tinc/src/openssl/cipher.c
2019-08-26 13:44:52 +02:00

172 lines
5.1 KiB
C

/*
cipher.c -- Symmetric block cipher handling
Copyright (C) 2007-2013 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.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "../system.h"
#include <openssl/rand.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include "../cipher.h"
#include "../logger.h"
#include "../xalloc.h"
struct cipher {
EVP_CIPHER_CTX *ctx;
const EVP_CIPHER *cipher;
};
static cipher_t *cipher_open(const EVP_CIPHER *evp_cipher) {
cipher_t *cipher = xzalloc(sizeof *cipher);
cipher->cipher = evp_cipher;
cipher->ctx = EVP_CIPHER_CTX_new();
if(!cipher->ctx)
abort();
return cipher;
}
cipher_t *cipher_open_by_name(const char *name) {
const EVP_CIPHER *evp_cipher = EVP_get_cipherbyname(name);
if(!evp_cipher) {
logger(DEBUG_ALWAYS, LOG_ERR, "Unknown cipher name '%s'!", name);
return NULL;
}
return cipher_open(evp_cipher);
}
cipher_t *cipher_open_by_nid(int nid) {
const EVP_CIPHER *evp_cipher = EVP_get_cipherbynid(nid);
if(!evp_cipher) {
logger(DEBUG_ALWAYS, LOG_ERR, "Unknown cipher nid %d!", nid);
return NULL;
}
return cipher_open(evp_cipher);
}
cipher_t *cipher_open_blowfish_ofb(void) {
return cipher_open(EVP_bf_ofb());
}
void cipher_close(cipher_t *cipher) {
if(!cipher)
return;
EVP_CIPHER_CTX_free(cipher->ctx);
free(cipher);
}
size_t cipher_keylength(const cipher_t *cipher) {
if(!cipher || !cipher->cipher)
return 0;
return EVP_CIPHER_key_length(cipher->cipher) + EVP_CIPHER_iv_length(cipher->cipher);
}
size_t cipher_blocksize(const cipher_t *cipher) {
if(!cipher || !cipher->cipher)
return 1;
return EVP_CIPHER_block_size(cipher->cipher);
}
bool cipher_set_key(cipher_t *cipher, void *key, bool encrypt) {
bool result;
if(encrypt)
result = EVP_EncryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher));
else
result = EVP_DecryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + EVP_CIPHER_key_length(cipher->cipher));
if(result)
return true;
logger(DEBUG_ALWAYS, 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) {
bool result;
if(encrypt)
result = EVP_EncryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - EVP_CIPHER_key_length(cipher->cipher), (unsigned char *)key + len - EVP_CIPHER_iv_length(cipher->cipher) - EVP_CIPHER_key_length(cipher->cipher));
else
result = EVP_DecryptInit_ex(cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - EVP_CIPHER_key_length(cipher->cipher), (unsigned char *)key + len - EVP_CIPHER_iv_length(cipher->cipher) - EVP_CIPHER_key_length(cipher->cipher));
if(result)
return true;
logger(DEBUG_ALWAYS, LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL));
return false;
}
bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
if(oneshot) {
int len, pad;
if(EVP_EncryptInit_ex(cipher->ctx, NULL, NULL, NULL, NULL)
&& EVP_EncryptUpdate(cipher->ctx, (unsigned char *)outdata, &len, indata, inlen)
&& EVP_EncryptFinal(cipher->ctx, (unsigned char *)outdata + len, &pad)) {
if(outlen) *outlen = len + pad;
return true;
}
} else {
int len;
if(EVP_EncryptUpdate(cipher->ctx, outdata, &len, indata, inlen)) {
if(outlen) *outlen = len;
return true;
}
}
logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
return false;
}
bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
if(oneshot) {
int len, pad;
if(EVP_DecryptInit_ex(cipher->ctx, NULL, NULL, NULL, NULL)
&& EVP_DecryptUpdate(cipher->ctx, (unsigned char *)outdata, &len, indata, inlen)
&& EVP_DecryptFinal(cipher->ctx, (unsigned char *)outdata + len, &pad)) {
if(outlen) *outlen = len + pad;
return true;
}
} else {
int len;
if(EVP_EncryptUpdate(cipher->ctx, outdata, &len, indata, inlen)) {
if(outlen) *outlen = len;
return true;
}
}
logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
return false;
}
int cipher_get_nid(const cipher_t *cipher) {
if(!cipher || !cipher->cipher)
return 0;
return EVP_CIPHER_nid(cipher->cipher);
}
bool cipher_active(const cipher_t *cipher) {
return cipher && cipher->cipher && EVP_CIPHER_nid(cipher->cipher) != 0;
}