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author | Patrick McHardy <kaber@trash.net> | 2008-06-17 15:51:47 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2008-06-17 15:51:47 -0700 |
commit | 68b80f11380889996aa7eadba29dbbb5c29a5864 (patch) | |
tree | e6425d1ee4d15713678e60cd03bd5f514385e6e5 /net | |
parent | 65c3e4715b1b934f8dcc002d9f46b4371ca7a9b1 (diff) | |
download | linux-stable-68b80f11380889996aa7eadba29dbbb5c29a5864.tar.gz linux-stable-68b80f11380889996aa7eadba29dbbb5c29a5864.tar.bz2 linux-stable-68b80f11380889996aa7eadba29dbbb5c29a5864.zip |
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 <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/ipv4/netfilter/nf_nat_core.c | 3 | ||||
-rw-r--r-- | net/netfilter/nf_conntrack_extend.c | 9 |
2 files changed, 9 insertions, 3 deletions
diff --git a/net/ipv4/netfilter/nf_nat_core.c b/net/ipv4/netfilter/nf_nat_core.c index 04578593e100..d2a887fc8d9b 100644 --- a/net/ipv4/netfilter/nf_nat_core.c +++ b/net/ipv4/netfilter/nf_nat_core.c @@ -556,7 +556,6 @@ static void nf_nat_cleanup_conntrack(struct nf_conn *ct) spin_lock_bh(&nf_nat_lock); hlist_del_rcu(&nat->bysource); - nat->ct = NULL; spin_unlock_bh(&nf_nat_lock); } @@ -570,8 +569,8 @@ static void nf_nat_move_storage(void *new, void *old) return; spin_lock_bh(&nf_nat_lock); - hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); new_nat->ct = ct; + hlist_replace_rcu(&old_nat->bysource, &new_nat->bysource); spin_unlock_bh(&nf_nat_lock); } 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; } |