Parse RSA private keys from PKCS#8 encoded blobs.

2012-02-01 18:27:45 +01:00
parent 5ec525c1d1
commit 9255aa87ec
4 changed files with 151 additions and 1 deletions
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2012 Tobias Brunner
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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 "pkcs8_builder.h"
+
+#include <debug.h>
+#include <asn1/oid.h>
+#include <asn1/asn1.h>
+#include <asn1/asn1_parser.h>
+#include <credentials/keys/private_key.h>
+
+/**
+ * ASN.1 definition of a privateKeyInfo structure
+ */
+static const asn1Object_t pkinfoObjects[] = {
+	{ 0, "privateKeyInfo",			ASN1_SEQUENCE,		ASN1_NONE	}, /* 0 */
+	{ 1,   "version",				ASN1_INTEGER,		ASN1_BODY	}, /* 1 */
+	{ 1,   "privateKeyAlgorithm",	ASN1_EOC,			ASN1_RAW	}, /* 2 */
+	{ 1,   "privateKey",			ASN1_OCTET_STRING,	ASN1_BODY	}, /* 3 */
+	{ 1,   "attributes",			ASN1_CONTEXT_C_0,	ASN1_OPT	}, /* 4 */
+	{ 1,   "end opt",				ASN1_EOC,			ASN1_END	}, /* 5 */
+	{ 0, "exit",					ASN1_EOC,			ASN1_EXIT	}
+};
+#define PKINFO_PRIVATE_KEY_ALGORITHM	2
+#define PKINFO_PRIVATE_KEY				3
+
+/**
+ * Load a generic private key from an ASN.1 encoded blob
+ */
+static private_key_t *parse_private_key(chunk_t blob)
+{
+	asn1_parser_t *parser;
+	chunk_t object;
+	int objectID;
+	private_key_t *key = NULL;
+	key_type_t type = KEY_ANY;
+
+	parser = asn1_parser_create(pkinfoObjects, blob);
+	parser->set_flags(parser, FALSE, TRUE);
+
+	while (parser->iterate(parser, &objectID, &object))
+	{
+		switch (objectID)
+		{
+			case PKINFO_PRIVATE_KEY_ALGORITHM:
+			{
+				int oid = asn1_parse_algorithmIdentifier(object,
+										parser->get_level(parser) + 1, NULL);
+
+				if (oid == OID_RSA_ENCRYPTION)
+				{
+					type = KEY_RSA;
+				}
+				else
+				{	/* key type not supported */
+					goto end;
+				}
+				break;
+			}
+			case PKINFO_PRIVATE_KEY:
+			{
+				DBG2(DBG_ASN, "-- > --");
+				key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY, type,
+										 BUILD_BLOB_ASN1_DER, object, BUILD_END);
+				DBG2(DBG_ASN, "-- < --");
+				break;
+			}
+		}
+	}
+
+end:
+	parser->destroy(parser);
+	return key;
+}
+
+/**
+ * See header.
+ */
+private_key_t *pkcs8_private_key_load(key_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;
+	}
+	return parse_private_key(blob);
+}
+