[PATCH AUTOSEL 4.20 05/72] netfilter: nft_compat: use refcnt_t type for nft_xt reference count

[PATCH AUTOSEL 4.20 05/72] netfilter: nft_compat: use refcnt_t type for nft_xt reference count

[Sasha Levin]

From: Florian Westphal <fw@strlen.de>

[ Upstream commit 12c44aba6618b7f6c437076e5722237190f6cd5f ]

Using standard integer type was fine while all operations on it were
guarded by the nftnl subsys mutex.

This isn't true anymore:
1. transactions are guarded only by a pernet mutex, so concurrent
   rule manipulation in different netns is racy
2. the ->destroy hook runs from a work queue after the transaction
   mutex has been released already.

cpu0                           cpu1 (net 1)        cpu2 (net 2)
 kworker
    nft_compat->destroy        nft_compat->init    nft_compat->init
      if (--nft_xt->ref == 0)   nft_xt->ref++        nft_xt->ref++

Switch to refcount_t.  Doing this however only fixes a minor aspect,
nft_compat also performs linked-list operations in an unsafe way.

This is addressed in the next two patches.

Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions")
Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release")
Reported-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nft_compat.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 7334e0b80a5ef..acc85acad31bd 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -26,7 +26,7 @@
 struct nft_xt {
 	struct list_head	head;
 	struct nft_expr_ops	ops;
-	unsigned int		refcnt;
+	refcount_t		refcnt;
 
 	/* Unlike other expressions, ops doesn't have static storage duration.
 	 * nft core assumes they do.  We use kfree_rcu so that nft core can
@@ -45,7 +45,7 @@ struct nft_xt_match_priv {
 
 static bool nft_xt_put(struct nft_xt *xt)
 {
-	if (--xt->refcnt == 0) {
+	if (refcount_dec_and_test(&xt->refcnt)) {
 		list_del(&xt->head);
 		kfree_rcu(xt, rcu_head);
 		return true;
@@ -273,7 +273,7 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 		return -EINVAL;
 
 	nft_xt = container_of(expr->ops, struct nft_xt, ops);
-	nft_xt->refcnt++;
+	refcount_inc(&nft_xt->refcnt);
 	return 0;
 }
 
@@ -486,7 +486,7 @@ __nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 		return ret;
 
 	nft_xt = container_of(expr->ops, struct nft_xt, ops);
-	nft_xt->refcnt++;
+	refcount_inc(&nft_xt->refcnt);
 	return 0;
 }
 
@@ -789,7 +789,7 @@ nft_match_select_ops(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	nft_match->refcnt = 0;
+	refcount_set(&nft_match->refcnt, 0);
 	nft_match->ops.type = &nft_match_type;
 	nft_match->ops.eval = nft_match_eval;
 	nft_match->ops.init = nft_match_init;
@@ -893,7 +893,7 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	nft_target->refcnt = 0;
+	refcount_set(&nft_target->refcnt, 0);
 	nft_target->ops.type = &nft_target_type;
 	nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
 	nft_target->ops.init = nft_target_init;
@@ -964,7 +964,7 @@ static void __exit nft_compat_module_exit(void)
 	list_for_each_entry_safe(xt, next, &nft_target_list, head) {
 		struct xt_target *target = xt->ops.data;
 
-		if (WARN_ON_ONCE(xt->refcnt))
+		if (WARN_ON_ONCE(refcount_read(&xt->refcnt)))
 			continue;
 		module_put(target->me);
 		kfree(xt);
@@ -973,7 +973,7 @@ static void __exit nft_compat_module_exit(void)
 	list_for_each_entry_safe(xt, next, &nft_match_list, head) {
 		struct xt_match *match = xt->ops.data;
 
-		if (WARN_ON_ONCE(xt->refcnt))
+		if (WARN_ON_ONCE(refcount_read(&xt->refcnt)))
 			continue;
 		module_put(match->me);
 		kfree(xt);
-- 
2.19.1

[PATCH AUTOSEL 4.20 06/72] netfilter: nft_compat: make lists per netns

[Sasha Levin]

From: Florian Westphal <fw@strlen.de>

[ Upstream commit cf52572ebbd7189a1966c2b5fc34b97078cd1dce ]

There are two problems with nft_compat since the netlink config
plane uses a per-netns mutex:

1. Concurrent add/del accesses to the same list
2. accesses to a list element after it has been free'd already.

This patch fixes the first problem.

