1 files changed, 47 insertions, 0 deletions
diff --git a/aio-check-for-multiplication-overflow-in-do_io_submit.patch b/aio-check-for-multiplication-overflow-in-do_io_submit.patch
new file mode 100644
index 0000000..36b949c
--- /dev/null
+++ b/aio-check-for-multiplication-overflow-in-do_io_submit.patch
@@ -0,0 +1,47 @@
+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: [PATCH] aio: check for multiplication overflow in do_io_submit
+MIME-Version: 1.0
+Content-Type: text/plain; charset=utf8
+Content-Transfer-Encoding: 8bit
+
+Tavis Ormandy pointed out that do_io_submit does not do proper bounds
+checking on the passed-in iocb array:
+
+Â  Â  Â  Â if (unlikely(nr < 0))
+Â  Â  Â  Â  Â  Â  Â  Â return -EINVAL;
+
+Â  Â  Â  Â if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(iocbpp)))))
+Â  Â  Â  Â  Â  Â  Â  Â return -EFAULT; Â  Â  Â  Â  Â  Â  Â  Â  Â  Â  Â ^^^^^^^^^^^^^^^^^^
+
+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. Â 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>
+---
+ fs/aio.c |    3 +++
+ 1 files changed, 3 insertions(+), 0 deletions(-)
+
+diff --git a/fs/aio.c b/fs/aio.c
+index 3006b5b..1320b2a 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;
+ 
+-- 
+1.7.2.3
+