Commit 87375ab4 authored by Julian Anastasov's avatar Julian Anastasov Committed by David S. Miller
Browse files

[IPVS]: ip_vs_ftp breaks connections using persistence 



ip_vs_ftp when loaded can create NAT connections with unknown client
port for passive FTP. For such expectations we lookup with cport=0 on
incoming packet but it matches the format of the persistence templates
causing packets to other persistent virtual servers to be forwarded to
real server without creating connection. Later the reply packets are
treated as foreign and not SNAT-ed.

This patch changes the connection lookup for packets from clients:

* introduce IP_VS_CONN_F_TEMPLATE connection flag to mark the
  connection as template

* create new connection lookup function just for templates -
  ip_vs_ct_in_get

* make sure ip_vs_conn_in_get hits only connections with
  IP_VS_CONN_F_NO_CPORT flag set when s_port is 0. By this way
  we avoid returning template when looking for cport=0 (ftp)

Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f5e229db

include/net/ip_vs.h

+3 −0
Original line number Diff line number Diff line
@@ -84,6 +84,7 @@ 
#define IP_VS_CONN_F_IN_SEQ	0x0400		/* must do input seq adjust */

#define IP_VS_CONN_F_SEQ_MASK	0x0600		/* in/out sequence mask */

#define IP_VS_CONN_F_NO_CPORT	0x0800		/* no client port set yet */

#define IP_VS_CONN_F_TEMPLATE	0x1000		/* template, not connection */



/* Move it to better place one day, for now keep it unique */

#define NFC_IPVS_PROPERTY	0x10000
@@ -739,6 +740,8 @@ enum { 


extern struct ip_vs_conn *ip_vs_conn_in_get

(int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port);

extern struct ip_vs_conn *ip_vs_ct_in_get

(int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port);

extern struct ip_vs_conn *ip_vs_conn_out_get

(int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port);

net/ipv4/ipvs/ip_vs_conn.c

+38 −3
Original line number Diff line number Diff line
@@ -196,6 +196,7 @@ static inline struct ip_vs_conn *__ip_vs_conn_in_get 
	list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {

		if (s_addr==cp->caddr && s_port==cp->cport &&

		    d_port==cp->vport && d_addr==cp->vaddr &&

		    ((!s_port) ^ (!(cp->flags & IP_VS_CONN_F_NO_CPORT))) &&

		    protocol==cp->protocol) {

			/* HIT */

			atomic_inc(&cp->refcnt);
@@ -227,6 +228,40 @@ struct ip_vs_conn *ip_vs_conn_in_get 
	return cp;

}



/* Get reference to connection template */

struct ip_vs_conn *ip_vs_ct_in_get

(int protocol, __u32 s_addr, __u16 s_port, __u32 d_addr, __u16 d_port)

{

	unsigned hash;

	struct ip_vs_conn *cp;



	hash = ip_vs_conn_hashkey(protocol, s_addr, s_port);



	ct_read_lock(hash);



	list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {

		if (s_addr==cp->caddr && s_port==cp->cport &&

		    d_port==cp->vport && d_addr==cp->vaddr &&

		    cp->flags & IP_VS_CONN_F_TEMPLATE &&

		    protocol==cp->protocol) {

			/* HIT */

			atomic_inc(&cp->refcnt);

			goto out;

		}

	}

	cp = NULL;



  out:

	ct_read_unlock(hash);



	IP_VS_DBG(7, "template lookup/in %s %u.%u.%u.%u:%d->%u.%u.%u.%u:%d %s\n",

		  ip_vs_proto_name(protocol),

		  NIPQUAD(s_addr), ntohs(s_port),

		  NIPQUAD(d_addr), ntohs(d_port),

		  cp?"hit":"not hit");



	return cp;

}



/*

 *  Gets ip_vs_conn associated with supplied parameters in the ip_vs_conn_tab.
@@ -367,7 +402,7 @@ ip_vs_bind_dest(struct ip_vs_conn *cp, struct ip_vs_dest *dest) 
		  atomic_read(&dest->refcnt));



	/* Update the connection counters */

	if (cp->cport || (cp->flags & IP_VS_CONN_F_NO_CPORT)) {

	if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {

		/* It is a normal connection, so increase the inactive

		   connection counter because it is in TCP SYNRECV

		   state (inactive) or other protocol inacive state */
@@ -406,7 +441,7 @@ static inline void ip_vs_unbind_dest(struct ip_vs_conn *cp) 
		  atomic_read(&dest->refcnt));



	/* Update the connection counters */

	if (cp->cport || (cp->flags & IP_VS_CONN_F_NO_CPORT)) {

	if (!(cp->flags & IP_VS_CONN_F_TEMPLATE)) {

		/* It is a normal connection, so decrease the inactconns

		   or activeconns counter */

		if (cp->flags & IP_VS_CONN_F_INACTIVE) {
@@ -776,7 +811,7 @@ void ip_vs_random_dropentry(void) 
		ct_write_lock_bh(hash);



		list_for_each_entry(cp, &ip_vs_conn_tab[hash], c_list) {

			if (!cp->cport && !(cp->flags & IP_VS_CONN_F_NO_CPORT))

			if (cp->flags & IP_VS_CONN_F_TEMPLATE)