Freeing occurs from a work queue, after transaction mutexes have been
released, i.e., it still possible for a new transaction (even from
same net ns) to find the to-be-deleted expression in the list.

The ->destroy functions are not allowed to have any such side effects,
i.e. the list_del() in the destroy function is not allowed.

This part of the problem is solved in the next patch.
I tried to make this work by serializing list access via mutex
and by moving list_del() to a deactivate callback, but
Taehee spotted following race on this approach:

  NET #0                          NET #1
   >select_ops()
   ->init()
                                   ->select_ops()
   ->deactivate()
   ->destroy()
      nft_xt_put()
       kfree_rcu(xt, rcu_head);
                                   ->init() <-- use-after-free occurred.

Unfortunately, we can't increment reference count in
select_ops(), because we can't undo the refcount increase in
case a different expression fails in the same batch.

(The destroy hook will only be called in case the expression
 was initialized successfully).

Fixes: f102d66b335a ("netfilter: nf_tables: use dedicated mutex to guard transactions")
Reported-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nft_compat.c | 129 +++++++++++++++++++++++++------------
 1 file changed, 89 insertions(+), 40 deletions(-)

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index acc85acad31bd..abed3490a8f8a 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -22,6 +22,7 @@
 #include <linux/netfilter_bridge/ebtables.h>
 #include <linux/netfilter_arp/arp_tables.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netns/generic.h>
 
 struct nft_xt {
 	struct list_head	head;
@@ -43,6 +44,20 @@ struct nft_xt_match_priv {
 	void *info;
 };
 
+struct nft_compat_net {
+	struct list_head nft_target_list;
+	struct list_head nft_match_list;
+};
+
+static unsigned int nft_compat_net_id __read_mostly;
+static struct nft_expr_type nft_match_type;
+static struct nft_expr_type nft_target_type;
+
+static struct nft_compat_net *nft_compat_pernet(struct net *net)
+{
+	return net_generic(net, nft_compat_net_id);
+}
+
 static bool nft_xt_put(struct nft_xt *xt)
 {
 	if (refcount_dec_and_test(&xt->refcnt)) {
@@ -734,10 +749,6 @@ static const struct nfnetlink_subsystem nfnl_compat_subsys = {
 	.cb		= nfnl_nft_compat_cb,
 };
 
-static LIST_HEAD(nft_match_list);
-
-static struct nft_expr_type nft_match_type;
-
 static bool nft_match_cmp(const struct xt_match *match,
 			  const char *name, u32 rev, u32 family)
 {
@@ -749,6 +760,7 @@ static const struct nft_expr_ops *
 nft_match_select_ops(const struct nft_ctx *ctx,
 		     const struct nlattr * const tb[])
 {
+	struct nft_compat_net *cn;
 	struct nft_xt *nft_match;
 	struct xt_match *match;
 	unsigned int matchsize;
@@ -765,8 +777,10 @@ nft_match_select_ops(const struct nft_ctx *ctx,
 	rev = ntohl(nla_get_be32(tb[NFTA_MATCH_REV]));
 	family = ctx->family;
 
+	cn = nft_compat_pernet(ctx->net);
+
 	/* Re-use the existing match if it's already loaded. */
-	list_for_each_entry(nft_match, &nft_match_list, head) {
+	list_for_each_entry(nft_match, &cn->nft_match_list, head) {
 		struct xt_match *match = nft_match->ops.data;
 
 		if (nft_match_cmp(match, mt_name, rev, family))
@@ -810,7 +824,7 @@ nft_match_select_ops(const struct nft_ctx *ctx,
 
 	nft_match->ops.size = matchsize;
 
-	list_add(&nft_match->head, &nft_match_list);
+	list_add(&nft_match->head, &cn->nft_match_list);
 
 	return &nft_match->ops;
 err:
@@ -826,10 +840,6 @@ static struct nft_expr_type nft_match_type __read_mostly = {
 	.owner		= THIS_MODULE,
 };
 
