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

Greg KH
2006-08-21T18:53:16Z

[-- Attachment #1: ip_tables-fix-table-locking-in-ipt_do_table.patch --]
[-- Type: text/plain, Size: 1989 bytes --]

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

------------------
From: Patrick McHardy <kaber@trash.net>

[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@trash.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
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]);

--