| From 75e1c70fc31490ef8a373ea2a4bea2524099b478 Mon Sep 17 00:00:00 2001 |
| From: Jeff Moyer <jmoyer@redhat.com> |
| Date: Fri, 10 Sep 2010 14:16:00 -0700 |
| Subject: aio: check for multiplication overflow in do_io_submit |
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| Content-Transfer-Encoding: 8bit |
| |
| From: Jeff Moyer <jmoyer@redhat.com> |
| |
| commit 75e1c70fc31490ef8a373ea2a4bea2524099b478 upstream. |
| |
| Tavis Ormandy pointed out that do_io_submit does not do proper bounds |
| checking on the passed-in iocb array: |
| |
| if (unlikely(nr < 0)) |
| return -EINVAL; |
| |
| if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(iocbpp))))) |
| return -EFAULT; ^^^^^^^^^^^^^^^^^^ |
| |
| The attached patch checks for overflow, and if it is detected, the |
| number of iocbs submitted is scaled down to a number that will fit in |
| the long. This is an ok thing to do, as sys_io_submit is documented as |
| returning the number of iocbs submitted, so callers should handle a |
| return value of less than the 'nr' argument passed in. |
| |
| Reported-by: Tavis Ormandy <taviso@cmpxchg8b.com> |
| Signed-off-by: Jeff Moyer <jmoyer@redhat.com> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/aio.c | 3 +++ |
| 1 file changed, 3 insertions(+) |
| |
| --- a/fs/aio.c |
| +++ b/fs/aio.c |
| @@ -1639,6 +1639,9 @@ SYSCALL_DEFINE3(io_submit, aio_context_t |
| if (unlikely(nr < 0)) |
| return -EINVAL; |
| |
| + if (unlikely(nr > LONG_MAX/sizeof(*iocbpp))) |
| + nr = LONG_MAX/sizeof(*iocbpp); |
| + |
| if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp))))) |
| return -EFAULT; |
| |
