+++ /dev/null
-/*
- cipher.c -- Symmetric block cipher handling
- Copyright (C) 2007-2012 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 "cipher.h"
-#include "logger.h"
-#include "xalloc.h"
-
-static struct {
- const char *name;
- int algo;
- int mode;
- int nid;
-} ciphertable[] = {
- {"none", GCRY_CIPHER_NONE, GCRY_CIPHER_MODE_NONE, 0},
-
- {NULL, GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_ECB, 92},
- {"blowfish", GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_CBC, 91},
- {NULL, GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_CFB, 93},
- {NULL, GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_OFB, 94},
-
- {NULL, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_ECB, 418},
- {"aes", GCRY_CIPHER_AES, GCRY_CIPHER_MODE_CBC, 419},
- {NULL, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_CFB, 421},
- {NULL, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_OFB, 420},
-
- {NULL, GCRY_CIPHER_AES192, GCRY_CIPHER_MODE_ECB, 422},
- {"aes192", GCRY_CIPHER_AES192, GCRY_CIPHER_MODE_CBC, 423},
- {NULL, GCRY_CIPHER_AES192, GCRY_CIPHER_MODE_CFB, 425},
- {NULL, GCRY_CIPHER_AES192, GCRY_CIPHER_MODE_OFB, 424},
-
- {NULL, GCRY_CIPHER_AES256, GCRY_CIPHER_MODE_ECB, 426},
- {"aes256", GCRY_CIPHER_AES256, GCRY_CIPHER_MODE_CBC, 427},
- {NULL, GCRY_CIPHER_AES256, GCRY_CIPHER_MODE_CFB, 429},
- {NULL, GCRY_CIPHER_AES256, GCRY_CIPHER_MODE_OFB, 428},
-};
-
-static bool nametocipher(const char *name, int *algo, int *mode) {
- size_t i;
-
- for(i = 0; i < sizeof ciphertable / sizeof *ciphertable; i++) {
- if(ciphertable[i].name && !strcasecmp(name, ciphertable[i].name)) {
- *algo = ciphertable[i].algo;
- *mode = ciphertable[i].mode;
- return true;
- }
- }
-
- return false;
-}
-
-static bool nidtocipher(int nid, int *algo, int *mode) {
- size_t i;
-
- for(i = 0; i < sizeof ciphertable / sizeof *ciphertable; i++) {
- if(nid == ciphertable[i].nid) {
- *algo = ciphertable[i].algo;
- *mode = ciphertable[i].mode;
- return true;
- }
- }
-
- return false;
-}
-
-static bool ciphertonid(int algo, int mode, int *nid) {
- size_t i;
-
- for(i = 0; i < sizeof ciphertable / sizeof *ciphertable; i++) {
- if(algo == ciphertable[i].algo && mode == ciphertable[i].mode) {
- *nid = ciphertable[i].nid;
- return true;
- }
- }
-
- return false;
-}
-
-static bool cipher_open(cipher_t *cipher, int algo, int mode) {
- gcry_error_t err;
-
- if(!ciphertonid(algo, mode, &cipher->nid)) {
- logger(DEBUG_ALWAYS, LOG_DEBUG, "Cipher %d mode %d has no corresponding nid!", algo, mode);
- return false;
- }
-
- if((err = gcry_cipher_open(&cipher->handle, algo, mode, 0))) {
- logger(DEBUG_ALWAYS, LOG_DEBUG, "Unable to intialise cipher %d mode %d: %s", algo, mode, gcry_strerror(err));
- return false;
- }
-
- cipher->keylen = gcry_cipher_get_algo_keylen(algo);
- cipher->blklen = gcry_cipher_get_algo_blklen(algo);
- cipher->key = xmalloc(cipher->keylen + cipher->blklen);
- cipher->padding = mode == GCRY_CIPHER_MODE_ECB || mode == GCRY_CIPHER_MODE_CBC;
-
- return true;
-}
-
-bool cipher_open_by_name(cipher_t *cipher, const char *name) {
- int algo, mode;
-
- if(!nametocipher(name, &algo, &mode)) {
- logger(DEBUG_ALWAYS, LOG_DEBUG, "Unknown cipher name '%s'!", name);
- return false;
- }
-
- return cipher_open(cipher, algo, mode);
-}
-
-bool cipher_open_by_nid(cipher_t *cipher, int nid) {
- int algo, mode;
-
- if(!nidtocipher(nid, &algo, &mode)) {
- logger(DEBUG_ALWAYS, LOG_DEBUG, "Unknown cipher ID %d!", nid);
- return false;
- }
-
