Patch "sg_start_req(): make sure that there's not too many elements in iovec" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
sg_start_req-make-sure-that-there-s-not-too-many-elements-in-iovec.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Al Viro <[email protected]>
Date: Sat, 21 Mar 2015 20:08:18 -0400
Subject: sg_start_req(): make sure that there's not too many elements in iovec

From: Al Viro <[email protected]>

commit 451a2886b6bf90e2fb378f7c46c655450fb96e81 upstream.

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)

[bwh: s/MAX_UIOVEC/UIO_MAXIOV/. This was fixed upstream by commit
fdc81f45e9f5 ("sg_start_req(): use import_iovec()"), but we don't have
that function.]

---
 drivers/scsi/sg.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -1694,6 +1694,9 @@ static int sg_start_req(Sg_request *srp,
 			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;

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/ipc-modify-message-queue-accounting-to-not-take-kernel-data-structures-into-account.patch queue-3.14/sg_start_req-make-sure-that-there-s-not-too-many-elements-in-iovec.patch