Netfilter zone directions

PATCH Applied Daniel Borkmann 2 participants 6 messages Aug 14, 2015 – Aug 19, 2015

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Networking netfilter Traffic control (tc)

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Daniel Borkmann

author

2015-08-14 14:03 UTC #0 lore raw

v5 cover Netfilter zone directions

This is a rework of the originally named flextuples [1] patch set, but after discussions from NFWS completely reworked towards integration into the existing zones infrastructure.

Please see individual patches for details. Unchanged user space iptables frontend is at [2]. As discussed, I will follow-up with libnetfilter_conntrack and conntrack support afterwards.

Thanks!

[1] http://thread.gmane.org/gmane.comp.security.firewalls.netfilter.devel/57412/
[2] http://patchwork.ozlabs.org/patch/505355/

v4 -> v5:
- Dropped patch 1 as already applied
- Changed stand-alone procfs output and ctnetlink tuples as discussed with Pablo, rest unchanged
- Retested everything
v3 -> v4:
- Rebased & retested everything onto latest nf-next
- Added nested CTA_TUPLE_ZONE attribute with direction meta data
- Renamed CTA_DIR; sysctl was already in it's own function
v2 -> v3:
- Have a global default zone object, use it directly
- Do not touch uapi-exposed ct->status bits, but integrate the marking flag into the zones structure
- Rebased onto latest nf-next, rerun all stress tests
v1 -> v2:
- Reworked entire set, integration into zones
- Rebased onto latest nf-next

Daniel Borkmann (2):
netfilter: nf_conntrack: add direction support for zones
netfilter: nf_conntrack: add efficient mark to zone mapping

 include/net/netfilter/nf_conntrack_zones.h         |  74 ++++++++-
 include/uapi/linux/netfilter/nfnetlink_conntrack.h |   1 +
 include/uapi/linux/netfilter/xt_CT.h               |   8 +-
 net/ipv4/netfilter/nf_conntrack_proto_icmp.c       |   3 +-
 net/ipv4/netfilter/nf_defrag_ipv4.c                |   8 +-
 net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c     |   4 +-
 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c          |   8 +-
 net/netfilter/nf_conntrack_core.c                  |  95 +++++------
 net/netfilter/nf_conntrack_expect.c                |   8 +-
 net/netfilter/nf_conntrack_netlink.c               | 176 +++++++++++++++------
 net/netfilter/nf_conntrack_standalone.c            |  30 +++-
 net/netfilter/nf_nat_core.c                        |  13 +-
 net/netfilter/xt_CT.c                              |  20 ++-
 net/sched/act_connmark.c                           |   1 +
 14 files changed, 321 insertions(+), 128 deletions(-)

Signature · 1 line

1.9.3

Daniel Borkmann

author

2015-08-14 14:03 UTC #1 lore raw

PATCH v5 1/2 netfilter: nf_conntrack: add direction support for zones

This work adds a direction parameter to netfilter zones, so identity separation can be performed only in original/reply or both directions (default). This basically opens up the possibility of doing NAT with conflicting IP address/port tuples from multiple, isolated tenants on a host (e.g. from a netns) without requiring each tenant to NAT twice resp. to use its own dedicated IP address to SNAT to, meaning overlapping tuples can be made unique with the zone identifier in original direction, where the NAT engine will then allocate a unique tuple in the commonly shared default zone for the reply direction. In some restricted, local DNAT cases, also port redirection could be used for making the reply traffic unique w/o requiring SNAT.

The consensus we've reached and discussed at NFWS and since the initial implementation [1] was to directly integrate the direction meta data into the existing zones infrastructure, as opposed to the ct->mark approach we proposed initially.

As we pass the nf_conntrack_zone object directly around, we don't have to touch all call-sites, but only those, that contain equality checks of zones. Thus, based on the current direction (original or reply), we either return the actual id, or the default NF_CT_DEFAULT_ZONE_ID. CT expectations are direction-agnostic entities when expectations are being compared among themselves, so we can only use the identifier in this case.

Note that zone identifiers can not be included into the hash mix anymore as they don't contain a "stable" value that would be equal for both directions at all times, f.e. if only zone->id would unconditionally be xor'ed into the table slot hash, then replies won't find the corresponding conntracking entry anymore.

If no particular direction is specified when configuring zones, the behaviour is exactly as we expect currently (both directions).

Support has been added for the CT netlink interface as well as the x_tables raw CT target, which both already offer existing interfaces to user space for the configuration of zones.

