[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 <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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 @@
/* 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 @@
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 @@
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 @@
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 @@
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 @@
{
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 @@
{
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 @@
{
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 @@
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 @@
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 @@
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 @@
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);