null: fix dereference before null check

This patch fixes potential null pointer access of eth_null_copy_tx().

Reported-by: John Mcnamara <john.mcnamara@intel.com>
Signed-off-by: Tetsuya Mukawa <mukawa@igel.co.jp>

diff --git a/lib/librte_pmd_null/rte_eth_null.c b/lib/librte_pmd_null/rte_eth_null.c
index 8fe1a2d5543437d34441370318e44d79ae728b0c..0e1850270490fe6329a45b2dbf1cbf860e390e1d 100644 (file)
--- a/lib/librte_pmd_null/rte_eth_null.c
+++ b/lib/librte_pmd_null/rte_eth_null.c
@@ -160,11 +160,12 @@ eth_null_copy_tx(void *q, struct rte_mbuf **bufs, uint16_t nb_bufs)
 {
        int i;
        struct null_queue *h = q;
-       unsigned packet_size = h->internals->packet_size;
+       unsigned packet_size;
 
        if ((q == NULL) || (bufs == NULL))
                return 0;
 
+       packet_size = h->internals->packet_size;
        for (i = 0; i < nb_bufs; i++) {
                rte_memcpy(h->dummy_packet, rte_pktmbuf_mtod(bufs[i], void *),
                                        packet_size);