netfilter: ipset: Check IPSET_ATTR_ETHER netlink attribute length

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.lawall@lip6.fr>
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
This commit is contained in:
Jozsef Kadlecsik 2016-03-08 20:29:10 +01:00
parent 45040978c8
commit d8aacd8718
2 changed files with 4 additions and 1 deletions

View file

@ -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;
}

View file

@ -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);