Below a minimal, simplified collision example (script in [2]) with netperf sessions:

  +--- tenant-1 ---+   mark := 1
  |    netperf     |--+
  +----------------+  |                CT zone := mark [ORIGINAL]
   [ip,sport] := X   +--------------+  +--- gateway ---+
                     | mark routing |--|     SNAT      |-- ... +
                     +--------------+  +---------------+       |
  +--- tenant-2 ---+  |                                     ~~~|~~~
  |    netperf     |--+                +-----------+           |
  +----------------+   mark := 2       | netserver |------ ... +
   [ip,sport] := X                     +-----------+
                                        [ip,port] := Y

On the gateway netns, example:

  iptables -t raw -A PREROUTING -j CT --zone mark --zone-dir ORIGINAL
  iptables -t nat -A POSTROUTING -o <dev> -j SNAT --to-source <ip> --random-fully

  iptables -t mangle -A PREROUTING -m conntrack --ctdir ORIGINAL -j CONNMARK --save-mark
  iptables -t mangle -A POSTROUTING -m conntrack --ctdir REPLY -j CONNMARK --restore-mark

conntrack dump from gateway netns:

netperf -H 10.1.1.2 -t TCP_STREAM -l60 -p12865,5555 from each tenant netns

tcp 6 431995 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=5555 dport=12865 zone-orig=1
src=10.1.1.2 dst=10.1.1.1 sport=12865 dport=1024
[ASSURED] mark=1 secctx=system_u:object_r:unlabeled_t:s0 use=1

tcp 6 431994 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=5555 dport=12865 zone-orig=2
src=10.1.1.2 dst=10.1.1.1 sport=12865 dport=5555
[ASSURED] mark=2 secctx=system_u:object_r:unlabeled_t:s0 use=1

tcp 6 299 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=39438 dport=33768 zone-orig=1
src=10.1.1.2 dst=10.1.1.1 sport=33768 dport=39438
[ASSURED] mark=1 secctx=system_u:object_r:unlabeled_t:s0 use=1

tcp 6 300 ESTABLISHED src=40.1.1.1 dst=10.1.1.2 sport=32889 dport=40206 zone-orig=2
src=10.1.1.2 dst=10.1.1.1 sport=40206 dport=32889
[ASSURED] mark=2 secctx=system_u:object_r:unlabeled_t:s0 use=2

Taking this further, test script in [2] creates 200 tenants and runs original-tuple colliding netperf sessions each. A conntrack -L dump in the gateway netns also confirms 200 overlapping entries, all in ESTABLISHED state as expected.

I also did run various other tests with some permutations of the script, to mention some: SNAT in random/random-fully/persistent mode, no zones (no overlaps), static zones (original, reply, both directions), etc.

[1] http://thread.gmane.org/gmane.comp.security.firewalls.netfilter.devel/57412/
[2] https://paste.fedoraproject.org/242835/65657871/

Signed-off-by Daniel Borkmann <[email protected]>

---
 include/net/netfilter/nf_conntrack_zones.h         |  31 +++-
 include/uapi/linux/netfilter/nfnetlink_conntrack.h |   1 +
 include/uapi/linux/netfilter/xt_CT.h               |   6 +-
 net/ipv4/netfilter/nf_defrag_ipv4.c                |   8 +-
 net/ipv6/netfilter/nf_defrag_ipv6_hooks.c          |   8 +-
 net/netfilter/nf_conntrack_core.c                  |  53 +++---
 net/netfilter/nf_conntrack_expect.c                |   8 +-
 net/netfilter/nf_conntrack_netlink.c               | 177 +++++++++++++++------
 net/netfilter/nf_conntrack_standalone.c            |  30 +++-
 net/netfilter/nf_nat_core.c                        |  13 +-
 net/netfilter/xt_CT.c                              |  17 +-
 net/sched/act_connmark.c                           |   1 +
 12 files changed, 259 insertions(+), 94 deletions(-)

include/net/netfilter/nf_conntrack_zones.h +30 -1

index 0788bb0..3942ddf 100644
@@ -1,10 +1,18 @@
 #ifndef _NF_CONNTRACK_ZONES_H
 #define _NF_CONNTRACK_ZONES_H
 
+#include <linux/netfilter/nf_conntrack_tuple_common.h>
+
 #define NF_CT_DEFAULT_ZONE_ID	0
 
+#define NF_CT_ZONE_DIR_ORIG	(1 << IP_CT_DIR_ORIGINAL)
+#define NF_CT_ZONE_DIR_REPL	(1 << IP_CT_DIR_REPLY)
+
+#define NF_CT_DEFAULT_ZONE_DIR	(NF_CT_ZONE_DIR_ORIG | NF_CT_ZONE_DIR_REPL)
+
 struct nf_conntrack_zone {
 	u16	id;
+	u16	dir;
 };
 
 extern const struct nf_conntrack_zone nf_ct_zone_dflt;