-static LIST_HEAD(nft_target_list);
-
-static struct nft_expr_type nft_target_type;
-
 static bool nft_target_cmp(const struct xt_target *tg,
 			   const char *name, u32 rev, u32 family)
 {
@@ -841,6 +851,7 @@ static const struct nft_expr_ops *
 nft_target_select_ops(const struct nft_ctx *ctx,
 		      const struct nlattr * const tb[])
 {
+	struct nft_compat_net *cn;
 	struct nft_xt *nft_target;
 	struct xt_target *target;
 	char *tg_name;
@@ -861,8 +872,9 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 	    strcmp(tg_name, "standard") == 0)
 		return ERR_PTR(-EINVAL);
 
+	cn = nft_compat_pernet(ctx->net);
 	/* Re-use the existing target if it's already loaded. */
-	list_for_each_entry(nft_target, &nft_target_list, head) {
+	list_for_each_entry(nft_target, &cn->nft_target_list, head) {
 		struct xt_target *target = nft_target->ops.data;
 
 		if (!target->target)
@@ -907,7 +919,7 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 	else
 		nft_target->ops.eval = nft_target_eval_xt;
 
-	list_add(&nft_target->head, &nft_target_list);
+	list_add(&nft_target->head, &cn->nft_target_list);
 
 	return &nft_target->ops;
 err:
@@ -923,13 +935,74 @@ static struct nft_expr_type nft_target_type __read_mostly = {
 	.owner		= THIS_MODULE,
 };
 
+static int __net_init nft_compat_init_net(struct net *net)
+{
+	struct nft_compat_net *cn = nft_compat_pernet(net);
+
+	INIT_LIST_HEAD(&cn->nft_target_list);
+	INIT_LIST_HEAD(&cn->nft_match_list);
+
+	return 0;
+}
+
+static void __net_exit nft_compat_exit_net(struct net *net)
+{
+	struct nft_compat_net *cn = nft_compat_pernet(net);
+	struct nft_xt *xt, *next;
+
+	if (list_empty(&cn->nft_match_list) &&
+	    list_empty(&cn->nft_target_list))
+		return;
+
+	/* If there was an error that caused nft_xt expr to not be initialized
+	 * fully and noone else requested the same expression later, the lists
+	 * contain 0-refcount entries that still hold module reference.
+	 *
+	 * Clean them here.
+	 */
+	mutex_lock(&net->nft.commit_mutex);
+	list_for_each_entry_safe(xt, next, &cn->nft_target_list, head) {
+		struct xt_target *target = xt->ops.data;
+
+		list_del_init(&xt->head);
+
+		if (refcount_read(&xt->refcnt))
+			continue;
+		module_put(target->me);
+		kfree(xt);
+	}
+
+	list_for_each_entry_safe(xt, next, &cn->nft_match_list, head) {
+		struct xt_match *match = xt->ops.data;
+
+		list_del_init(&xt->head);
+
+		if (refcount_read(&xt->refcnt))
+			continue;
+		module_put(match->me);
+		kfree(xt);
+	}
+	mutex_unlock(&net->nft.commit_mutex);
+}
+
+static struct pernet_operations nft_compat_net_ops = {
+	.init	= nft_compat_init_net,
+	.exit	= nft_compat_exit_net,
+	.id	= &nft_compat_net_id,
+	.size	= sizeof(struct nft_compat_net),
+};
+
 static int __init nft_compat_module_init(void)
 {
 	int ret;
 
+	ret = register_pernet_subsys(&nft_compat_net_ops);
+	if (ret < 0)
+		goto err_target;
+
 	ret = nft_register_expr(&nft_match_type);
 	if (ret < 0)
-		return ret;
+		goto err_pernet;
 
 	ret = nft_register_expr(&nft_target_type);
 	if (ret < 0)
@@ -942,45 +1015,21 @@ static int __init nft_compat_module_init(void)
 	}
 
 	return ret;
-
 err_target:
 	nft_unregister_expr(&nft_target_type);
 err_match:
 	nft_unregister_expr(&nft_match_type);
+err_pernet:
+	unregister_pernet_subsys(&nft_compat_net_ops);
 	return ret;
 }
 
