gcrypt RSA public key implementation
authorMartin Willi <martin@strongswan.org>
Mon, 8 Jun 2009 09:45:32 +0000 (11:45 +0200)
committerMartin Willi <martin@strongswan.org>
Tue, 9 Jun 2009 09:27:26 +0000 (11:27 +0200)
src/libstrongswan/plugins/gcrypt/Makefile.am
src/libstrongswan/plugins/gcrypt/gcrypt_plugin.c
src/libstrongswan/plugins/gcrypt/gcrypt_rsa_private_key.c
src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.c [new file with mode: 0644]
src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.h [new file with mode: 0644]

index cf251b8..72cc409 100644 (file)
@@ -6,6 +6,7 @@ AM_CFLAGS = -rdynamic $(LIBGCRYPT_CFLAGS)
 plugin_LTLIBRARIES = libstrongswan-gcrypt.la
 
 libstrongswan_gcrypt_la_SOURCES = gcrypt_plugin.h gcrypt_plugin.c \
+       gcrypt_rsa_public_key.h gcrypt_rsa_public_key.c \
        gcrypt_rsa_private_key.h gcrypt_rsa_private_key.c \
        gcrypt_dh.h gcrypt_dh.c \
        gcrypt_rng.h gcrypt_rng.c \
index f1ccf0f..18e26e7 100644 (file)
@@ -20,6 +20,7 @@
 #include "gcrypt_rng.h"
 #include "gcrypt_dh.h"
 #include "gcrypt_rsa_private_key.h"
+#include "gcrypt_rsa_public_key.h"
 
 #include <library.h>
 #include <debug.h>
@@ -107,6 +108,8 @@ static void destroy(private_gcrypt_plugin_t *this)
                                        (dh_constructor_t)gcrypt_dh_create);
        lib->creds->remove_builder(lib->creds,
                                        (builder_constructor_t)gcrypt_rsa_private_key_builder);
+       lib->creds->remove_builder(lib->creds,
+                                       (builder_constructor_t)gcrypt_rsa_public_key_builder);
        free(this);
 }
 
@@ -200,6 +203,8 @@ plugin_t *plugin_create()
        /* RSA */
        lib->creds->add_builder(lib->creds, CRED_PRIVATE_KEY, KEY_RSA,
                                        (builder_constructor_t)gcrypt_rsa_private_key_builder);
+       lib->creds->add_builder(lib->creds, CRED_PUBLIC_KEY, KEY_RSA,
+                                       (builder_constructor_t)gcrypt_rsa_public_key_builder);
        
        return &this->public.plugin;
 }
index 8a65eec..4bca5a5 100644 (file)
@@ -56,9 +56,14 @@ struct private_gcrypt_rsa_private_key_t {
 };
 
 /**
+ * Implemented in gcrypt_rsa_public_key.c
+ */
+public_key_t *gcrypt_rsa_public_key_create_from_sexp(gcry_sexp_t key);
+
+/**
  * find a token in a S-expression
  */
-static chunk_t gcrypt_rsa_find_token(gcry_sexp_t sexp, char *name)
+chunk_t gcrypt_rsa_find_token(gcry_sexp_t sexp, char *name)
 {
        gcry_sexp_t token;
        chunk_t data = chunk_empty;
@@ -198,7 +203,7 @@ static identification_t* get_id(private_gcrypt_rsa_private_key_t *this,
  */
 static public_key_t* get_public_key(private_gcrypt_rsa_private_key_t *this)
 {
-       return NULL;
+       return gcrypt_rsa_public_key_create_from_sexp(this->key);
 }
 
 /**
@@ -375,8 +380,8 @@ static private_gcrypt_rsa_private_key_t *gcrypt_rsa_private_key_create_empty()
 /**
  * build the keyids of a private/public key
  */
-static bool gcrypt_rsa_build_keyids(gcry_sexp_t key, identification_t **keyid,
-                                                                       identification_t **keyid_info)
+bool gcrypt_rsa_build_keyids(gcry_sexp_t key, identification_t **keyid,
+                                                        identification_t **keyid_info)
 {
        chunk_t publicKeyInfo, publicKey, hash;
        hasher_t *hasher;
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 (file)
index 0000000..4c84ad6
--- /dev/null
@@ -0,0 +1,436 @@
+/*
+ * 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 an EMPSA 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_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);
+               case SIGN_DEFAULT:
+                       /* parsing hash OID currently not supported by gcrypt, fall */
+               default:
+                       DBG1("signature scheme %N not supported in RSA",
+                                signature_scheme_names, scheme);
+                       return FALSE;
+       }
+}
+
+/**
+ * Implementation of public_key_t.get_keysize.
+ */
+static bool encrypt_(private_gcrypt_rsa_public_key_t *this, chunk_t crypto,
+                                       chunk_t *plain)
+{
+       DBG1("RSA public key encryption not implemented");
+       return FALSE;
+}
+
+/**
+ * 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_wrap(ASN1_INTEGER, "m", gcrypt_rsa_find_token(this->key, "n")),
+                       asn1_wrap(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;
+       
+       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;
+}
+
diff --git a/src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.h b/src/libstrongswan/plugins/gcrypt/gcrypt_rsa_public_key.h
new file mode 100644 (file)
index 0000000..1025472
--- /dev/null
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 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.
+ */
+
+/**
+ * @defgroup gcrypt_rsa_public_key gcrypt_rsa_public_key
+ * @{ @ingroup gcrypt_p
+ */
+
+#ifndef GCRYPT_RSA_PUBLIC_KEY_H_
+#define GCRYPT_RSA_PUBLIC_KEY_H_
+
+typedef struct gcrypt_rsa_public_key_t gcrypt_rsa_public_key_t;
+
+#include <credentials/keys/public_key.h>
+
+/**
+ * public_key_t implementation of RSA algorithm using libgcrypt.
+ */
+struct gcrypt_rsa_public_key_t {
+
+       /**
+        * Implements the public_key_t interface
+        */
+       public_key_t interface;
+};
+
+/**
+ * Create the builder for a public key.
+ *
+ * @param type         type of the key, must be KEY_RSA
+ * @return                     builder instance
+ */
+builder_t *gcrypt_rsa_public_key_builder(key_type_t type);
+
+#endif /** GCRYPT_RSA_PUBLIC_KEY_H_ @}*/