[PATCH 0/4] Netfilter fixes for net

[PATCH 0/4] Netfilter fixes for net

[Pablo Neira Ayuso]

Hi David,

The following patchset contains Netfilter fixes for your net tree,
they are:

1) Missing check for full sock in ip_route_me_harder(), from
   Florian Westphal.

2) Incorrect sip helper structure initilization that breaks it when
   several ports are used, from Christophe Leroy.

3) Fix incorrect assumption when looking up for matching with adjacent
   intervals in the nft_set_rbtree.

4) Fix broken netlink event error reporting in nf_tables that results
   in misleading ESRCH errors propagated to userspace listeners.

You can pull these changes from:

  git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf.git

Thanks!

----------------------------------------------------------------

The following changes since commit 2f44f75257d57f0d5668dba3a6ada0f4872132c9:

  Merge branch 'qed-fixes' (2017-02-27 09:22:10 -0500)

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf.git HEAD

for you to fetch changes up to 25e94a997b324b5f167f56d56d7106d38b78c9de:

  netfilter: nf_tables: don't call nfnetlink_set_err() if nfnetlink_send() fails (2017-03-03 13:48:34 +0100)

----------------------------------------------------------------
Christophe Leroy (1):
      netfilter: nf_conntrack_sip: fix wrong memory initialisation

Florian Westphal (1):
      netfilter: use skb_to_full_sk in ip_route_me_harder

Pablo Neira Ayuso (2):
      netfilter: nft_set_rbtree: incorrect assumption on lower interval lookups
      netfilter: nf_tables: don't call nfnetlink_set_err() if nfnetlink_send() fails

 include/net/netfilter/nf_tables.h |   6 +-
 net/ipv4/netfilter.c              |   7 +-
 net/netfilter/nf_conntrack_sip.c  |   2 -
 net/netfilter/nf_tables_api.c     | 133 ++++++++++++++++----------------------
 net/netfilter/nft_set_rbtree.c    |   9 ++-
 5 files changed, 66 insertions(+), 91 deletions(-)

[PATCH 1/4] netfilter: use skb_to_full_sk in ip_route_me_harder

[Pablo Neira Ayuso]

From: Florian Westphal <fw@strlen.de>

inet_sk(skb->sk) is illegal in case skb is attached to request socket.

Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener")
Reported by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Florian Westphal <fw@strlen.de>
Tested-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/ipv4/netfilter.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index b3cc1335adbc..c0cc6aa8cfaa 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -23,7 +23,8 @@ int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_t
 	struct rtable *rt;
 	struct flowi4 fl4 = {};
 	__be32 saddr = iph->saddr;
-	__u8 flags = skb->sk ? inet_sk_flowi_flags(skb->sk) : 0;
+	const struct sock *sk = skb_to_full_sk(skb);
+	__u8 flags = sk ? inet_sk_flowi_flags(sk) : 0;
 	struct net_device *dev = skb_dst(skb)->dev;
 	unsigned int hh_len;
 
@@ -40,7 +41,7 @@ int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_t
 	fl4.daddr = iph->daddr;
 	fl4.saddr = saddr;
 	fl4.flowi4_tos = RT_TOS(iph->tos);
-	fl4.flowi4_oif = skb->sk ? skb->sk->sk_bound_dev_if : 0;
+	fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0;
 	if (!fl4.flowi4_oif)
 		fl4.flowi4_oif = l3mdev_master_ifindex(dev);
 	fl4.flowi4_mark = skb->mark;
@@ -61,7 +62,7 @@ int ip_route_me_harder(struct net *net, struct sk_buff *skb, unsigned int addr_t
 	    xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) {
 		struct dst_entry *dst = skb_dst(skb);
 		skb_dst_set(skb, NULL);
-		dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), skb->sk, 0);
+		dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0);
 		if (IS_ERR(dst))
 			return PTR_ERR(dst);
 		skb_dst_set(skb, dst);
-- 
2.1.4

[PATCH 2/4] netfilter: nf_conntrack_sip: fix wrong memory initialisation

[Pablo Neira Ayuso]

From: Christophe Leroy <christophe.leroy@c-s.fr>

In commit 82de0be6862cd ("netfilter: Add helper array
register/unregister functions"),
struct nf_conntrack_helper sip[MAX_PORTS][4] was changed to
sip[MAX_PORTS * 4], so the memory init should have been changed to
memset(&sip[4 * i], 0, 4 * sizeof(sip[i]));

