Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/gi…

…t/pablo/nf

Pablo Neira Ayuso says:

====================
The following patchset contains three netfilter fixes for your net
tree, they are:

* A couple of fixes to resolve info leak to userspace due to uninitialized
  memory area in ulogd, from Mathias Krause.

* Fix instruction ordering issues that may lead to the access of
  uninitialized data in x_tables. The problem involves the table update
 (producer) and the main packet matching (consumer) routines. Detected in
  SMP ARMv7, from Will Deacon.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

net/bridge/netfilter/ebt_ulog.c

@@ -181,6 +181,7 @@ static void ebt_ulog_packet(struct net *net, unsigned int hooknr,
 	ub->qlen++;
 
 	pm = nlmsg_data(nlh);
+	memset(pm, 0, sizeof(*pm));
 
 	/* Fill in the ulog data */
 	pm->version = EBT_ULOG_VERSION;
@@ -193,8 +194,6 @@ static void ebt_ulog_packet(struct net *net, unsigned int hooknr,
 	pm->hook = hooknr;
 	if (uloginfo->prefix != NULL)
 		strcpy(pm->prefix, uloginfo->prefix);
-	else
-		*(pm->prefix) = '\0';
 
 	if (in) {
 		strcpy(pm->physindev, in->name);
@@ -204,16 +203,14 @@ static void ebt_ulog_packet(struct net *net, unsigned int hooknr,
 			strcpy(pm->indev, br_port_get_rcu(in)->br->dev->name);
 		else
 			strcpy(pm->indev, in->name);
-	} else
-		pm->indev[0] = pm->physindev[0] = '\0';
+	}
 
 	if (out) {
 		/* If out exists, then out is a bridge port */
 		strcpy(pm->physoutdev, out->name);
 		/* rcu_read_lock()ed by nf_hook_slow */
 		strcpy(pm->outdev, br_port_get_rcu(out)->br->dev->name);
-	} else
-		pm->outdev[0] = pm->physoutdev[0] = '\0';
+	}
 
 	if (skb_copy_bits(skb, -ETH_HLEN, pm->data, copy_len) < 0)
 		BUG();

net/ipv4/netfilter/arp_tables.c

@@ -271,6 +271,11 @@ unsigned int arpt_do_table(struct sk_buff *skb,
 	local_bh_disable();
 	addend = xt_write_recseq_begin();
 	private = table->private;
+	/*
+	 * Ensure we load private-> members after we've fetched the base
+	 * pointer.
+	 */
+	smp_read_barrier_depends();
 	table_base = private->entries[smp_processor_id()];
 
 	e = get_entry(table_base, private->hook_entry[hook]);

net/ipv4/netfilter/ip_tables.c

@@ -327,6 +327,11 @@ ipt_do_table(struct sk_buff *skb,
 	addend = xt_write_recseq_begin();
 	private = table->private;
 	cpu        = smp_processor_id();
+	/*
+	 * Ensure we load private-> members after we've fetched the base
+	 * pointer.
+	 */
+	smp_read_barrier_depends();
 	table_base = private->entries[cpu];
 	jumpstack  = (struct ipt_entry **)private->jumpstack[cpu];
 	stackptr   = per_cpu_ptr(private->stackptr, cpu);

net/ipv4/netfilter/ipt_ULOG.c

@@ -220,6 +220,7 @@ static void ipt_ulog_packet(struct net *net,
 	ub->qlen++;
 
 	pm = nlmsg_data(nlh);
+	memset(pm, 0, sizeof(*pm));
 
 	/* We might not have a timestamp, get one */
 	if (skb->tstamp.tv64 == 0)
@@ -238,8 +239,6 @@ static void ipt_ulog_packet(struct net *net,
 	}
 	else if (loginfo->prefix[0] != '\0')
 		strncpy(pm->prefix, loginfo->prefix, sizeof(pm->prefix));
-	else
-		*(pm->prefix) = '\0';
 
 	if (in && in->hard_header_len > 0 &&
 	    skb->mac_header != skb->network_header &&
@@ -251,13 +250,9 @@ static void ipt_ulog_packet(struct net *net,
 
 	if (in)
 		strncpy(pm->indev_name, in->name, sizeof(pm->indev_name));
-	else
-		pm->indev_name[0] = '\0';
 
 	if (out)
 		strncpy(pm->outdev_name, out->name, sizeof(pm->outdev_name));
-	else
-		pm->outdev_name[0] = '\0';
 
 	/* copy_len <= skb->len, so can't fail. */
 	if (skb_copy_bits(skb, 0, pm->payload, copy_len) < 0)

net/ipv6/netfilter/ip6_tables.c

@@ -349,6 +349,11 @@ ip6t_do_table(struct sk_buff *skb,
 	local_bh_disable();
 	addend = xt_write_recseq_begin();
 	private = table->private;
+	/*
+	 * Ensure we load private-> members after we've fetched the base
+	 * pointer.
+	 */
+	smp_read_barrier_depends();
 	cpu        = smp_processor_id();
 	table_base = private->entries[cpu];
 	jumpstack  = (struct ip6t_entry **)private->jumpstack[cpu];

net/netfilter/x_tables.c

@@ -845,8 +845,13 @@ xt_replace_table(struct xt_table *table,
 		return NULL;
 	}
 
-	table->private = newinfo;
 	newinfo->initial_entries = private->initial_entries;
+	/*
+	 * Ensure contents of newinfo are visible before assigning to
+	 * private.
+	 */
+	smp_wmb();
+	table->private = newinfo;
 
 	/*
 	 * Even though table entries have now been swapped, other CPU's