 static void __exit nft_compat_module_exit(void)
 {
-	struct nft_xt *xt, *next;
-
-	/* list should be empty here, it can be non-empty only in case there
-	 * was an error that caused nft_xt expr to not be initialized fully
-	 * and noone else requested the same expression later.
-	 *
-	 * In this case, the lists contain 0-refcount entries that still
-	 * hold module reference.
-	 */
-	list_for_each_entry_safe(xt, next, &nft_target_list, head) {
-		struct xt_target *target = xt->ops.data;
-
-		if (WARN_ON_ONCE(refcount_read(&xt->refcnt)))
-			continue;
-		module_put(target->me);
-		kfree(xt);
-	}
-
-	list_for_each_entry_safe(xt, next, &nft_match_list, head) {
-		struct xt_match *match = xt->ops.data;
-
-		if (WARN_ON_ONCE(refcount_read(&xt->refcnt)))
-			continue;
-		module_put(match->me);
-		kfree(xt);
-	}
 	nfnetlink_subsys_unregister(&nfnl_compat_subsys);
 	nft_unregister_expr(&nft_target_type);
 	nft_unregister_expr(&nft_match_type);
+	unregister_pernet_subsys(&nft_compat_net_ops);
 }
 
 MODULE_ALIAS_NFNL_SUBSYS(NFNL_SUBSYS_NFT_COMPAT);
-- 
2.19.1

[PATCH AUTOSEL 4.20 07/72] netfilter: nft_compat: destroy function must not have side effects

[Sasha Levin]

From: Florian Westphal <fw@strlen.de>

[ Upstream commit b2e3d68d1251a051a620f9086e18f7ffa6833b5b ]

The nft_compat destroy function deletes the nft_xt object from a list.
This isn't allowed anymore. Destroy functions are called asynchronously,
i.e. next batch can find the object that has a pending ->destroy()
invocation:

cpu0                       cpu1
 worker
   ->destroy               for_each_entry()
	                     if (x == ...
			        return x->ops;
     list_del(x)
     kfree_rcu(x)
                           expr->ops->... // ops was free'd

To resolve this, the list_del needs to occur before the transaction
mutex gets released.  nf_tables has a 'deactivate' hook for this
purpose, so use that to unlink the object from the list.

Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release")
Reported-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nft_compat.c | 48 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index abed3490a8f8a..5eb269428832c 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -29,6 +29,9 @@ struct nft_xt {
 	struct nft_expr_ops	ops;
 	refcount_t		refcnt;
 
+	/* used only when transaction mutex is locked */
+	unsigned int		listcnt;
+
 	/* Unlike other expressions, ops doesn't have static storage duration.
 	 * nft core assumes they do.  We use kfree_rcu so that nft core can
 	 * can check expr->ops->size even after nft_compat->destroy() frees
@@ -61,7 +64,7 @@ static struct nft_compat_net *nft_compat_pernet(struct net *net)
 static bool nft_xt_put(struct nft_xt *xt)
 {
 	if (refcount_dec_and_test(&xt->refcnt)) {
-		list_del(&xt->head);
+		WARN_ON_ONCE(!list_empty(&xt->head));
 		kfree_rcu(xt, rcu_head);
 		return true;
 	}
@@ -555,6 +558,43 @@ nft_match_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 	__nft_match_destroy(ctx, expr, nft_expr_priv(expr));
 }
 
+static void nft_compat_activate(const struct nft_ctx *ctx,
+				const struct nft_expr *expr,
+				struct list_head *h)
+{
+	struct nft_xt *xt = container_of(expr->ops, struct nft_xt, ops);
+
+	if (xt->listcnt == 0)
+		list_add(&xt->head, h);
+
+	xt->listcnt++;
+}
+
+static void nft_compat_activate_mt(const struct nft_ctx *ctx,
+				   const struct nft_expr *expr)
+{
+	struct nft_compat_net *cn = nft_compat_pernet(ctx->net);
+
+	nft_compat_activate(ctx, expr, &cn->nft_match_list);
+}
+
+static void nft_compat_activate_tg(const struct nft_ctx *ctx,
+				   const struct nft_expr *expr)
+{
+	struct nft_compat_net *cn = nft_compat_pernet(ctx->net);
+
+	nft_compat_activate(ctx, expr, &cn->nft_target_list);
+}
+
+static void nft_compat_deactivate(const struct nft_ctx *ctx,
+				  const struct nft_expr *expr)
+{
+	struct nft_xt *xt = container_of(expr->ops, struct nft_xt, ops);
+
+	if (--xt->listcnt == 0)
+		list_del_init(&xt->head);
+}
+
 static void
 nft_match_large_destroy(const struct nft_ctx *ctx, const struct nft_expr *expr)
 {
@@ -808,6 +848,8 @@ nft_match_select_ops(const struct nft_ctx *ctx,
 	nft_match->ops.eval = nft_match_eval;
 	nft_match->ops.init = nft_match_init;
 	nft_match->ops.destroy = nft_match_destroy;
+	nft_match->ops.activate = nft_compat_activate_mt;
+	nft_match->ops.deactivate = nft_compat_deactivate;
 	nft_match->ops.dump = nft_match_dump;
 	nft_match->ops.validate = nft_match_validate;
 	nft_match->ops.data = match;
@@ -824,6 +866,7 @@ nft_match_select_ops(const struct nft_ctx *ctx,
 