But as the sip[] table is allocated in the BSS, it is already set to 0

Fixes: 82de0be6862cd ("netfilter: Add helper array register/unregister functions")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nf_conntrack_sip.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/net/netfilter/nf_conntrack_sip.c b/net/netfilter/nf_conntrack_sip.c
index 24174c520239..0d17894798b5 100644
--- a/net/netfilter/nf_conntrack_sip.c
+++ b/net/netfilter/nf_conntrack_sip.c
@@ -1628,8 +1628,6 @@ static int __init nf_conntrack_sip_init(void)
 		ports[ports_c++] = SIP_PORT;
 
 	for (i = 0; i < ports_c; i++) {
-		memset(&sip[i], 0, sizeof(sip[i]));
-
 		nf_ct_helper_init(&sip[4 * i], AF_INET, IPPROTO_UDP, "sip",
 				  SIP_PORT, ports[i], i, sip_exp_policy,
 				  SIP_EXPECT_MAX,
-- 
2.1.4

[PATCH 3/4] netfilter: nft_set_rbtree: incorrect assumption on lower interval lookups

[Pablo Neira Ayuso]

In case of adjacent ranges, we may indeed see either the high part of
the range in first place or the low part of it. Remove this incorrect
assumption, let's make sure we annotate the low part of the interval in
case of we have adjacent interva intervals so we hit a matching in
lookups.

Reported-by: Simon Hanisch <hanisch@wh2.tu-dresden.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netfilter/nft_set_rbtree.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/net/netfilter/nft_set_rbtree.c b/net/netfilter/nft_set_rbtree.c
index 71e8fb886a73..78dfbf9588b3 100644
--- a/net/netfilter/nft_set_rbtree.c
+++ b/net/netfilter/nft_set_rbtree.c
@@ -60,11 +60,10 @@ static bool nft_rbtree_lookup(const struct net *net, const struct nft_set *set,
 		d = memcmp(this, key, set->klen);
 		if (d < 0) {
 			parent = parent->rb_left;
-			/* In case of adjacent ranges, we always see the high
-			 * part of the range in first place, before the low one.
-			 * So don't update interval if the keys are equal.
-			 */
-			if (interval && nft_rbtree_equal(set, this, interval))
+			if (interval &&
+			    nft_rbtree_equal(set, this, interval) &&
+			    nft_rbtree_interval_end(this) &&
+			    !nft_rbtree_interval_end(interval))
 				continue;
 			interval = rbe;
 		} else if (d > 0)
-- 
2.1.4

[PATCH 4/4] netfilter: nf_tables: don't call nfnetlink_set_err() if nfnetlink_send() fails

[Pablo Neira Ayuso]

The underlying nlmsg_multicast() already sets sk->sk_err for us to
notify socket overruns, so we should not do anything with this return
value. So we just call nfnetlink_set_err() if:

1) We fail to allocate the netlink message.

or

2) We don't have enough space in the netlink message to place attributes,
   which means that we likely need to allocate a larger message.

Before this patch, the internal ESRCH netlink error code was propagated
to userspace, which is quite misleading. Netlink semantics mandate that
listeners just hit ENOBUFS if the socket buffer overruns.

Reported-by: Alexander Alemayhu <alexander@alemayhu.com>
Tested-by: Alexander Alemayhu <alexander@alemayhu.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/net/netfilter/nf_tables.h |   6 +-
 net/netfilter/nf_tables_api.c     | 133 ++++++++++++++++----------------------
 2 files changed, 58 insertions(+), 81 deletions(-)

diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h
index ac84686aaafb..2aa8a9d80fbe 100644
--- a/include/net/netfilter/nf_tables.h
+++ b/include/net/netfilter/nf_tables.h
@@ -988,9 +988,9 @@ struct nft_object *nf_tables_obj_lookup(const struct nft_table *table,
 					const struct nlattr *nla, u32 objtype,
 					u8 genmask);
 
-int nft_obj_notify(struct net *net, struct nft_table *table,
-		   struct nft_object *obj, u32 portid, u32 seq,
-		   int event, int family, int report, gfp_t gfp);
+void nft_obj_notify(struct net *net, struct nft_table *table,
+		    struct nft_object *obj, u32 portid, u32 seq,
+		    int event, int family, int report, gfp_t gfp);
 
 /**
  *	struct nft_object_type - stateful object type
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index ff7304ae58ac..5e0ccfd5bb37 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -461,16 +461,15 @@ static int nf_tables_fill_table_info(struct sk_buff *skb, struct net *net,
 	return -1;
 }
 
