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Commit a441dfdb authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: ip_nat: properly use RCU API for ip_nat_protos array 



Replace preempt_{enable,disable} based RCU by proper use of the
RCU API and add missing rcu_read_lock/rcu_read_unlock calls in
paths used outside of packet processing context (nfnetlink_conntrack).

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e92ad99c

net/ipv4/netfilter/ip_nat_core.c

+29 −32
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ static struct ip_nat_protocol *ip_nat_protos[MAX_IP_NAT_PROTO]; 
static inline struct ip_nat_protocol *

__ip_nat_proto_find(u_int8_t protonum)

{

	return ip_nat_protos[protonum];

	return rcu_dereference(ip_nat_protos[protonum]);

}



struct ip_nat_protocol *
@@ -58,13 +58,11 @@ ip_nat_proto_find_get(u_int8_t protonum) 
{

	struct ip_nat_protocol *p;



	/* we need to disable preemption to make sure 'p' doesn't get

	 * removed until we've grabbed the reference */

	preempt_disable();

	rcu_read_lock();

	p = __ip_nat_proto_find(protonum);

	if (!try_module_get(p->me))

		p = &ip_nat_unknown_protocol;

	preempt_enable();

	rcu_read_unlock();



	return p;

}
@@ -120,8 +118,8 @@ static int 
in_range(const struct ip_conntrack_tuple *tuple,

	 const struct ip_nat_range *range)

{

	struct ip_nat_protocol *proto =

				__ip_nat_proto_find(tuple->dst.protonum);

	struct ip_nat_protocol *proto;

	int ret = 0;



	/* If we are supposed to map IPs, then we must be in the

	   range specified, otherwise let this drag us onto a new src IP. */
@@ -131,12 +129,15 @@ in_range(const struct ip_conntrack_tuple *tuple, 
			return 0;

	}



	rcu_read_lock();

	proto = __ip_nat_proto_find(tuple->dst.protonum);

	if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)

	    || proto->in_range(tuple, IP_NAT_MANIP_SRC,

			       &range->min, &range->max))

		return 1;

		ret = 1;

	rcu_read_unlock();



	return 0;

	return ret;

}



static inline int
@@ -260,27 +261,25 @@ get_unique_tuple(struct ip_conntrack_tuple *tuple, 
	/* 3) The per-protocol part of the manip is made to map into

	   the range to make a unique tuple. */



	proto = ip_nat_proto_find_get(orig_tuple->dst.protonum);

	rcu_read_lock();

	proto = __ip_nat_proto_find(orig_tuple->dst.protonum);



	/* Change protocol info to have some randomization */

	if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {

		proto->unique_tuple(tuple, range, maniptype, conntrack);

		ip_nat_proto_put(proto);

		return;

		goto out;

	}



	/* Only bother mapping if it's not already in range and unique */

	if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)

	     || proto->in_range(tuple, maniptype, &range->min, &range->max))

	    && !ip_nat_used_tuple(tuple, conntrack)) {

		ip_nat_proto_put(proto);

		return;

	}

	    && !ip_nat_used_tuple(tuple, conntrack))

		goto out;



	/* Last change: get protocol to try to obtain unique tuple. */

	proto->unique_tuple(tuple, range, maniptype, conntrack);



	ip_nat_proto_put(proto);

out:

	rcu_read_unlock();

}



unsigned int
@@ -360,12 +359,11 @@ manip_pkt(u_int16_t proto, 
	iph = (void *)(*pskb)->data + iphdroff;



	/* Manipulate protcol part. */

	p = ip_nat_proto_find_get(proto);

	if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) {

		ip_nat_proto_put(p);



	/* rcu_read_lock()ed by nf_hook_slow */

	p = __ip_nat_proto_find(proto);

	if (!p->manip_pkt(pskb, iphdroff, target, maniptype))

		return 0;

	}

	ip_nat_proto_put(p);



	iph = (void *)(*pskb)->data + iphdroff;
@@ -515,7 +513,7 @@ int ip_nat_protocol_register(struct ip_nat_protocol *proto) 
		ret = -EBUSY;

		goto out;

	}

	ip_nat_protos[proto->protonum] = proto;

	rcu_assign_pointer(ip_nat_protos[proto->protonum], proto);

 out:

	write_unlock_bh(&ip_nat_lock);

	return ret;
@@ -526,11 +524,10 @@ EXPORT_SYMBOL(ip_nat_protocol_register); 
void ip_nat_protocol_unregister(struct ip_nat_protocol *proto)

{

	write_lock_bh(&ip_nat_lock);

	ip_nat_protos[proto->protonum] = &ip_nat_unknown_protocol;

	rcu_assign_pointer(ip_nat_protos[proto->protonum],

			   &ip_nat_unknown_protocol);

	write_unlock_bh(&ip_nat_lock);



	/* Someone could be still looking at the proto in a bh. */

	synchronize_net();

	synchronize_rcu();

}

EXPORT_SYMBOL(ip_nat_protocol_unregister);
@@ -594,10 +591,10 @@ static int __init ip_nat_init(void) 
	/* Sew in builtin protocols. */

	write_lock_bh(&ip_nat_lock);

	for (i = 0; i < MAX_IP_NAT_PROTO; i++)

		ip_nat_protos[i] = &ip_nat_unknown_protocol;

	ip_nat_protos[IPPROTO_TCP] = &ip_nat_protocol_tcp;

	ip_nat_protos[IPPROTO_UDP] = &ip_nat_protocol_udp;

	ip_nat_protos[IPPROTO_ICMP] = &ip_nat_protocol_icmp;

		rcu_assign_pointer(ip_nat_protos[i], &ip_nat_unknown_protocol);

	rcu_assign_pointer(ip_nat_protos[IPPROTO_TCP], &ip_nat_protocol_tcp);

	rcu_assign_pointer(ip_nat_protos[IPPROTO_UDP], &ip_nat_protocol_udp);

	rcu_assign_pointer(ip_nat_protos[IPPROTO_ICMP], &ip_nat_protocol_icmp);

	write_unlock_bh(&ip_nat_lock);



	for (i = 0; i < ip_nat_htable_size; i++) {