@@ -29,8 +37,29 @@ nf_ct_zone_tmpl(const struct nf_conn *tmpl)
 	return tmpl ? nf_ct_zone(tmpl) : &nf_ct_zone_dflt;
 }
 
+static inline bool nf_ct_zone_matches_dir(const struct nf_conntrack_zone *zone,
+					  enum ip_conntrack_dir dir)
+{
+	return zone->dir & (1 << dir);
+}
+
+static inline u16 nf_ct_zone_id(const struct nf_conntrack_zone *zone,
+				enum ip_conntrack_dir dir)
+{
+	return nf_ct_zone_matches_dir(zone, dir) ?
+	       zone->id : NF_CT_DEFAULT_ZONE_ID;
+}
+
 static inline bool nf_ct_zone_equal(const struct nf_conn *a,
-				    const struct nf_conntrack_zone *b)
+				    const struct nf_conntrack_zone *b,
+				    enum ip_conntrack_dir dir)
+{
+	return nf_ct_zone_id(nf_ct_zone(a), dir) ==
+	       nf_ct_zone_id(b, dir);
+}
+
+static inline bool nf_ct_zone_equal_any(const struct nf_conn *a,
+					const struct nf_conntrack_zone *b)
 {
 	return nf_ct_zone(a)->id == b->id;
 }

include/uapi/linux/netfilter/nfnetlink_conntrack.h +1 -0

index acad6c5..c1a4e144 100644
@@ -61,6 +61,7 @@ enum ctattr_tuple {
 	CTA_TUPLE_UNSPEC,
 	CTA_TUPLE_IP,
 	CTA_TUPLE_PROTO,
+	CTA_TUPLE_ZONE,
 	__CTA_TUPLE_MAX
 };
 #define CTA_TUPLE_MAX (__CTA_TUPLE_MAX - 1)

include/uapi/linux/netfilter/xt_CT.h +5 -1

index 5a688c1..452005f 100644
@@ -6,7 +6,11 @@
 enum {
 	XT_CT_NOTRACK		= 1 << 0,
 	XT_CT_NOTRACK_ALIAS	= 1 << 1,
-	XT_CT_MASK		= XT_CT_NOTRACK | XT_CT_NOTRACK_ALIAS,
+	XT_CT_ZONE_DIR_ORIG	= 1 << 2,
+	XT_CT_ZONE_DIR_REPL	= 1 << 3,
+
+	XT_CT_MASK		= XT_CT_NOTRACK | XT_CT_NOTRACK_ALIAS |
+				  XT_CT_ZONE_DIR_ORIG | XT_CT_ZONE_DIR_REPL,
 };
 
 struct xt_ct_target_info {

net/ipv4/netfilter/nf_defrag_ipv4.c +6 -2

index 20fe8e6..9306ec4 100644
@@ -45,8 +45,12 @@ static enum ip_defrag_users nf_ct_defrag_user(unsigned int hooknum,
 {
 	u16 zone_id = NF_CT_DEFAULT_ZONE_ID;
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
-	if (skb->nfct)
-		zone_id = nf_ct_zone((struct nf_conn *)skb->nfct)->id;
+	if (skb->nfct) {
+		enum ip_conntrack_info ctinfo;
+		const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+
+		zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo));
+	}
 #endif
 	if (nf_bridge_in_prerouting(skb))
 		return IP_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id;

net/ipv6/netfilter/nf_defrag_ipv6_hooks.c +6 -2

index 9d3de9b..6d9c0b3 100644
@@ -35,8 +35,12 @@ static enum ip6_defrag_users nf_ct6_defrag_user(unsigned int hooknum,
 {
 	u16 zone_id = NF_CT_DEFAULT_ZONE_ID;
 #if IS_ENABLED(CONFIG_NF_CONNTRACK)
-	if (skb->nfct)
-		zone_id = nf_ct_zone((struct nf_conn *)skb->nfct)->id;
+	if (skb->nfct) {
+		enum ip_conntrack_info ctinfo;
+		const struct nf_conn *ct = nf_ct_get(skb, &ctinfo);
+
+		zone_id = nf_ct_zone_id(nf_ct_zone(ct), CTINFO2DIR(ctinfo));
+	}
 #endif
 	if (nf_bridge_in_prerouting(skb))
 		return IP6_DEFRAG_CONNTRACK_BRIDGE_IN + zone_id;

