From 68b80f11380889996aa7eadba29dbbb5c29a5864 Mon Sep 17 00:00:00 2001 From: Patrick McHardy Date: Tue, 17 Jun 2008 15:51:47 -0700 Subject: netfilter: nf_nat: fix RCU races Fix three ct_extend/NAT extension related races: - When cleaning up the extension area and removing it from the bysource hash, the nat->ct pointer must not be set to NULL since it may still be used in a RCU read side - When replacing a NAT extension area in the bysource hash, the nat->ct pointer must be assigned before performing the replacement - When reallocating extension storage in ct_extend, the old memory must not be freed immediately since it may still be used by a RCU read side Possibly fixes https://bugzilla.redhat.com/show_bug.cgi?id=449315 and/or http://bugzilla.kernel.org/show_bug.cgi?id=10875 Signed-off-by: Patrick McHardy Signed-off-by: David S. Miller --- net/netfilter/nf_conntrack_extend.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'net/netfilter/nf_conntrack_extend.c') diff --git a/net/netfilter/nf_conntrack_extend.c b/net/netfilter/nf_conntrack_extend.c index bcc19fa4ed1e..8a3f8b34e466 100644 --- a/net/netfilter/nf_conntrack_extend.c +++ b/net/netfilter/nf_conntrack_extend.c @@ -59,12 +59,19 @@ nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp) if (!*ext) return NULL; + INIT_RCU_HEAD(&(*ext)->rcu); (*ext)->offset[id] = off; (*ext)->len = len; return (void *)(*ext) + off; } +static void __nf_ct_ext_free_rcu(struct rcu_head *head) +{ + struct nf_ct_ext *ext = container_of(head, struct nf_ct_ext, rcu); + kfree(ext); +} + void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) { struct nf_ct_ext *new; @@ -106,7 +113,7 @@ void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) (void *)ct->ext + ct->ext->offset[i]); rcu_read_unlock(); } - kfree(ct->ext); + call_rcu(&ct->ext->rcu, __nf_ct_ext_free_rcu); ct->ext = new; } -- cgit v1.2.3