Finish crypto wrapping. Also provide wrappers for OpenSSL.

Disable libgcrypt by default. Since it doesn't support the OFB cipher mode,
we can't use it in a backwards compatible way.

src/openssl/cipher.c

@@ -0,0 +1,182 @@
+/*
+    cipher.c -- Symmetric block cipher handling
+    Copyright (C) 2007 Guus Sliepen <guus@tinc-vpn.org>
+
+    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.
+
+    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.
+
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    $Id$
+*/
+
+#include "system.h"
+
+#include <openssl/rand.h>
+#include <openssl/err.h>
+
+#include "cipher.h"
+#include "logger.h"
+#include "xalloc.h"
+
+static bool cipher_open(cipher_t *cipher) {
+	cipher->keylen = cipher->cipher->key_len;
+	cipher->blklen = cipher->cipher->iv_len;
+
+	cipher->key = xmalloc(cipher->keylen + cipher->blklen);
+
+	EVP_CIPHER_CTX_init(&cipher->ctx);
+
+	return true;
+}
+
+bool cipher_open_by_name(cipher_t *cipher, const char *name) {
+	cipher->cipher = EVP_get_cipherbyname(name);
+
+	if(cipher->cipher)
+		return cipher_open(cipher);
+
+	logger(LOG_DEBUG, _("Unknown cipher name '%s'!"), name);
+	return false;
+}
+
+bool cipher_open_by_nid(cipher_t *cipher, int nid) {
+	cipher->cipher = EVP_get_cipherbynid(nid);
+
+	if(cipher->cipher)
+		return cipher_open(cipher);
+
+	logger(LOG_DEBUG, _("Unknown cipher nid %d!"), nid);
+	return false;
+}
+
+bool cipher_open_blowfish_ofb(cipher_t *cipher) {
+	cipher->cipher = EVP_bf_ofb();
+	return cipher_open(cipher);
+}
+
+void cipher_close(cipher_t *cipher) {
+	EVP_CIPHER_CTX_cleanup(&cipher->ctx);
+
+	if(cipher->key) {
+		free(cipher->key);
+		cipher->key = NULL;
+	}
+}
+
+size_t cipher_keylength(const cipher_t *cipher) {
+	return cipher->keylen + cipher->blklen;
+}
+
+void cipher_get_key(const cipher_t *cipher, void *key) {
+	memcpy(key, cipher->key, cipher->keylen + cipher->blklen);
+}
+
+bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) {
+	memcpy(cipher->key, key, cipher->keylen + cipher->blklen);
+	bool result;
+
+	if(encrypt)
+		result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+	else
+		result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+
+	if(result)
+		return true;
+
+	logger(LOG_ERR, _("Error while setting key: %s"), ERR_error_string(ERR_get_error(), NULL));
+	return false;
+}
+
+bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encrypt) {
+	memcpy(cipher->key, key + len - (size_t)cipher->keylen, cipher->keylen);
+	memcpy(cipher->key + cipher->keylen, key + len - (size_t)cipher->keylen - (size_t)cipher->blklen, cipher->blklen);
+	bool result;
+
+	if(encrypt)
+		result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+	else
+		result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+
+	if(result)
+		return true;
+
+	logger(LOG_ERR, _("Error while setting key: %s"), ERR_error_string(ERR_get_error(), NULL));
+	return false;
+}
+
+bool cipher_regenerate_key(cipher_t *cipher, bool encrypt) {
+	bool result;
+
+	RAND_pseudo_bytes((unsigned char *)cipher->key, cipher->keylen + cipher->blklen);
+
+	if(encrypt)
+		result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+	else
+		result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)cipher->key, (unsigned char *)cipher->key + cipher->keylen);
+
+	if(result)
+		return true;
+	
+	logger(LOG_ERR, _("Error while regenerating key: %s"), ERR_error_string(ERR_get_error(), NULL));
+	return false;
+}
+
+bool cipher_encrypt(cipher_t *cipher, void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
+	if(oneshot) {
+		int len = *outlen, pad;
+		if(EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, NULL)
+				&&EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)
+				&& EVP_EncryptFinal(&cipher->ctx, outdata + len, &pad)) {
+			*outlen = len + pad;
+			return true;
+		}
+	} else {
+		int len = *outlen;
+		if(EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)) {
+			*outlen = len;
+			return true;
+		}
+	}
+
+	logger(LOG_ERR, _("Error while encrypting: %s"), ERR_error_string(ERR_get_error(), NULL));
+	return false;
+}
+
+bool cipher_decrypt(cipher_t *cipher, void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
+	if(oneshot) {
+		int len = *outlen, pad;
+		if(EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, NULL)
+				&& EVP_DecryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)
+				&& EVP_DecryptFinal(&cipher->ctx, outdata + len, &pad)) {
+			*outlen = len + pad;
+			return true;
+		}
+	} else {
+		int len = *outlen;
+		if(EVP_EncryptUpdate(&cipher->ctx, outdata, &len, indata, inlen)) {
+			*outlen = len;
+			return true;
+		}
+	}
+
+	logger(LOG_ERR, _("Error while encrypting: %s"), ERR_error_string(ERR_get_error(), NULL));
+	return false;
+}
+
+int cipher_get_nid(const cipher_t *cipher) {
+	return cipher->cipher ? cipher->cipher->nid : 0;
+}
+
+bool cipher_active(const cipher_t *cipher) {
+	return cipher->cipher && cipher->cipher->nid != 0;
+}