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@@ -193,6 +193,7 @@ static void drop_futex_key_refs(union futex_key *key)
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* @uaddr: virtual address of the futex
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* @fshared: 0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
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* @key: address where result is stored.
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+ * @rw: mapping needs to be read/write (values: VERIFY_READ, VERIFY_WRITE)
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*
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* Returns a negative error code or 0
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* The key words are stored in *key on success.
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@@ -203,7 +204,8 @@ static void drop_futex_key_refs(union futex_key *key)
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*
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* lock_page() might sleep, the caller should not hold a spinlock.
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*/
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-static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
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+static int
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+get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
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{
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unsigned long address = (unsigned long)uaddr;
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struct mm_struct *mm = current->mm;
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@@ -226,7 +228,7 @@ static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
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* but access_ok() should be faster than find_vma()
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*/
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if (!fshared) {
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- if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
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+ if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
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return -EFAULT;
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key->private.mm = mm;
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key->private.address = address;
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@@ -235,7 +237,7 @@ static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
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}
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again:
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- err = get_user_pages_fast(address, 1, 0, &page);
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+ err = get_user_pages_fast(address, 1, rw == VERIFY_WRITE, &page);
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if (err < 0)
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return err;
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@@ -677,7 +679,7 @@ static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset)
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if (!bitset)
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return -EINVAL;
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- ret = get_futex_key(uaddr, fshared, &key);
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+ ret = get_futex_key(uaddr, fshared, &key, VERIFY_READ);
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if (unlikely(ret != 0))
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goto out;
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@@ -723,10 +725,10 @@ futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
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int ret, op_ret;
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retry:
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- ret = get_futex_key(uaddr1, fshared, &key1);
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+ ret = get_futex_key(uaddr1, fshared, &key1, VERIFY_READ);
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if (unlikely(ret != 0))
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goto out;
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- ret = get_futex_key(uaddr2, fshared, &key2);
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+ ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_WRITE);
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if (unlikely(ret != 0))
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goto out_put_key1;
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@@ -814,10 +816,10 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
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int ret, drop_count = 0;
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retry:
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- ret = get_futex_key(uaddr1, fshared, &key1);
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+ ret = get_futex_key(uaddr1, fshared, &key1, VERIFY_READ);
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if (unlikely(ret != 0))
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goto out;
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- ret = get_futex_key(uaddr2, fshared, &key2);
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+ ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_READ);
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if (unlikely(ret != 0))
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goto out_put_key1;
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@@ -1140,7 +1142,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
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q.bitset = bitset;
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retry:
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q.key = FUTEX_KEY_INIT;
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- ret = get_futex_key(uaddr, fshared, &q.key);
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+ ret = get_futex_key(uaddr, fshared, &q.key, VERIFY_READ);
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if (unlikely(ret != 0))
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goto out;
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@@ -1330,7 +1332,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
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q.pi_state = NULL;
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retry:
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q.key = FUTEX_KEY_INIT;
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- ret = get_futex_key(uaddr, fshared, &q.key);
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+ ret = get_futex_key(uaddr, fshared, &q.key, VERIFY_WRITE);
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if (unlikely(ret != 0))
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goto out;
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@@ -1594,7 +1596,7 @@ retry:
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if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current))
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return -EPERM;
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- ret = get_futex_key(uaddr, fshared, &key);
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+ ret = get_futex_key(uaddr, fshared, &key, VERIFY_WRITE);
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if (unlikely(ret != 0))
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goto out;
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