From: Jason Baron jbaron@akamai.com
[ 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 edumazet@google.com Signed-off-by: Eric Dumazet edumazet@google.com Acked-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: Jason Baron jbaron@akamai.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/net/flow_dissector.h | 9 +++++++++ net/sched/cls_flower.c | 1 + 2 files changed, 10 insertions(+)
--- a/include/net/flow_dissector.h +++ b/include/net/flow_dissector.h @@ -5,6 +5,7 @@ #include <linux/types.h> #include <linux/in6.h> #include <linux/siphash.h> +#include <linux/string.h> #include <uapi/linux/if_ether.h>
struct sk_buff; @@ -349,4 +350,12 @@ 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 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -305,6 +305,7 @@ static int fl_classify(struct sk_buff *s 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);