[ovs-dev] [PATCH v2] netdev-dpdk: fix snprintf call

Aaron Conole aconole at redhat.com
Fri Jun 15 13:20:12 UTC 2018


lib/netdev-dpdk.c: In function :
lib/netdev-dpdk.c:2865:49: warning:  output may be truncated before the last format character [-Wformat-truncation=]
        snprintf(vhost_vring, 16, "vring_%d_size", i);
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since vring_num is 16 bits, the largest value ever would only be 17 bytes,
including the terminating nul.  Stretch it to 18 bytes (as a precaution
against a signed value, which again would never happen).

Suggested-by: Ben Pfaff <blp at ovn.org>
Signed-off-by: Aaron Conole <aconole at redhat.com>
---
 lib/netdev-dpdk.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
index a76e489a2..1bde9cfe7 100644
--- a/lib/netdev-dpdk.c
+++ b/lib/netdev-dpdk.c
@@ -2883,11 +2883,10 @@ netdev_dpdk_vhost_user_get_status(const struct netdev *netdev,
 
     for (int i = 0; i < vring_num; i++) {
         struct rte_vhost_vring vring;
-        char vhost_vring[16];
 
         rte_vhost_get_vhost_vring(vid, i, &vring);
-        snprintf(vhost_vring, 16, "vring_%d_size", i);
-        smap_add_format(args, vhost_vring, "%d", vring.size);
+        smap_add_nocopy(args, xasprintf("vring_%d_size", i),
+                        xasprintf("%d", vring.size));
     }
 
     ovs_mutex_unlock(&dev->mutex);
-- 
2.14.3



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