[PATCH 2/8] netfilter: nfnl_cthelper: fix runtime expectation policy updates
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2017-03-29 12:14:04
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
We only allow runtime updates of expectation policies for timeout and maximum number of expectations, otherwise reject the update. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Acked-by: Liping Zhang <redacted> --- net/netfilter/nfnetlink_cthelper.c | 86 +++++++++++++++++++++++++++++++++++++- 1 file changed, 84 insertions(+), 2 deletions(-)
diff --git a/net/netfilter/nfnetlink_cthelper.c b/net/netfilter/nfnetlink_cthelper.c
index 3cd41d105407..90f291e27eb1 100644
--- a/net/netfilter/nfnetlink_cthelper.c
+++ b/net/netfilter/nfnetlink_cthelper.c@@ -256,6 +256,89 @@ nfnl_cthelper_create(const struct nlattr * const tb[], } static int +nfnl_cthelper_update_policy_one(const struct nf_conntrack_expect_policy *policy, + struct nf_conntrack_expect_policy *new_policy, + const struct nlattr *attr) +{ + struct nlattr *tb[NFCTH_POLICY_MAX + 1]; + int err; + + err = nla_parse_nested(tb, NFCTH_POLICY_MAX, attr, + nfnl_cthelper_expect_pol); + if (err < 0) + return err; + + if (!tb[NFCTH_POLICY_NAME] || + !tb[NFCTH_POLICY_EXPECT_MAX] || + !tb[NFCTH_POLICY_EXPECT_TIMEOUT]) + return -EINVAL; + + if (nla_strcmp(tb[NFCTH_POLICY_NAME], policy->name)) + return -EBUSY; + + new_policy->max_expected = + ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_MAX])); + new_policy->timeout = + ntohl(nla_get_be32(tb[NFCTH_POLICY_EXPECT_TIMEOUT])); + + return 0; +} + +static int nfnl_cthelper_update_policy_all(struct nlattr *tb[], + struct nf_conntrack_helper *helper) +{ + struct nf_conntrack_expect_policy new_policy[helper->expect_class_max + 1]; + struct nf_conntrack_expect_policy *policy; + int i, err; + + /* Check first that all policy attributes are well-formed, so we don't + * leave things in inconsistent state on errors. + */ + for (i = 0; i < helper->expect_class_max + 1; i++) { + + if (!tb[NFCTH_POLICY_SET + i]) + return -EINVAL; + + err = nfnl_cthelper_update_policy_one(&helper->expect_policy[i], + &new_policy[i], + tb[NFCTH_POLICY_SET + i]); + if (err < 0) + return err; + } + /* Now we can safely update them. */ + for (i = 0; i < helper->expect_class_max + 1; i++) { + policy = (struct nf_conntrack_expect_policy *) + &helper->expect_policy[i]; + policy->max_expected = new_policy->max_expected; + policy->timeout = new_policy->timeout; + } + + return 0; +} + +static int nfnl_cthelper_update_policy(struct nf_conntrack_helper *helper, + const struct nlattr *attr) +{ + struct nlattr *tb[NFCTH_POLICY_SET_MAX + 1]; + unsigned int class_max; + int err; + + err = nla_parse_nested(tb, NFCTH_POLICY_SET_MAX, attr, + nfnl_cthelper_expect_policy_set); + if (err < 0) + return err; + + if (!tb[NFCTH_POLICY_SET_NUM]) + return -EINVAL; + + class_max = ntohl(nla_get_be32(tb[NFCTH_POLICY_SET_NUM])); + if (helper->expect_class_max + 1 != class_max) + return -EBUSY; + + return nfnl_cthelper_update_policy_all(tb, helper); +} + +static int nfnl_cthelper_update(const struct nlattr * const tb[], struct nf_conntrack_helper *helper) {
@@ -265,8 +348,7 @@ nfnl_cthelper_update(const struct nlattr * const tb[], return -EBUSY; if (tb[NFCTH_POLICY]) { - ret = nfnl_cthelper_parse_expect_policy(helper, - tb[NFCTH_POLICY]); + ret = nfnl_cthelper_update_policy(helper, tb[NFCTH_POLICY]); if (ret < 0) return ret; }
--
2.1.4