Implement generic PKCS#7 contentInfo parsing

src/libstrongswan/plugins/pkcs7/Makefile.am

@@ -10,6 +10,7 @@ plugin_LTLIBRARIES = libstrongswan-pkcs7.la
 endif
 
 libstrongswan_pkcs7_la_SOURCES = \
+	pkcs7_generic.h pkcs7_generic.c \
 	pkcs7_plugin.h pkcs7_plugin.c
 
 libstrongswan_pkcs7_la_LDFLAGS = -module -avoid-version

src/libstrongswan/plugins/pkcs7/pkcs7_generic.c

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ * Copyright (C) 2012 Tobias Brunner
+ * Copyright (C) 2002-2008 Andreas Steffen
+ * Copyright (C) 2005 Jan Hutter, Martin Willi
+ * Hochschule fuer Technik Rapperswil, Switzerland
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+#include "pkcs7_generic.h"
+
+#include <utils/debug.h>
+#include <asn1/oid.h>
+#include <asn1/asn1.h>
+#include <asn1/asn1_parser.h>
+
+/**
+ * ASN.1 definition of the PKCS#7 ContentInfo type
+ */
+static const asn1Object_t contentInfoObjects[] = {
+	{ 0, "contentInfo",		ASN1_SEQUENCE,		ASN1_NONE }, /* 0 */
+	{ 1,   "contentType",	ASN1_OID,			ASN1_BODY }, /* 1 */
+	{ 1,   "content",		ASN1_CONTEXT_C_0,	ASN1_OPT |
+												ASN1_BODY }, /* 2 */
+	{ 1,   "end opt",		ASN1_EOC,			ASN1_END  }, /* 3 */
+	{ 0, "exit",			ASN1_EOC,			ASN1_EXIT }
+};
+#define PKCS7_INFO_TYPE		1
+#define PKCS7_INFO_CONTENT	2
+
+/**
+ * Parse PKCS#7 contentInfo object
+ */
+static pkcs7_t* parse_contentInfo(chunk_t blob)
+{
+	asn1_parser_t *parser;
+	chunk_t object, content = chunk_empty;
+	int objectID, type = OID_UNKNOWN;
+	bool success = FALSE;
+
+	parser = asn1_parser_create(contentInfoObjects, blob);
+	parser->set_top_level(parser, 0);
+
+	while (parser->iterate(parser, &objectID, &object))
+	{
+		if (objectID == PKCS7_INFO_TYPE)
+		{
+			type = asn1_known_oid(object);
+			if (type < OID_PKCS7_DATA || type > OID_PKCS7_ENCRYPTED_DATA)
+			{
+				DBG1(DBG_ASN, "unknown pkcs7 content type");
+				goto end;
+			}
+		}
+		else if (objectID == PKCS7_INFO_CONTENT)
+		{
+			content = object;
+		}
+	}
+	success = parser->success(parser);
+
+end:
+	parser->destroy(parser);
+
+	if (success)
+	{
+		switch (type)
+		{
+			default:
+				DBG1(DBG_ASN, "pkcs7 content type %d not supported", type);
+				return NULL;
+		}
+	}
+	return NULL;
+}
+
+
+pkcs7_t *pkcs7_generic_load(container_type_t type, va_list args)
+{
+	chunk_t blob = chunk_empty;
+
+	while (TRUE)
+	{
+		switch (va_arg(args, builder_part_t))
+		{
+			case BUILD_BLOB_ASN1_DER:
+				blob = va_arg(args, chunk_t);
+				continue;
+			case BUILD_END:
+				break;
+			default:
+				return NULL;
+		}
+		break;
+	}
+	if (blob.len)
+	{
+		return parse_contentInfo(blob);
+	}
+	return NULL;
+}

src/libstrongswan/plugins/pkcs7/pkcs7_generic.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2012 Martin Willi
+ * Copyright (C) 2012 revosec AG
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ */
+
+/**
+ * @defgroup pkcs7_generic pkcs7_generic
+ * @{ @ingroup pkcs7
+ */
+
+#ifndef PKCS7_GENERIC_H_
+#define PKCS7_GENERIC_H_
+
+#include <credentials/builder.h>
+#include <credentials/containers/pkcs7.h>
+
+/**
+ * Load a generic PKCS#7 container.
+ *
+ * The argument list must contain a single BUILD_BLOB_ASN1_DER argument.
+ *
+ * @param type		type of the container, CONTAINER_PKCS7
+ * @param args		builder_part_t argument list
+ * @return			container, NULL on failure
+ */
+pkcs7_t *pkcs7_generic_load(container_type_t type, va_list args);
+
+#endif /** PKCS7_GENERIC_H_ @}*/

src/libstrongswan/plugins/pkcs7/pkcs7_plugin.c

@@ -14,6 +14,7 @@
  */
 
 #include "pkcs7_plugin.h"
+#include "pkcs7_generic.h"
 
 #include <library.h>
 
@@ -40,6 +41,8 @@ METHOD(plugin_t, get_features, int,
 	private_pkcs7_plugin_t *this, plugin_feature_t *features[])
 {
 	static plugin_feature_t f[] = {
+		PLUGIN_REGISTER(CONTAINER_DECODE, pkcs7_generic_load, TRUE),
+			PLUGIN_PROVIDE(CONTAINER_DECODE, CONTAINER_PKCS7),
 	};
 	*features = f;
 	return countof(f);