Merge branch 'android-4.14-spl-topic' into exynos9609

[GitHub/moto-9609/android_kernel_motorola_exynos9610.git] / kernel / seccomp.c

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 0ae832e13b974041002c508f03a7c9cc8d6d7a6d..075e344a87c3f9d4fbdd6b4aa9929248cd7e9a63 100644 (file)
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * linux/kernel/seccomp.c
  *
@@ -18,6 +19,8 @@
 #include <linux/compat.h>
 #include <linux/coredump.h>
 #include <linux/kmemleak.h>
+#include <linux/nospec.h>
+#include <linux/prctl.h>
 #include <linux/sched.h>
 #include <linux/sched/task_stack.h>
 #include <linux/seccomp.h>
@@ -189,7 +192,7 @@ static u32 seccomp_run_filters(const struct seccomp_data *sd,
        u32 ret = SECCOMP_RET_ALLOW;
        /* Make sure cross-thread synced filter points somewhere sane. */
        struct seccomp_filter *f =
-                       lockless_dereference(current->seccomp.filter);
+                       READ_ONCE(current->seccomp.filter);
 
        /* Ensure unexpected behavior doesn't result in failing open. */
        if (unlikely(WARN_ON(f == NULL)))
@@ -226,8 +229,11 @@ static inline bool seccomp_may_assign_mode(unsigned long seccomp_mode)
        return true;
 }
 
+void __weak arch_seccomp_spec_mitigate(struct task_struct *task) { }
+
 static inline void seccomp_assign_mode(struct task_struct *task,
-                                      unsigned long seccomp_mode)
+                                      unsigned long seccomp_mode,
+                                      unsigned long flags)
 {
        assert_spin_locked(&task->sighand->siglock);
 
@@ -237,6 +243,9 @@ static inline void seccomp_assign_mode(struct task_struct *task,
         * filter) is set.
         */
        smp_mb__before_atomic();
+       /* Assume default seccomp processes want spec flaw mitigation. */
+       if ((flags & SECCOMP_FILTER_FLAG_SPEC_ALLOW) == 0)
+               arch_seccomp_spec_mitigate(task);
        set_tsk_thread_flag(task, TIF_SECCOMP);
 }
 
@@ -304,7 +313,7 @@ static inline pid_t seccomp_can_sync_threads(void)
  * without dropping the locks.
  *
  */
-static inline void seccomp_sync_threads(void)
+static inline void seccomp_sync_threads(unsigned long flags)
 {
        struct task_struct *thread, *caller;
 
@@ -345,7 +354,8 @@ static inline void seccomp_sync_threads(void)
                 * allow one thread to transition the other.
                 */
                if (thread->seccomp.mode == SECCOMP_MODE_DISABLED)
-                       seccomp_assign_mode(thread, SECCOMP_MODE_FILTER);
+                       seccomp_assign_mode(thread, SECCOMP_MODE_FILTER,
+                                           flags);
        }
 }
 
@@ -468,7 +478,7 @@ static long seccomp_attach_filter(unsigned int flags,
 
        /* Now that the new filter is in place, synchronize to all threads. */
        if (flags & SECCOMP_FILTER_FLAG_TSYNC)
-               seccomp_sync_threads();
+               seccomp_sync_threads(flags);
 
        return 0;
 }
@@ -817,7 +827,7 @@ static long seccomp_set_mode_strict(void)
 #ifdef TIF_NOTSC
        disable_TSC();
 #endif
-       seccomp_assign_mode(current, seccomp_mode);
+       seccomp_assign_mode(current, seccomp_mode, 0);
        ret = 0;
 
 out:
@@ -875,7 +885,7 @@ static long seccomp_set_mode_filter(unsigned int flags,
        /* Do not free the successfully attached filter. */
        prepared = NULL;
 
-       seccomp_assign_mode(current, seccomp_mode);
+       seccomp_assign_mode(current, seccomp_mode, flags);
 out:
        spin_unlock_irq(&current->sighand->siglock);
        if (flags & SECCOMP_FILTER_FLAG_TSYNC)