netfilter: nf_ct_helper: implement variable length helper private data

This patch uses the new variable length conntrack extensions.

Instead of using union nf_conntrack_help that contain all the
helper private data information, we allocate variable length
area to store the private helper data.

This patch includes the modification of all existing helpers.
It also includes a couple of include header to avoid compilation
warnings.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 1ee2082..cf48755 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -819,7 +819,8 @@
 		__set_bit(IPS_EXPECTED_BIT, &ct->status);
 		ct->master = exp->master;
 		if (exp->helper) {
-			help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
+			help = nf_ct_helper_ext_add(ct, exp->helper,
+						    GFP_ATOMIC);
 			if (help)
 				rcu_assign_pointer(help->helper, exp->helper);
 		}
diff --git a/net/netfilter/nf_conntrack_ftp.c b/net/netfilter/nf_conntrack_ftp.c
index 44e47c9..4bb771d 100644
--- a/net/netfilter/nf_conntrack_ftp.c
+++ b/net/netfilter/nf_conntrack_ftp.c
@@ -358,7 +358,7 @@
 	u32 seq;
 	int dir = CTINFO2DIR(ctinfo);
 	unsigned int uninitialized_var(matchlen), uninitialized_var(matchoff);
-	struct nf_ct_ftp_master *ct_ftp_info = &nfct_help(ct)->help.ct_ftp_info;
+	struct nf_ct_ftp_master *ct_ftp_info = nfct_help_data(ct);
 	struct nf_conntrack_expect *exp;
 	union nf_inet_addr *daddr;
 	struct nf_conntrack_man cmd = {};
@@ -554,6 +554,7 @@
 		ftp[i][0].tuple.src.l3num = PF_INET;
 		ftp[i][1].tuple.src.l3num = PF_INET6;
 		for (j = 0; j < 2; j++) {
+			ftp[i][j].data_len = sizeof(struct nf_ct_ftp_master);
 			ftp[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 			ftp[i][j].tuple.dst.protonum = IPPROTO_TCP;
 			ftp[i][j].expect_policy = &ftp_exp_policy;
diff --git a/net/netfilter/nf_conntrack_h323_main.c b/net/netfilter/nf_conntrack_h323_main.c
index 46d69d7..ed21992 100644
--- a/net/netfilter/nf_conntrack_h323_main.c
+++ b/net/netfilter/nf_conntrack_h323_main.c
@@ -114,7 +114,7 @@
 			 struct nf_conn *ct, enum ip_conntrack_info ctinfo,
 			 unsigned char **data, int *datalen, int *dataoff)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	const struct tcphdr *th;
 	struct tcphdr _tcph;
@@ -618,6 +618,7 @@
 static struct nf_conntrack_helper nf_conntrack_helper_h245 __read_mostly = {
 	.name			= "H.245",
 	.me			= THIS_MODULE,
+	.data_len		= sizeof(struct nf_ct_h323_master),
 	.tuple.src.l3num	= AF_UNSPEC,
 	.tuple.dst.protonum	= IPPROTO_UDP,
 	.help			= h245_help,
@@ -1170,6 +1171,7 @@
 	{
 		.name			= "Q.931",
 		.me			= THIS_MODULE,
+		.data_len		= sizeof(struct nf_ct_h323_master),
 		.tuple.src.l3num	= AF_INET,
 		.tuple.src.u.tcp.port	= cpu_to_be16(Q931_PORT),
 		.tuple.dst.protonum	= IPPROTO_TCP,
@@ -1245,7 +1247,7 @@
 		       unsigned char **data,
 		       TransportAddress *taddr, int count)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int ret = 0;
 	int i;
@@ -1360,7 +1362,7 @@
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, RegistrationRequest *rrq)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int ret;
 	typeof(set_ras_addr_hook) set_ras_addr;
 
