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| author | Liping Zhang <zlpnobody@gmail.com> | 2017-03-19 22:35:59 +0800 |
|---|---|---|
| committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2017-03-21 15:47:09 +0100 |
| commit | ae5c682113f9f94cc5e76f92cf041ee624c173ee (patch) | |
| tree | 228c9db7cad11d2de27c8614237016ca4d7dce4f | |
| parent | db7f00b8dba6d687b6ab1f2e9309acfd214fcb4b (diff) | |
| download | linux-ae5c682113f9f94cc5e76f92cf041ee624c173ee.tar.gz | |
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>
| -rw-r--r-- | net/netfilter/nfnetlink_cthelper.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c index de8782345c86..3cd41d105407 100644 --- a/net/netfilter/nfnetlink_cthelper.c +++ b/net/netfilter/nfnetlink_cthelper.c @@ -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) |