src: add support for new secmark object

The new object will hold security context strings.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

6 files changed, 186 insertions, 1 deletions

diff --git a/include/libnftnl/object.h b/include/libnftnl/object.h
index 0279705..4ce2230 100644
--- a/include/libnftnl/object.h
+++ b/include/libnftnl/object.h
@@ -97,6 +97,10 @@ enum {
 	NFTNL_OBJ_TUNNEL_ERSPAN_V2_DIR,
 };
 
+enum {
+	NFTNL_OBJ_SECMARK_CTX	= NFTNL_OBJ_BASE,
+};
+
 struct nftnl_obj;
 
 struct nftnl_obj *nftnl_obj_alloc(void);
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index da2c291..f2ee638 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -1161,6 +1161,21 @@ enum nft_quota_attributes {
 #define NFTA_QUOTA_MAX		(__NFTA_QUOTA_MAX - 1)
 
 /**
+ * enum nft_secmark_attributes - nf_tables secmark expression netlink attributes
+ *
+ * @NFTA_SECMARK_CTX: security context (NLA_STRING)
+ */
+enum nft_secmark_attributes {
+	NFTA_SECMARK_UNSPEC,
+	NFTA_SECMARK_CTX,
+	__NFTA_SECMARK_MAX,
+};
+#define NFTA_SECMARK_MAX	(__NFTA_SECMARK_MAX - 1)
+
+/* Max security context length */
+#define NFT_SECMARK_CTX_MAXLEN		256
+
+/**
  * enum nft_reject_types - nf_tables reject expression reject types
  *
  * @NFT_REJECT_ICMP_UNREACH: reject using ICMP unreachable
@@ -1416,7 +1431,8 @@ enum nft_ct_timeout_attributes {
 #define NFT_OBJECT_CONNLIMIT	5
 #define NFT_OBJECT_TUNNEL	6
 #define NFT_OBJECT_CT_TIMEOUT	7
-#define __NFT_OBJECT_MAX	8
+#define NFT_OBJECT_SECMARK	8
+#define __NFT_OBJECT_MAX	9
 #define NFT_OBJECT_MAX		(__NFT_OBJECT_MAX - 1)
 
 /**
diff --git a/include/obj.h b/include/obj.h
index 26184da..435d8a0 100644
--- a/include/obj.h
+++ b/include/obj.h
@@ -77,6 +77,9 @@ struct nftnl_obj {
 				} tun_erspan;
 			} u;
 		} tunnel;
+		struct nftnl_obj_secmark {
+			char		ctx[NFT_SECMARK_CTX_MAXLEN];
+		} secmark;
 	} data;
 };
 
@@ -100,6 +103,7 @@ extern struct obj_ops obj_ops_ct_helper;
 extern struct obj_ops obj_ops_ct_timeout;
 extern struct obj_ops obj_ops_limit;
 extern struct obj_ops obj_ops_tunnel;
+extern struct obj_ops obj_ops_secmark;
 
