[dpdk-dev] [PATCH v2] net/tap: fix potential buffer overrun

[Herakliusz Lipiec]

When secondary to primary process synchronization occours
there is no check for number of fds which could cause buffer overrun.

Bugzilla ID: 252
Fixes: c9aa56edec8e ("net/tap: access primary process queues from secondary")
Cc: rasl...@mellanox.com
Cc: sta...@dpdk.org

Signed-off-by: Herakliusz Lipiec <herakliusz.lip...@intel.com>
---
 drivers/net/tap/rte_eth_tap.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index e9fda8cf6..4a2ef5ce7 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -2111,6 +2111,10 @@ tap_mp_attach_queues(const char *port_name, struct 
rte_eth_dev *dev)
        TAP_LOG(DEBUG, "Received IPC reply for %s", reply_param->port_name);
 
        /* Attach the queues from received file descriptors */
+       if (reply_param->rxq_count + reply_param->txq_count != reply->num_fds) {
+               TAP_LOG(ERR, "Unexpected number of fds received");
+               return -1;
+       }
        dev->data->nb_rx_queues = reply_param->rxq_count;
        dev->data->nb_tx_queues = reply_param->txq_count;
        fd_iterator = 0;
@@ -2151,12 +2155,16 @@ tap_mp_sync_queues(const struct rte_mp_msg *request, 
const void *peer)
        /* Fill file descriptors for all queues */
        reply.num_fds = 0;
        reply_param->rxq_count = 0;
+       if (dev->data->nb_rx_queues + dev->data->nb_tx_queues >
+                       RTE_MP_MAX_FD_NUM){
+               TAP_LOG(ERR, "Number of rx/tx queues exceeds max number of 
fds");
+               return -1;
+       }
        for (queue = 0; queue < dev->data->nb_rx_queues; queue++) {
                reply.fds[reply.num_fds++] = process_private->rxq_fds[queue];
                reply_param->rxq_count++;
        }
        RTE_ASSERT(reply_param->rxq_count == dev->data->nb_rx_queues);
-       RTE_ASSERT(reply_param->txq_count == dev->data->nb_tx_queues);
        RTE_ASSERT(reply.num_fds <= RTE_MP_MAX_FD_NUM);
 
        reply_param->txq_count = 0;
@@ -2164,7 +2172,8 @@ tap_mp_sync_queues(const struct rte_mp_msg *request, 
const void *peer)
                reply.fds[reply.num_fds++] = process_private->txq_fds[queue];
                reply_param->txq_count++;
        }
-
+       RTE_ASSERT(reply_param->txq_count == dev->data->nb_tx_queues);
+       RTE_ASSERT(reply.num_fds <= RTE_MP_MAX_FD_NUM);
        /* Send reply */
        strlcpy(reply.name, request->name, sizeof(reply.name));
        strlcpy(reply_param->port_name, request_param->port_name,
-- 
2.17.2