@@ -1395,7 +1397,7 @@
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, RegistrationConfirm *rcf)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int ret;
 	struct nf_conntrack_expect *exp;
@@ -1444,7 +1446,7 @@
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, UnregistrationRequest *urq)
 {
-	struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	int ret;
 	typeof(set_sig_addr_hook) set_sig_addr;
@@ -1476,7 +1478,7 @@
 		       enum ip_conntrack_info ctinfo,
 		       unsigned char **data, AdmissionRequest *arq)
 {
-	const struct nf_ct_h323_master *info = &nfct_help(ct)->help.ct_h323_info;
+	const struct nf_ct_h323_master *info = nfct_help_data(ct);
 	int dir = CTINFO2DIR(ctinfo);
 	__be16 port;
 	union nf_inet_addr addr;
@@ -1743,6 +1745,7 @@
 	{
 		.name			= "RAS",
 		.me			= THIS_MODULE,
+		.data_len		= sizeof(struct nf_ct_h323_master),
 		.tuple.src.l3num	= AF_INET,
 		.tuple.src.u.udp.port	= cpu_to_be16(RAS_PORT),
 		.tuple.dst.protonum	= IPPROTO_UDP,
@@ -1752,6 +1755,7 @@
 	{
 		.name			= "RAS",
 		.me			= THIS_MODULE,
+		.data_len		= sizeof(struct nf_ct_h323_master),
 		.tuple.src.l3num	= AF_INET6,
 		.tuple.src.u.udp.port	= cpu_to_be16(RAS_PORT),
 		.tuple.dst.protonum	= IPPROTO_UDP,
diff --git a/net/netfilter/nf_conntrack_helper.c b/net/netfilter/nf_conntrack_helper.c
index 4fa2ff9..9c18ecb 100644
--- a/net/netfilter/nf_conntrack_helper.c
+++ b/net/netfilter/nf_conntrack_helper.c
@@ -161,11 +161,14 @@
 }
 EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get);
 
-struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
+struct nf_conn_help *
+nf_ct_helper_ext_add(struct nf_conn *ct,
+		     struct nf_conntrack_helper *helper, gfp_t gfp)
 {
 	struct nf_conn_help *help;
 
-	help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp);
+	help = nf_ct_ext_add_length(ct, NF_CT_EXT_HELPER,
+				    helper->data_len, gfp);
 	if (help)
 		INIT_HLIST_HEAD(&help->expectations);
 	else
@@ -218,13 +221,13 @@
 	}
 
 	if (help == NULL) {
-		help = nf_ct_helper_ext_add(ct, flags);
+		help = nf_ct_helper_ext_add(ct, helper, flags);
 		if (help == NULL) {
 			ret = -ENOMEM;
 			goto out;
 		}
 	} else {
-		memset(&help->help, 0, sizeof(help->help));
+		memset(help->data, 0, helper->data_len);
 	}
 
 	rcu_assign_pointer(help->helper, helper);
diff --git a/net/netfilter/nf_conntrack_netlink.c b/net/netfilter/nf_conntrack_netlink.c
index 6f4b00a..a088920 100644
--- a/net/netfilter/nf_conntrack_netlink.c
+++ b/net/netfilter/nf_conntrack_netlink.c
@@ -1218,7 +1218,7 @@
 		if (help->helper)
 			return -EBUSY;
 		/* need to zero data of old helper */
-		memset(&help->help, 0, sizeof(help->help));
+		memset(help->data, 0, help->helper->data_len);
 	} else {
 		/* we cannot set a helper for an existing conntrack */
 		return -EOPNOTSUPP;
@@ -1440,7 +1440,7 @@
 		} else {
 			struct nf_conn_help *help;
 
-			help = nf_ct_helper_ext_add(ct, GFP_ATOMIC);
+			help = nf_ct_helper_ext_add(ct, helper, GFP_ATOMIC);
 			if (help == NULL) {
 				err = -ENOMEM;
 				goto err2;
diff --git a/net/netfilter/nf_conntrack_pptp.c b/net/netfilter/nf_conntrack_pptp.c
index 31d56b2..6fed9ec 100644
--- a/net/netfilter/nf_conntrack_pptp.c
+++ b/net/netfilter/nf_conntrack_pptp.c
@@ -174,7 +174,7 @@
 static void pptp_destroy_siblings(struct nf_conn *ct)
 {
 	struct net *net = nf_ct_net(ct);
-	const struct nf_conn_help *help = nfct_help(ct);
+	const struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
 	struct nf_conntrack_tuple t;
 
 	nf_ct_gre_keymap_destroy(ct);
@@ -182,16 +182,16 @@
 	/* try original (pns->pac) tuple */
 	memcpy(&t, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, sizeof(t));
 	t.dst.protonum = IPPROTO_GRE;
-	t.src.u.gre.key = help->help.ct_pptp_info.pns_call_id;
-	t.dst.u.gre.key = help->help.ct_pptp_info.pac_call_id;
+	t.src.u.gre.key = ct_pptp_info->pns_call_id;
+	t.dst.u.gre.key = ct_pptp_info->pac_call_id;
 	if (!destroy_sibling_or_exp(net, ct, &t))
 		pr_debug("failed to timeout original pns->pac ct/exp\n");
 
