1 files changed, 199 insertions, 8 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 5cc8083a4c89..054105854e0e 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -44,6 +44,7 @@
  *  along with this program; if not, write to the Free Software
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
+#include <linux/compat.h>
 #include <linux/slab.h>
 #include <linux/poll.h>
 #include <linux/fs.h>
@@ -173,8 +174,10 @@
  * double_lock_hb() and double_unlock_hb(), respectively.
  */
 
-#ifndef CONFIG_HAVE_FUTEX_CMPXCHG
-int __read_mostly futex_cmpxchg_enabled;
+#ifdef CONFIG_HAVE_FUTEX_CMPXCHG
+#define futex_cmpxchg_enabled 1
+#else
+static int  __read_mostly futex_cmpxchg_enabled;
 #endif
 
 /*
@@ -3417,7 +3420,7 @@ err_unlock:
  * Process a futex-list entry, check whether it's owned by the
  * dying task, and do notification if so:
  */
-int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi)
+static int handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi)
 {
 	u32 uval, uninitialized_var(nval), mval;
 
@@ -3612,10 +3615,10 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
 
 
 SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
-		struct timespec __user *, utime, u32 __user *, uaddr2,
+		struct __kernel_timespec __user *, utime, u32 __user *, uaddr2,
 		u32, val3)
 {
-	struct timespec ts;
+	struct timespec64 ts;
 	ktime_t t, *tp = NULL;
 	u32 val2 = 0;
 	int cmd = op & FUTEX_CMD_MASK;
@@ -3625,12 +3628,12 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
 		      cmd == FUTEX_WAIT_REQUEUE_PI)) {
 		if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
 			return -EFAULT;
-		if (copy_from_user(&ts, utime, sizeof(ts)) != 0)
+		if (get_timespec64(&ts, utime))
 			return -EFAULT;
-		if (!timespec_valid(&ts))
+		if (!timespec64_valid(&ts))
 			return -EINVAL;
 
-		t = timespec_to_ktime(ts);
+		t = timespec64_to_ktime(ts);
 		if (cmd == FUTEX_WAIT)
 			t = ktime_add_safe(ktime_get(), t);
 		tp = &t;
@@ -3646,6 +3649,194 @@ SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
 	return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
 }
 
