| From | Paul Gortmaker <> | Subject | [34-longterm 135/260] aio: check for multiplication overflow in do_io_submit | Date | Sun, 2 Jan 2011 02:17:11 -0500 |
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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: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/aio.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c index 48fdeeb..94b6cd6 100644 --- a/fs/aio.c +++ b/fs/aio.c @@ -1659,6 +1659,9 @@ long do_io_submit(aio_context_t ctx_id, long nr, 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; -- 1.7.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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