netfilter: nfnl_cthelper: fix incorrect helper->expect_class_max

The helper->expect_class_max must be set to the total number of
expect_policy minus 1, since we will use the statement "if (class >
helper->expect_class_max)" to validate the CTA_EXPECT_CLASS attr in
ctnetlink_alloc_expect.

So for compatibility, set the helper->expect_class_max to the
NFCTH_POLICY_SET_NUM attr's value minus 1.

Also: it's invalid when the NFCTH_POLICY_SET_NUM attr's value is zero.
1. this will result "expect_policy = kzalloc(0, GFP_KERNEL);";
2. we cannot set the helper->expect_class_max to a proper value.

So if nla_get_be32(tb[NFCTH_POLICY_SET_NUM]) is zero, report -EINVAL to
the userspace.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Liping Zhang 2017-03-19 22:35:59 +08:00 committed by Pablo Neira Ayuso
parent db7f00b8db
commit ae5c682113
1 changed files with 11 additions and 9 deletions

View File

@ -161,6 +161,7 @@ nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
int i, ret;
struct nf_conntrack_expect_policy *expect_policy;
struct nlattr *tb[NFCTH_POLICY_SET_MAX+1];
unsigned int class_max;
ret = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr,
nfnl_cthelper_expect_policy_set);
@ -170,19 +171,18 @@ nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
if (!tb[NFCTH_POLICY_SET_NUM])
return -EINVAL;
helper->expect_class_max =
ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
if (helper->expect_class_max != 0 &&
helper->expect_class_max > NF_CT_MAX_EXPECT_CLASSES)
class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM]));
if (class_max == 0)
return -EINVAL;
if (class_max > NF_CT_MAX_EXPECT_CLASSES)
return -EOVERFLOW;
expect_policy = kzalloc(sizeof(struct nf_conntrack_expect_policy) *
helper->expect_class_max, GFP_KERNEL);
class_max, GFP_KERNEL);
if (expect_policy == NULL)
return -ENOMEM;
for (i=0; i<helper->expect_class_max; i++) {
for (i = 0; i < class_max; i++) {
if (!tb[NFCTH_POLICY_SET+i])
goto err;
@ -191,6 +191,8 @@ nfnl_cthelper_parse_expect_policy(struct nf_conntrack_helper *helper,
if (ret < 0)
goto err;
}
helper->expect_class_max = class_max - 1;
helper->expect_policy = expect_policy;
return 0;
err:
@ -377,10 +379,10 @@ nfnl_cthelper_dump_policy(struct sk_buff *skb,
goto nla_put_failure;
if (nla_put_be32(skb, NFCTH_POLICY_SET_NUM,
htonl(helper->expect_class_max)))
htonl(helper->expect_class_max + 1)))
goto nla_put_failure;
for (i=0; i<helper->expect_class_max; i++) {
for (i = 0; i < helper->expect_class_max + 1; i++) {
nest_parms2 = nla_nest_start(skb,
(NFCTH_POLICY_SET+i) | NLA_F_NESTED);
if (nest_parms2 == NULL)