[PATCH 5.7 018/265] openvswitch: take into account de-fragmentation/gso_size in execute_check_pkt_len

Sasha Levin
2020-06-29T21:32:53Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit 17843655708e1941c0653af3cd61be6948e36f43 ]

ovs connection tracking module performs de-fragmentation on incoming
fragmented traffic. Take info account if traffic has been de-fragmented
in execute_check_pkt_len action otherwise we will perform the wrong
nested action considering the original packet size. This issue typically
occurs if ovs-vswitchd adds a rule in the pipeline that requires connection
tracking (e.g. OVN stateful ACLs) before execute_check_pkt_len action.
Moreover take into account GSO fragment size for GSO packet in
execute_check_pkt_len routine

Fixes: 4d5ec89fc8d14 ("net: openvswitch: Add a new action check_pkt_len")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/openvswitch/actions.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index fc0efd8833c84..2611657f40cac 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -1169,9 +1169,10 @@ static int execute_check_pkt_len(struct datapath *dp, struct sk_buff *skb,
struct sw_flow_key *key,
const struct nlattr *attr, bool last)
{
+ struct ovs_skb_cb *ovs_cb = OVS_CB(skb);
const struct nlattr *actions, *cpl_arg;
+ int len, max_len, rem = nla_len(attr);
const struct check_pkt_len_arg *arg;
- int rem = nla_len(attr);
bool clone_flow_key;

/* The first netlink attribute in 'attr' is always
@@ -1180,7 +1181,11 @@ static int execute_check_pkt_len(struct datapath *dp, struct sk_buff *skb,
cpl_arg = nla_data(attr);
arg = nla_data(cpl_arg);

- if (skb->len <= arg->pkt_len) {
+ len = ovs_cb->mru ? ovs_cb->mru + skb->mac_len : skb->len;
+ max_len = arg->pkt_len;
+
+ if ((skb_is_gso(skb) && skb_gso_validate_mac_len(skb, max_len)) ||
+ len <= max_len) {
/* Second netlink attribute in 'attr' is always
* 'OVS_CHECK_PKT_LEN_ATTR_ACTIONS_IF_LESS_EQUAL'.
*/
--
2.25.1