s390x/s390-virtio-ccw: fix off-by-one in loadparm getter

As pointed out by Peter, g_memdup(ms->loadparm, sizeof(ms->loadparm) + 1)
reads one past of the end of ms->loadparm, so g_memdup() can not be used
here.

Let's use g_strndup instead!

Fixes: d6645483285f ("s390x/s390-virtio-ccw: fix loadparm property getter")
Fixes: Coverity CID 1431058
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-Id: <20200730130156.35063-1-pasic@linux.ibm.com>
Signed-off-by: Cornelia Huck <cohuck@redhat.com>

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 403d30e13bca346c9adbffcb0941e610e323ed47..e72c61d2eae0343e66605eeba365f8036ca668f6 100644 (file)
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -701,12 +701,9 @@ bool hpage_1m_allowed(void)
 static char *machine_get_loadparm(Object *obj, Error **errp)
 {
     S390CcwMachineState *ms = S390_CCW_MACHINE(obj);
-    char *loadparm_str;
 
     /* make a NUL-terminated string */
-    loadparm_str = g_memdup(ms->loadparm, sizeof(ms->loadparm) + 1);
-    loadparm_str[sizeof(ms->loadparm)] = 0;
-    return loadparm_str;
+    return g_strndup((char *) ms->loadparm, sizeof(ms->loadparm));
 }
 
 static void machine_set_loadparm(Object *obj, const char *val, Error **errp)