net/netfilter/nf_conntrack_core.c +27 ~~-26~~

187 lines not on this page · raw message

net/netfilter/nf_conntrack_expect.c +4 -4

index 980db85..acf5c7b 100644
@@ -101,7 +101,7 @@ __nf_ct_expect_find(struct net *net,
 	h = nf_ct_expect_dst_hash(tuple);
 	hlist_for_each_entry_rcu(i, &net->ct.expect_hash[h], hnode) {
 		if (nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) &&
-		    nf_ct_zone_equal(i->master, zone))
+		    nf_ct_zone_equal_any(i->master, zone))
 			return i;
 	}
 	return NULL;

@@ -143,7 +143,7 @@ nf_ct_find_expectation(struct net *net,
 	hlist_for_each_entry(i, &net->ct.expect_hash[h], hnode) {
 		if (!(i->flags & NF_CT_EXPECT_INACTIVE) &&
 		    nf_ct_tuple_mask_cmp(tuple, &i->tuple, &i->mask) &&
-		    nf_ct_zone_equal(i->master, zone)) {
+		    nf_ct_zone_equal_any(i->master, zone)) {
 			exp = i;
 			break;
 		}

@@ -223,7 +223,7 @@ static inline int expect_clash(const struct nf_conntrack_expect *a,
 	}
 
 	return nf_ct_tuple_mask_cmp(&a->tuple, &b->tuple, &intersect_mask) &&
-	       nf_ct_zone_equal(a->master, nf_ct_zone(b->master));
+	       nf_ct_zone_equal_any(a->master, nf_ct_zone(b->master));
 }
 
 static inline int expect_matches(const struct nf_conntrack_expect *a,

@@ -232,7 +232,7 @@ static inline int expect_matches(const struct nf_conntrack_expect *a,
 	return a->master == b->master && a->class == b->class &&
 	       nf_ct_tuple_equal(&a->tuple, &b->tuple) &&
 	       nf_ct_tuple_mask_equal(&a->mask, &b->mask) &&
-	       nf_ct_zone_equal(a->master, nf_ct_zone(b->master));
+	       nf_ct_zone_equal_any(a->master, nf_ct_zone(b->master));
 }
 
 /* Generally a bad idea to call this: could have matched already. */

net/netfilter/nf_conntrack_netlink.c +131 ~~-46~~

360 lines not on this page · raw message

net/netfilter/nf_conntrack_standalone.c +26 -4

index 28c8b2b..1fb3cac 100644
@@ -141,12 +141,30 @@ static inline void ct_show_secctx(struct seq_file *s, const struct nf_conn *ct)
 #endif
 
 #ifdef CONFIG_NF_CONNTRACK_ZONES
-static void ct_show_zone(struct seq_file *s, const struct nf_conn *ct)
+static void ct_show_zone(struct seq_file *s, const struct nf_conn *ct,
+			 int dir)
 {
-	seq_printf(s, "zone=%u ", nf_ct_zone(ct)->id);
+	const struct nf_conntrack_zone *zone = nf_ct_zone(ct);
+
+	if (zone->dir != dir)
+		return;
+	switch (zone->dir) {
+	case NF_CT_DEFAULT_ZONE_DIR:
+		seq_printf(s, "zone=%u ", zone->id);
+		break;
+	case NF_CT_ZONE_DIR_ORIG:
+		seq_printf(s, "zone-orig=%u ", zone->id);
+		break;
+	case NF_CT_ZONE_DIR_REPL:
+		seq_printf(s, "zone-reply=%u ", zone->id);
+		break;
+	default:
+		break;
+	}
 }
 #else
-static inline void ct_show_zone(struct seq_file *s, const struct nf_conn *ct)
+static inline void ct_show_zone(struct seq_file *s, const struct nf_conn *ct,
+				int dir)
 {
 }
 #endif

@@ -213,6 +231,8 @@ static int ct_seq_show(struct seq_file *s, void *v)
 	print_tuple(s, &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple,
 		    l3proto, l4proto);
 
+	ct_show_zone(s, ct, NF_CT_ZONE_DIR_ORIG);
+
 	if (seq_has_overflowed(s))
 		goto release;

@@ -225,6 +245,8 @@ static int ct_seq_show(struct seq_file *s, void *v)
 	print_tuple(s, &ct->tuplehash[IP_CT_DIR_REPLY].tuple,
 		    l3proto, l4proto);
 
