[PATCH 4.20 07/80] net: ip_gre: use erspan key field for tunnel lookup

Greg Kroah-Hartman
2019-02-04T10:51:59Z

From: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>

[ Upstream commit cb73ee40b1b381eaf3749e6dbeed567bb38e5258 ]

Use ERSPAN key header field as tunnel key in gre_parse_header routine
since ERSPAN protocol sets the key field of the external GRE header to
0 resulting in a tunnel lookup fail in ip6gre_err.
In addition remove key field parsing and pskb_may_pull check in
erspan_rcv and ip6erspan_rcv

Fixes: 5a963eb61b7c ("ip6_gre: Add ERSPAN native tunnel support")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/ipv4/gre_demux.c | 17 +++++++++++++++++
net/ipv4/ip_gre.c | 9 ---------
net/ipv6/ip6_gre.c | 4 ----
3 files changed, 17 insertions(+), 13 deletions(-)

--- a/net/ipv4/gre_demux.c
+++ b/net/ipv4/gre_demux.c
@@ -25,6 +25,7 @@
#include <linux/spinlock.h>
#include <net/protocol.h>
#include <net/gre.h>
+#include <net/erspan.h>

#include <net/icmp.h>
#include <net/route.h>
@@ -119,6 +120,22 @@ int gre_parse_header(struct sk_buff *skb
hdr_len += 4;
}
tpi->hdr_len = hdr_len;
+
+ /* ERSPAN ver 1 and 2 protocol sets GRE key field
+ * to 0 and sets the configured key in the
+ * inner erspan header field
+ */
+ if (greh->protocol == htons(ETH_P_ERSPAN) ||
+ greh->protocol == htons(ETH_P_ERSPAN2)) {
+ struct erspan_base_hdr *ershdr;
+
+ if (!pskb_may_pull(skb, nhs + hdr_len + sizeof(*ershdr)))
+ return -EINVAL;
+
+ ershdr = (struct erspan_base_hdr *)options;
+ tpi->key = cpu_to_be32(get_session_id(ershdr));
+ }
+
return hdr_len;
}
EXPORT_SYMBOL(gre_parse_header);
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -266,20 +266,11 @@ static int erspan_rcv(struct sk_buff *sk
int len;

itn = net_generic(net, erspan_net_id);
- len = gre_hdr_len + sizeof(*ershdr);
-
- /* Check based hdr len */
- if (unlikely(!pskb_may_pull(skb, len)))
- return PACKET_REJECT;

iph = ip_hdr(skb);
ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
ver = ershdr->ver;

- /* The original GRE header does not have key field,
- * Use ERSPAN 10-bit session ID as key.
- */
- tpi->key = cpu_to_be32(get_session_id(ershdr));
tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
tpi->flags | TUNNEL_KEY,
iph->saddr, iph->daddr, tpi->key);
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -532,13 +532,9 @@ static int ip6erspan_rcv(struct sk_buff
struct ip6_tnl *tunnel;
u8 ver;

- if (unlikely(!pskb_may_pull(skb, sizeof(*ershdr))))
- return PACKET_REJECT;
-
ipv6h = ipv6_hdr(skb);
ershdr = (struct erspan_base_hdr *)skb->data;
ver = ershdr->ver;
- tpi->key = cpu_to_be32(get_session_id(ershdr));

tunnel = ip6gre_tunnel_lookup(skb->dev,
&ipv6h->saddr, &ipv6h->daddr, tpi->key,