 	/* try reply (pac->pns) tuple */
 	memcpy(&t, &ct->tuplehash[IP_CT_DIR_REPLY].tuple, sizeof(t));
 	t.dst.protonum = IPPROTO_GRE;
-	t.src.u.gre.key = help->help.ct_pptp_info.pac_call_id;
-	t.dst.u.gre.key = help->help.ct_pptp_info.pns_call_id;
+	t.src.u.gre.key = ct_pptp_info->pac_call_id;
+	t.dst.u.gre.key = ct_pptp_info->pns_call_id;
 	if (!destroy_sibling_or_exp(net, ct, &t))
 		pr_debug("failed to timeout reply pac->pns ct/exp\n");
 }
@@ -269,7 +269,7 @@
 		 struct nf_conn *ct,
 		 enum ip_conntrack_info ctinfo)
 {
-	struct nf_ct_pptp_master *info = &nfct_help(ct)->help.ct_pptp_info;
+	struct nf_ct_pptp_master *info = nfct_help_data(ct);
 	u_int16_t msg;
 	__be16 cid = 0, pcid = 0;
 	typeof(nf_nat_pptp_hook_inbound) nf_nat_pptp_inbound;
@@ -396,7 +396,7 @@
 		  struct nf_conn *ct,
 		  enum ip_conntrack_info ctinfo)
 {
-	struct nf_ct_pptp_master *info = &nfct_help(ct)->help.ct_pptp_info;
+	struct nf_ct_pptp_master *info = nfct_help_data(ct);
 	u_int16_t msg;
 	__be16 cid = 0, pcid = 0;
 	typeof(nf_nat_pptp_hook_outbound) nf_nat_pptp_outbound;
@@ -506,7 +506,7 @@
 
 {
 	int dir = CTINFO2DIR(ctinfo);
-	const struct nf_ct_pptp_master *info = &nfct_help(ct)->help.ct_pptp_info;
+	const struct nf_ct_pptp_master *info = nfct_help_data(ct);
 	const struct tcphdr *tcph;
 	struct tcphdr _tcph;
 	const struct pptp_pkt_hdr *pptph;
@@ -592,6 +592,7 @@
 static struct nf_conntrack_helper pptp __read_mostly = {
 	.name			= "pptp",
 	.me			= THIS_MODULE,
+	.data_len		= sizeof(struct nf_ct_pptp_master),
 	.tuple.src.l3num	= AF_INET,
 	.tuple.src.u.tcp.port	= cpu_to_be16(PPTP_CONTROL_PORT),
 	.tuple.dst.protonum	= IPPROTO_TCP,
diff --git a/net/netfilter/nf_conntrack_proto_gre.c b/net/netfilter/nf_conntrack_proto_gre.c
index 25ba5a2..5cac41c 100644
--- a/net/netfilter/nf_conntrack_proto_gre.c
+++ b/net/netfilter/nf_conntrack_proto_gre.c
@@ -117,10 +117,10 @@
 {
 	struct net *net = nf_ct_net(ct);
 	struct netns_proto_gre *net_gre = gre_pernet(net);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
 	struct nf_ct_gre_keymap **kmp, *km;
 