 #define nftnl_obj_data(obj) (void *)&obj->data
 
diff --git a/src/Makefile.am b/src/Makefile.am
index 05dbeaa..90704e6 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -66,4 +66,5 @@ libnftnl_la_SOURCES = utils.c		\
 		      obj/tunnel.c	\
 		      obj/limit.c	\
 		      obj/ct_timeout.c 	\
+		      obj/secmark.c	\
 		      libnftnl.map
diff --git a/src/obj/secmark.c b/src/obj/secmark.c
new file mode 100644
index 0000000..f68cb3e
--- /dev/null
+++ b/src/obj/secmark.c
@@ -0,0 +1,159 @@
+/*
+ * (C) 2012-2016 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <inttypes.h>
+
+#include <linux/netfilter/nf_tables.h>
+
+#include "internal.h"
+#include <libmnl/libmnl.h>
+#include <libnftnl/object.h>
+
+#include "obj.h"
+
+static int nftnl_obj_secmark_set(struct nftnl_obj *e, uint16_t type,
+				const void *data, uint32_t data_len)
+{
+	struct nftnl_obj_secmark *secmark = nftnl_obj_data(e);
+
+	switch (type) {
+	case NFTNL_OBJ_SECMARK_CTX:
+		snprintf(secmark->ctx, sizeof(secmark->ctx), "%s", (const char *)data);
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *nftnl_obj_secmark_get(const struct nftnl_obj *e,
+					uint16_t type, uint32_t *data_len)
+{
+	struct nftnl_obj_secmark *secmark = nftnl_obj_data(e);
+
+	switch (type) {
+	case NFTNL_OBJ_SECMARK_CTX:
+		*data_len = strlen(secmark->ctx);
+		return secmark->ctx;
+	}
+	return NULL;
+}
+
+static int nftnl_obj_secmark_cb(const struct nlattr *attr, void *data)
+{
+	const struct nftnl_obj_secmark *secmark = NULL;
+	int type = mnl_attr_get_type(attr);
+	const struct nlattr **tb = data;
+
+	if (mnl_attr_type_valid(attr, NFTA_SECMARK_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTA_SECMARK_CTX:
+		if (mnl_attr_validate(attr, MNL_TYPE_STRING) < 0)
+			abi_breakage();
+		if (mnl_attr_get_payload_len(attr) >= sizeof(secmark->ctx))
+			abi_breakage();
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nftnl_obj_secmark_build(struct nlmsghdr *nlh, const struct nftnl_obj *e)
+{
+	struct nftnl_obj_secmark *secmark = nftnl_obj_data(e);
+
+	if (e->flags & (1 << NFTNL_OBJ_SECMARK_CTX))
+		mnl_attr_put_str(nlh, NFTA_SECMARK_CTX, secmark->ctx);
+}
+
+static int
+nftnl_obj_secmark_parse(struct nftnl_obj *e, struct nlattr *attr)
+{
+	struct nftnl_obj_secmark *secmark = nftnl_obj_data(e);
+	struct nlattr *tb[NFTA_SECMARK_MAX + 1] = {};
+
+	if (mnl_attr_parse_nested(attr, nftnl_obj_secmark_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_SECMARK_CTX]) {
+		snprintf(secmark->ctx, sizeof(secmark->ctx), "%s",
+			 mnl_attr_get_str(tb[NFTA_SECMARK_CTX]));
+		e->flags |= (1 << NFTNL_OBJ_SECMARK_CTX);
+	}
+
+	return 0;
+}
+
+static int
+nftnl_obj_secmark_json_parse(struct nftnl_obj *e, json_t *root,
+				 struct nftnl_parse_err *err)
+{
+	errno = EOPNOTSUPP;
+	return -1;
+}
+
+static int nftnl_obj_secmark_export(char *buf, size_t size,
+				    const struct nftnl_obj *e, int type)
+{
+	struct nftnl_obj_secmark *secmark = nftnl_obj_data(e);
+	NFTNL_BUF_INIT(b, buf, size);
+
+	if (e->flags & (1 << NFTNL_OBJ_SECMARK_CTX))
+		nftnl_buf_str(&b, type, secmark->ctx, NAME);
+
+	return nftnl_buf_done(&b);
+}
+
+static int nftnl_obj_secmark_snprintf_default(char *buf, size_t len,
+					       const struct nftnl_obj *e)
+{
+	struct nftnl_obj_secmark *secmark = nftnl_obj_data(e);
+
+	return snprintf(buf, len, "context %s ", secmark->ctx);
+}
+
+static int nftnl_obj_secmark_snprintf(char *buf, size_t len, uint32_t type,
+				       uint32_t flags,
+				       const struct nftnl_obj *e)
+{
+	if (len)
+		buf[0] = '\0';
+
+	switch (type) {
+	case NFTNL_OUTPUT_DEFAULT:
+		return nftnl_obj_secmark_snprintf_default(buf, len, e);
+	case NFTNL_OUTPUT_XML:
+	case NFTNL_OUTPUT_JSON:
+		return nftnl_obj_secmark_export(buf, len, e, type);
+	default:
+		break;
+	}
+	return -1;
+}
+
+struct obj_ops obj_ops_secmark = {
+	.name		= "secmark",
+	.type		= NFT_OBJECT_SECMARK,
+	.alloc_len	= sizeof(struct nftnl_obj_secmark),
+	.max_attr	= NFTA_SECMARK_MAX,
+	.set		= nftnl_obj_secmark_set,
+	.get		= nftnl_obj_secmark_get,
+	.parse		= nftnl_obj_secmark_parse,
+	.build		= nftnl_obj_secmark_build,
+	.snprintf	= nftnl_obj_secmark_snprintf,
+	.json_parse	= nftnl_obj_secmark_json_parse,
+};
diff --git a/src/object.c b/src/object.c
index 434f999..f62395d 100644
--- a/src/object.c
+++ b/src/object.c
@@ -32,6 +32,7 @@ static struct obj_ops *obj_ops[] = {
 	[NFT_OBJECT_LIMIT]	= &obj_ops_limit,
 	[NFT_OBJECT_TUNNEL]	= &obj_ops_tunnel,
 	[NFT_OBJECT_CT_TIMEOUT] = &obj_ops_ct_timeout,
+	[NFT_OBJECT_SECMARK]	= &obj_ops_secmark,
 };
 
 static struct obj_ops *nftnl_obj_ops_lookup(uint32_t type)