[dpdk-dev] [PATCH] rte_eth_af_packet: refactor error handling to avoid NULL pointer dereference

[John W. Linville]

Coverity CID # 13321

Checking *internals != NULL before accessing req is not good enough,
because **internals is a function argument and the function doesn't
really know what is passed-in.  We can close our eyes and ignore the
warning on the basis of controlling all the calling code, or we can
refactor the error exit to avoid the issue entirely...

Signed-off-by: John W. Linville <linville at tuxdriver.com>
---
 drivers/net/af_packet/rte_eth_af_packet.c | 44 +++++++++++++++----------------
 1 file changed, 21 insertions(+), 23 deletions(-)

diff --git a/drivers/net/af_packet/rte_eth_af_packet.c 
b/drivers/net/af_packet/rte_eth_af_packet.c
index bdd9628674cb..cac26e533813 100644
--- a/drivers/net/af_packet/rte_eth_af_packet.c
+++ b/drivers/net/af_packet/rte_eth_af_packet.c
@@ -454,7 +454,7 @@ rte_pmd_init_internals(const char *name,
                RTE_LOG(ERR, PMD,
                        "%s: no interface specified for AF_PACKET ethdev\n",
                        name);
-               goto error;
+               goto error_early;
        }

        RTE_LOG(INFO, PMD,
@@ -467,16 +467,16 @@ rte_pmd_init_internals(const char *name,
         */
        data = rte_zmalloc_socket(name, sizeof(*data), 0, numa_node);
        if (data == NULL)
-               goto error;
+               goto error_early;

        pci_dev = rte_zmalloc_socket(name, sizeof(*pci_dev), 0, numa_node);
        if (pci_dev == NULL)
-               goto error;
+               goto error_early;

        *internals = rte_zmalloc_socket(name, sizeof(**internals),
                                        0, numa_node);
        if (*internals == NULL)
-               goto error;
+               goto error_early;

        for (q = 0; q < nb_queues; q++) {
                (*internals)->rx_queue[q].map = MAP_FAILED;
@@ -498,13 +498,13 @@ rte_pmd_init_internals(const char *name,
                RTE_LOG(ERR, PMD,
                        "%s: I/F name too long (%s)\n",
                        name, pair->value);
-               goto error;
+               goto error_early;
        }
        if (ioctl(sockfd, SIOCGIFINDEX, &ifr) == -1) {
                RTE_LOG(ERR, PMD,
                        "%s: ioctl failed (SIOCGIFINDEX)\n",
                        name);
-               goto error;
+               goto error_early;
        }
        (*internals)->if_index = ifr.ifr_ifindex;

@@ -512,7 +512,7 @@ rte_pmd_init_internals(const char *name,
                RTE_LOG(ERR, PMD,
                        "%s: ioctl failed (SIOCGIFHWADDR)\n",
                        name);
-               goto error;
+               goto error_early;
        }
        memcpy(&(*internals)->eth_addr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);

@@ -678,24 +678,22 @@ rte_pmd_init_internals(const char *name,
        return 0;

 error:
-       rte_free(data);
-       rte_free(pci_dev);
-
-       if (*internals) {
-               for (q = 0; q < nb_queues; q++) {
-                       munmap((*internals)->rx_queue[q].map,
-                              2 * req->tp_block_size * req->tp_block_nr);
-
-                       rte_free((*internals)->rx_queue[q].rd);
-                       rte_free((*internals)->tx_queue[q].rd);
-                       if (((*internals)->rx_queue[q].sockfd != 0) &&
-                               ((*internals)->rx_queue[q].sockfd != qsockfd))
-                               close((*internals)->rx_queue[q].sockfd);
-               }
-               rte_free(*internals);
-       }
        if (qsockfd != -1)
                close(qsockfd);
+       for (q = 0; q < nb_queues; q++) {
+               munmap((*internals)->rx_queue[q].map,
+                      2 * req->tp_block_size * req->tp_block_nr);
+
+               rte_free((*internals)->rx_queue[q].rd);
+               rte_free((*internals)->tx_queue[q].rd);
+               if (((*internals)->rx_queue[q].sockfd != 0) &&
+                       ((*internals)->rx_queue[q].sockfd != qsockfd))
+                       close((*internals)->rx_queue[q].sockfd);
+       }
+       rte_free(*internals);
+error_early:
+       rte_free(pci_dev);
+       rte_free(data);
        return -1;
 }

-- 
2.4.3