Commit 339ba878 authored by Hadar Hen Zion's avatar Hadar Hen Zion Committed by David S. Miller
Browse files

net_sched: flower: Avoid dissection of unmasked keys 



The current flower implementation checks the mask range and set all the
keys included in that range as "used_keys", even if a specific key in
the range has a zero mask.

This behavior can cause a false positive return value of
dissector_uses_key function and unnecessary dissection in
__skb_flow_dissect.

This patch checks explicitly the mask of each key and "used_keys" will
be set accordingly.

Fixes: 77b9900e ('tc: introduce Flower classifier')
Signed-off-by: default avatarHadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f6a66927

net/sched/cls_flower.c

+13 −15
Original line number Diff line number Diff line
@@ -404,12 +404,10 @@ static int fl_init_hashtable(struct cls_fl_head *head, 


#define FL_KEY_MEMBER_OFFSET(member) offsetof(struct fl_flow_key, member)

#define FL_KEY_MEMBER_SIZE(member) (sizeof(((struct fl_flow_key *) 0)->member))

#define FL_KEY_MEMBER_END_OFFSET(member)					\

	(FL_KEY_MEMBER_OFFSET(member) + FL_KEY_MEMBER_SIZE(member))



#define FL_KEY_IN_RANGE(mask, member)						\

        (FL_KEY_MEMBER_OFFSET(member) <= (mask)->range.end &&			\

         FL_KEY_MEMBER_END_OFFSET(member) >= (mask)->range.start)

#define FL_KEY_IS_MASKED(mask, member)						\

	memchr_inv(((char *)mask) + FL_KEY_MEMBER_OFFSET(member),		\

		   0, FL_KEY_MEMBER_SIZE(member))				\



#define FL_KEY_SET(keys, cnt, id, member)					\

	do {									\
@@ -418,9 +416,9 @@ static int fl_init_hashtable(struct cls_fl_head *head, 
		cnt++;								\

	} while(0);



#define FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt, id, member)			\

#define FL_KEY_SET_IF_MASKED(mask, keys, cnt, id, member)			\

	do {									\

		if (FL_KEY_IN_RANGE(mask, member))				\

		if (FL_KEY_IS_MASKED(mask, member))				\

			FL_KEY_SET(keys, cnt, id, member);			\

	} while(0);
@@ -432,13 +430,13 @@ static void fl_init_dissector(struct cls_fl_head *head, 


	FL_KEY_SET(keys, cnt, FLOW_DISSECTOR_KEY_CONTROL, control);

	FL_KEY_SET(keys, cnt, FLOW_DISSECTOR_KEY_BASIC, basic);

	FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,

	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,

			     FLOW_DISSECTOR_KEY_ETH_ADDRS, eth);

	FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,

	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,

			     FLOW_DISSECTOR_KEY_IPV4_ADDRS, ipv4);

	FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,

	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,

			     FLOW_DISSECTOR_KEY_IPV6_ADDRS, ipv6);

	FL_KEY_SET_IF_IN_RANGE(mask, keys, cnt,

	FL_KEY_SET_IF_MASKED(&mask->key, keys, cnt,

			     FLOW_DISSECTOR_KEY_PORTS, tp);



	skb_flow_dissector_init(&head->dissector, keys, cnt);

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