-static int nf_tables_table_notify(const struct nft_ctx *ctx, int event)
+static void nf_tables_table_notify(const struct nft_ctx *ctx, int event)
 {
 	struct sk_buff *skb;
 	int err;
 
 	if (!ctx->report &&
 	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (skb == NULL)
 		goto err;
@@ -482,14 +481,11 @@ static int nf_tables_table_notify(const struct nft_ctx *ctx, int event)
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
-			     ctx->report, GFP_KERNEL);
+	nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+		       ctx->report, GFP_KERNEL);
+	return;
 err:
-	if (err < 0) {
-		nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES,
-				  err);
-	}
-	return err;
+	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 
 static int nf_tables_dump_tables(struct sk_buff *skb,
@@ -1050,16 +1046,15 @@ static int nf_tables_fill_chain_info(struct sk_buff *skb, struct net *net,
 	return -1;
 }
 
-static int nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
+static void nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
 {
 	struct sk_buff *skb;
 	int err;
 
 	if (!ctx->report &&
 	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (skb == NULL)
 		goto err;
@@ -1072,14 +1067,11 @@ static int nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
-			     ctx->report, GFP_KERNEL);
+	nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+		       ctx->report, GFP_KERNEL);
+	return;
 err:
-	if (err < 0) {
-		nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES,
-				  err);
-	}
-	return err;
+	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 
 static int nf_tables_dump_chains(struct sk_buff *skb,
@@ -1934,18 +1926,16 @@ static int nf_tables_fill_rule_info(struct sk_buff *skb, struct net *net,
 	return -1;
 }
 
-static int nf_tables_rule_notify(const struct nft_ctx *ctx,
-				 const struct nft_rule *rule,
-				 int event)
+static void nf_tables_rule_notify(const struct nft_ctx *ctx,
+				  const struct nft_rule *rule, int event)
 {
 	struct sk_buff *skb;
 	int err;
 
 	if (!ctx->report &&
 	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (skb == NULL)
 		goto err;
@@ -1958,14 +1948,11 @@ static int nf_tables_rule_notify(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
-			     ctx->report, GFP_KERNEL);
+	nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+		       ctx->report, GFP_KERNEL);
+	return;
 err:
-	if (err < 0) {
-		nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES,
-				  err);
-	}
-	return err;
+	nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 
 struct nft_rule_dump_ctx {
@@ -2696,9 +2683,9 @@ static int nf_tables_fill_set(struct sk_buff *skb, const struct nft_ctx *ctx,
 	return -1;
 }
 
-static int nf_tables_set_notify(const struct nft_ctx *ctx,
-				const struct nft_set *set,
-				int event, gfp_t gfp_flags)
+static void nf_tables_set_notify(const struct nft_ctx *ctx,
+				 const struct nft_set *set, int event,
+			         gfp_t gfp_flags)
 {
 	struct sk_buff *skb;
 	u32 portid = ctx->portid;
@@ -2706,9 +2693,8 @@ static int nf_tables_set_notify(const struct nft_ctx *ctx,
 
 	if (!ctx->report &&
 	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb = nlmsg_new(NLMSG_GOODSIZE, gfp_flags);
 	if (skb == NULL)
 		goto err;
@@ -2719,12 +2705,11 @@ static int nf_tables_set_notify(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, ctx->net, portid, NFNLGRP_NFTABLES,
-			     ctx->report, gfp_flags);
+	nfnetlink_send(skb, ctx->net, portid, NFNLGRP_NFTABLES, ctx->report,
+		       gfp_flags);
+	return;
 err:
-	if (err < 0)
-		nfnetlink_set_err(ctx->net, portid, NFNLGRP_NFTABLES, err);
-	return err;
+	nfnetlink_set_err(ctx->net, portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 
 static int nf_tables_dump_sets(struct sk_buff *skb, struct netlink_callback *cb)
@@ -3504,10 +3489,10 @@ static int nf_tables_fill_setelem_info(struct sk_buff *skb,
 	return -1;
 }
 
-static int nf_tables_setelem_notify(const struct nft_ctx *ctx,
-				    const struct nft_set *set,
-				    const struct nft_set_elem *elem,
-				    int event, u16 flags)
+static void nf_tables_setelem_notify(const struct nft_ctx *ctx,
+				     const struct nft_set *set,
+				     const struct nft_set_elem *elem,
+				     int event, u16 flags)
 {
 	struct net *net = ctx->net;
 	u32 portid = ctx->portid;
@@ -3515,9 +3500,8 @@ static int nf_tables_setelem_notify(const struct nft_ctx *ctx,
 	int err;
 
 	if (!ctx->report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (skb == NULL)
 		goto err;
@@ -3529,12 +3513,11 @@ static int nf_tables_setelem_notify(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, ctx->report,
-			     GFP_KERNEL);
+	nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, ctx->report,
+		       GFP_KERNEL);
+	return;
 err:
-	if (err < 0)
-		nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, err);
-	return err;
+	nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 
 static struct nft_trans *nft_trans_elem_alloc(struct nft_ctx *ctx,
@@ -4476,18 +4459,17 @@ static int nf_tables_delobj(struct net *net, struct sock *nlsk,
 	return nft_delobj(&ctx, obj);
 }
 
