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

Pablo Neira Ayuso says:

====================
netfilter fixes for net

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

1) Fix missing MODULE_LICENSE() in the new nf_reject_ipv{4,6} modules.

2) Restrict nat and masq expressions to the nat chain type. Otherwise,
   users may crash their kernel if they attach a nat/masq rule to a non
   nat chain.

3) Fix hook validation in nft_compat when non-base chains are used.
   Basically, initialize hook_mask to zero.

4) Make sure you use match/targets in nft_compat from the right chain
   type. The existing validation relies on the table name which can be
   avoided by

5) Better netlink attribute validation in nft_nat. This expression has
   to reject the configuration when no address and proto configurations
   are specified.

6) Interpret NFTA_NAT_REG_*_MAX if only if NFTA_NAT_REG_*_MIN is set.
   Yet another sanity check to reject incorrect configurations from
   userspace.

7) Conditional NAT attribute dumping depending on the existing
   configuration.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 150 insertions, 41 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 556a0dfa4abc..65eb2a1160d5 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -3744,6 +3744,20 @@ static const struct nfnetlink_subsystem nf_tables_subsys = {
 	.abort		= nf_tables_abort,
 };
 
+int nft_chain_validate_dependency(const struct nft_chain *chain,
+				  enum nft_chain_type type)
+{
+	const struct nft_base_chain *basechain;
+
+	if (chain->flags & NFT_BASE_CHAIN) {
+		basechain = nft_base_chain(chain);
+		if (basechain->type->type != type)
+			return -EOPNOTSUPP;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nft_chain_validate_dependency);
+
 /*
  * Loop detection - walk through the ruleset beginning at the destination chain
  * of a new jump until either the source chain is reached (loop) or all
diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 7e2683c8a44a..0480f57a4eb6 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -19,9 +19,52 @@
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv6/ip6_tables.h>
-#include <asm/uaccess.h> /* for set_fs */
 #include <net/netfilter/nf_tables.h>
 
+static const struct {
+       const char	*name;
+       u8		type;
+} table_to_chaintype[] = {
+       { "filter",     NFT_CHAIN_T_DEFAULT },
+       { "raw",        NFT_CHAIN_T_DEFAULT },
+       { "security",   NFT_CHAIN_T_DEFAULT },
+       { "mangle",     NFT_CHAIN_T_ROUTE },
+       { "nat",        NFT_CHAIN_T_NAT },
+       { },
+};
+
+static int nft_compat_table_to_chaintype(const char *table)
+{
+	int i;
+
+	for (i = 0; table_to_chaintype[i].name != NULL; i++) {
+		if (strcmp(table_to_chaintype[i].name, table) == 0)
+			return table_to_chaintype[i].type;
+	}
+
+	return -1;
+}
+
+static int nft_compat_chain_validate_dependency(const char *tablename,
+						const struct nft_chain *chain)
+{
+	enum nft_chain_type type;
+	const struct nft_base_chain *basechain;
+
+	if (!tablename || !(chain->flags & NFT_BASE_CHAIN))
+		return 0;
+
+	type = nft_compat_table_to_chaintype(tablename);
+	if (type < 0)
+		return -EINVAL;
+
+	basechain = nft_base_chain(chain);
+	if (basechain->type->type != type)
+		return -EINVAL;
+
+	return 0;
+}
+
 union nft_entry {
 	struct ipt_entry e4;
 	struct ip6t_entry e6;
@@ -95,6 +138,8 @@ nft_target_set_tgchk_param(struct xt_tgchk_param *par,
 		const struct nf_hook_ops *ops = &basechain->ops[0];
 
 		par->hook_mask = 1 << ops->hooknum;
+	} else {
+		par->hook_mask = 0;
 	}
 	par->family	= ctx->afi->family;
 }
@@ -151,6 +196,10 @@ nft_target_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 	union nft_entry e = {};
 	int ret;
 
+	ret = nft_compat_chain_validate_dependency(target->table, ctx->chain);
+	if (ret < 0)
+		goto err;
+
 	target_compat_from_user(target, nla_data(tb[NFTA_TARGET_INFO]), info);
 
 	if (ctx->nla[NFTA_RULE_COMPAT]) {
@@ -216,6 +265,7 @@ static int nft_target_validate(const struct nft_ctx *ctx,
 {
 	struct xt_target *target = expr->ops->data;
 	unsigned int hook_mask = 0;
+	int ret;
 
 	if (ctx->chain->flags & NFT_BASE_CHAIN) {
 		const struct nft_base_chain *basechain =
@@ -223,11 +273,13 @@ static int nft_target_validate(const struct nft_ctx *ctx,
 		const struct nf_hook_ops *ops = &basechain->ops[0];
 
 		hook_mask = 1 << ops->hooknum;
-		if (hook_mask & target->hooks)
-			return 0;
+		if (!(hook_mask & target->hooks))
+			return -EINVAL;
 
