-/*
- cipher.c -- Symmetric block cipher handling
- Copyright (C) 2014 Guus Sliepen <guus@meshlink.io>
-
- 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;
- struct cipher_counter *counter;
-};
-
-typedef struct cipher_counter {
- unsigned char counter[CIPHER_MAX_IV_SIZE];
- unsigned char block[CIPHER_MAX_IV_SIZE];
- int n;
-} cipher_counter_t;
-
-static cipher_t *cipher_open(const EVP_CIPHER *evp_cipher) {
- cipher_t *cipher = xzalloc(sizeof *cipher);
- cipher->cipher = evp_cipher;
- EVP_CIPHER_CTX_init(&cipher->ctx);
-
- 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_cleanup(&cipher->ctx);
- free(cipher->counter);
- free(cipher);
-}
-
-size_t cipher_keylength(const cipher_t *cipher) {
- if(!cipher || !cipher->cipher)
- return 0;
-
- return cipher->cipher->key_len + cipher->cipher->iv_len;
-}
-
-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 + cipher->cipher->key_len);
- else
- result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, (unsigned char *)key + cipher->cipher->key_len);
-
- 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 - cipher->cipher->key_len, (unsigned char *)key + len - cipher->cipher->iv_len - cipher->cipher->key_len);
- else
- result = EVP_DecryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key + len - cipher->cipher->key_len, (unsigned char *)key + len - cipher->cipher->iv_len - cipher->cipher->key_len);
-
- 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_counter(cipher_t *cipher, const void *counter, size_t len) {
- if(len > cipher->cipher->iv_len - 4) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Counter too long");
- return false;
- }
-
- memcpy(cipher->counter->counter, counter, len);
- cipher->counter->n = 0;
-
- return true;
-}
-
-bool cipher_set_counter_key(cipher_t *cipher, void *key) {
- int result = EVP_EncryptInit_ex(&cipher->ctx, cipher->cipher, NULL, (unsigned char *)key, NULL);
- if(!result) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while setting key: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
-
- if(!cipher->counter)
- cipher->counter = xzalloc(sizeof *cipher->counter);
- else
- cipher->counter->n = 0;
-
- memcpy(cipher->counter->counter, (unsigned char *)key + cipher->cipher->key_len, cipher->cipher->iv_len);
-
- return true;
-}
-
-bool cipher_gcm_encrypt_start(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
- int len = 0;
- if(!EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter)
- || (inlen && !EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen))) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
- if(outlen)
- *outlen = len;
- return true;
-}
-
-bool cipher_gcm_encrypt_finish(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
- int len = 0, pad = 0;
- if((inlen && !EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen))
- || !EVP_EncryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
- EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_GET_TAG, 16, (unsigned char *)outdata + len + pad);
- if(outlen)
- *outlen = len + pad + 16;
- return true;
-}
-
-bool cipher_gcm_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
- int len = 0, pad = 0;
- if(!EVP_EncryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter) ||
- !EVP_EncryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen) ||
- !EVP_EncryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
- EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_GET_TAG, 16, (unsigned char *)outdata + len + pad);
- if(outlen)
- *outlen = len + pad + 16;
- return true;
-}
-
-bool cipher_gcm_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
- if(inlen < 16)
- return false;
-
- int len = 0, pad = 0;
- if(!EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
-
- EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_SET_TAG, 16, (unsigned char *)indata + inlen - 16);
-
- if(!EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen - 16) ||
- !EVP_DecryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
- if(outlen)
- *outlen = len;
- return true;
-}
-
-bool cipher_gcm_decrypt_start(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
- int len = 0;
- if(!EVP_DecryptInit_ex(&cipher->ctx, NULL, NULL, NULL, cipher->counter->counter)
- || (inlen && !EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen))) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
- if(outlen)
- *outlen = len;
- return true;
-}
-
-bool cipher_gcm_decrypt_finish(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen) {
- if(inlen < 16)
- return false;
-
- EVP_CIPHER_CTX_ctrl(&cipher->ctx, EVP_CTRL_GCM_SET_TAG, 16, (unsigned char *)indata + inlen - 16);
-
- int len = 0, pad = 0;
- if((inlen > 16 && !EVP_DecryptUpdate(&cipher->ctx, (unsigned char *)outdata, &len, (unsigned char *)indata, inlen - 16))
- || !EVP_DecryptFinal(&cipher->ctx, (unsigned char *)outdata + len, &pad)) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", ERR_error_string(ERR_get_error(), NULL));
- return false;
- }
- return true;
-}
-
-
-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 cipher->cipher->nid;
-}
-
-bool cipher_active(const cipher_t *cipher) {
- return cipher && cipher->cipher && cipher->cipher->nid != 0;
-}