+	ct_show_zone(s, ct, NF_CT_ZONE_DIR_REPL);
+
 	if (seq_print_acct(s, ct, IP_CT_DIR_REPLY))
 		goto release;

@@ -239,7 +261,7 @@ static int ct_seq_show(struct seq_file *s, void *v)
 #endif
 
 	ct_show_secctx(s, ct);
-	ct_show_zone(s, ct);
+	ct_show_zone(s, ct, NF_CT_DEFAULT_ZONE_DIR);
 	ct_show_delta_time(s, ct);
 
 	seq_printf(s, "use=%u\n", atomic_read(&ct->ct_general.use));

net/netfilter/nf_nat_core.c +6 -7

index 65ebaf9..5113dfd 100644
@@ -118,15 +118,13 @@ EXPORT_SYMBOL(nf_xfrm_me_harder);
 
 /* We keep an extra hash for each conntrack, for fast searching. */
 static inline unsigned int
-hash_by_src(const struct net *net,
-	    const struct nf_conntrack_zone *zone,
-	    const struct nf_conntrack_tuple *tuple)
+hash_by_src(const struct net *net, const struct nf_conntrack_tuple *tuple)
 {
 	unsigned int hash;
 
 	/* Original src, to ensure we map it consistently if poss. */
 	hash = jhash2((u32 *)&tuple->src, sizeof(tuple->src) / sizeof(u32),
-		      tuple->dst.protonum ^ zone->id ^ nf_conntrack_hash_rnd);
+		      tuple->dst.protonum ^ nf_conntrack_hash_rnd);
 
 	return reciprocal_scale(hash, net->ct.nat_htable_size);
 }

@@ -194,13 +192,14 @@ find_appropriate_src(struct net *net,
 		     struct nf_conntrack_tuple *result,
 		     const struct nf_nat_range *range)
 {
-	unsigned int h = hash_by_src(net, zone, tuple);
+	unsigned int h = hash_by_src(net, tuple);
 	const struct nf_conn_nat *nat;
 	const struct nf_conn *ct;
 
 	hlist_for_each_entry_rcu(nat, &net->ct.nat_bysource[h], bysource) {
 		ct = nat->ct;
-		if (same_src(ct, tuple) && nf_ct_zone_equal(ct, zone)) {
+		if (same_src(ct, tuple) &&
+		    nf_ct_zone_equal(ct, zone, IP_CT_DIR_ORIGINAL)) {
 			/* Copy source part from reply tuple. */
 			nf_ct_invert_tuplepr(result,
 				       &ct->tuplehash[IP_CT_DIR_REPLY].tuple);

@@ -425,7 +424,7 @@ nf_nat_setup_info(struct nf_conn *ct,
 	if (maniptype == NF_NAT_MANIP_SRC) {
 		unsigned int srchash;
 
-		srchash = hash_by_src(net, nf_ct_zone(ct),
+		srchash = hash_by_src(net,
 				      &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple);
 		spin_lock_bh(&nf_nat_lock);
 		/* nf_conntrack_alter_reply might re-allocate extension aera */

net/netfilter/xt_CT.c +16 -1

index 29e2856..536cb67 100644
@@ -181,6 +181,19 @@ out:
 #endif
 }
 
+static u16 xt_ct_flags_to_dir(const struct xt_ct_target_info_v1 *info)
+{
+	switch (info->flags & (XT_CT_ZONE_DIR_ORIG |
+			       XT_CT_ZONE_DIR_REPL)) {
+	case XT_CT_ZONE_DIR_ORIG:
+		return NF_CT_ZONE_DIR_ORIG;
+	case XT_CT_ZONE_DIR_REPL:
+		return NF_CT_ZONE_DIR_REPL;
+	default:
+		return NF_CT_DEFAULT_ZONE_DIR;
+	}
+}
+
 static int xt_ct_tg_check(const struct xt_tgchk_param *par,
 			  struct xt_ct_target_info_v1 *info)
 {

@@ -194,7 +207,8 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
 	}
 
 #ifndef CONFIG_NF_CONNTRACK_ZONES
-	if (info->zone)
+	if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
+					 XT_CT_ZONE_DIR_REPL))
 		goto err1;
 #endif

@@ -204,6 +218,7 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
 
 	memset(&zone, 0, sizeof(zone));
 	zone.id = info->zone;
+	zone.dir = xt_ct_flags_to_dir(info);
 
 	ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
 	ret = PTR_ERR(ct);

net/sched/act_connmark.c +1 -0

index e67a1bd..5019a47 100644
@@ -72,6 +72,7 @@ static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
 		goto out;
 
 	zone.id = ca->zone;
+	zone.dir = NF_CT_DEFAULT_ZONE_DIR;
 
 	thash = nf_conntrack_find_get(dev_net(skb->dev), &zone, &tuple);
 	if (!thash)

