Commit b0313728 authored Mar 21, 2015 by Al Viro Committed by Sasha Levin Aug 27, 2015

sg_start_req(): make sure that there's not too many elements in iovec



[ Upstream commit 451a2886b6bf90e2fb378f7c46c655450fb96e81 ]

unfortunately, allowing an arbitrary 16bit value means a possibility of
overflow in the calculation of total number of pages in bio_map_user_iov() -
we rely on there being no more than PAGE_SIZE members of sum in the
first loop there.  If that sum wraps around, we end up allocating
too small array of pointers to pages and it's easy to overflow it in
the second loop.

X-Coverup: TINC (and there's no lumber cartel either)
Cc: stable@vger.kernel.org # way, way back
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent cc252804

drivers/scsi/sg.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -1785,6 +1785,9 @@ sg_start_req(Sg_request srp, unsigned char cmd)
		md->from_user = 0;
		}

		if (unlikely(iov_count > UIO_MAXIOV))
		return -EINVAL;

		if (iov_count) {
		int len, size = sizeof(struct sg_iovec) * iov_count;
		struct iovec *iov;