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[PATCH 3.16 304/305] netfilter: ensure number of counters is >0 in do_replace()

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3.16.37-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dave Jones <davej@codemonkey.org.uk>

commit 1086bbe97a074844188c6c988fa0b1a98c3ccbb9 upstream.

After improving setsockopt() coverage in trinity, I started triggering
vmalloc failures pretty reliably from this code path:

warn_alloc_failed+0xe9/0x140
__vmalloc_node_range+0x1be/0x270
vzalloc+0x4b/0x50
__do_replace+0x52/0x260 [ip_tables]
do_ipt_set_ctl+0x15d/0x1d0 [ip_tables]
nf_setsockopt+0x65/0x90
ip_setsockopt+0x61/0xa0
raw_setsockopt+0x16/0x60
sock_common_setsockopt+0x14/0x20
SyS_setsockopt+0x71/0xd0

It turns out we don't validate that the num_counters field in the
struct we pass in from userspace is initialized.

The same problem also exists in ebtables, arptables, ipv6, and the
compat variants.

Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 net/bridge/netfilter/ebtables.c | 4 ++++
 net/ipv4/netfilter/arp_tables.c | 6 ++++++
 net/ipv4/netfilter/ip_tables.c  | 6 ++++++
 net/ipv6/netfilter/ip6_tables.c | 6 ++++++
 4 files changed, 22 insertions(+)

--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1105,6 +1105,8 @@ static int do_replace(struct net *net, c
 		return -ENOMEM;
 	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
 
 	tmp.name[sizeof(tmp.name) - 1] = 0;
 
@@ -2150,6 +2152,8 @@ static int compat_copy_ebt_replace_from_
 		return -ENOMEM;
 	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
 
 	memcpy(repl, &tmp, offsetof(struct ebt_replace, hook_entry));
 
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -1082,6 +1082,9 @@ static int do_replace(struct net *net, c
 	/* overflow check */
 	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
+
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
 	newinfo = xt_alloc_table_info(tmp.size);
@@ -1392,6 +1395,9 @@ static int compat_do_replace(struct net
 		return -ENOMEM;
 	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
+
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
 	newinfo = xt_alloc_table_info(tmp.size);
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1268,6 +1268,9 @@ do_replace(struct net *net, const void _
 	/* overflow check */
 	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
+
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
 	newinfo = xt_alloc_table_info(tmp.size);
@@ -1669,6 +1672,9 @@ compat_do_replace(struct net *net, void
 		return -ENOMEM;
 	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
+
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
 	newinfo = xt_alloc_table_info(tmp.size);
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1278,6 +1278,9 @@ do_replace(struct net *net, const void _
 	/* overflow check */
 	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
+
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
 	newinfo = xt_alloc_table_info(tmp.size);
@@ -1672,6 +1675,9 @@ compat_do_replace(struct net *net, void
 		return -ENOMEM;
 	if (tmp.num_counters >= INT_MAX / sizeof(struct xt_counters))
 		return -ENOMEM;
+	if (tmp.num_counters == 0)
+		return -EINVAL;
+
 	tmp.name[sizeof(tmp.name)-1] = 0;
 
 	newinfo = xt_alloc_table_info(tmp.size);

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[PATCH 3.16 304/305] netfilter: ensure number of counters is >0  in do_replace() Ben Hutchings <ben@decadent.org.uk> - 2016-08-14 13:50 +0200
  Re: [PATCH 3.16 304/305] netfilter: ensure number of counters is >0  in do_replace() Dave Jones <davej@codemonkey.org.uk> - 2016-08-14 17:10 +0200
    Re: [PATCH 3.16 304/305] netfilter: ensure number of counters is >0  in do_replace() Ben Hutchings <ben@decadent.org.uk> - 2016-08-15 01:10 +0200

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