Signature · 1 line

1.9.3

Pablo Neira Ayuso

maintainer Applied

2015-08-18 22:23 UTC #2 lore raw

Re: [PATCH nf-next v5 1/2] netfilter: nf_conntrack: add direction support for zones

Quoted 11 lines · Daniel Borkmann

This work adds a direction parameter to netfilter zones, so identity separation can be performed only in original/reply or both directions (default). This basically opens up the possibility of doing NAT with conflicting IP address/port tuples from multiple, isolated tenants on a host (e.g. from a netns) without requiring each tenant to NAT twice resp. to use its own dedicated IP address to SNAT to, meaning overlapping tuples can be made unique with the zone identifier in original direction, where the NAT engine will then allocate a unique tuple in the commonly shared default zone for the reply direction. In some restricted, local DNAT cases, also port redirection could be used for making the reply traffic unique w/o requiring SNAT.

Applied, thanks Daniel.

Daniel Borkmann

author

2015-08-14 14:03 UTC #3 lore raw

PATCH v5 2/2 netfilter: nf_conntrack: add efficient mark to zone mapping

In reply to Daniel Borkmann

This work adds the possibility of deriving the zone id from the skb->mark field in a scalable manner. This allows for having only a single template serving hundreds/thousands of different zones, for example, instead of the need to have one match for each zone as an extra CT jump target.

Note that we'd need to have this information attached to the template as at the time when we're trying to lookup a possible ct object, we already need to know zone information for a possible match when going into __nf_conntrack_find_get(). This work provides a minimal implementation for a possible mapping.

In order to not add/expose an extra ct->status bit, the zone structure has been extended to carry a flag for deriving the mark.

Signed-off-by Daniel Borkmann <[email protected]>

---
 include/net/netfilter/nf_conntrack_zones.h     | 45 +++++++++++++++++++++--
 include/uapi/linux/netfilter/xt_CT.h           |  4 ++-
 net/ipv4/netfilter/nf_conntrack_proto_icmp.c   |  3 +-
 net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c |  4 ++-
 net/netfilter/nf_conntrack_core.c              | 50 +++++++++-----------------
 net/netfilter/nf_conntrack_netlink.c           |  5 ++-
 net/netfilter/xt_CT.c                          |  5 ++-
 7 files changed, 72 insertions(+), 44 deletions(-)

include/net/netfilter/nf_conntrack_zones.h +42 -3

index 3942ddf..5316c7b 100644
@@ -10,9 +10,12 @@
 
 #define NF_CT_DEFAULT_ZONE_DIR	(NF_CT_ZONE_DIR_ORIG | NF_CT_ZONE_DIR_REPL)
 
+#define NF_CT_FLAG_MARK		1
+
 struct nf_conntrack_zone {
 	u16	id;
-	u16	dir;
+	u8	flags;
+	u8	dir;
 };
 
 extern const struct nf_conntrack_zone nf_ct_zone_dflt;

@@ -32,9 +35,45 @@ nf_ct_zone(const struct nf_conn *ct)
 }
 
 static inline const struct nf_conntrack_zone *
-nf_ct_zone_tmpl(const struct nf_conn *tmpl)
+nf_ct_zone_init(struct nf_conntrack_zone *zone, u16 id, u8 dir, u8 flags)
+{
+	zone->id = id;
+	zone->flags = flags;
+	zone->dir = dir;
+
+	return zone;
+}
+
+static inline const struct nf_conntrack_zone *
+nf_ct_zone_tmpl(const struct nf_conn *tmpl, const struct sk_buff *skb,
+		struct nf_conntrack_zone *tmp)
+{
+	const struct nf_conntrack_zone *zone;
+
+	if (!tmpl)
+		return &nf_ct_zone_dflt;
+
+	zone = nf_ct_zone(tmpl);
+	if (zone->flags & NF_CT_FLAG_MARK)
+		zone = nf_ct_zone_init(tmp, skb->mark, zone->dir, 0);
+
+	return zone;
+}
+
+static inline int nf_ct_zone_add(struct nf_conn *ct, gfp_t flags,
+				 const struct nf_conntrack_zone *info)
 {
-	return tmpl ? nf_ct_zone(tmpl) : &nf_ct_zone_dflt;
+#ifdef CONFIG_NF_CONNTRACK_ZONES
+	struct nf_conntrack_zone *nf_ct_zone;
+
+	nf_ct_zone = nf_ct_ext_add(ct, NF_CT_EXT_ZONE, flags);
+	if (!nf_ct_zone)
+		return -ENOMEM;
+
+	nf_ct_zone_init(nf_ct_zone, info->id, info->dir,
+			info->flags);
+#endif
+	return 0;
 }
 
