[NETFILTER]: nf_nat: properly use RCU API for nf_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: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -53,7 +53,7 @@ static struct nf_nat_protocol *nf_nat_protos[MAX_IP_NAT_PROTO];
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static inline struct nf_nat_protocol *
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__nf_nat_proto_find(u_int8_t protonum)
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{
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return nf_nat_protos[protonum];
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return rcu_dereference(nf_nat_protos[protonum]);
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}
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struct nf_nat_protocol *
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@ -61,13 +61,11 @@ nf_nat_proto_find_get(u_int8_t protonum)
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{
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struct nf_nat_protocol *p;
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/* we need to disable preemption to make sure 'p' doesn't get
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* removed until we've grabbed the reference */
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preempt_disable();
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rcu_read_lock();
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p = __nf_nat_proto_find(protonum);
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if (!try_module_get(p->me))
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p = &nf_nat_unknown_protocol;
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preempt_enable();
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rcu_read_unlock();
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return p;
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}
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@ -126,8 +124,8 @@ in_range(const struct nf_conntrack_tuple *tuple,
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const struct nf_nat_range *range)
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{
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struct nf_nat_protocol *proto;
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int ret = 0;
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proto = __nf_nat_proto_find(tuple->dst.protonum);
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/* If we are supposed to map IPs, then we must be in the
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range specified, otherwise let this drag us onto a new src IP. */
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if (range->flags & IP_NAT_RANGE_MAP_IPS) {
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@ -136,12 +134,15 @@ in_range(const struct nf_conntrack_tuple *tuple,
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return 0;
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}
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rcu_read_lock();
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proto = __nf_nat_proto_find(tuple->dst.protonum);
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if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
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proto->in_range(tuple, IP_NAT_MANIP_SRC,
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&range->min, &range->max))
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return 1;
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ret = 1;
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rcu_read_unlock();
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return 0;
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return ret;
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}
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static inline int
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@ -268,27 +269,25 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple,
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/* 3) The per-protocol part of the manip is made to map into
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the range to make a unique tuple. */
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proto = nf_nat_proto_find_get(orig_tuple->dst.protonum);
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rcu_read_lock();
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proto = __nf_nat_proto_find(orig_tuple->dst.protonum);
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/* Change protocol info to have some randomization */
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if (range->flags & IP_NAT_RANGE_PROTO_RANDOM) {
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proto->unique_tuple(tuple, range, maniptype, ct);
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nf_nat_proto_put(proto);
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return;
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goto out;
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}
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/* Only bother mapping if it's not already in range and unique */
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if ((!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED) ||
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proto->in_range(tuple, maniptype, &range->min, &range->max)) &&
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!nf_nat_used_tuple(tuple, ct)) {
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nf_nat_proto_put(proto);
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return;
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}
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!nf_nat_used_tuple(tuple, ct))
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goto out;
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/* Last change: get protocol to try to obtain unique tuple. */
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proto->unique_tuple(tuple, range, maniptype, ct);
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nf_nat_proto_put(proto);
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out:
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rcu_read_unlock();
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}
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unsigned int
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@ -369,12 +368,11 @@ manip_pkt(u_int16_t proto,
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iph = (void *)(*pskb)->data + iphdroff;
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/* Manipulate protcol part. */
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p = nf_nat_proto_find_get(proto);
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if (!p->manip_pkt(pskb, iphdroff, target, maniptype)) {
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nf_nat_proto_put(p);
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/* rcu_read_lock()ed by nf_hook_slow */
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p = __nf_nat_proto_find(proto);
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if (!p->manip_pkt(pskb, iphdroff, target, maniptype))
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return 0;
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}
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nf_nat_proto_put(p);
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iph = (void *)(*pskb)->data + iphdroff;
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@ -529,7 +527,7 @@ int nf_nat_protocol_register(struct nf_nat_protocol *proto)
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ret = -EBUSY;
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goto out;
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}
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nf_nat_protos[proto->protonum] = proto;
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rcu_assign_pointer(nf_nat_protos[proto->protonum], proto);
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out:
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write_unlock_bh(&nf_nat_lock);
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return ret;
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@ -540,11 +538,10 @@ EXPORT_SYMBOL(nf_nat_protocol_register);
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void nf_nat_protocol_unregister(struct nf_nat_protocol *proto)
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{
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write_lock_bh(&nf_nat_lock);
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nf_nat_protos[proto->protonum] = &nf_nat_unknown_protocol;
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rcu_assign_pointer(nf_nat_protos[proto->protonum],
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&nf_nat_unknown_protocol);
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write_unlock_bh(&nf_nat_lock);
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/* Someone could be still looking at the proto in a bh. */
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synchronize_net();
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synchronize_rcu();
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}
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EXPORT_SYMBOL(nf_nat_protocol_unregister);
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@ -608,10 +605,10 @@ static int __init nf_nat_init(void)
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/* Sew in builtin protocols. */
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write_lock_bh(&nf_nat_lock);
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for (i = 0; i < MAX_IP_NAT_PROTO; i++)
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nf_nat_protos[i] = &nf_nat_unknown_protocol;
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nf_nat_protos[IPPROTO_TCP] = &nf_nat_protocol_tcp;
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nf_nat_protos[IPPROTO_UDP] = &nf_nat_protocol_udp;
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nf_nat_protos[IPPROTO_ICMP] = &nf_nat_protocol_icmp;
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rcu_assign_pointer(nf_nat_protos[i], &nf_nat_unknown_protocol);
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rcu_assign_pointer(nf_nat_protos[IPPROTO_TCP], &nf_nat_protocol_tcp);
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rcu_assign_pointer(nf_nat_protos[IPPROTO_UDP], &nf_nat_protocol_udp);
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rcu_assign_pointer(nf_nat_protos[IPPROTO_ICMP], &nf_nat_protocol_icmp);
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write_unlock_bh(&nf_nat_lock);
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for (i = 0; i < nf_nat_htable_size; i++) {
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