				/* connection template */

				continue;

net/ipv4/ipvs/ip_vs_core.c

+8 −8
Original line number Diff line number Diff line
@@ -243,10 +243,10 @@ ip_vs_sched_persist(struct ip_vs_service *svc, 
	if (ports[1] == svc->port) {

		/* Check if a template already exists */

		if (svc->port != FTPPORT)

			ct = ip_vs_conn_in_get(iph->protocol, snet, 0,

			ct = ip_vs_ct_in_get(iph->protocol, snet, 0,

					       iph->daddr, ports[1]);

		else

			ct = ip_vs_conn_in_get(iph->protocol, snet, 0,

			ct = ip_vs_ct_in_get(iph->protocol, snet, 0,

					       iph->daddr, 0);



		if (!ct || !ip_vs_check_template(ct)) {
@@ -272,14 +272,14 @@ ip_vs_sched_persist(struct ip_vs_service *svc, 
						    iph->daddr,

						    ports[1],

						    dest->addr, dest->port,

						    0,

						    IP_VS_CONN_F_TEMPLATE,

						    dest);

			else

				ct = ip_vs_conn_new(iph->protocol,

						    snet, 0,

						    iph->daddr, 0,

						    dest->addr, 0,

						    0,

						    IP_VS_CONN_F_TEMPLATE,

						    dest);

			if (ct == NULL)

				return NULL;
@@ -298,10 +298,10 @@ ip_vs_sched_persist(struct ip_vs_service *svc, 
		 * port zero template: <protocol,caddr,0,vaddr,0,daddr,0>

		 */

		if (svc->fwmark)

			ct = ip_vs_conn_in_get(IPPROTO_IP, snet, 0,

			ct = ip_vs_ct_in_get(IPPROTO_IP, snet, 0,

					       htonl(svc->fwmark), 0);

		else

			ct = ip_vs_conn_in_get(iph->protocol, snet, 0,

			ct = ip_vs_ct_in_get(iph->protocol, snet, 0,

					       iph->daddr, 0);



		if (!ct || !ip_vs_check_template(ct)) {
@@ -326,14 +326,14 @@ ip_vs_sched_persist(struct ip_vs_service *svc, 
						    snet, 0,

						    htonl(svc->fwmark), 0,

						    dest->addr, 0,

						    0,

						    IP_VS_CONN_F_TEMPLATE,

						    dest);

			else

				ct = ip_vs_conn_new(iph->protocol,

						    snet, 0,

						    iph->daddr, 0,

						    dest->addr, 0,

						    0,

						    IP_VS_CONN_F_TEMPLATE,

						    dest);

			if (ct == NULL)

				return NULL;

net/ipv4/ipvs/ip_vs_sync.c

+14 −6
Original line number Diff line number Diff line
@@ -297,16 +297,24 @@ static void ip_vs_process_message(const char *buffer, const size_t buflen) 


	p = (char *)buffer + sizeof(struct ip_vs_sync_mesg);

	for (i=0; i<m->nr_conns; i++) {

		unsigned flags;



		s = (struct ip_vs_sync_conn *)p;

		flags = ntohs(s->flags);

		if (!(flags & IP_VS_CONN_F_TEMPLATE))

			cp = ip_vs_conn_in_get(s->protocol,

					       s->caddr, s->cport,

					       s->vaddr, s->vport);

		else

			cp = ip_vs_ct_in_get(s->protocol,

					       s->caddr, s->cport,

					       s->vaddr, s->vport);

		if (!cp) {

			cp = ip_vs_conn_new(s->protocol,

					    s->caddr, s->cport,

					    s->vaddr, s->vport,

					    s->daddr, s->dport,

					    ntohs(s->flags), NULL);

					    flags, NULL);

			if (!cp) {

				IP_VS_ERR("ip_vs_conn_new failed\n");

				return;
@@ -315,11 +323,11 @@ static void ip_vs_process_message(const char *buffer, const size_t buflen) 
		} else if (!cp->dest) {

			/* it is an entry created by the synchronization */

			cp->state = ntohs(s->state);

			cp->flags = ntohs(s->flags) | IP_VS_CONN_F_HASHED;

			cp->flags = flags | IP_VS_CONN_F_HASHED;

		}	/* Note that we don't touch its state and flags

			   if it is a normal entry. */



		if (ntohs(s->flags) & IP_VS_CONN_F_SEQ_MASK) {

		if (flags & IP_VS_CONN_F_SEQ_MASK) {

			opt = (struct ip_vs_sync_conn_options *)&s[1];

			memcpy(&cp->in_seq, opt, sizeof(*opt));

			p += FULL_CONN_SIZE;

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