 	nft_match->ops.size = matchsize;
 
+	nft_match->listcnt = 1;
 	list_add(&nft_match->head, &cn->nft_match_list);
 
 	return &nft_match->ops;
@@ -910,6 +953,8 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 	nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
 	nft_target->ops.init = nft_target_init;
 	nft_target->ops.destroy = nft_target_destroy;
+	nft_target->ops.activate = nft_compat_activate_tg;
+	nft_target->ops.deactivate = nft_compat_deactivate;
 	nft_target->ops.dump = nft_target_dump;
 	nft_target->ops.validate = nft_target_validate;
 	nft_target->ops.data = target;
@@ -919,6 +964,7 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 	else
 		nft_target->ops.eval = nft_target_eval_xt;
 
+	nft_target->listcnt = 1;
 	list_add(&nft_target->head, &cn->nft_target_list);
 
 	return &nft_target->ops;
-- 
2.19.1

[PATCH AUTOSEL 4.20 17/72] ipvs: Fix signed integer overflow when setsockopt timeout

[Sasha Levin]

From: ZhangXiaoxu <zhangxiaoxu5@huawei.com>

[ Upstream commit 53ab60baa1ac4f20b080a22c13b77b6373922fd7 ]

There is a UBSAN bug report as below:
UBSAN: Undefined behaviour in net/netfilter/ipvs/ip_vs_ctl.c:2227:21
signed integer overflow:
-2147483647 * 1000 cannot be represented in type 'int'

Reproduce program:
	#include <stdio.h>
	#include <sys/types.h>
	#include <sys/socket.h>

	#define IPPROTO_IP 0
	#define IPPROTO_RAW 255

	#define IP_VS_BASE_CTL		(64+1024+64)
	#define IP_VS_SO_SET_TIMEOUT	(IP_VS_BASE_CTL+10)

	/* The argument to IP_VS_SO_GET_TIMEOUT */
	struct ipvs_timeout_t {
		int tcp_timeout;
		int tcp_fin_timeout;
		int udp_timeout;
	};

	int main() {
		int ret = -1;
		int sockfd = -1;
		struct ipvs_timeout_t to;

		sockfd = socket(AF_INET, SOCK_RAW, IPPROTO_RAW);
		if (sockfd == -1) {
			printf("socket init error\n");
			return -1;
		}

		to.tcp_timeout = -2147483647;
		to.tcp_fin_timeout = -2147483647;
		to.udp_timeout = -2147483647;

		ret = setsockopt(sockfd,
				 IPPROTO_IP,
				 IP_VS_SO_SET_TIMEOUT,
				 (char *)(&to),
				 sizeof(to));

		printf("setsockopt return %d\n", ret);
		return ret;
	}

Return -EINVAL if the timeout value is negative or max than 'INT_MAX / HZ'.

Signed-off-by: ZhangXiaoxu <zhangxiaoxu5@huawei.com>
Acked-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/ipvs/ip_vs_ctl.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 432141f04af3d..7d6318664eb24 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -2220,6 +2220,18 @@ static int ip_vs_set_timeout(struct netns_ipvs *ipvs, struct ip_vs_timeout_user
 		  u->tcp_fin_timeout,
 		  u->udp_timeout);
 