- return cipher_open(cipher, algo, mode);
-}
-
-bool cipher_open_blowfish_ofb(cipher_t *cipher) {
- return cipher_open(cipher, GCRY_CIPHER_BLOWFISH, GCRY_CIPHER_MODE_OFB);
-}
-
-void cipher_close(cipher_t *cipher) {
- if(cipher->handle) {
- gcry_cipher_close(cipher->handle);
- cipher->handle = NULL;
- }
-
- 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);
-
- gcry_cipher_setkey(cipher->handle, cipher->key, cipher->keylen);
- gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
-
- return true;
-}
-
-bool cipher_set_key_from_rsa(cipher_t *cipher, void *key, size_t len, bool encrypt) {
- memcpy(cipher->key, key + len - cipher->keylen, cipher->keylen + cipher->blklen);
- memcpy(cipher->key + cipher->keylen, key + len - cipher->keylen - cipher->blklen, cipher->blklen);
-
- gcry_cipher_setkey(cipher->handle, cipher->key, cipher->keylen);
- gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
-
- return true;
-}
-
-bool cipher_regenerate_key(cipher_t *cipher, bool encrypt) {
- gcry_create_nonce(cipher->key, cipher->keylen + cipher->blklen);
-
- gcry_cipher_setkey(cipher->handle, cipher->key, cipher->keylen);
- gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
-
- return true;
-}
-
-bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
- gcry_error_t err;
- uint8_t pad[cipher->blklen];
-
- if(cipher->padding) {
- if(!oneshot)
- return false;
-
- size_t reqlen = ((inlen + cipher->blklen) / cipher->blklen) * cipher->blklen;
-
- if(*outlen < reqlen) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: not enough room for padding");
- return false;
- }
-
- uint8_t padbyte = reqlen - inlen;
- inlen = reqlen - cipher->blklen;
-
- for(int i = 0; i < cipher->blklen; i++)
- if(i < cipher->blklen - padbyte)
- pad[i] = ((uint8_t *)indata)[inlen + i];
- else
- pad[i] = padbyte;
- }
-
- if(oneshot)
- gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
-
- if((err = gcry_cipher_encrypt(cipher->handle, outdata, *outlen, indata, inlen))) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", gcry_strerror(err));
- return false;
- }
-
- if(cipher->padding) {
- if((err = gcry_cipher_encrypt(cipher->handle, outdata + inlen, cipher->blklen, pad, cipher->blklen))) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: %s", gcry_strerror(err));
- return false;
- }
-
- inlen += cipher->blklen;
- }
-
- *outlen = inlen;
- return true;
-}
-
-bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
- gcry_error_t err;
-
- if(oneshot)
- gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
-
- if((err = gcry_cipher_decrypt(cipher->handle, outdata, *outlen, indata, inlen))) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: %s", gcry_strerror(err));
- return false;
- }
-
- if(cipher->padding) {
- if(!oneshot)
- return false;
-
- uint8_t padbyte = ((uint8_t *)outdata)[inlen - 1];
-
- if(padbyte == 0 || padbyte > cipher->blklen || padbyte > inlen) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: invalid padding");
- return false;
- }
-
- size_t origlen = inlen - padbyte;
-
- for(int i = inlen - 1; i >= origlen; i--)
- if(((uint8_t *)outdata)[i] != padbyte) {
- logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: invalid padding");
- return false;
- }
-
- *outlen = origlen;
- } else
- *outlen = inlen;
-
- return true;
-}
-
-int cipher_get_nid(const cipher_t *cipher) {
- return cipher->nid;
-}
-
-bool cipher_active(const cipher_t *cipher) {
- return cipher->nid != 0;
-}
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