eal: fix hotplug device parsing

snprintf returns the length it would have written had the given length
been enough, *terminating null byte excluded*.

It will however limit the length of its writing to given length minus
one, and always put a terminating null-byte at the end of the string.

This must be taken into account when calculating the total length of the
device declaration string.

Fixes: 3054036f054a ("eal: fix possible crash in hotplug")

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 fc8a4d2..e251275 100644 (file)
--- a/lib/librte_eal/common/eal_common_dev.c
+++ b/lib/librte_eal/common/eal_common_dev.c
@@ -133,7 +133,7 @@ full_dev_name(const char *bus, const char *dev, const char *args)
        char *name;
        size_t len;
 
-       len = snprintf(NULL, 0, "%s:%s,%s", bus, dev, args);
+       len = snprintf(NULL, 0, "%s:%s,%s", bus, dev, args) + 1;
        name = calloc(1, len);
        if (name == NULL) {
                RTE_LOG(ERR, EAL, "Could not allocate full device name\n");