-		/* This target is being called from an invalid chain */
-		return -EINVAL;
+		ret = nft_compat_chain_validate_dependency(target->table,
+							   ctx->chain);
+		if (ret < 0)
+			return ret;
 	}
 	return 0;
 }
@@ -293,6 +345,8 @@ nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
 		const struct nf_hook_ops *ops = &basechain->ops[0];
 
 		par->hook_mask = 1 << ops->hooknum;
+	} else {
+		par->hook_mask = 0;
 	}
 	par->family	= ctx->afi->family;
 }
@@ -320,6 +374,10 @@ nft_match_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 	union nft_entry e = {};
 	int ret;
 
+	ret = nft_compat_chain_validate_dependency(match->name, ctx->chain);
+	if (ret < 0)
+		goto err;
+
 	match_compat_from_user(match, nla_data(tb[NFTA_MATCH_INFO]), info);
 
 	if (ctx->nla[NFTA_RULE_COMPAT]) {
@@ -379,6 +437,7 @@ static int nft_match_validate(const struct nft_ctx *ctx,
 {
 	struct xt_match *match = expr->ops->data;
 	unsigned int hook_mask = 0;
+	int ret;
 
 	if (ctx->chain->flags & NFT_BASE_CHAIN) {
 		const struct nft_base_chain *basechain =
@@ -386,11 +445,13 @@ static int nft_match_validate(const struct nft_ctx *ctx,
 		const struct nf_hook_ops *ops = &basechain->ops[0];
 
 		hook_mask = 1 << ops->hooknum;
-		if (hook_mask & match->hooks)
-			return 0;
+		if (!(hook_mask & match->hooks))
+			return -EINVAL;
 
-		/* This match is being called from an invalid chain */
-		return -EINVAL;
+		ret = nft_compat_chain_validate_dependency(match->name,
+							   ctx->chain);
+		if (ret < 0)
+			return ret;
 	}
 	return 0;
 }
diff --git a/net/netfilter/nft_masq.c b/net/netfilter/nft_masq.c
index 6637bab00567..d1ffd5eb3a9b 100644
--- a/net/netfilter/nft_masq.c
+++ b/net/netfilter/nft_masq.c
@@ -26,6 +26,11 @@ int nft_masq_init(const struct nft_ctx *ctx,
 		  const struct nlattr * const tb[])
 {
 	struct nft_masq *priv = nft_expr_priv(expr);
+	int err;
+
+	err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
+	if (err < 0)
+		return err;
 
 	if (tb[NFTA_MASQ_FLAGS] == NULL)
 		return 0;
@@ -55,5 +60,12 @@ nla_put_failure:
 }
 EXPORT_SYMBOL_GPL(nft_masq_dump);
 
+int nft_masq_validate(const struct nft_ctx *ctx, const struct nft_expr *expr,
+		      const struct nft_data **data)
+{
+	return nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
+}
+EXPORT_SYMBOL_GPL(nft_masq_validate);
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>");
diff --git a/net/netfilter/nft_nat.c b/net/netfilter/nft_nat.c
index 799550b476fb..afe2b0b45ec4 100644
--- a/net/netfilter/nft_nat.c
+++ b/net/netfilter/nft_nat.c
@@ -95,7 +95,13 @@ static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 	u32 family;
 	int err;
 
-	if (tb[NFTA_NAT_TYPE] == NULL)
+	err = nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
+	if (err < 0)
+		return err;
+
+	if (tb[NFTA_NAT_TYPE] == NULL ||
+	    (tb[NFTA_NAT_REG_ADDR_MIN] == NULL &&
+	     tb[NFTA_NAT_REG_PROTO_MIN] == NULL))
 		return -EINVAL;
 
 	switch (ntohl(nla_get_be32(tb[NFTA_NAT_TYPE]))) {
@@ -120,38 +126,44 @@ static int nft_nat_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
 	priv->family = family;
 
 	if (tb[NFTA_NAT_REG_ADDR_MIN]) {
-		priv->sreg_addr_min = ntohl(nla_get_be32(
-						tb[NFTA_NAT_REG_ADDR_MIN]));
+		priv->sreg_addr_min =
+			ntohl(nla_get_be32(tb[NFTA_NAT_REG_ADDR_MIN]));
+
 		err = nft_validate_input_register(priv->sreg_addr_min);
 		if (err < 0)
 			return err;
-	}
 