-	kmp = &help->help.ct_pptp_info.keymap[dir];
+	kmp = &ct_pptp_info->keymap[dir];
 	if (*kmp) {
 		/* check whether it's a retransmission */
 		read_lock_bh(&net_gre->keymap_lock);
@@ -158,19 +158,19 @@
 {
 	struct net *net = nf_ct_net(ct);
 	struct netns_proto_gre *net_gre = gre_pernet(net);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_pptp_master *ct_pptp_info = nfct_help_data(ct);
 	enum ip_conntrack_dir dir;
 
 	pr_debug("entering for ct %p\n", ct);
 
 	write_lock_bh(&net_gre->keymap_lock);
 	for (dir = IP_CT_DIR_ORIGINAL; dir < IP_CT_DIR_MAX; dir++) {
-		if (help->help.ct_pptp_info.keymap[dir]) {
+		if (ct_pptp_info->keymap[dir]) {
 			pr_debug("removing %p from list\n",
-				 help->help.ct_pptp_info.keymap[dir]);
-			list_del(&help->help.ct_pptp_info.keymap[dir]->list);
-			kfree(help->help.ct_pptp_info.keymap[dir]);
-			help->help.ct_pptp_info.keymap[dir] = NULL;
+				 ct_pptp_info->keymap[dir]);
+			list_del(&ct_pptp_info->keymap[dir]->list);
+			kfree(ct_pptp_info->keymap[dir]);
+			ct_pptp_info->keymap[dir] = NULL;
 		}
 	}
 	write_unlock_bh(&net_gre->keymap_lock);
diff --git a/net/netfilter/nf_conntrack_sane.c b/net/netfilter/nf_conntrack_sane.c
index ec3fc18..295429f 100644
--- a/net/netfilter/nf_conntrack_sane.c
+++ b/net/netfilter/nf_conntrack_sane.c
@@ -69,13 +69,12 @@
 	void *sb_ptr;
 	int ret = NF_ACCEPT;
 	int dir = CTINFO2DIR(ctinfo);
-	struct nf_ct_sane_master *ct_sane_info;
+	struct nf_ct_sane_master *ct_sane_info = nfct_help_data(ct);
 	struct nf_conntrack_expect *exp;
 	struct nf_conntrack_tuple *tuple;
 	struct sane_request *req;
 	struct sane_reply_net_start *reply;
 
-	ct_sane_info = &nfct_help(ct)->help.ct_sane_info;
 	/* Until there's been traffic both ways, don't look in packets. */
 	if (ctinfo != IP_CT_ESTABLISHED &&
 	    ctinfo != IP_CT_ESTABLISHED_REPLY)
@@ -203,6 +202,7 @@
 		sane[i][0].tuple.src.l3num = PF_INET;
 		sane[i][1].tuple.src.l3num = PF_INET6;
 		for (j = 0; j < 2; j++) {
+			sane[i][j].data_len = sizeof(struct nf_ct_sane_master);
 			sane[i][j].tuple.src.u.tcp.port = htons(ports[i]);
 			sane[i][j].tuple.dst.protonum = IPPROTO_TCP;
 			sane[i][j].expect_policy = &sane_exp_policy;
diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index dfd3ff3..758a1ba 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1075,12 +1075,12 @@
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
 
 	if ((code >= 100 && code <= 199) ||
 	    (code >= 200 && code <= 299))
 		return process_sdp(skb, dataoff, dptr, datalen, cseq);
-	else if (help->help.ct_sip_info.invite_cseq == cseq)
+	else if (ct_sip_info->invite_cseq == cseq)
 		flush_expectations(ct, true);
 	return NF_ACCEPT;
 }
@@ -1091,12 +1091,12 @@
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
 
 	if ((code >= 100 && code <= 199) ||
 	    (code >= 200 && code <= 299))
 		return process_sdp(skb, dataoff, dptr, datalen, cseq);
-	else if (help->help.ct_sip_info.invite_cseq == cseq)
+	else if (ct_sip_info->invite_cseq == cseq)
 		flush_expectations(ct, true);
 	return NF_ACCEPT;
 }
@@ -1107,12 +1107,12 @@
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
 
 	if ((code >= 100 && code <= 199) ||
 	    (code >= 200 && code <= 299))
 		return process_sdp(skb, dataoff, dptr, datalen, cseq);
-	else if (help->help.ct_sip_info.invite_cseq == cseq)
+	else if (ct_sip_info->invite_cseq == cseq)
 		flush_expectations(ct, true);
 	return NF_ACCEPT;
 }
@@ -1123,13 +1123,13 @@
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
 	unsigned int ret;
 
 	flush_expectations(ct, true);
 	ret = process_sdp(skb, dataoff, dptr, datalen, cseq);
 	if (ret == NF_ACCEPT)
-		help->help.ct_sip_info.invite_cseq = cseq;
+		ct_sip_info->invite_cseq = cseq;
 	return ret;
 }
 