 static inline bool nf_ct_zone_matches_dir(const struct nf_conntrack_zone *zone,

include/uapi/linux/netfilter/xt_CT.h +3 -1

index 452005f..9e52041 100644
@@ -8,9 +8,11 @@ enum {
 	XT_CT_NOTRACK_ALIAS	= 1 << 1,
 	XT_CT_ZONE_DIR_ORIG	= 1 << 2,
 	XT_CT_ZONE_DIR_REPL	= 1 << 3,
+	XT_CT_ZONE_MARK		= 1 << 4,
 
 	XT_CT_MASK		= XT_CT_NOTRACK | XT_CT_NOTRACK_ALIAS |
-				  XT_CT_ZONE_DIR_ORIG | XT_CT_ZONE_DIR_REPL,
+				  XT_CT_ZONE_DIR_ORIG | XT_CT_ZONE_DIR_REPL |
+				  XT_CT_ZONE_MARK,
 };
 
 struct xt_ct_target_info {

net/ipv4/netfilter/nf_conntrack_proto_icmp.c +2 -1

index 8a2f41c..cdde3ec 100644
@@ -135,9 +135,10 @@ icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
 	const struct nf_conntrack_l4proto *innerproto;
 	const struct nf_conntrack_tuple_hash *h;
 	const struct nf_conntrack_zone *zone;
+	struct nf_conntrack_zone tmp;
 
 	NF_CT_ASSERT(skb->nfct == NULL);
-	zone = nf_ct_zone_tmpl(tmpl);
+	zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);
 
 	/* Are they talking about one of our connections? */
 	if (!nf_ct_get_tuplepr(skb,

net/ipv6/netfilter/nf_conntrack_proto_icmpv6.c +3 -1

index 2029141..0e6fae1 100644
@@ -150,6 +150,7 @@ icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
 	struct nf_conntrack_tuple intuple, origtuple;
 	const struct nf_conntrack_tuple_hash *h;
 	const struct nf_conntrack_l4proto *inproto;
+	struct nf_conntrack_zone tmp;
 
 	NF_CT_ASSERT(skb->nfct == NULL);

@@ -176,7 +177,8 @@ icmpv6_error_message(struct net *net, struct nf_conn *tmpl,
 
 	*ctinfo = IP_CT_RELATED;
 
-	h = nf_conntrack_find_get(net, nf_ct_zone_tmpl(tmpl), &intuple);
+	h = nf_conntrack_find_get(net, nf_ct_zone_tmpl(tmpl, skb, &tmp),
+				  &intuple);
 	if (!h) {
 		pr_debug("icmpv6_error: no match\n");
 		return -NF_ACCEPT;

net/netfilter/nf_conntrack_core.c +16 ~~-34~~

106 lines not on this page · raw message

net/netfilter/nf_conntrack_netlink.c +2 -3

index 4eaf925..94a6654 100644
@@ -956,9 +956,8 @@ static int
 ctnetlink_parse_zone(const struct nlattr *attr,
 		     struct nf_conntrack_zone *zone)
 {
-	zone->id  = NF_CT_DEFAULT_ZONE_ID;
-	zone->dir = NF_CT_DEFAULT_ZONE_DIR;
-
+	nf_ct_zone_init(zone, NF_CT_DEFAULT_ZONE_ID,
+			NF_CT_DEFAULT_ZONE_DIR, 0);
 #ifdef CONFIG_NF_CONNTRACK_ZONES
 	if (attr)
 		zone->id = ntohs(nla_get_be16(attr));

net/netfilter/xt_CT.c +4 -1

index 536cb67..3465098 100644
@@ -208,7 +208,8 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
 
 #ifndef CONFIG_NF_CONNTRACK_ZONES
 	if (info->zone || info->flags & (XT_CT_ZONE_DIR_ORIG |
-					 XT_CT_ZONE_DIR_REPL))
+					 XT_CT_ZONE_DIR_REPL |
+					 XT_CT_ZONE_MARK))
 		goto err1;
 #endif

