sig >= SIGRTMIN && info->si_code != SI_USER) {
                        /*
@@ -1626,13 +1658,12 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
         */
        rcu_read_lock();
        info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
-       info.si_uid = __task_cred(tsk)->uid;
+       info.si_uid = map_cred_ns(__task_cred(tsk),
+                       task_cred_xxx(tsk->parent, user_ns));
        rcu_read_unlock();
 
-       info.si_utime = cputime_to_clock_t(cputime_add(tsk->utime,
-                               tsk->signal->utime));
-       info.si_stime = cputime_to_clock_t(cputime_add(tsk->stime,
-                               tsk->signal->stime));
+       info.si_utime = cputime_to_clock_t(tsk->utime + tsk->signal->utime);
+       info.si_stime = cputime_to_clock_t(tsk->stime + tsk->signal->stime);
 
        info.si_status = tsk->exit_code & 0x7f;
        if (tsk->exit_code & 0x80)
@@ -1711,7 +1742,8 @@ static void do_notify_parent_cldstop(struct task_struct *tsk,
         */
        rcu_read_lock();
        info.si_pid = task_pid_nr_ns(tsk, parent->nsproxy->pid_ns);
-       info.si_uid = __task_cred(tsk)->uid;
+       info.si_uid = map_cred_ns(__task_cred(tsk),
+                       task_cred_xxx(parent, user_ns));
        rcu_read_unlock();
 
        info.si_utime = cputime_to_clock_t(tsk->utime);
@@ -2129,8 +2161,11 @@ static int ptrace_signal(int signr, siginfo_t *info,
                info->si_signo = signr;
                info->si_errno = 0;
                info->si_code = SI_USER;
+               rcu_read_lock();
                info->si_pid = task_pid_vnr(current->parent);
-               info->si_uid = task_uid(current->parent);
+               info->si_uid = map_cred_ns(__task_cred(current->parent),
+                               current_user_ns());
+               rcu_read_unlock();
        }
 
        /* If the (new) signal is now blocked, requeue it.  */
@@ -2149,6 +2184,9 @@ int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
        struct signal_struct *signal = current->signal;
        int signr;
 
+       if (unlikely(uprobe_deny_signal()))
+               return 0;
+
 relock:
        /*
         * We'll jump back here after any time we were stopped in TASK_STOPPED.
@@ -2359,8 +2397,15 @@ void exit_signals(struct task_struct *tsk)
        int group_stop = 0;
        sigset_t unblocked;
 
+       /*
+        * @tsk is about to have PF_EXITING set - lock out users which
+        * expect stable threadgroup.
+        */
+       threadgroup_change_begin(tsk);
+
        if (thread_group_empty(tsk) || signal_group_exit(tsk->signal)) {
                tsk->flags |= PF_EXITING;
+               threadgroup_change_end(tsk);
                return;
        }
 
@@ -2370,6 +2415,9 @@ void exit_signals(struct task_struct *tsk)
         * see wants_signal(), do_signal_stop().
         */
        tsk->flags |= PF_EXITING;
+
+       threadgroup_change_end(tsk);
+
        if (!signal_pending(tsk))
                goto out;