-int nft_obj_notify(struct net *net, struct nft_table *table,
-		   struct nft_object *obj, u32 portid, u32 seq, int event,
-		   int family, int report, gfp_t gfp)
+void nft_obj_notify(struct net *net, struct nft_table *table,
+		    struct nft_object *obj, u32 portid, u32 seq, int event,
+		    int family, int report, gfp_t gfp)
 {
 	struct sk_buff *skb;
 	int err;
 
 	if (!report &&
 	    !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb = nlmsg_new(NLMSG_GOODSIZE, gfp);
 	if (skb == NULL)
 		goto err;
@@ -4499,21 +4481,18 @@ int nft_obj_notify(struct net *net, struct nft_table *table,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report, gfp);
+	nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report, gfp);
+	return;
 err:
-	if (err < 0) {
-		nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, err);
-	}
-	return err;
+	nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, -ENOBUFS);
 }
 EXPORT_SYMBOL_GPL(nft_obj_notify);
 
-static int nf_tables_obj_notify(const struct nft_ctx *ctx,
-				struct nft_object *obj, int event)
+static void nf_tables_obj_notify(const struct nft_ctx *ctx,
+				 struct nft_object *obj, int event)
 {
-	return nft_obj_notify(ctx->net, ctx->table, obj, ctx->portid,
-			      ctx->seq, event, ctx->afi->family, ctx->report,
-			      GFP_KERNEL);
+	nft_obj_notify(ctx->net, ctx->table, obj, ctx->portid, ctx->seq, event,
+		       ctx->afi->family, ctx->report, GFP_KERNEL);
 }
 
 static int nf_tables_fill_gen_info(struct sk_buff *skb, struct net *net,
@@ -4543,7 +4522,8 @@ static int nf_tables_fill_gen_info(struct sk_buff *skb, struct net *net,
 	return -EMSGSIZE;
 }
 
-static int nf_tables_gen_notify(struct net *net, struct sk_buff *skb, int event)
+static void nf_tables_gen_notify(struct net *net, struct sk_buff *skb,
+				 int event)
 {
 	struct nlmsghdr *nlh = nlmsg_hdr(skb);
 	struct sk_buff *skb2;
@@ -4551,9 +4531,8 @@ static int nf_tables_gen_notify(struct net *net, struct sk_buff *skb, int event)
 
 	if (nlmsg_report(nlh) &&
 	    !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
-		return 0;
+		return;
 
-	err = -ENOBUFS;
 	skb2 = nlmsg_new(NLMSG_GOODSIZE, GFP_KERNEL);
 	if (skb2 == NULL)
 		goto err;
@@ -4565,14 +4544,12 @@ static int nf_tables_gen_notify(struct net *net, struct sk_buff *skb, int event)
 		goto err;
 	}
 
-	err = nfnetlink_send(skb2, net, NETLINK_CB(skb).portid,
-			     NFNLGRP_NFTABLES, nlmsg_report(nlh), GFP_KERNEL);
+	nfnetlink_send(skb2, net, NETLINK_CB(skb).portid, NFNLGRP_NFTABLES,
+		       nlmsg_report(nlh), GFP_KERNEL);
+	return;
 err:
-	if (err < 0) {
-		nfnetlink_set_err(net, NETLINK_CB(skb).portid, NFNLGRP_NFTABLES,
-				  err);
-	}
-	return err;
+	nfnetlink_set_err(net, NETLINK_CB(skb).portid, NFNLGRP_NFTABLES,
+			  -ENOBUFS);
 }
 
 static int nf_tables_getgen(struct net *net, struct sock *nlsk,
-- 
2.1.4

Re: [PATCH 0/4] Netfilter fixes for net

[David Miller]

From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Fri,  3 Mar 2017 20:22:21 +0100

> The following patchset contains Netfilter fixes for your net tree,
> they are:
> 
> 1) Missing check for full sock in ip_route_me_harder(), from
>    Florian Westphal.
> 
> 2) Incorrect sip helper structure initilization that breaks it when
>    several ports are used, from Christophe Leroy.
> 
> 3) Fix incorrect assumption when looking up for matching with adjacent
>    intervals in the nft_set_rbtree.
> 
> 4) Fix broken netlink event error reporting in nf_tables that results
>    in misleading ESRCH errors propagated to userspace listeners.
> 
> You can pull these changes from:
> 
>   git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf.git

Pulled, thanks a lot Pablo.