eal: fix possible crash in hotplug

If devargs is NULL, building the full_dev_name will segfault
when using strlen on it.

Coverity issue: 158630
Fixes: 7e8b26650146 ("eal: fix hotplug add / remove")

Signed-off-by: Gaetan Rivet <gaetan.rivet@6wind.com>

diff --git a/lib/librte_eal/common/eal_common_dev.c b/lib/librte_eal/common/eal_common_dev.c
index f98302d..d19232d 100644 (file)
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -133,16 +133,13 @@ full_dev_name(const char *bus, const char *dev, const char *args)
        char *name;
        size_t len;
 
-       len = strlen(bus) + 1 +
-             strlen(dev) + 1 +
-             strlen(args) + 1;
+       len = snprintf(NULL, 0, "%s:%s,%s", bus, dev, args);
        name = calloc(1, len);
        if (name == NULL) {
                RTE_LOG(ERR, EAL, "Could not allocate full device name\n");
                return NULL;
        }
-       snprintf(name, len, "%s:%s,%s", bus, dev,
-                args ? args : "");
+       snprintf(name, len, "%s:%s,%s", bus, dev, args);
        return name;
 }