+#ifdef CONFIG_COMPAT
+/*
+ * Fetch a robust-list pointer. Bit 0 signals PI futexes:
+ */
+static inline int
+compat_fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,
+		   compat_uptr_t __user *head, unsigned int *pi)
+{
+	if (get_user(*uentry, head))
+		return -EFAULT;
+
+	*entry = compat_ptr((*uentry) & ~1);
+	*pi = (unsigned int)(*uentry) & 1;
+
+	return 0;
+}
+
+static void __user *futex_uaddr(struct robust_list __user *entry,
+				compat_long_t futex_offset)
+{
+	compat_uptr_t base = ptr_to_compat(entry);
+	void __user *uaddr = compat_ptr(base + futex_offset);
+
+	return uaddr;
+}
+
+/*
+ * Walk curr->robust_list (very carefully, it's a userspace list!)
+ * and mark any locks found there dead, and notify any waiters.
+ *
+ * We silently return on any sign of list-walking problem.
+ */
+void compat_exit_robust_list(struct task_struct *curr)
+{
+	struct compat_robust_list_head __user *head = curr->compat_robust_list;
+	struct robust_list __user *entry, *next_entry, *pending;
+	unsigned int limit = ROBUST_LIST_LIMIT, pi, pip;
+	unsigned int uninitialized_var(next_pi);
+	compat_uptr_t uentry, next_uentry, upending;
+	compat_long_t futex_offset;
+	int rc;
+
+	if (!futex_cmpxchg_enabled)
+		return;
+
+	/*
+	 * Fetch the list head (which was registered earlier, via
+	 * sys_set_robust_list()):
+	 */
+	if (compat_fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))
+		return;
+	/*
+	 * Fetch the relative futex offset:
+	 */
+	if (get_user(futex_offset, &head->futex_offset))
+		return;
+	/*
+	 * Fetch any possibly pending lock-add first, and handle it
+	 * if it exists:
+	 */
+	if (compat_fetch_robust_entry(&upending, &pending,
+			       &head->list_op_pending, &pip))
+		return;
+
+	next_entry = NULL;	/* avoid warning with gcc */
+	while (entry != (struct robust_list __user *) &head->list) {
+		/*
+		 * Fetch the next entry in the list before calling
+		 * handle_futex_death:
+		 */
+		rc = compat_fetch_robust_entry(&next_uentry, &next_entry,
+			(compat_uptr_t __user *)&entry->next, &next_pi);
+		/*
+		 * A pending lock might already be on the list, so
+		 * dont process it twice:
+		 */
+		if (entry != pending) {
+			void __user *uaddr = futex_uaddr(entry, futex_offset);
+
+			if (handle_futex_death(uaddr, curr, pi))
+				return;
+		}
+		if (rc)
+			return;
+		uentry = next_uentry;
+		entry = next_entry;
+		pi = next_pi;
+		/*
+		 * Avoid excessively long or circular lists:
+		 */
+		if (!--limit)
+			break;
+
+		cond_resched();
+	}
+	if (pending) {
+		void __user *uaddr = futex_uaddr(pending, futex_offset);
+
+		handle_futex_death(uaddr, curr, pip);
+	}
+}
+
+COMPAT_SYSCALL_DEFINE2(set_robust_list,
+		struct compat_robust_list_head __user *, head,
+		compat_size_t, len)
+{
+	if (!futex_cmpxchg_enabled)
+		return -ENOSYS;
+
+	if (unlikely(len != sizeof(*head)))
+		return -EINVAL;
+
+	current->compat_robust_list = head;
+
+	return 0;
+}
+
+COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
+			compat_uptr_t __user *, head_ptr,
+			compat_size_t __user *, len_ptr)
+{
+	struct compat_robust_list_head __user *head;
+	unsigned long ret;
+	struct task_struct *p;
+
+	if (!futex_cmpxchg_enabled)
+		return -ENOSYS;
+
+	rcu_read_lock();
+
+	ret = -ESRCH;
+	if (!pid)
+		p = current;
+	else {
+		p = find_task_by_vpid(pid);
+		if (!p)
+			goto err_unlock;
+	}
+
+	ret = -EPERM;
+	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
+		goto err_unlock;
+
+	head = p->compat_robust_list;
+	rcu_read_unlock();
+
+	if (put_user(sizeof(*head), len_ptr))
+		return -EFAULT;
+	return put_user(ptr_to_compat(head), head_ptr);
+
+err_unlock:
+	rcu_read_unlock();
+
+	return ret;
+}
+#endif /* CONFIG_COMPAT */
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+COMPAT_SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
+		struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
+		u32, val3)
+{
+	struct timespec64 ts;
+	ktime_t t, *tp = NULL;
+	int val2 = 0;
+	int cmd = op & FUTEX_CMD_MASK;
+
+	if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI ||
+		      cmd == FUTEX_WAIT_BITSET ||
+		      cmd == FUTEX_WAIT_REQUEUE_PI)) {
+		if (get_old_timespec32(&ts, utime))
+			return -EFAULT;
+		if (!timespec64_valid(&ts))
+			return -EINVAL;
+
+		t = timespec64_to_ktime(ts);
+		if (cmd == FUTEX_WAIT)
+			t = ktime_add_safe(ktime_get(), t);
+		tp = &t;
+	}
+	if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE ||
+	    cmd == FUTEX_CMP_REQUEUE_PI || cmd == FUTEX_WAKE_OP)
+		val2 = (int) (unsigned long) utime;
+
+	return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);
+}
+#endif /* CONFIG_COMPAT_32BIT_TIME */
+
 static void __init futex_detect_cmpxchg(void)
 {
 #ifndef CONFIG_HAVE_FUTEX_CMPXCHG