MIPS: VDSO: Prevent use of smp_processor_id()

[android-x86/kernel.git] / kernel / seccomp.c

diff --git a/kernel/seccomp.c b/kernel/seccomp.c
index 0db7c8a..3975856 100644 (file)
--- a/kernel/seccomp.c
+++ b/kernel/seccomp.c
@@ -16,6 +16,8 @@
 #include <linux/atomic.h>
 #include <linux/audit.h>
 #include <linux/compat.h>
+#include <linux/nospec.h>
+#include <linux/prctl.h>
 #include <linux/sched.h>
 #include <linux/seccomp.h>
 #include <linux/slab.h>
@@ -214,8 +216,11 @@ 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);
 
@@ -225,6 +230,9 @@ 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);
 }
 
@@ -292,7 +300,7 @@ 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;
 
@@ -333,7 +341,8 @@ 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);
        }
 }
 
@@ -452,19 +461,24 @@ 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;
 }
 
+void __get_seccomp_filter(struct seccomp_filter *filter)
+{
+       /* Reference count is bounded by the number of total processes. */
+       atomic_inc(&filter->usage);
+}
+
 /* get_seccomp_filter - increments the reference count of the filter on @tsk */
 void get_seccomp_filter(struct task_struct *tsk)
 {
        struct seccomp_filter *orig = tsk->seccomp.filter;
        if (!orig)
                return;
-       /* Reference count is bounded by the number of total processes. */
-       atomic_inc(&orig->usage);
+       __get_seccomp_filter(orig);
 }
 
 static inline void seccomp_filter_free(struct seccomp_filter *filter)
@@ -475,10 +489,8 @@ static inline void seccomp_filter_free(struct seccomp_filter *filter)
        }
 }
 
-/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
-void put_seccomp_filter(struct task_struct *tsk)
+static void __put_seccomp_filter(struct seccomp_filter *orig)
 {
-       struct seccomp_filter *orig = tsk->seccomp.filter;
        /* Clean up single-reference branches iteratively. */
        while (orig && atomic_dec_and_test(&orig->usage)) {
                struct seccomp_filter *freeme = orig;
@@ -487,6 +499,12 @@ void put_seccomp_filter(struct task_struct *tsk)
        }
 }
 
+/* put_seccomp_filter - decrements the ref count of tsk->seccomp.filter */
+void put_seccomp_filter(struct task_struct *tsk)
+{
+       __put_seccomp_filter(tsk->seccomp.filter);
+}
+
 /**
  * seccomp_send_sigsys - signals the task to allow in-process syscall emulation
  * @syscall: syscall number to send to userland
@@ -703,7 +721,7 @@ 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:
@@ -761,7 +779,7 @@ 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)
@@ -892,13 +910,13 @@ long seccomp_get_filter(struct task_struct *task, unsigned long filter_off,
        if (!data)
                goto out;
 
-       get_seccomp_filter(task);
+       __get_seccomp_filter(filter);
        spin_unlock_irq(&task->sighand->siglock);
 
        if (copy_to_user(data, fprog->filter, bpf_classic_proglen(fprog)))
                ret = -EFAULT;
 
-       put_seccomp_filter(task);
+       __put_seccomp_filter(filter);
        return ret;
 
 out: