1 files changed, 512 insertions, 0 deletions
diff --git a/src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.c b/src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.c
new file mode 100644
index 000000000..8024f58a7
--- /dev/null
+++ b/src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.c
@@ -0,0 +1,512 @@
+/*
+ * Copyright (C) 2005-2009 Martin Willi
+ * 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 <gcrypt.h>
+
+#include "gcrypt_rsa_public_key.h"
+
+#include <debug.h>
+#include <asn1/oid.h>
+#include <asn1/asn1.h>
+#include <asn1/asn1_parser.h>
+#include <asn1/pem.h>
+#include <crypto/hashers/hasher.h>
+
+typedef struct private_gcrypt_rsa_public_key_t private_gcrypt_rsa_public_key_t;
+
+/**
+ * Private data structure with signing context.
+ */
+struct private_gcrypt_rsa_public_key_t {
+	
+	/**
+	 * Public interface for this signer.
+	 */
+	gcrypt_rsa_public_key_t public;
+	
+	/**
+	 * gcrypt S-expression representing an public RSA key
+	 */
+	gcry_sexp_t key;
+	
+	/**
+	 * Keyid formed as a SHA-1 hash of a publicKey object
+	 */
+	identification_t* keyid;
+	
+	/**
+	 * Keyid formed as a SHA-1 hash of a publicKeyInfo object
+	 */
+	identification_t* keyid_info;
+	
+	/**
+	 * reference counter
+	 */
+	refcount_t ref;
+};
+
+/**
+ * Implemented in gcrypt_rsa_private_key.c
+ */
+chunk_t gcrypt_rsa_find_token(gcry_sexp_t sexp, char *name);
+bool gcrypt_rsa_build_keyids(gcry_sexp_t key, identification_t **keyid,
+							 identification_t **keyid_info);
+
+/**
+ * verification of a padded PKCS1 signature without an OID
+ */
+static bool verify_raw(private_gcrypt_rsa_public_key_t *this,
+						 chunk_t data, chunk_t signature)
+{
+	gcry_sexp_t in, sig;
+	gcry_error_t err;
+	chunk_t em;
+	size_t k;
+	
+	/* EM = 0x00 || 0x01 || PS || 0x00 || T
+	 * PS = 0xFF padding, with length to fill em
+	 * T  = data
+	 */
+	k = gcry_pk_get_nbits(this->key) / 8;
+	if (data.len > k - 3)
+	{
+		return FALSE;
+	}
+	em = chunk_alloc(k);
+	memset(em.ptr, 0xFF, em.len);
+	em.ptr[0] = 0x00;
+	em.ptr[1] = 0x01;
+	em.ptr[em.len - data.len - 1] = 0x00;
+	memcpy(em.ptr + em.len - data.len, data.ptr, data.len);
+	
+	err = gcry_sexp_build(&in, NULL, "(data(flags raw)(value %b))",
+						  em.len, em.ptr);
+	chunk_free(&em);
+	if (err)
+	{
+		DBG1("building data S-expression failed: %s", gpg_strerror(err));
+		return FALSE;
+	}
+	err = gcry_sexp_build(&sig, NULL, "(sig-val(rsa(s %b)))",
+						  signature.len, signature.ptr);
+	if (err)
+	{
+		DBG1("building signature S-expression failed: %s", gpg_strerror(err));
+		gcry_sexp_release(in);
+		return FALSE;
+	}
+	err = gcry_pk_verify(sig, in, this->key);
+	gcry_sexp_release(in);
+	gcry_sexp_release(sig);
+	if (err)
+	{
+		DBG1("RSA signature verification failed: %s", gpg_strerror(err));
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * Verification of an EMSA PKCS1 signature described in PKCS#1
+ */
+static bool verify_pkcs1(private_gcrypt_rsa_public_key_t *this,
+						 hash_algorithm_t algorithm, char *hash_name,
+						 chunk_t data, chunk_t signature)
+{
+	hasher_t *hasher;
+	chunk_t hash;
+	gcry_error_t err;
+	gcry_sexp_t in, sig;
+	
+	hasher = lib->crypto->create_hasher(lib->crypto, algorithm);
+	if (!hasher)
+	{
+		return FALSE;
+	}
+	hasher->allocate_hash(hasher, data, &hash);
+	hasher->destroy(hasher);
+	
+	err = gcry_sexp_build(&in, NULL, "(data(flags pkcs1)(hash %s %b))",
+						  hash_name, hash.len, hash.ptr);
+	chunk_free(&hash);
+	if (err)
+	{
+		DBG1("building data S-expression failed: %s", gpg_strerror(err));
+		return FALSE;
+	}
+	
+	err = gcry_sexp_build(&sig, NULL, "(sig-val(rsa(s %b)))",
+						  signature.len, signature.ptr);
+	if (err)
+	{
+		DBG1("building signature S-expression failed: %s", gpg_strerror(err));
+		gcry_sexp_release(in);
+		return FALSE;
+	}
+	err = gcry_pk_verify(sig, in, this->key);
+	gcry_sexp_release(in);
+	gcry_sexp_release(sig);
+	if (err)
+	{
+		DBG1("RSA signature verification failed: %s", gpg_strerror(err));
+		return FALSE;
+	}
+	return TRUE;
+}
+
+/**
+ * Implementation of public_key_t.get_type.
