botan: Add support for Ed25519 keys

2018-10-26 11:06:45 +02:00
parent 5cd24d26e2
commit 4bcc4bacd4
9 changed files with 635 additions and 2 deletions
@@ -0,0 +1,279 @@
+/*
+ * Copyright (C) 2018 Tobias Brunner
+ * HSR Hochschule fuer Technik Rapperswil
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "botan_ed_private_key.h"
+#include "botan_ed_public_key.h"
+#include "botan_util.h"
+
+#include <botan/build.h>
+
+#ifdef BOTAN_HAS_ED25519
+
+#include <asn1/asn1.h>
+#include <utils/debug.h>
+
+typedef struct private_private_key_t private_private_key_t;
+
+#define ED25519_KEY_LEN 32
+
+/**
+ * Private data
+ */
+struct private_private_key_t {
+
+	/**
+	 * Public interface
+	 */
+	private_key_t public;
+
+	/**
+	 * Botan private key object
+	 */
+	botan_privkey_t key;
+
+	/**
+	 * Reference count
+	 */
+	refcount_t ref;
+};
+
+METHOD(private_key_t, sign, bool,
+	private_private_key_t *this, signature_scheme_t scheme,
+	void *params, chunk_t data, chunk_t *signature)
+{
+	switch (scheme)
+	{
+		case SIGN_ED25519:
+			return botan_get_signature(this->key, "Pure", data, signature);
+		default:
+			DBG1(DBG_LIB, "signature scheme %N not supported via botan",
+				 signature_scheme_names, scheme);
+			return FALSE;
+	}
+}
+
+METHOD(private_key_t, decrypt, bool,
+	private_private_key_t *this, encryption_scheme_t scheme,
+	chunk_t crypto, chunk_t *plain)
+{
+	DBG1(DBG_LIB, "EdDSA private key decryption not implemented");
+	return FALSE;
+}
+
+METHOD(private_key_t, get_keysize, int,
+	private_private_key_t *this)
+{
+	return ED25519_KEY_LEN * 8;
+}
+
+METHOD(private_key_t, get_type, key_type_t,
+	private_private_key_t *this)
+{
+	return KEY_ED25519;
+}
+
+METHOD(private_key_t, get_public_key, public_key_t*,
+	private_private_key_t *this)
+{
+	botan_pubkey_t pubkey;
+
+	if (botan_privkey_export_pubkey(&pubkey, this->key))
+	{
+		return NULL;
+	}
+	return botan_ed_public_key_adopt(pubkey);
+}
+
+METHOD(private_key_t, get_fingerprint, bool,
+	private_private_key_t *this, cred_encoding_type_t type,
+	chunk_t *fingerprint)
+{
+	botan_pubkey_t pubkey;
+	bool success = FALSE;
+
+	/* check the cache before doing the export */
+	if (lib->encoding->get_cache(lib->encoding, type, this, fingerprint))
+	{
+		return TRUE;
+	}
+
+	if (botan_privkey_export_pubkey(&pubkey, this->key))
+	{
+		return FALSE;
+	}
+	success = botan_get_fingerprint(pubkey, this, type, fingerprint);
+	botan_pubkey_destroy(pubkey);
+	return success;
+}
+
+METHOD(private_key_t, get_encoding, bool,
+	private_private_key_t *this, cred_encoding_type_t type,
+	chunk_t *encoding)
+{
+	return botan_get_privkey_encoding(this->key, type, encoding);
+}
+
+METHOD(private_key_t, get_ref, private_key_t*,
+	private_private_key_t *this)
+{
+	ref_get(&this->ref);
+	return &this->public;
+}
+
+METHOD(private_key_t, destroy, void,
+	private_private_key_t *this)
+{
+	if (ref_put(&this->ref))
+	{
+		lib->encoding->clear_cache(lib->encoding, this);
+		botan_privkey_destroy(this->key);
+		free(this);
+	}
+}
+
+/**
+ * Internal generic constructor
+ */
+static private_private_key_t *create_empty()
+{
+	private_private_key_t *this;
+
+	INIT(this,
+		.public = {
+			.get_type = _get_type,
+			.sign = _sign,
+			.decrypt = _decrypt,
+			.get_keysize = _get_keysize,
+			.get_public_key = _get_public_key,
+			.equals = private_key_equals,
+			.belongs_to = private_key_belongs_to,
+			.get_fingerprint = _get_fingerprint,
+			.has_fingerprint = private_key_has_fingerprint,
+			.get_encoding = _get_encoding,
+			.get_ref = _get_ref,
+			.destroy = _destroy,
+		},
+		.ref = 1,
+	);
+
+	return this;
+}
+
+/*
+ * Described in header
+ */
+private_key_t *botan_ed_private_key_adopt(botan_privkey_t key)
+{
+	private_private_key_t *this;
+
+	this = create_empty();
+	this->key = key;
+
+	return &this->public;
+}
+
+/*
+ * Described in header
+ */
+private_key_t *botan_ed_private_key_gen(key_type_t type, va_list args)
+{
+	private_private_key_t *this;
+	botan_rng_t rng;
+
+	while (TRUE)
+	{
+		switch (va_arg(args, builder_part_t))
+		{
+			case BUILD_KEY_SIZE:
+				/* just ignore the key size */
+				va_arg(args, u_int);
+				continue;
+			case BUILD_END:
+				break;
+			default:
+				return NULL;
+		}
+		break;
+	}
+
+	if (botan_rng_init(&rng, "system"))
+	{
+		return NULL;
+	}
+
+	this = create_empty();
+
+	if (botan_privkey_create(&this->key, "Ed25519", NULL, rng))
+	{
+		DBG1(DBG_LIB, "EdDSA private key generation failed");
+		botan_rng_destroy(rng);
+		free(this);
+		return NULL;
+	}
+
+	botan_rng_destroy(rng);
+	return &this->public;
+}
+
+/*
+ * Described in header
+ */
+private_key_t *botan_ed_private_key_load(key_type_t type, va_list args)
+{
+	private_private_key_t *this;
+	chunk_t key = chunk_empty;
+
+	while (TRUE)
+	{
+		switch (va_arg(args, builder_part_t))
+		{
+			case BUILD_EDDSA_PRIV_ASN1_DER:
+				key = va_arg(args, chunk_t);
+				continue;
+			case BUILD_END:
+				break;
+			default:
+				return NULL;
+		}
+		break;
+	}
+
+	/* PKCS#8-encoded keys are handled generically, so we only handle the
+	 * explicit case */
+	if (asn1_unwrap(&key, &key) != ASN1_OCTET_STRING ||
+		key.len != ED25519_KEY_LEN)
+	{
+		return NULL;
+	}
+
+	this = create_empty();
+
+	if (botan_privkey_load_ed25519(&this->key, key.ptr))
+	{
+		free(this);
+		return NULL;
+	}
+	return &this->public;
+}
+
+#endif