From bd0779370588386e4a67ba5d0b176cfded8e6a53 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Wed, 7 Aug 2013 18:13:20 +0200 Subject: [PATCH] netfilter: nfnetlink_queue: allow to attach expectations to conntracks This patch adds the capability to attach expectations via nfnetlink_queue. This is required by conntrack helpers that trigger expectations based on the first packet seen like the TFTP and the DHCPv6 user-space helpers. Signed-off-by: Pablo Neira Ayuso --- include/linux/netfilter.h | 2 + include/net/netfilter/nfnetlink_queue.h | 8 ++ .../uapi/linux/netfilter/nfnetlink_queue.h | 1 + net/netfilter/nf_conntrack_netlink.c | 95 ++++++++++++++++--- net/netfilter/nfnetlink_queue_core.c | 9 +- net/netfilter/nfnetlink_queue_ct.c | 15 +++ 6 files changed, 114 insertions(+), 16 deletions(-) diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h index 655d5d198d4..e2cf786be22 100644 --- a/include/linux/netfilter.h +++ b/include/linux/netfilter.h @@ -325,6 +325,8 @@ struct nfq_ct_hook { size_t (*build_size)(const struct nf_conn *ct); int (*build)(struct sk_buff *skb, struct nf_conn *ct); int (*parse)(const struct nlattr *attr, struct nf_conn *ct); + int (*attach_expect)(const struct nlattr *attr, struct nf_conn *ct, + u32 portid, u32 report); }; extern struct nfq_ct_hook __rcu *nfq_ct_hook; diff --git a/include/net/netfilter/nfnetlink_queue.h b/include/net/netfilter/nfnetlink_queue.h index 86267a52951..aff88ba9139 100644 --- a/include/net/netfilter/nfnetlink_queue.h +++ b/include/net/netfilter/nfnetlink_queue.h @@ -15,6 +15,8 @@ int nfqnl_ct_put(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo); void nfqnl_ct_seq_adjust(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo, int diff); +int nfqnl_attach_expect(struct nf_conn *ct, const struct nlattr *attr, + u32 portid, u32 report); #else inline struct nf_conn * nfqnl_ct_get(struct sk_buff *entskb, size_t *size, enum ip_conntrack_info *ctinfo) @@ -39,5 +41,11 @@ inline void nfqnl_ct_seq_adjust(struct sk_buff *skb, struct nf_conn *ct, enum ip_conntrack_info ctinfo, int diff) { } + +inline int nfqnl_attach_expect(struct nf_conn *ct, const struct nlattr *attr, + u32 portid, u32 report) +{ + return 0; +} #endif /* NF_CONNTRACK */ #endif diff --git a/include/uapi/linux/netfilter/nfnetlink_queue.h b/include/uapi/linux/netfilter/nfnetlink_queue.h index 3a9b9214733..0132bad79de 100644 --- a/include/uapi/linux/netfilter/nfnetlink_queue.h +++ b/include/uapi/linux/netfilter/nfnetlink_queue.h @@ -46,6 +46,7 @@ enum nfqnl_attr_type { NFQA_CT_INFO, /* enum ip_conntrack_info */ NFQA_CAP_LEN, /* __u32 length of captured packet */ NFQA_SKB_INFO, /* __u32 skb meta information */ + NFQA_EXP, /* nf_conntrack_netlink.h */ __NFQA_MAX }; diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c index 9aaa68bbbcd..fa61fea6323 100644 --- a/net/netfilter/nf_conntrack_netlink.c +++ b/net/netfilter/nf_conntrack_netlink.c @@ -1987,6 +1987,27 @@ out: return err == -EAGAIN ? -ENOBUFS : err; } +static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = { + [CTA_EXPECT_MASTER] = { .type = NLA_NESTED }, + [CTA_EXPECT_TUPLE] = { .type = NLA_NESTED }, + [CTA_EXPECT_MASK] = { .type = NLA_NESTED }, + [CTA_EXPECT_TIMEOUT] = { .type = NLA_U32 }, + [CTA_EXPECT_ID] = { .type = NLA_U32 }, + [CTA_EXPECT_HELP_NAME] = { .type = NLA_NUL_STRING, + .len = NF_CT_HELPER_NAME_LEN - 1 }, + [CTA_EXPECT_ZONE] = { .type = NLA_U16 }, + [CTA_EXPECT_FLAGS] = { .type = NLA_U32 }, + [CTA_EXPECT_CLASS] = { .type = NLA_U32 }, + [CTA_EXPECT_NAT] = { .type = NLA_NESTED }, + [CTA_EXPECT_FN] = { .type = NLA_NUL_STRING }, +}; + +static struct nf_conntrack_expect * +ctnetlink_alloc_expect(const struct nlattr *const cda[], struct nf_conn *ct, + struct nf_conntrack_helper *helper, + struct nf_conntrack_tuple *tuple, + struct nf_conntrack_tuple *mask); + #ifdef CONFIG_NETFILTER_NETLINK_QUEUE_CT static size_t ctnetlink_nfqueue_build_size(const struct nf_conn *ct) @@ -2127,10 +2148,69 @@ ctnetlink_nfqueue_parse(const struct nlattr *attr, struct nf_conn *ct) return ret; } +static int ctnetlink_nfqueue_exp_parse(const struct nlattr * const *cda, + const struct nf_conn *ct, + struct nf_conntrack_tuple *tuple, + struct nf_conntrack_tuple *mask) +{ + int err; + + err = ctnetlink_parse_tuple(cda, tuple, CTA_EXPECT_TUPLE, + nf_ct_l3num(ct)); + if (err < 0) + return err; + + return ctnetlink_parse_tuple(cda, mask, CTA_EXPECT_MASK, + nf_ct_l3num(ct)); +} + +static int +ctnetlink_nfqueue_attach_expect(const struct nlattr *attr, struct nf_conn *ct, + u32 portid, u32 report) +{ + struct nlattr *cda[CTA_EXPECT_MAX+1]; + struct nf_conntrack_tuple tuple, mask; + struct nf_conntrack_helper *helper; + struct nf_conntrack_expect *exp; + int err; + + err = nla_parse_nested(cda, CTA_EXPECT_MAX, attr, exp_nla_policy); + if (err < 0) + return err; + + err = ctnetlink_nfqueue_exp_parse((const struct nlattr * const *)cda, + ct, &tuple, &mask); + if (err < 0) + return err; + + if (cda[CTA_EXPECT_HELP_NAME]) { + const char *helpname = nla_data(cda[CTA_EXPECT_HELP_NAME]); + + helper = __nf_conntrack_helper_find(helpname, nf_ct_l3num(ct), + nf_ct_protonum(ct)); + if (helper == NULL) + return -EOPNOTSUPP; + } + + exp = ctnetlink_alloc_expect((const struct nlattr * const *)cda, ct, + helper, &tuple, &mask); + if (IS_ERR(exp)) + return PTR_ERR(exp); + + err = nf_ct_expect_related_report(exp, portid, report); + if (err < 0) { + nf_ct_expect_put(exp); + return err; + } + + return 0; +} + static struct nfq_ct_hook ctnetlink_nfqueue_hook = { .build_size = ctnetlink_nfqueue_build_size, .build = ctnetlink_nfqueue_build, .parse = ctnetlink_nfqueue_parse, + .attach_expect = ctnetlink_nfqueue_attach_expect, }; #endif /* CONFIG_NETFILTER_NETLINK_QUEUE_CT */ @@ -2498,21 +2578,6 @@ static int ctnetlink_dump_exp_ct(struct sock *ctnl, struct sk_buff *skb, return err; } -static const struct nla_policy exp_nla_policy[CTA_EXPECT_MAX+1] = { - [CTA_EXPECT_MASTER] = { .type = NLA_NESTED }, - [CTA_EXPECT_TUPLE] = { .type = NLA_NESTED }, - [CTA_EXPECT_MASK] = { .type = NLA_NESTED }, - [CTA_EXPECT_TIMEOUT] = { .type = NLA_U32 }, - [CTA_EXPECT_ID] = { .type = NLA_U32 }, - [CTA_EXPECT_HELP_NAME] = { .type = NLA_NUL_STRING, - .len = NF_CT_HELPER_NAME_LEN - 1 }, - [CTA_EXPECT_ZONE] = { .type = NLA_U16 }, - [CTA_EXPECT_FLAGS] = { .type = NLA_U32 }, - [CTA_EXPECT_CLASS] = { .type = NLA_U32 }, - [CTA_EXPECT_NAT] = { .type = NLA_NESTED }, - [CTA_EXPECT_FN] = { .type = NLA_NUL_STRING }, -}; - static int ctnetlink_get_expect(struct sock *ctnl, struct sk_buff *skb, const struct nlmsghdr *nlh, diff --git a/net/netfilter/nfnetlink_queue_core.c b/net/netfilter/nfnetlink_queue_core.c index ec9de12aa48..e8c9f3bb779 100644 --- a/net/netfilter/nfnetlink_queue_core.c +++ b/net/netfilter/nfnetlink_queue_core.c @@ -859,6 +859,7 @@ static const struct nla_policy nfqa_verdict_policy[NFQA_MAX+1] = { [NFQA_MARK] = { .type = NLA_U32 }, [NFQA_PAYLOAD] = { .type = NLA_UNSPEC }, [NFQA_CT] = { .type = NLA_UNSPEC }, + [NFQA_EXP] = { .type = NLA_UNSPEC }, }; static const struct nla_policy nfqa_verdict_batch_policy[NFQA_MAX+1] = { @@ -987,8 +988,14 @@ nfqnl_recv_verdict(struct sock *ctnl, struct sk_buff *skb, if (entry == NULL) return -ENOENT; - if (nfqa[NFQA_CT]) + if (nfqa[NFQA_CT]) { ct = nfqnl_ct_parse(entry->skb, nfqa[NFQA_CT], &ctinfo); + if (ct && nfqa[NFQA_EXP]) { + nfqnl_attach_expect(ct, nfqa[NFQA_EXP], + NETLINK_CB(skb).portid, + nlmsg_report(nlh)); + } + } if (nfqa[NFQA_PAYLOAD]) { u16 payload_len = nla_len(nfqa[NFQA_PAYLOAD]); diff --git a/net/netfilter/nfnetlink_queue_ct.c b/net/netfilter/nfnetlink_queue_ct.c index ab61d66bc0b..be893039966 100644 --- a/net/netfilter/nfnetlink_queue_ct.c +++ b/net/netfilter/nfnetlink_queue_ct.c @@ -96,3 +96,18 @@ void nfqnl_ct_seq_adjust(struct sk_buff *skb, struct nf_conn *ct, if ((ct->status & IPS_NAT_MASK) && diff) nfq_nat_ct->seq_adjust(skb, ct, ctinfo, diff); } + +int nfqnl_attach_expect(struct nf_conn *ct, const struct nlattr *attr, + u32 portid, u32 report) +{ + struct nfq_ct_hook *nfq_ct; + + if (nf_ct_is_untracked(ct)) + return 0; + + nfq_ct = rcu_dereference(nfq_ct_hook); + if (nfq_ct == NULL) + return -EOPNOTSUPP; + + return nfq_ct->attach_expect(attr, ct, portid, report); +} -- 2.43.2