From c3a47ab3e5ad62601449e4e5401352271b777e28 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Mon, 12 Feb 2007 11:09:19 -0800 Subject: [PATCH] [NETFILTER]: Properly use RCU in nf_ct_attach Use rcu_assign_pointer/rcu_dereference for ip_ct_attach pointer instead of self-made RCU and use rcu_read_lock to make sure the conntrack module doesn't disappear below us while calling it, since this function can be called from outside the netfilter hooks. Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/ipv4/netfilter/ip_conntrack_core.c | 4 ++-- net/netfilter/core.c | 9 ++++++--- net/netfilter/nf_conntrack_core.c | 4 ++-- 3 files changed, 10 insertions(+), 7 deletions(-) diff --git a/net/ipv4/netfilter/ip_conntrack_core.c b/net/ipv4/netfilter/ip_conntrack_core.c index 04e466d53c..508e6007a1 100644 --- a/net/ipv4/netfilter/ip_conntrack_core.c +++ b/net/ipv4/netfilter/ip_conntrack_core.c @@ -1354,7 +1354,7 @@ static void free_conntrack_hash(struct list_head *hash, int vmalloced,int size) supposed to kill the mall. */ void ip_conntrack_cleanup(void) { - ip_ct_attach = NULL; + rcu_assign_pointer(ip_ct_attach, NULL); /* This makes sure all current packets have passed through netfilter framework. Roll on, two-stage module @@ -1515,7 +1515,7 @@ int __init ip_conntrack_init(void) write_unlock_bh(&ip_conntrack_lock); /* For use by ipt_REJECT */ - ip_ct_attach = ip_conntrack_attach; + rcu_assign_pointer(ip_ct_attach, ip_conntrack_attach); /* Set up fake conntrack: - to never be deleted, not in any hashes */ diff --git a/net/netfilter/core.c b/net/netfilter/core.c index 291b8c6862..ad24d0c005 100644 --- a/net/netfilter/core.c +++ b/net/netfilter/core.c @@ -248,9 +248,12 @@ void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) { void (*attach)(struct sk_buff *, struct sk_buff *); - if (skb->nfct && (attach = ip_ct_attach) != NULL) { - mb(); /* Just to be sure: must be read before executing this */ - attach(new, skb); + if (skb->nfct) { + rcu_read_lock(); + attach = rcu_dereference(ip_ct_attach); + if (attach) + attach(new, skb); + rcu_read_unlock(); } } EXPORT_SYMBOL(nf_ct_attach); diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 9b02ec4012..59bcab1d10 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1105,7 +1105,7 @@ void nf_conntrack_cleanup(void) { int i; - ip_ct_attach = NULL; + rcu_assign_pointer(ip_ct_attach, NULL); /* This makes sure all current packets have passed through netfilter framework. Roll on, two-stage module @@ -1273,7 +1273,7 @@ int __init nf_conntrack_init(void) write_unlock_bh(&nf_conntrack_lock); /* For use by REJECT target */ - ip_ct_attach = __nf_conntrack_attach; + rcu_assign_pointer(ip_ct_attach, __nf_conntrack_attach); /* Set up fake conntrack: - to never be deleted, not in any hashes */ -- 2.39.5