[PATCH 07/18] netfilter: ipset: Check IPSET_ATTR_ETHER netlink attribute length

[Pablo Neira Ayuso]

From: Jozsef Kadlecsik <kad...@blackhole.kfki.hu>

Julia Lawall pointed out that IPSET_ATTR_ETHER netlink attribute length
was not checked explicitly, just for the maximum possible size. Malicious
netlink clients could send shorter attribute and thus resulting a kernel
read after the buffer.

The patch adds the explicit length checkings.

Reported-by: Julia Lawall <julia.law...@lip6.fr>
Signed-off-by: Jozsef Kadlecsik <kad...@blackhole.kfki.hu>
---
 net/netfilter/ipset/ip_set_bitmap_ipmac.c | 2 ++
 net/netfilter/ipset/ip_set_hash_mac.c     | 3 ++-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/ipset/ip_set_bitmap_ipmac.c 
b/net/netfilter/ipset/ip_set_bitmap_ipmac.c
index 29dde20..9a065f6 100644
--- a/net/netfilter/ipset/ip_set_bitmap_ipmac.c
+++ b/net/netfilter/ipset/ip_set_bitmap_ipmac.c
@@ -267,6 +267,8 @@ bitmap_ipmac_uadt(struct ip_set *set, struct nlattr *tb[],
 
        e.id = ip_to_id(map, ip);
        if (tb[IPSET_ATTR_ETHER]) {
+               if (nla_len(tb[IPSET_ATTR_ETHER]) != ETH_ALEN)
+                       return -IPSET_ERR_PROTOCOL;
                memcpy(e.ether, nla_data(tb[IPSET_ATTR_ETHER]), ETH_ALEN);
                e.add_mac = 1;
        }
diff --git a/net/netfilter/ipset/ip_set_hash_mac.c 
b/net/netfilter/ipset/ip_set_hash_mac.c
index f1e7d2c..8f004ed 100644
--- a/net/netfilter/ipset/ip_set_hash_mac.c
+++ b/net/netfilter/ipset/ip_set_hash_mac.c
@@ -110,7 +110,8 @@ hash_mac4_uadt(struct ip_set *set, struct nlattr *tb[],
        if (tb[IPSET_ATTR_LINENO])
                *lineno = nla_get_u32(tb[IPSET_ATTR_LINENO]);
 
-       if (unlikely(!tb[IPSET_ATTR_ETHER]))
+       if (unlikely(!tb[IPSET_ATTR_ETHER] ||
+                    nla_len(tb[IPSET_ATTR_ETHER]) != ETH_ALEN))
                return -IPSET_ERR_PROTOCOL;
 
        ret = ip_set_get_extensions(set, tb, &ext);
-- 
2.1.4