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Merge branch 'core/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 

* 'core/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: setup writeable mapping for futex ops which modify user space data
This commit is contained in:
Linus Torvalds 2009-05-19 18:42:45 -07:00
parent 33252572e7 64d1304a64
commit 007a93a1ba
1 changed files with 13 additions and 11 deletions
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24
kernel/futex.c
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@ -193,6 +193,7 @@ static void drop_futex_key_refs(union futex_key *key)
* @uaddr: virtual address of the futex
* @fshared: 0 for a PROCESS_PRIVATE futex, 1 for PROCESS_SHARED
* @key: address where result is stored.
* @rw: mapping needs to be read/write (values: VERIFY_READ, VERIFY_WRITE)
*
* Returns a negative error code or 0
* The key words are stored in *key on success.
@ -203,7 +204,8 @@ static void drop_futex_key_refs(union futex_key *key)
*
* lock_page() might sleep, the caller should not hold a spinlock.
*/
static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
static int
get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
{
unsigned long address = (unsigned long)uaddr;
struct mm_struct *mm = current->mm;
@ -226,7 +228,7 @@ static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
* but access_ok() should be faster than find_vma()
*/
if (!fshared) {
if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
return -EFAULT;
key->private.mm = mm;
key->private.address = address;
@ -235,7 +237,7 @@ static int get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key)
}
again:
err = get_user_pages_fast(address, 1, 0, &page);
err = get_user_pages_fast(address, 1, rw == VERIFY_WRITE, &page);
if (err < 0)
return err;
@ -677,7 +679,7 @@ static int futex_wake(u32 __user *uaddr, int fshared, int nr_wake, u32 bitset)
if (!bitset)
return -EINVAL;
ret = get_futex_key(uaddr, fshared, &key);
ret = get_futex_key(uaddr, fshared, &key, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
@ -723,10 +725,10 @@ futex_wake_op(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
int ret, op_ret;
retry:
ret = get_futex_key(uaddr1, fshared, &key1);
ret = get_futex_key(uaddr1, fshared, &key1, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
ret = get_futex_key(uaddr2, fshared, &key2);
ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out_put_key1;
@ -814,10 +816,10 @@ static int futex_requeue(u32 __user *uaddr1, int fshared, u32 __user *uaddr2,
int ret, drop_count = 0;
retry:
ret = get_futex_key(uaddr1, fshared, &key1);
ret = get_futex_key(uaddr1, fshared, &key1, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
ret = get_futex_key(uaddr2, fshared, &key2);
ret = get_futex_key(uaddr2, fshared, &key2, VERIFY_READ);
if (unlikely(ret != 0))
goto out_put_key1;
@ -1140,7 +1142,7 @@ static int futex_wait(u32 __user *uaddr, int fshared,
q.bitset = bitset;
retry:
q.key = FUTEX_KEY_INIT;
ret = get_futex_key(uaddr, fshared, &q.key);
ret = get_futex_key(uaddr, fshared, &q.key, VERIFY_READ);
if (unlikely(ret != 0))
goto out;
@ -1330,7 +1332,7 @@ static int futex_lock_pi(u32 __user *uaddr, int fshared,
q.pi_state = NULL;
retry:
q.key = FUTEX_KEY_INIT;
ret = get_futex_key(uaddr, fshared, &q.key);
ret = get_futex_key(uaddr, fshared, &q.key, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;
@ -1594,7 +1596,7 @@ static int futex_unlock_pi(u32 __user *uaddr, int fshared)
if ((uval & FUTEX_TID_MASK) != task_pid_vnr(current))
return -EPERM;
ret = get_futex_key(uaddr, fshared, &key);
ret = get_futex_key(uaddr, fshared, &key, VERIFY_WRITE);
if (unlikely(ret != 0))
goto out;