openvswitch: retain parsed IPv6 header fields in flow on error skipping extension...

When an error occurs skipping IPv6 extension headers retain the already
parsed IP protocol and IPv6 addresses in the flow. Also assume that the
packet is not a fragment in the absence of information to the contrary;
that is always use the frag_off value set by ipv6_skip_exthdr().

This allows matching on the IP protocol and IPv6 addresses of packets
with malformed extension headers.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index 9760dc43bdb99815dc4af7dd8e2c1a34a184a27b..9db87331e2111144b223d831045715d928ce4d2f 100644 (file)
--- a/net/openvswitch/flow.c
+++ b/net/openvswitch/flow.c
@@ -272,8 +272,6 @@ static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
        key->ipv6.addr.dst = nh->daddr;
 
        payload_ofs = ipv6_skip_exthdr(skb, payload_ofs, &nexthdr, &frag_off);
-       if (unlikely(payload_ofs < 0))
-               return -EINVAL;
 
        if (frag_off) {
                if (frag_off & htons(~0x7))
@@ -284,6 +282,13 @@ static int parse_ipv6hdr(struct sk_buff *skb, struct sw_flow_key *key)
                key->ip.frag = OVS_FRAG_TYPE_NONE;
        }
 
+       /* Delayed handling of error in ipv6_skip_exthdr() as it
+        * always sets frag_off to a valid value which may be
+        * used to set key->ip.frag above.
+        */
+       if (unlikely(payload_ofs < 0))
+               return -EPROTO;
+
        nh_len = payload_ofs - nh_ofs;
        skb_set_transport_header(skb, nh_ofs + nh_len);
        key->ip.proto = nexthdr;
@@ -623,12 +628,16 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
 
                nh_len = parse_ipv6hdr(skb, key);
                if (unlikely(nh_len < 0)) {
-                       memset(&key->ip, 0, sizeof(key->ip));
-                       memset(&key->ipv6.addr, 0, sizeof(key->ipv6.addr));
-                       if (nh_len == -EINVAL) {
+                       switch (nh_len) {
+                       case -EINVAL:
+                               memset(&key->ip, 0, sizeof(key->ip));
+                               memset(&key->ipv6.addr, 0, sizeof(key->ipv6.addr));
+                               /* fall-through */
+                       case -EPROTO:
                                skb->transport_header = skb->network_header;
                                error = 0;
-                       } else {
+                               break;
+                       default:
                                error = nh_len;
                        }
                        return error;