+ */
+static key_type_t get_type(private_gcrypt_rsa_public_key_t *this)
+{
+	return KEY_RSA;
+}
+
+/**
+ * Implementation of public_key_t.verify.
+ */
+static bool verify(private_gcrypt_rsa_public_key_t *this,
+				   signature_scheme_t scheme, chunk_t data, chunk_t signature)
+{
+	switch (scheme)
+	{
+		case SIGN_RSA_EMSA_PKCS1_NULL:
+			return verify_raw(this, data, signature);
+		case SIGN_RSA_EMSA_PKCS1_MD5:
+			return verify_pkcs1(this, HASH_MD5, "md5", data, signature);
+		case SIGN_RSA_EMSA_PKCS1_SHA1:
+			return verify_pkcs1(this, HASH_SHA1, "sha1", data, signature);
+		case SIGN_RSA_EMSA_PKCS1_SHA256:
+			return verify_pkcs1(this, HASH_SHA256, "sha256", data, signature);
+		case SIGN_RSA_EMSA_PKCS1_SHA384:
+			return verify_pkcs1(this, HASH_SHA384, "sha384", data, signature);
+		case SIGN_RSA_EMSA_PKCS1_SHA512:
+			return verify_pkcs1(this, HASH_SHA512, "sha512", data, signature);
+		default:
+			DBG1("signature scheme %N not supported in RSA",
+				 signature_scheme_names, scheme);
+			return FALSE;
+	}
+}
+
+/**
+ * Implementation of public_key_t.encrypt.
+ */
+static bool encrypt_(private_gcrypt_rsa_public_key_t *this, chunk_t plain,
+					 chunk_t *encrypted)
+{
+	gcry_sexp_t in, out;
+	gcry_error_t err;
+	
+	/* "pkcs1" uses PKCS 1.5 (section 8.1) block type 2 encryption:
+	 * 00 | 02 | RANDOM | 00 | DATA */
+	err = gcry_sexp_build(&in, NULL, "(data(flags pkcs1)(value %b))",
+						  plain.len, plain.ptr);
+	if (err)
+	{
+		DBG1("building encryption S-expression failed: %s", gpg_strerror(err));
+		return FALSE;
+	}
+	err = gcry_pk_encrypt(&out, in, this->key);
+	gcry_sexp_release(in);
+	if (err)
+	{
+		DBG1("encrypting data using pkcs1 failed: %s", gpg_strerror(err));
+		return FALSE;
+	}
+	*encrypted = gcrypt_rsa_find_token(out, "a");
+	gcry_sexp_release(out);
+	return !!encrypted->len;
+}
+
+/**
+ * Implementation of gcrypt_rsa_public_key.equals.
+ */
+static bool equals(private_gcrypt_rsa_public_key_t *this, public_key_t *other)
+{
+	identification_t *keyid;
+
+	if (&this->public.interface == other)
+	{
+		return TRUE;
+	}
+	if (other->get_type(other) != KEY_RSA)
+	{
+		return FALSE;
+	}
+	keyid = other->get_id(other, ID_PUBKEY_SHA1);
+	if (keyid && keyid->equals(keyid, this->keyid))
+	{
+		return TRUE;
+	}
+	keyid = other->get_id(other, ID_PUBKEY_INFO_SHA1);
+	if (keyid && keyid->equals(keyid, this->keyid_info))
+	{
+		return TRUE;
+	}
+	return FALSE;
+}
+
+/**
+ * Implementation of public_key_t.get_keysize.
+ */
+static size_t get_keysize(private_gcrypt_rsa_public_key_t *this)
+{
+	return gcry_pk_get_nbits(this->key) / 8;
+}
+
+/**
+ * Implementation of public_key_t.get_id.
+ */
+static identification_t *get_id(private_gcrypt_rsa_public_key_t *this,
+								id_type_t type)
+{
+	switch (type)
+	{
+		case ID_PUBKEY_INFO_SHA1:
+			return this->keyid_info;
+		case ID_PUBKEY_SHA1:
+			return this->keyid;
+		default:
+			return NULL;
+	}
+}
+
+/*
+ * Implementation of public_key_t.get_encoding.
+ */
+static chunk_t get_encoding(private_gcrypt_rsa_public_key_t *this)
+{
+	return asn1_wrap(ASN1_SEQUENCE, "mm",
+			asn1_integer("m", gcrypt_rsa_find_token(this->key, "n")),
+			asn1_integer("m", gcrypt_rsa_find_token(this->key, "e")));
+}
+
+/**
+ * Implementation of public_key_t.get_ref.
+ */
+static public_key_t* get_ref(private_gcrypt_rsa_public_key_t *this)
+{
+	ref_get(&this->ref);
+	return &this->public.interface;
+}
+
+/**
+ * Implementation of gcrypt_rsa_public_key.destroy.
+ */
+static void destroy(private_gcrypt_rsa_public_key_t *this)
+{
+	if (ref_put(&this->ref))
+	{
+		DESTROY_IF(this->keyid);
+		DESTROY_IF(this->keyid_info);
+		gcry_sexp_release(this->key);
+		free(this);
+	}
+}
+
+/**
+ * Generic private constructor
+ */
+static private_gcrypt_rsa_public_key_t *gcrypt_rsa_public_key_create_empty()
+{
+	private_gcrypt_rsa_public_key_t *this = malloc_thing(private_gcrypt_rsa_public_key_t);
+	
+	this->public.interface.get_type = (key_type_t (*)(public_key_t *this))get_type;
+	this->public.interface.verify = (bool (*)(public_key_t *this, signature_scheme_t scheme, chunk_t data, chunk_t signature))verify;
+	this->public.interface.encrypt = (bool (*)(public_key_t *this, chunk_t crypto, chunk_t *plain))encrypt_;
+	this->public.interface.equals = (bool (*) (public_key_t*, public_key_t*))equals;
+	this->public.interface.get_keysize = (size_t (*) (public_key_t *this))get_keysize;
+	this->public.interface.get_id = (identification_t* (*) (public_key_t *this,id_type_t))get_id;
+	this->public.interface.get_encoding = (chunk_t(*)(public_key_t*))get_encoding;
+	this->public.interface.get_ref = (public_key_t* (*)(public_key_t *this))get_ref;
+	this->public.interface.destroy = (void (*)(public_key_t *this))destroy;
+	
+	this->key = NULL;
+	this->keyid = NULL;
+	this->keyid_info = NULL;
+	this->ref = 1;
+	
+	return this;
+}
+
+/**
+ * Create a public key from a S-expression, used in gcrypt_rsa_private_key
+ */
+public_key_t *gcrypt_rsa_public_key_create_from_sexp(gcry_sexp_t key)
+{
+	private_gcrypt_rsa_public_key_t *this;
+	gcry_error_t err;
+	chunk_t n, e;
+	
+	this = gcrypt_rsa_public_key_create_empty();
+	n = gcrypt_rsa_find_token(key, "n");
+	e = gcrypt_rsa_find_token(key, "e");
+	
+	err = gcry_sexp_build(&this->key, NULL, "(public-key(rsa(n %b)(e %b)))",
+						  n.len, n.ptr, e.len, e.ptr);
+	chunk_free(&n);
+	chunk_free(&e);
+	if (err)
+	{
+		DBG1("loading public key failed: %s", gpg_strerror(err));
+		free(this);
+		return NULL;
+	}
