1 files changed, 38 insertions, 51 deletions

diff --git a/kernel/futex.c b/kernel/futex.c
index 1614be20173d..e2b0fb9a0b3b 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -59,6 +59,7 @@
 #include <linux/magic.h>
 #include <linux/pid.h>
 #include <linux/nsproxy.h>
+#include <linux/ptrace.h>
 
 #include <asm/futex.h>
 
@@ -2443,40 +2444,31 @@ SYSCALL_DEFINE3(get_robust_list, int, pid,
 {
         struct robust_list_head __user *head;
         unsigned long ret;
-        const struct cred *cred = current_cred(), *pcred;
+        struct task_struct *p;
 
         if (!futex_cmpxchg_enabled)
                 return -ENOSYS;
 
+        WARN_ONCE(1, "deprecated: get_robust_list will be deleted in 2013.\n");
+
+        rcu_read_lock();
+
+        ret = -ESRCH;
         if (!pid)
-                head = current->robust_list;
+                p = current;
         else {
-                struct task_struct *p;
-
-                ret = -ESRCH;
-                rcu_read_lock();
                 p = find_task_by_vpid(pid);
                 if (!p)
                         goto err_unlock;
-                ret = -EPERM;
-                pcred = __task_cred(p);
-                /* If victim is in different user_ns, then uids are not
-                   comparable, so we must have CAP_SYS_PTRACE */
-                if (cred->user->user_ns != pcred->user->user_ns) {
-                        if (!ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
-                                goto err_unlock;
-                        goto ok;
-                }
-                /* If victim is in same user_ns, then uids are comparable */
-                if (cred->euid != pcred->euid &&
-                    cred->euid != pcred->uid &&
-                    !ns_capable(pcred->user->user_ns, CAP_SYS_PTRACE))
-                        goto err_unlock;
-ok:
-                head = p->robust_list;
-                rcu_read_unlock();
         }
 
+        ret = -EPERM;
+        if (!ptrace_may_access(p, PTRACE_MODE_READ))
+                goto err_unlock;
+
+        head = p->robust_list;
+        rcu_read_unlock();
+
         if (put_user(sizeof(*head), len_ptr))
                 return -EFAULT;
         return put_user(head, head_ptr);
@@ -2628,7 +2620,7 @@ void exit_robust_list(struct task_struct *curr)
 long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
                 u32 __user *uaddr2, u32 val2, u32 val3)
 {
-        int ret = -ENOSYS, cmd = op & FUTEX_CMD_MASK;
+        int cmd = op & FUTEX_CMD_MASK;
         unsigned int flags = 0;
 
         if (!(op & FUTEX_PRIVATE_FLAG))
@@ -2641,49 +2633,44 @@ long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
         }
 
         switch (cmd) {
+        case FUTEX_LOCK_PI:
+        case FUTEX_UNLOCK_PI:
+        case FUTEX_TRYLOCK_PI:
+        case FUTEX_WAIT_REQUEUE_PI:
+        case FUTEX_CMP_REQUEUE_PI:
+                if (!futex_cmpxchg_enabled)
+                        return -ENOSYS;
+        }
+
+        switch (cmd) {
         case FUTEX_WAIT:
                 val3 = FUTEX_BITSET_MATCH_ANY;
         case FUTEX_WAIT_BITSET:
-                ret = futex_wait(uaddr, flags, val, timeout, val3);
-                break;
+                return futex_wait(uaddr, flags, val, timeout, val3);
         case FUTEX_WAKE:
                 val3 = FUTEX_BITSET_MATCH_ANY;
         case FUTEX_WAKE_BITSET:
-                ret = futex_wake(uaddr, flags, val, val3);
-                break;
+                return futex_wake(uaddr, flags, val, val3);
         case FUTEX_REQUEUE:
-                ret = futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
-                break;
+                return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
         case FUTEX_CMP_REQUEUE:
-                ret = futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
-                break;
+                return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
         case FUTEX_WAKE_OP:
-                ret = futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
-                break;
+                return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
         case FUTEX_LOCK_PI:
-                if (futex_cmpxchg_enabled)
-                        ret = futex_lock_pi(uaddr, flags, val, timeout, 0);
-                break;
+                return futex_lock_pi(uaddr, flags, val, timeout, 0);
         case FUTEX_UNLOCK_PI:
-                if (futex_cmpxchg_enabled)
-                        ret = futex_unlock_pi(uaddr, flags);
-                break;
+                return futex_unlock_pi(uaddr, flags);
         case FUTEX_TRYLOCK_PI:
-                if (futex_cmpxchg_enabled)
-                        ret = futex_lock_pi(uaddr, flags, 0, timeout, 1);
-                break;
+                return futex_lock_pi(uaddr, flags, 0, timeout, 1);
         case FUTEX_WAIT_REQUEUE_PI:
                 val3 = FUTEX_BITSET_MATCH_ANY;
-                ret = futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
-                                            uaddr2);
-                break;
+                return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
+                                             uaddr2);
         case FUTEX_CMP_REQUEUE_PI:
-                ret = futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
-                break;
-        default:
-                ret = -ENOSYS;
+                return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
         }
-        return ret;
+        return -ENOSYS;
 }