From 50acd32ea7f682916b615103d32d2ccecf7e5fc8 Mon Sep 17 00:00:00 2001 From: Jason Baron Date: Mon, 17 Feb 2020 15:38:09 -0500 Subject: [PATCH] net: sched: correct flower port blocking [ Upstream commit 8a9093c79863b58cc2f9874d7ae788f0d622a596 ] tc flower rules that are based on src or dst port blocking are sometimes ineffective due to uninitialized stack data. __skb_flow_dissect() extracts ports from the skb for tc flower to match against. However, the port dissection is not done when when the FLOW_DIS_IS_FRAGMENT bit is set in key_control->flags. All callers of __skb_flow_dissect(), zero-out the key_control field except for fl_classify() as used by the flower classifier. Thus, the FLOW_DIS_IS_FRAGMENT may be set on entry to __skb_flow_dissect(), since key_control is allocated on the stack and may not be initialized. Since key_basic and key_control are present for all flow keys, let's make sure they are initialized. Fixes: 62230715fd24 ("flow_dissector: do not dissect l4 ports for fragments") Co-developed-by: Eric Dumazet Signed-off-by: Eric Dumazet Acked-by: Cong Wang Signed-off-by: Jason Baron Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/net/flow_dissector.h | 9 +++++++++ net/sched/cls_flower.c | 1 + 2 files changed, 10 insertions(+) diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h index e5fc8db..78f6437 100644 --- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -5,6 +5,7 @@ #include #include #include +#include #include /** @@ -338,4 +339,12 @@ struct bpf_flow_dissector { void *data_end; }; +static inline void +flow_dissector_init_keys(struct flow_dissector_key_control *key_control, + struct flow_dissector_key_basic *key_basic) +{ + memset(key_control, 0, sizeof(*key_control)); + memset(key_basic, 0, sizeof(*key_basic)); +} + #endif diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 5eceeee..1d27054 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -303,6 +303,7 @@ static int fl_classify(struct sk_buff *skb, const struct tcf_proto *tp, struct cls_fl_filter *f; list_for_each_entry_rcu(mask, &head->masks, list) { + flow_dissector_init_keys(&skb_key.control, &skb_key.basic); fl_clear_masked_range(&skb_key, mask); skb_flow_dissect_meta(skb, &mask->dissector, &skb_key); -- 2.7.4