[dpdk-dev] [PATCH v3] gro: add missing invalid TCP header length check

[Jiayu Hu <jiayu.hu@intel.com>]

When the TCP header length of input packets is invalid (i.e., less
than 20 bytes or greater than 60 bytes), check_seq_option() will
access illegal memory area when compare TCP Options, which may
cause a segmentation fault.

This patch adds missing invalid TCP header length check to avoid
illegal memory accesses.

Fixes: 0d2cbe59b719 ("lib/gro: support TCP/IPv4")
Fixes: 9e0b9d2ec0f4 ("gro: support VxLAN GRO")
Cc: stable@dpdk.org

Signed-off-by: Jiayu Hu <jiayu.hu@intel.com>
Tested-by: Yinan Wang <yinan.wang@intel.com>
---
changes in v3:
- remove l2 and l3 length checks
- rename macro
changes in v2:
- fix VxLAN header length check bug for VxLAN GRO;
- fix ethernet header length check bug;
- use sizeof() and macro to present valid header length;
- add VLAN related comments since GRO cannot process VLAN tagged packets.

 lib/librte_gro/gro_tcp4.c       | 7 +++++++
 lib/librte_gro/gro_tcp4.h       | 5 +++++
 lib/librte_gro/gro_vxlan_tcp4.c | 7 +++++++
 3 files changed, 19 insertions(+)

diff --git a/lib/librte_gro/gro_tcp4.c b/lib/librte_gro/gro_tcp4.c
index 2fe9aab..7d128a4 100644
--- a/lib/librte_gro/gro_tcp4.c
+++ b/lib/librte_gro/gro_tcp4.c
@@ -208,6 +208,13 @@ gro_tcp4_reassemble(struct rte_mbuf *pkt,
 	int cmp;
 	uint8_t find;
 
+	/*
+	 * Don't process the packet whose TCP header length is greater
+	 * than 60 bytes or less than 20 bytes.
+	 */
+	if (unlikely(INVALID_TCP_HDRLEN(pkt->l4_len)))
+		return -1;
+
 	eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
 	ipv4_hdr = (struct ipv4_hdr *)((char *)eth_hdr + pkt->l2_len);
 	tcp_hdr = (struct tcp_hdr *)((char *)ipv4_hdr + pkt->l3_len);
diff --git a/lib/librte_gro/gro_tcp4.h b/lib/librte_gro/gro_tcp4.h
index 6bb30cd..d979248 100644
--- a/lib/librte_gro/gro_tcp4.h
+++ b/lib/librte_gro/gro_tcp4.h
@@ -17,6 +17,11 @@
  */
 #define MAX_IPV4_PKT_LENGTH UINT16_MAX
 
+/* The maximum TCP header length */
+#define MAX_TCP_HLEN 60
+#define INVALID_TCP_HDRLEN(len) \
+	(((len) < sizeof(struct tcp_hdr)) || ((len) > MAX_TCP_HLEN))
+
 /* Header fields representing a TCP/IPv4 flow */
 struct tcp4_flow_key {
 	struct ether_addr eth_saddr;
diff --git a/lib/librte_gro/gro_vxlan_tcp4.c b/lib/librte_gro/gro_vxlan_tcp4.c
index 955ae4b..acb9bc9 100644
--- a/lib/librte_gro/gro_vxlan_tcp4.c
+++ b/lib/librte_gro/gro_vxlan_tcp4.c
@@ -306,6 +306,13 @@ gro_vxlan_tcp4_reassemble(struct rte_mbuf *pkt,
 	uint16_t hdr_len;
 	uint8_t find;
 
+	/*
+	 * Don't process the packet whose TCP header length is greater
+	 * than 60 bytes or less than 20 bytes.
+	 */
+	if (unlikely(INVALID_TCP_HDRLEN(pkt->l4_len)))
+		return -1;
+
 	outer_eth_hdr = rte_pktmbuf_mtod(pkt, struct ether_hdr *);
 	outer_ipv4_hdr = (struct ipv4_hdr *)((char *)outer_eth_hdr +
 			pkt->outer_l2_len);
-- 
2.7.4