[patch 14/20] : ip_tables: fix table locking in ipt_do_table

[Greg KH]

-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Patrick McHardy <kaber@xxxxxxxxx>

[NETFILTER]: ip_tables: fix table locking in ipt_do_table

table->private might change because of ruleset changes, don't use it without
holding the lock.

Signed-off-by: Patrick McHardy <kaber@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/ipv4/netfilter/arp_tables.c |    3 ++-
 net/ipv4/netfilter/ip_tables.c  |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

--- linux-2.6.17.9.orig/net/ipv4/netfilter/arp_tables.c
+++ linux-2.6.17.9/net/ipv4/netfilter/arp_tables.c
@@ -237,7 +237,7 @@ unsigned int arpt_do_table(struct sk_buf
 	struct arpt_entry *e, *back;
 	const char *indev, *outdev;
 	void *table_base;
-	struct xt_table_info *private = table->private;
+	struct xt_table_info *private;
 
 	/* ARP header, plus 2 device addresses, plus 2 IP addresses.  */
 	if (!pskb_may_pull((*pskb), (sizeof(struct arphdr) +
@@ -249,6 +249,7 @@ unsigned int arpt_do_table(struct sk_buf
 	outdev = out ? out->name : nulldevname;
 
 	read_lock_bh(&table->lock);
+	private = table->private;
 	table_base = (void *)private->entries[smp_processor_id()];
 	e = get_entry(table_base, private->hook_entry[hook]);
 	back = get_entry(table_base, private->underflow[hook]);
--- linux-2.6.17.9.orig/net/ipv4/netfilter/ip_tables.c
+++ linux-2.6.17.9/net/ipv4/netfilter/ip_tables.c
@@ -231,7 +231,7 @@ ipt_do_table(struct sk_buff **pskb,
 	const char *indev, *outdev;
 	void *table_base;
 	struct ipt_entry *e, *back;
-	struct xt_table_info *private = table->private;
+	struct xt_table_info *private;
 
 	/* Initialization */
 	ip = (*pskb)->nh.iph;
@@ -248,6 +248,7 @@ ipt_do_table(struct sk_buff **pskb,
 
 	read_lock_bh(&table->lock);
 	IP_NF_ASSERT(table->valid_hooks & (1 << hook));
+	private = table->private;
 	table_base = (void *)private->entries[smp_processor_id()];
 	e = get_entry(table_base, private->hook_entry[hook]);
 

--
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