[dpdk-dev] [PATCH] ether: check the first segment length on SW VLAN insertion

[Andrew Rybchenko <arybchenko@solarflare.com>]

SW VLAN insertion relies on Ethernet addresses location in contigous
memory (do not split across mbuf segments). There is no any formal
requirements on data location and mbuf structure which guarantee it.
So, check it explicitly to avoid corrupted packets if the condition
is violated. Typically software VLAN insertion is done on Tx prepare
stage and application will get indication that the packet is invalid
and cannot be transmitted.

Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
---
 lib/librte_net/rte_ether.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/librte_net/rte_ether.h b/lib/librte_net/rte_ether.h
index 0ae4e75b6c..d7c076bba8 100644
--- a/lib/librte_net/rte_ether.h
+++ b/lib/librte_net/rte_ether.h
@@ -357,6 +357,10 @@ static inline int rte_vlan_insert(struct rte_mbuf **m)
 	if (!RTE_MBUF_DIRECT(*m) || rte_mbuf_refcnt_read(*m) > 1)
 		return -EINVAL;
 
+	/* Can't insert header if the first segment is too short */
+	if (rte_pktmbuf_data_len(*m) < 2 * RTE_ETHER_ADDR_LEN)
+		return -EINVAL;
+
 	oh = rte_pktmbuf_mtod(*m, struct rte_ether_hdr *);
 	nh = (struct rte_ether_hdr *)
 		rte_pktmbuf_prepend(*m, sizeof(struct rte_vlan_hdr));
-- 
2.17.1