+	if (!gcrypt_rsa_build_keyids(this->key, &this->keyid, &this->keyid_info))
+	{
+		destroy(this);
+		return NULL;
+	}
+	return &this->public.interface;
+}
+
+/**
+ * ASN.1 definition of RSApublicKey
+ */
+static const asn1Object_t pubkeyObjects[] = {
+	{ 0, "RSAPublicKey",		ASN1_SEQUENCE,	ASN1_OBJ  }, /*  0 */
+	{ 1,   "modulus",			ASN1_INTEGER,	ASN1_BODY }, /*  1 */
+	{ 1,   "publicExponent",	ASN1_INTEGER,	ASN1_BODY }, /*  2 */
+	{ 0, "exit",				ASN1_EOC,		ASN1_EXIT }
+};
+#define PUB_KEY_RSA_PUBLIC_KEY		0
+#define PUB_KEY_MODULUS				1
+#define PUB_KEY_EXPONENT			2
+
+/**
+ * Load a public key from an ASN1 encoded blob
+ */
+static gcrypt_rsa_public_key_t *load(chunk_t blob)
+{
+	private_gcrypt_rsa_public_key_t *this;
+	asn1_parser_t *parser;
+	chunk_t object, n, e;
+	int objectID;
+	bool success = FALSE;
+	gcry_error_t err;
+	
+	n = e = chunk_empty;
+	
+	parser = asn1_parser_create(pubkeyObjects, blob);
+	while (parser->iterate(parser, &objectID, &object))
+	{
+		switch (objectID)
+		{
+			case PUB_KEY_MODULUS:
+				n = object;
+				break;
+			case PUB_KEY_EXPONENT:
+				e = object;
+				break;
+		}
+	}
+	success = parser->success(parser);
+	parser->destroy(parser);
+	
+	if (!success)
+	{
+		return NULL;
+	}
+	
+	this = gcrypt_rsa_public_key_create_empty();
+	err = gcry_sexp_build(&this->key, NULL, "(public-key(rsa(n %b)(e %b)))",
+						  n.len, n.ptr, e.len, e.ptr);
+	if (err)
+	{
+		DBG1("loading public key failed: %s", gpg_strerror(err));
+		free(this);
+		return NULL;
+	}
+	if (!gcrypt_rsa_build_keyids(this->key, &this->keyid, &this->keyid_info))
+	{
+		destroy(this);
+		return NULL;
+	}
+	return &this->public;
+}
+
+typedef struct private_builder_t private_builder_t;
+/**
+ * Builder implementation for key loading
+ */
+struct private_builder_t {
+	/** implements the builder interface */
+	builder_t public;
+	/** loaded public key */
+	gcrypt_rsa_public_key_t *key;
+};
+
+/**
+ * Implementation of builder_t.build
+ */
+static gcrypt_rsa_public_key_t *build(private_builder_t *this)
+{
+	gcrypt_rsa_public_key_t *key = this->key;
+	
+	free(this);
+	return key;
+}
+
+/**
+ * Implementation of builder_t.add
+ */
+static void add(private_builder_t *this, builder_part_t part, ...)
+{
+	if (!this->key)
+	{
+		va_list args;
+		
+		switch (part)
+		{
+			case BUILD_BLOB_ASN1_DER:
+			{
+				va_start(args, part);
+				this->key = load(va_arg(args, chunk_t));
+				va_end(args);
+				return;
+			}
+			default:
+				break;
+		}
+	}
+	if (this->key)
+	{
+		destroy((private_gcrypt_rsa_public_key_t*)this->key);
+	}
+	builder_cancel(&this->public);
+}
+
+/**
+ * Builder construction function
+ */
+builder_t *gcrypt_rsa_public_key_builder(key_type_t type)
+{
+	private_builder_t *this;
+	
+	if (type != KEY_RSA)
+	{
+		return NULL;
+	}
+	
+	this = malloc_thing(private_builder_t);
+	
+	this->key = NULL;
+	this->public.add = (void(*)(builder_t *this, builder_part_t part, ...))add;
+	this->public.build = (void*(*)(builder_t *this))build;
+	
+	return &this->public;
+}
+