path: root/net/sched/cls_api.c
diff options
authorCong Wang <xiyou.wangcong@gmail.com>2019-01-11 18:55:42 -0800
committerDavid S. Miller <davem@davemloft.net>2019-01-16 13:25:11 -0800
commitcd0c4e70fc0ccfa705cdf55efb27519ce9337a26 (patch)
tree7a4995e44d642b96327846447b71ac8081cb343a /net/sched/cls_api.c
parentnet: phy: meson-gxl: Use the genphy_soft_reset callback (diff)
net_sched: refetch skb protocol for each filter
Martin reported a set of filters don't work after changing from reclassify to continue. Looking into the code, it looks like skb protocol is not always fetched for each iteration of the filters. But, as demonstrated by Martin, TC actions could modify skb->protocol, for example act_vlan, this means we have to refetch skb protocol in each iteration, rather than using the one we fetch in the beginning of the loop. This bug is _not_ introduced by commit 3b3ae880266d ("net: sched: consolidate tc_classify{,_compat}"), technically, if act_vlan is the only action that modifies skb protocol, then it is commit c7e2b9689ef8 ("sched: introduce vlan action") which introduced this bug. Reported-by: Martin Olsson <martin.olsson+netdev@sentorsecurity.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: Jiri Pirko <jiri@resnulli.us> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/cls_api.c')
1 files changed, 1 insertions, 2 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index 8ce2a0507970..e2b5cb2eb34e 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -1277,7 +1277,6 @@ EXPORT_SYMBOL(tcf_block_cb_unregister);
int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
struct tcf_result *res, bool compat_mode)
- __be16 protocol = tc_skb_protocol(skb);
const int max_reclassify_loop = 4;
const struct tcf_proto *orig_tp = tp;
@@ -1287,6 +1286,7 @@ int tcf_classify(struct sk_buff *skb, const struct tcf_proto *tp,
for (; tp; tp = rcu_dereference_bh(tp->next)) {
+ __be16 protocol = tc_skb_protocol(skb);
int err;
if (tp->protocol != protocol &&
@@ -1319,7 +1319,6 @@ reset:
tp = first_tp;
- protocol = tc_skb_protocol(skb);
goto reclassify;