-	if (tb[NFTA_NAT_REG_ADDR_MAX]) {
-		priv->sreg_addr_max = ntohl(nla_get_be32(
-						tb[NFTA_NAT_REG_ADDR_MAX]));
-		err = nft_validate_input_register(priv->sreg_addr_max);
-		if (err < 0)
-			return err;
-	} else
-		priv->sreg_addr_max = priv->sreg_addr_min;
+		if (tb[NFTA_NAT_REG_ADDR_MAX]) {
+			priv->sreg_addr_max =
+				ntohl(nla_get_be32(tb[NFTA_NAT_REG_ADDR_MAX]));
+
+			err = nft_validate_input_register(priv->sreg_addr_max);
+			if (err < 0)
+				return err;
+		} else {
+			priv->sreg_addr_max = priv->sreg_addr_min;
+		}
+	}
 
 	if (tb[NFTA_NAT_REG_PROTO_MIN]) {
-		priv->sreg_proto_min = ntohl(nla_get_be32(
-						tb[NFTA_NAT_REG_PROTO_MIN]));
+		priv->sreg_proto_min =
+			ntohl(nla_get_be32(tb[NFTA_NAT_REG_PROTO_MIN]));
+
 		err = nft_validate_input_register(priv->sreg_proto_min);
 		if (err < 0)
 			return err;
-	}
 
-	if (tb[NFTA_NAT_REG_PROTO_MAX]) {
-		priv->sreg_proto_max = ntohl(nla_get_be32(
-						tb[NFTA_NAT_REG_PROTO_MAX]));
-		err = nft_validate_input_register(priv->sreg_proto_max);
-		if (err < 0)
-			return err;
-	} else
-		priv->sreg_proto_max = priv->sreg_proto_min;
+		if (tb[NFTA_NAT_REG_PROTO_MAX]) {
+			priv->sreg_proto_max =
+				ntohl(nla_get_be32(tb[NFTA_NAT_REG_PROTO_MAX]));
+
+			err = nft_validate_input_register(priv->sreg_proto_max);
+			if (err < 0)
+				return err;
+		} else {
+			priv->sreg_proto_max = priv->sreg_proto_min;
+		}
+	}
 
 	if (tb[NFTA_NAT_FLAGS]) {
 		priv->flags = ntohl(nla_get_be32(tb[NFTA_NAT_FLAGS]));
@@ -179,17 +191,19 @@ static int nft_nat_dump(struct sk_buff *skb, const struct nft_expr *expr)
 
 	if (nla_put_be32(skb, NFTA_NAT_FAMILY, htonl(priv->family)))
 		goto nla_put_failure;
-	if (nla_put_be32(skb,
-			 NFTA_NAT_REG_ADDR_MIN, htonl(priv->sreg_addr_min)))
-		goto nla_put_failure;
-	if (nla_put_be32(skb,
-			 NFTA_NAT_REG_ADDR_MAX, htonl(priv->sreg_addr_max)))
-		goto nla_put_failure;
+
+	if (priv->sreg_addr_min) {
+		if (nla_put_be32(skb, NFTA_NAT_REG_ADDR_MIN,
+				 htonl(priv->sreg_addr_min)) ||
+		    nla_put_be32(skb, NFTA_NAT_REG_ADDR_MAX,
+				 htonl(priv->sreg_addr_max)))
+			goto nla_put_failure;
+	}
+
 	if (priv->sreg_proto_min) {
 		if (nla_put_be32(skb, NFTA_NAT_REG_PROTO_MIN,
-				 htonl(priv->sreg_proto_min)))
-			goto nla_put_failure;
-		if (nla_put_be32(skb, NFTA_NAT_REG_PROTO_MAX,
+				 htonl(priv->sreg_proto_min)) ||
+		    nla_put_be32(skb, NFTA_NAT_REG_PROTO_MAX,
 				 htonl(priv->sreg_proto_max)))
 			goto nla_put_failure;
 	}
@@ -205,6 +219,13 @@ nla_put_failure:
 	return -1;
 }
 
+static int nft_nat_validate(const struct nft_ctx *ctx,
+			    const struct nft_expr *expr,
+			    const struct nft_data **data)
+{
+	return nft_chain_validate_dependency(ctx->chain, NFT_CHAIN_T_NAT);
+}
+
 static struct nft_expr_type nft_nat_type;
 static const struct nft_expr_ops nft_nat_ops = {
 	.type           = &nft_nat_type,
@@ -212,6 +233,7 @@ static const struct nft_expr_ops nft_nat_ops = {
 	.eval           = nft_nat_eval,
 	.init           = nft_nat_init,
 	.dump           = nft_nat_dump,
+	.validate	= nft_nat_validate,
 };
 
 static struct nft_expr_type nft_nat_type __read_mostly = {