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.hor...@netronome.com>
---
v2
* As suggested by Pravin Shelar
- Use new errno for the case handled by this patch in order
to retain the old behaviour if the call to check_header()
in parse_ipv6hdr() returns -EINVAL, which it may.
* Dropped RFC from prefix
* Some consideration should be given to unwanted side effects of this patch
as it affects the handling of malformed packets.
---
net/openvswitch/flow.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c
index 5a3195e538ce..daf914ec58d0 100644
--- 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;
--
2.1.4
--
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