From 923f4902fefdf4e89b0fb32c4e069d4f57d704f5 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 12 Feb 2007 11:12:57 -0800 Subject: [NETFILTER]: nf_conntrack: properly use RCU API for nf_ct_protos/nf_ct_l3protos arrays Replace preempt_{enable,disable} based RCU by proper use of the RCU API and add missing rcu_read_lock/rcu_read_unlock calls in all paths not obviously only used within packet process context (nfnetlink_conntrack). Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- include/net/netfilter/nf_conntrack_l3proto.h | 2 +- net/ipv4/netfilter/nf_conntrack_proto_icmp.c | 2 ++ net/ipv4/netfilter/nf_nat_core.c | 9 +++---- net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c | 1 + net/netfilter/nf_conntrack_core.c | 27 ++++++++++++++++----- net/netfilter/nf_conntrack_proto.c | 33 +++++++++++--------------- 6 files changed, 44 insertions(+), 30 deletions(-) diff --git a/include/net/netfilter/nf_conntrack_l3proto.h b/include/net/netfilter/nf_conntrack_l3proto.h index 664ddcf..ba760fe 100644 --- a/include/net/netfilter/nf_conntrack_l3proto.h +++ b/include/net/netfilter/nf_conntrack_l3proto.h @@ -106,7 +106,7 @@ __nf_ct_l3proto_find(u_int16_t l3proto) { if (unlikely(l3proto >= AF_MAX)) return &nf_conntrack_l3proto_generic; - return nf_ct_l3protos[l3proto]; + return rcu_dereference(nf_ct_l3protos[l3proto]); } #endif /*_NF_CONNTRACK_L3PROTO_H*/ diff --git a/net/ipv4/netfilter/nf_conntrack_proto_icmp.c b/net/ipv4/netfilter/nf_conntrack_proto_icmp.c index 677b6c8..e5aa4d8 100644 --- a/net/ipv4/netfilter/nf_conntrack_proto_icmp.c +++ b/net/ipv4/netfilter/nf_conntrack_proto_icmp.c @@ -170,7 +170,9 @@ icmp_error_message(struct sk_buff *skb, return -NF_ACCEPT; } + /* rcu_read_lock()ed by nf_hook_slow */ innerproto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol); + dataoff = skb->nh.iph->ihl*4 + sizeof(inside->icmp); /* Are they talking about one of our connections? */ if (!nf_ct_get_tuple(skb, dataoff, dataoff + inside->ip.ihl*4, PF_INET, diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c index 6d0061f..5156d5d 100644 --- a/net/ipv4/netfilter/nf_nat_core.c +++ b/net/ipv4/netfilter/nf_nat_core.c @@ -429,6 +429,7 @@ int nf_nat_icmp_reply_translation(struct nf_conn *ct, struct icmphdr icmp; struct iphdr ip; } *inside; + struct nf_conntrack_l4proto *l4proto; struct nf_conntrack_tuple inner, target; int hdrlen = (*pskb)->nh.iph->ihl * 4; enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo); @@ -464,16 +465,16 @@ int nf_nat_icmp_reply_translation(struct nf_conn *ct, DEBUGP("icmp_reply_translation: translating error %p manp %u dir %s\n", *pskb, manip, dir == IP_CT_DIR_ORIGINAL ? "ORIG" : "REPLY"); + /* rcu_read_lock()ed by nf_hook_slow */ + l4proto = __nf_ct_l4proto_find(PF_INET, inside->ip.protocol); + if (!nf_ct_get_tuple(*pskb, (*pskb)->nh.iph->ihl*4 + sizeof(struct icmphdr), (*pskb)->nh.iph->ihl*4 + sizeof(struct icmphdr) + inside->ip.ihl*4, (u_int16_t)AF_INET, inside->ip.protocol, - &inner, - l3proto, - __nf_ct_l4proto_find((u_int16_t)PF_INET, - inside->ip.protocol))) + &inner, l3proto, l4proto)) return 0; /* Change inner back to look like incoming packet. We do the diff --git a/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c b/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c index b08622c..19bdb7c 100644 --- a/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c +++ b/net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c @@ -182,6 +182,7 @@ icmpv6_error_message(struct sk_buff *skb, return -NF_ACCEPT; } + /* rcu_read_lock()ed by nf_hook_slow */ inproto = __nf_ct_l4proto_find(PF_INET6, inprotonum); /* Are they talking about one of our connections? */ diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 59bcab1..3deeb90 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -332,13 +332,16 @@ destroy_conntrack(struct nf_conntrack *nfct) /* To make sure we don't get any weird locking issues here: * destroy_conntrack() MUST NOT be called with a write lock * to nf_conntrack_lock!!! -HW */ + rcu_read_lock(); l3proto = __nf_ct_l3proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num); if (l3proto && l3proto->destroy) l3proto->destroy(ct); - l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum); + l4proto = __nf_ct_l4proto_find(ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.l3num, + ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.protonum); if (l4proto && l4proto->destroy) l4proto->destroy(ct); + rcu_read_unlock(); if (nf_conntrack_destroyed) nf_conntrack_destroyed(ct); @@ -647,9 +650,14 @@ struct nf_conn *nf_conntrack_alloc(const struct nf_conntrack_tuple *orig, const struct nf_conntrack_tuple *repl) { struct nf_conntrack_l3proto *l3proto; + struct nf_conn *ct; + rcu_read_lock(); l3proto = __nf_ct_l3proto_find(orig->src.l3num); - return __nf_conntrack_alloc(orig, repl, l3proto, 0); + ct = __nf_conntrack_alloc(orig, repl, l3proto, 0); + rcu_read_unlock(); + + return ct; } EXPORT_SYMBOL_GPL(nf_conntrack_alloc); @@ -817,7 +825,9 @@ nf_conntrack_in(int pf, unsigned int hooknum, struct sk_buff **pskb) return NF_ACCEPT; } + /* rcu_read_lock()ed by nf_hook_slow */ l3proto = __nf_ct_l3proto_find((u_int16_t)pf); + if ((ret = l3proto->prepare(pskb, hooknum, &dataoff, &protonum)) <= 0) { DEBUGP("not prepared to track yet or error occured\n"); return -ret; @@ -872,10 +882,15 @@ EXPORT_SYMBOL_GPL(nf_conntrack_in); int nf_ct_invert_tuplepr(struct nf_conntrack_tuple *inverse, const struct nf_conntrack_tuple *orig) { - return nf_ct_invert_tuple(inverse, orig, - __nf_ct_l3proto_find(orig->src.l3num), - __nf_ct_l4proto_find(orig->src.l3num, - orig->dst.protonum)); + int ret; + + rcu_read_lock(); + ret = nf_ct_invert_tuple(inverse, orig, + __nf_ct_l3proto_find(orig->src.l3num), + __nf_ct_l4proto_find(orig->src.l3num, + orig->dst.protonum)); + rcu_read_unlock(); + return ret; } EXPORT_SYMBOL_GPL(nf_ct_invert_tuplepr); diff --git a/net/netfilter/nf_conntrack_proto.c b/net/netfilter/nf_conntrack_proto.c index 1a61b72..4dab3fa 100644 --- a/net/netfilter/nf_conntrack_proto.c +++ b/net/netfilter/nf_conntrack_proto.c @@ -66,7 +66,7 @@ __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto) if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL)) return &nf_conntrack_l4proto_generic; - return nf_ct_protos[l3proto][l4proto]; + return rcu_dereference(nf_ct_protos[l3proto][l4proto]); } EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find); @@ -77,11 +77,11 @@ nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto) { struct nf_conntrack_l4proto *p; - preempt_disable(); + rcu_read_lock(); p = __nf_ct_l4proto_find(l3proto, l4proto); if (!try_module_get(p->me)) p = &nf_conntrack_l4proto_generic; - preempt_enable(); + rcu_read_unlock(); return p; } @@ -98,11 +98,11 @@ nf_ct_l3proto_find_get(u_int16_t l3proto) { struct nf_conntrack_l3proto *p; - preempt_disable(); + rcu_read_lock(); p = __nf_ct_l3proto_find(l3proto); if (!try_module_get(p->me)) p = &nf_conntrack_l3proto_generic; - preempt_enable(); + rcu_read_unlock(); return p; } @@ -137,10 +137,8 @@ void nf_ct_l3proto_module_put(unsigned short l3proto) { struct nf_conntrack_l3proto *p; - preempt_disable(); + /* rcu_read_lock not necessary since the caller holds a reference */ p = __nf_ct_l3proto_find(l3proto); - preempt_enable(); - module_put(p->me); } EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put); @@ -202,7 +200,7 @@ int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto) ret = -EBUSY; goto out_unlock; } - nf_ct_l3protos[proto->l3proto] = proto; + rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto); write_unlock_bh(&nf_conntrack_lock); ret = nf_ct_l3proto_register_sysctl(proto); @@ -233,14 +231,13 @@ int nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto) goto out; } - nf_ct_l3protos[proto->l3proto] = &nf_conntrack_l3proto_generic; + rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], + &nf_conntrack_l3proto_generic); write_unlock_bh(&nf_conntrack_lock); + synchronize_rcu(); nf_ct_l3proto_unregister_sysctl(proto); - /* Somebody could be still looking at the proto in bh. */ - synchronize_net(); - /* Remove all contrack entries for this protocol */ nf_ct_iterate_cleanup(kill_l3proto, proto); @@ -356,7 +353,7 @@ retry: goto retry; } - nf_ct_protos[l4proto->l3proto][l4proto->l4proto] = l4proto; + rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], l4proto); write_unlock_bh(&nf_conntrack_lock); ret = nf_ct_l4proto_register_sysctl(l4proto); @@ -392,15 +389,13 @@ int nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto) ret = -EBUSY; goto out; } - nf_ct_protos[l4proto->l3proto][l4proto->l4proto] - = &nf_conntrack_l4proto_generic; + rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], + &nf_conntrack_l4proto_generic); write_unlock_bh(&nf_conntrack_lock); + synchronize_rcu(); nf_ct_l4proto_unregister_sysctl(l4proto); - /* Somebody could be still looking at the proto in bh. */ - synchronize_net(); - /* Remove all contrack entries for this protocol */ nf_ct_iterate_cleanup(kill_l4proto, l4proto); -- cgit v1.1