[PATCH 4.4 120/230] netfilter: x_tables: enforce nul-terminated table name from getsockopt GET_ENTRIES

[Greg Kroah-Hartman]

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

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

From: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>

commit b301f2538759933cf9ff1f7c4f968da72e3f0757 upstream.

Make sure the table names via getsockopt GET_ENTRIES is nul-terminated
in ebtables and all the x_tables variants and their respective compat
code. Uncovered by KASAN.

Reported-by: Baozeng Ding <sploving1@xxxxxxxxx>
Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>
Cc: Zubin Mithra <zsm@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 net/bridge/netfilter/ebtables.c |    4 ++++
 net/ipv4/netfilter/arp_tables.c |    2 ++
 net/ipv4/netfilter/ip_tables.c  |    2 ++
 net/ipv6/netfilter/ip6_tables.c |    2 ++
 4 files changed, 10 insertions(+)

--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -1528,6 +1528,8 @@ static int do_ebt_get_ctl(struct sock *s
 	if (copy_from_user(&tmp, user, sizeof(tmp)))
 		return -EFAULT;
 
+	tmp.name[sizeof(tmp.name) - 1] = '\0';
+
 	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
 	if (!t)
 		return ret;
@@ -2368,6 +2370,8 @@ static int compat_do_ebt_get_ctl(struct
 	if (copy_from_user(&tmp, user, sizeof(tmp)))
 		return -EFAULT;
 
+	tmp.name[sizeof(tmp.name) - 1] = '\0';
+
 	t = find_table_lock(net, tmp.name, &ret, &ebt_mutex);
 	if (!t)
 		return ret;
--- a/net/ipv4/netfilter/arp_tables.c
+++ b/net/ipv4/netfilter/arp_tables.c
@@ -983,6 +983,7 @@ static int get_entries(struct net *net,
 			 sizeof(struct arpt_get_entries) + get.size);
 		return -EINVAL;
 	}
+	get.name[sizeof(get.name) - 1] = '\0';
 
 	t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
 	if (!IS_ERR_OR_NULL(t)) {
@@ -1557,6 +1558,7 @@ static int compat_get_entries(struct net
 			 *len, sizeof(get) + get.size);
 		return -EINVAL;
 	}
+	get.name[sizeof(get.name) - 1] = '\0';
 
 	xt_compat_lock(NFPROTO_ARP);
 	t = xt_find_table_lock(net, NFPROTO_ARP, get.name);
--- a/net/ipv4/netfilter/ip_tables.c
+++ b/net/ipv4/netfilter/ip_tables.c
@@ -1171,6 +1171,7 @@ get_entries(struct net *net, struct ipt_
 			 *len, sizeof(get) + get.size);
 		return -EINVAL;
 	}
+	get.name[sizeof(get.name) - 1] = '\0';
 
 	t = xt_find_table_lock(net, AF_INET, get.name);
 	if (!IS_ERR_OR_NULL(t)) {
@@ -1799,6 +1800,7 @@ compat_get_entries(struct net *net, stru
 			 *len, sizeof(get) + get.size);
 		return -EINVAL;
 	}
+	get.name[sizeof(get.name) - 1] = '\0';
 
 	xt_compat_lock(AF_INET);
 	t = xt_find_table_lock(net, AF_INET, get.name);
--- a/net/ipv6/netfilter/ip6_tables.c
+++ b/net/ipv6/netfilter/ip6_tables.c
@@ -1182,6 +1182,7 @@ get_entries(struct net *net, struct ip6t
 			 *len, sizeof(get) + get.size);
 		return -EINVAL;
 	}
+	get.name[sizeof(get.name) - 1] = '\0';
 
 	t = xt_find_table_lock(net, AF_INET6, get.name);
 	if (!IS_ERR_OR_NULL(t)) {
@@ -1800,6 +1801,7 @@ compat_get_entries(struct net *net, stru
 			 *len, sizeof(get) + get.size);
 		return -EINVAL;
 	}
+	get.name[sizeof(get.name) - 1] = '\0';
 
 	xt_compat_lock(AF_INET6);
 	t = xt_find_table_lock(net, AF_INET6, get.name);