@@ -219,6 +220,8 @@ static int xt_ct_tg_check(const struct xt_tgchk_param *par,
 	memset(&zone, 0, sizeof(zone));
 	zone.id = info->zone;
 	zone.dir = xt_ct_flags_to_dir(info);
+	if (info->flags & XT_CT_ZONE_MARK)
+		zone.flags |= NF_CT_FLAG_MARK;
 
 	ct = nf_ct_tmpl_alloc(par->net, &zone, GFP_KERNEL);
 	ret = PTR_ERR(ct);

Signature · 1 line

1.9.3

Pablo Neira Ayuso

maintainer

2015-08-18 22:59 UTC #4 lore raw

Re: [PATCH nf-next v5 2/2] netfilter: nf_conntrack: add efficient mark to zone mapping

Quoted 5 lines · Daniel Borkmann

This work adds the possibility of deriving the zone id from the skb->mark field in a scalable manner. This allows for having only a single template serving hundreds/thousands of different zones, for example, instead of the need to have one match for each zone as an extra CT jump target.

Quoted 8 lines

Note that we'd need to have this information attached to the template as at the time when we're trying to lookup a possible ct object, we already need to know zone information for a possible match when going into __nf_conntrack_find_get(). This work provides a minimal implementation for a possible mapping.
In order to not add/expose an extra ct->status bit, the zone structure has been extended to carry a flag for deriving the mark.

Also applied, thanks. A slightly large comment below though.

[...]

net/ipv4/netfilter/nf_conntrack_proto_icmp.c icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb, · line 141

Quoted 13 lines

net/ipv4/netfilter/nf_conntrack_proto_icmp.c +2 -1

index 8a2f41c..cdde3ec 100644
@@ -135,9 +135,10 @@ icmp_error_message(struct net *net, struct nf_conn *tmpl, struct sk_buff *skb,
 	const struct nf_conntrack_l4proto *innerproto;
 	const struct nf_conntrack_tuple_hash *h;
 	const struct nf_conntrack_zone *zone;
+	struct nf_conntrack_zone tmp;
 
 	NF_CT_ASSERT(skb->nfct == NULL);
-	zone = nf_ct_zone_tmpl(tmpl);
+	zone = nf_ct_zone_tmpl(tmpl, skb, &tmp);

This change to nf_ct_zone_tmpl() is OK by now. I can see you're doing this because we cannot use the template object to perform tmpl->mark = skb->mark since the template is shared between all packets.

However, this is showing the limitations that we have in iptables since we can't do mappings there, with nft we could do things in the near future that look like:

        meta mark { 0x123 : ct template zone 1, ... }

I think this can be refined by having a scratchpad template object per-cpu that we can modify from the CT target. This will also resolve the existing limitations that we have: Only the first rule that uses the CT target to attach a template actually applies, follow up rules trying to attach a template are simply ignored.

This per-cpu template object should have a zone and timeout extension area preallocated, so we skip that memory allocation overhead from the packet path. Another alternative can be to add a struct nf_conn_tmpl object whose layout until the status flag is the same, so we can place the configuration there without the need of the extension areas, a trick similar to what we have with reqsock and twsock objects.

Would you have a look into this so we can get this in better shape and resolve the existing limitations by the next merge window? Thanks!

Daniel Borkmann

author

2015-08-19 15:11 UTC #5 lore raw

Re: [PATCH nf-next v5 2/2] netfilter: nf_conntrack: add efficient mark to zone mapping

On 08/19/2015 01:05 AM, Pablo Neira Ayuso wrote:
...

Quoted 23 lines

This change to nf_ct_zone_tmpl() is OK by now. I can see you're doing this because we cannot use the template object to perform tmpl->mark = skb->mark since the template is shared between all packets.
However, this is showing the limitations that we have in iptables since we can't do mappings there, with nft we could do things in the near future that look like:
         meta mark { 0x123 : ct template zone 1, ... }
I think this can be refined by having a scratchpad template object per-cpu that we can modify from the CT target. This will also resolve the existing limitations that we have: Only the first rule that uses the CT target to attach a template actually applies, follow up rules trying to attach a template are simply ignored.
This per-cpu template object should have a zone and timeout extension area preallocated, so we skip that memory allocation overhead from the packet path. Another alternative can be to add a struct nf_conn_tmpl object whose layout until the status flag is the same, so we can place the configuration there without the need of the extension areas, a trick similar to what we have with reqsock and twsock objects.

Quoted 2 lines

Would you have a look into this so we can get this in better shape and resolve the existing limitations by the next merge window? Thanks!

Yes, I'll look into this and will get back to you. Btw, the remaining two user space patches (conntrack, libnetfilter_conntrack) I'll post next week when I'm back from Plumbers.

Thanks Pablo!

Best,
Daniel