+#ifdef CONFIG_IP_VS_PROTO_TCP
+	if (u->tcp_timeout < 0 || u->tcp_timeout > (INT_MAX / HZ) ||
+	    u->tcp_fin_timeout < 0 || u->tcp_fin_timeout > (INT_MAX / HZ)) {
+		return -EINVAL;
+	}
+#endif
+
+#ifdef CONFIG_IP_VS_PROTO_UDP
+	if (u->udp_timeout < 0 || u->udp_timeout > (INT_MAX / HZ))
+		return -EINVAL;
+#endif
+
 #ifdef CONFIG_IP_VS_PROTO_TCP
 	if (u->tcp_timeout) {
 		pd = ip_vs_proto_data_get(ipvs, IPPROTO_TCP);
-- 
2.19.1

[PATCH AUTOSEL 4.20 37/72] netfilter: ebtables: compat: un-break 32bit setsockopt when no rules are present

[Sasha Levin]

From: Florian Westphal <fw@strlen.de>

[ Upstream commit 2035f3ff8eaa29cfb5c8e2160b0f6e85eeb21a95 ]

Unlike ip(6)tables ebtables only counts user-defined chains.

The effect is that a 32bit ebtables binary on a 64bit kernel can do
'ebtables -N FOO' only after adding at least one rule, else the request
fails with -EINVAL.

This is a similar fix as done in
3f1e53abff84 ("netfilter: ebtables: don't attempt to allocate 0-sized compat array").

Fixes: 7d7d7e02111e9 ("netfilter: compat: reject huge allocation requests")
Reported-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/bridge/netfilter/ebtables.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/net/bridge/netfilter/ebtables.c b/net/bridge/netfilter/ebtables.c
index 5e55cef0cec39..6693e209efe80 100644
--- a/net/bridge/netfilter/ebtables.c
+++ b/net/bridge/netfilter/ebtables.c
@@ -2293,9 +2293,12 @@ static int compat_do_replace(struct net *net, void __user *user,
 
 	xt_compat_lock(NFPROTO_BRIDGE);
 
-	ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
-	if (ret < 0)
-		goto out_unlock;
+	if (tmp.nentries) {
+		ret = xt_compat_init_offsets(NFPROTO_BRIDGE, tmp.nentries);
+		if (ret < 0)
+			goto out_unlock;
+	}
+
 	ret = compat_copy_entries(entries_tmp, tmp.entries_size, &state);
 	if (ret < 0)
 		goto out_unlock;
-- 
2.19.1

[PATCH AUTOSEL 4.20 38/72] netfilter: nfnetlink_osf: add missing fmatch check

[Sasha Levin]

From: Fernando Fernandez Mancera <ffmancera@riseup.net>

[ Upstream commit 1a6a0951fc009f6d9fe8ebea2d2417d80d54097b ]

When we check the tcp options of a packet and it doesn't match the current
fingerprint, the tcp packet option pointer must be restored to its initial
value in order to do the proper tcp options check for the next fingerprint.

Here we can see an example.
Assumming the following fingerprint base with two lines:

S10:64:1:60:M*,S,T,N,W6:      Linux:3.0::Linux 3.0
S20:64:1:60:M*,S,T,N,W7:      Linux:4.19:arch:Linux 4.1

Where TCP options are the last field in the OS signature, all of them overlap
except by the last one, ie. 'W6' versus 'W7'.

In case a packet for Linux 4.19 kicks in, the osf finds no matching because the
TCP options pointer is updated after checking for the TCP options in the first
line.

Therefore, reset pointer back to where it should be.

Fixes: 11eeef41d5f6 ("netfilter: passive OS fingerprint xtables match")
Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/netfilter/nfnetlink_osf.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/netfilter/nfnetlink_osf.c b/net/netfilter/nfnetlink_osf.c
index 6f41dd74729d9..1f1d90c1716b5 100644
--- a/net/netfilter/nfnetlink_osf.c
+++ b/net/netfilter/nfnetlink_osf.c
@@ -66,6 +66,7 @@ static bool nf_osf_match_one(const struct sk_buff *skb,
 			     int ttl_check,
 			     struct nf_osf_hdr_ctx *ctx)
 {
+	const __u8 *optpinit = ctx->optp;
 	unsigned int check_WSS = 0;
 	int fmatch = FMATCH_WRONG;
 	int foptsize, optnum;
@@ -155,6 +156,9 @@ static bool nf_osf_match_one(const struct sk_buff *skb,
 		}
 	}
 
+	if (fmatch != FMATCH_OK)
+		ctx->optp = optpinit;
+
 	return fmatch == FMATCH_OK;
 }
 
-- 
2.19.1