/*
cipher.c -- Symmetric block cipher handling
- Copyright (C) 2007 Guus Sliepen <guus@tinc-vpn.org>
+ 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
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.
-
- $Id$
+ 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"
static bool nametocipher(const char *name, int *algo, int *mode) {
size_t i;
- for(i = 0; i < sizeof ciphertable / sizeof *ciphertable; 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;
static bool nidtocipher(int nid, int *algo, int *mode) {
size_t i;
- for(i = 0; i < sizeof ciphertable / sizeof *ciphertable; i++) {
+ for(i = 0; i < sizeof(ciphertable) / sizeof(*ciphertable); i++) {
if(nid == ciphertable[i].nid) {
*algo = ciphertable[i].algo;
*mode = ciphertable[i].mode;
static bool ciphertonid(int algo, int mode, int *nid) {
size_t i;
- for(i = 0; i < sizeof ciphertable / sizeof *ciphertable; 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;
gcry_error_t err;
if(!ciphertonid(algo, mode, &cipher->nid)) {
- logger(LOG_DEBUG, _("Cipher %d mode %d has no corresponding nid!"), algo, mode);
+ 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(LOG_DEBUG, _("Unable to intialise cipher %d mode %d: %s"), algo, mode, gcry_strerror(err));
+ logger(DEBUG_ALWAYS, LOG_DEBUG, "Unable to initialise cipher %d mode %d: %s", algo, mode, gcry_strerror(err));
return false;
}
cipher->keylen = gcry_cipher_get_algo_keylen(algo);
- if(mode == GCRY_CIPHER_MODE_ECB || mode == GCRY_CIPHER_MODE_CBC)
- cipher->blklen = gcry_cipher_get_algo_blklen(algo);
- else
- cipher->blklen = 0;
+ 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;
}
int algo, mode;
if(!nametocipher(name, &algo, &mode)) {
- logger(LOG_DEBUG, _("Unknown cipher name '%s'!"), name);
+ logger(DEBUG_ALWAYS, LOG_DEBUG, "Unknown cipher name '%s'!", name);
return false;
}
int algo, mode;
if(!nidtocipher(nid, &algo, &mode)) {
- logger(LOG_DEBUG, _("Unknown cipher ID %d!"), nid);
+ logger(DEBUG_ALWAYS, LOG_DEBUG, "Unknown cipher ID %d!", nid);
return false;
}
return true;
}
-static bool cipher_add_padding(cipher_t *cipher, void *indata, size_t inlen, size_t *outlen) {
- size_t reqlen;
+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->blklen == 1) {
- *outlen = inlen;
- return true;
- }
+ if(cipher->padding) {
+ if(!oneshot) {
+ return false;
+ }
- reqlen = ((inlen + 1) / cipher->blklen) * cipher->blklen;
- if(reqlen > *outlen)
- return false;
+ size_t reqlen = ((inlen + cipher->blklen) / cipher->blklen) * cipher->blklen;
- // add padding
+ if(*outlen < reqlen) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Error while encrypting: not enough room for padding");
+ return false;
+ }
- *outlen = reqlen;
- return true;
-}
+ uint8_t padbyte = reqlen - inlen;
+ inlen = reqlen - cipher->blklen;
-static bool cipher_remove_padding(cipher_t *cipher, void *indata, size_t inlen, size_t *outlen) {
- size_t origlen;
+ 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(cipher->blklen == 1) {
- *outlen = inlen;
- return true;
+ if(oneshot) {
+ gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
}
- if(inlen % 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;
+ }
- // check and remove padding
+ 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;
+ }
- *outlen = origlen;
+ inlen += cipher->blklen;
+ }
+
+ *outlen = inlen;
return true;
}
-bool cipher_encrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
+bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
gcry_error_t err;
- // To be fixed
+ if(oneshot) {
+ gcry_cipher_setiv(cipher->handle, cipher->key + cipher->keylen, cipher->blklen);
+ }
- if((err = gcry_cipher_encrypt(cipher->handle, outdata, inlen, indata, inlen))) {
- logger(LOG_ERR, _("Error while encrypting: %s"), gcry_strerror(err));
+ 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;
}
- return true;
-}
+ if(cipher->padding) {
+ if(!oneshot) {
+ return false;
+ }
-bool cipher_decrypt(cipher_t *cipher, const void *indata, size_t inlen, void *outdata, size_t *outlen, bool oneshot) {
- gcry_error_t err;
+ uint8_t padbyte = ((uint8_t *)outdata)[inlen - 1];
- // To be fixed
+ if(padbyte == 0 || padbyte > cipher->blklen || padbyte > inlen) {
+ logger(DEBUG_ALWAYS, LOG_ERR, "Error while decrypting: invalid padding");
+ return false;
+ }
- if((err = gcry_cipher_decrypt(cipher->handle, outdata, inlen, indata, inlen))) {
- logger(LOG_ERR, _("Error while decrypting: %s"), gcry_strerror(err));
- 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;
projects / tinc / blobdiff