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[NETFILTER]: nf_nat: don't add NAT extension for confirmed conntracks 

Adding extensions to confirmed conntracks is not allowed to avoid races
on reallocation. Don't setup NAT for confirmed conntracks in case NAT
module is loaded late.

The has one side-effect, the connections existing before the NAT module
was loaded won't enter the bysource hash. The only case where this actually
makes a difference is in case of SNAT to a multirange where the IP before
NAT is also part of the range. Since old connections don't enter the
bysource hash the first new connection from the IP will have a new address
selected. This shouldn't matter at all.

Signed-off-by: Patrick McHardy <kaber@trash.net>
hifive-unleashed-5.1
Patrick McHardy 2008-04-14 11:15:51 +02:00
parent 42cf800c24
commit 8c87238b72
3 changed files with 4 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/net/netfilter/nf_nat_rule.h
View File

@ -14,7 +14,4 @@ extern int nf_nat_rule_find(struct sk_buff *skb,
extern unsigned int
alloc_null_binding(struct nf_conn *ct, unsigned int hooknum);
extern unsigned int
alloc_null_binding_confirmed(struct nf_conn *ct, unsigned int hooknum);
#endif /* _NF_NAT_RULE_H */

19
net/ipv4/netfilter/nf_nat_rule.c
View File

@ -188,25 +188,6 @@ alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
return nf_nat_setup_info(ct, &range, HOOK2MANIP(hooknum));
}
unsigned int
alloc_null_binding_confirmed(struct nf_conn *ct, unsigned int hooknum)
{
__be32 ip
= (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
? ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip
: ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip);
__be16 all
= (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
? ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.all
: ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u.all);
struct nf_nat_range range
= { IP_NAT_RANGE_MAP_IPS, ip, ip, { all }, { all } };
pr_debug("Allocating NULL binding for confirmed %p (%u.%u.%u.%u)\n",
ct, NIPQUAD(ip));
return nf_nat_setup_info(ct, &range, HOOK2MANIP(hooknum));
}
int nf_nat_rule_find(struct sk_buff *skb,
unsigned int hooknum,
const struct net_device *in,

8
net/ipv4/netfilter/nf_nat_standalone.c
View File

@ -102,6 +102,9 @@ nf_nat_fn(unsigned int hooknum,
nat = nfct_nat(ct);
if (!nat) {
/* NAT module was loaded late. */
if (nf_ct_is_confirmed(ct))
return NF_ACCEPT;
nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
if (nat == NULL) {
pr_debug("failed to add NAT extension\n");
@ -127,10 +130,7 @@ nf_nat_fn(unsigned int hooknum,
if (!nf_nat_initialized(ct, maniptype)) {
unsigned int ret;
if (unlikely(nf_ct_is_confirmed(ct)))
/* NAT module was loaded late */
ret = alloc_null_binding_confirmed(ct, hooknum);
else if (hooknum == NF_INET_LOCAL_IN)
if (hooknum == NF_INET_LOCAL_IN)
/* LOCAL_IN hook doesn't have a chain! */
ret = alloc_null_binding(ct, hooknum);
else