From: dim <dim@FreeBSD.org>
Date: Wed, 14 Dec 2016 19:28:19 +0000 (+0000)
Subject: In xbd_connect(), use correct scanf conversion specifiers for the
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=0c8256861b80bccf8f38db07faa7bb97c1f14021;p=people%2Froyger%2Ffreebsd.git

In xbd_connect(), use correct scanf conversion specifiers for the
feature_barrier and feature_flush variables.  Otherwise, adjacent
variables on the stack, such as sector_size, may be overwritten, with
disastrous results.

Note that I did not see a good reason to revert the addition of zero
checks introduced in r310013.  Better safe than sorry.

PR:		215209
Tested by:	royger
MFC after:	3 days
---

diff --git a/sys/dev/xen/blkfront/blkfront.c b/sys/dev/xen/blkfront/blkfront.c
index 2e09c2eb4094..9eca2201f89b 100644
--- a/sys/dev/xen/blkfront/blkfront.c
+++ b/sys/dev/xen/blkfront/blkfront.c
@@ -1259,13 +1259,13 @@ xbd_connect(struct xbd_softc *sc)
 	if (err || phys_sector_size <= sector_size)
 		phys_sector_size = 0;
 	err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
-	     "feature-barrier", "%lu", &feature_barrier,
+	     "feature-barrier", "%d", &feature_barrier,
 	     NULL);
 	if (err == 0 && feature_barrier != 0)
 		sc->xbd_flags |= XBDF_BARRIER;
 
 	err = xs_gather(XST_NIL, xenbus_get_otherend_path(dev),
-	     "feature-flush-cache", "%lu", &feature_flush,
+	     "feature-flush-cache", "%d", &feature_flush,
 	     NULL);
 	if (err == 0 && feature_flush != 0)
 		sc->xbd_flags |= XBDF_FLUSH;