@@ -1154,7 +1154,7 @@
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
 	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 	unsigned int matchoff, matchlen;
 	struct nf_conntrack_expect *exp;
@@ -1235,7 +1235,7 @@
 
 store_cseq:
 	if (ret == NF_ACCEPT)
-		help->help.ct_sip_info.register_cseq = cseq;
+		ct_sip_info->register_cseq = cseq;
 	return ret;
 }
 
@@ -1245,7 +1245,7 @@
 {
 	enum ip_conntrack_info ctinfo;
 	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
-	struct nf_conn_help *help = nfct_help(ct);
+	struct nf_ct_sip_master *ct_sip_info = nfct_help_data(ct);
 	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
 	union nf_inet_addr addr;
 	__be16 port;
@@ -1262,7 +1262,7 @@
 	 * responses, so we store the sequence number of the last valid
 	 * request and compare it here.
 	 */
-	if (help->help.ct_sip_info.register_cseq != cseq)
+	if (ct_sip_info->register_cseq != cseq)
 		return NF_ACCEPT;
 
 	if (code >= 100 && code <= 199)
@@ -1578,6 +1578,7 @@
 		sip[i][3].help = sip_help_tcp;
 
 		for (j = 0; j < ARRAY_SIZE(sip[i]); j++) {
+			sip[i][j].data_len = sizeof(struct nf_ct_sip_master);
 			sip[i][j].tuple.src.u.udp.port = htons(ports[i]);
 			sip[i][j].expect_policy = sip_exp_policy;
 			sip[i][j].expect_class_max = SIP_EXPECT_MAX;
diff --git a/net/netfilter/xt_CT.c b/net/netfilter/xt_CT.c
index a51de9b..1160185 100644
--- a/net/netfilter/xt_CT.c
+++ b/net/netfilter/xt_CT.c
@@ -112,6 +112,8 @@
 		goto err3;
 
 	if (info->helper[0]) {
+		struct nf_conntrack_helper *helper;
+
 		ret = -ENOENT;
 		proto = xt_ct_find_proto(par);
 		if (!proto) {
@@ -120,19 +122,21 @@
 			goto err3;
 		}
 
-		ret = -ENOMEM;
-		help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
-		if (help == NULL)
-			goto err3;
-
 		ret = -ENOENT;
-		help->helper = nf_conntrack_helper_try_module_get(info->helper,
-								  par->family,
-								  proto);
-		if (help->helper == NULL) {
+		helper = nf_conntrack_helper_try_module_get(info->helper,
+							    par->family,
+							    proto);
+		if (helper == NULL) {
 			pr_info("No such helper \"%s\"\n", info->helper);
 			goto err3;
 		}
+
+		ret = -ENOMEM;
+		help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
+		if (help == NULL)
+			goto err3;
+
+		help->helper = helper;
 	}
 
 	__set_bit(IPS_TEMPLATE_BIT, &ct->status);
@@ -202,6 +206,8 @@
 		goto err3;
 
 	if (info->helper[0]) {
+		struct nf_conntrack_helper *helper;
+
 		ret = -ENOENT;
 		proto = xt_ct_find_proto(par);
 		if (!proto) {
@@ -210,19 +216,21 @@
 			goto err3;
 		}
 
-		ret = -ENOMEM;
-		help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
-		if (help == NULL)
-			goto err3;
-
 		ret = -ENOENT;
-		help->helper = nf_conntrack_helper_try_module_get(info->helper,
-								  par->family,
-								  proto);
-		if (help->helper == NULL) {
+		helper = nf_conntrack_helper_try_module_get(info->helper,
+							    par->family,
+							    proto);
+		if (helper == NULL) {
 			pr_info("No such helper \"%s\"\n", info->helper);
 			goto err3;
 		}
+
+		ret = -ENOMEM;
+		help = nf_ct_helper_ext_add(ct, helper, GFP_KERNEL);
+		if (help == NULL)
+			goto err3;
+
+		help->helper = helper;
 	}
 
 #ifdef CONFIG_NF_CONNTRACK_TIMEOUT