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/*
* Dropbear SSH
*
* Copyright (c) 2002,2003 Matt Johnston
* Copyright (c) 2004 by Mihnea Stoenescu
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE. */
#include "algo.h"
#include "dbutil.h"
/* This file (algo.c) organises the ciphers which can be used, and is used to
* decide which ciphers/hashes/compression/signing to use during key exchange*/
/* Mappings for ciphers, parameters are
{&cipher_desc, keysize, blocksize} */
#ifdef DROPBEAR_AES256_CBC
static const struct dropbear_cipher dropbear_aes256 =
{&aes_desc, 32, 16};
#endif
#ifdef DROPBEAR_AES128_CBC
static const struct dropbear_cipher dropbear_aes128 =
{&aes_desc, 16, 16};
#endif
#ifdef DROPBEAR_BLOWFISH_CBC
static const struct dropbear_cipher dropbear_blowfish =
{&blowfish_desc, 16, 8};
#endif
#ifdef DROPBEAR_TWOFISH256_CBC
static const struct dropbear_cipher dropbear_twofish256 =
{&twofish_desc, 32, 16};
#endif
#ifdef DROPBEAR_TWOFISH128_CBC
static const struct dropbear_cipher dropbear_twofish128 =
{&twofish_desc, 16, 16};
#endif
#ifdef DROPBEAR_3DES_CBC
static const struct dropbear_cipher dropbear_3des =
{&des3_desc, 24, 8};
#endif
/* used to indicate no encryption, as defined in rfc2410 */
const struct dropbear_cipher dropbear_nocipher =
{NULL, 16, 8};
/* Mapping of ssh hashes to libtomcrypt hashes, including keysize etc.
{&hash_desc, keysize, hashsize} */
#ifdef DROPBEAR_SHA1_HMAC
static const struct dropbear_hash dropbear_sha1 =
{&sha1_desc, 20, 20};
#endif
#ifdef DROPBEAR_SHA1_96_HMAC
static const struct dropbear_hash dropbear_sha1_96 =
{&sha1_desc, 20, 12};
#endif
#ifdef DROPBEAR_MD5_HMAC
static const struct dropbear_hash dropbear_md5 =
{&md5_desc, 16, 16};
#endif
const struct dropbear_hash dropbear_nohash =
{NULL, 16, 0}; /* used initially */
/* The following map ssh names to internal values */
algo_type sshciphers[] = {
#ifdef DROPBEAR_AES128_CBC
{"aes128-cbc", 0, (void*)&dropbear_aes128, 1},
#endif
#ifdef DROPBEAR_3DES_CBC
{"3des-cbc", 0, (void*)&dropbear_3des, 1},
#endif
#ifdef DROPBEAR_AES256_CBC
{"aes256-cbc", 0, (void*)&dropbear_aes256, 1},
#endif
#ifdef DROPBEAR_TWOFISH256_CBC
{"twofish256-cbc", 0, (void*)&dropbear_twofish256, 1},
{"twofish-cbc", 0, (void*)&dropbear_twofish256, 1},
#endif
#ifdef DROPBEAR_TWOFISH128_CBC
{"twofish128-cbc", 0, (void*)&dropbear_twofish128, 1},
#endif
#ifdef DROPBEAR_BLOWFISH_CBC
{"blowfish-cbc", 0, (void*)&dropbear_blowfish, 1},
#endif
{NULL, 0, NULL, 0}
};
algo_type sshhashes[] = {
#ifdef DROPBEAR_SHA1_96_HMAC
{"hmac-sha1-96", 0, (void*)&dropbear_sha1_96, 1},
#endif
#ifdef DROPBEAR_SHA1_HMAC
{"hmac-sha1", 0, (void*)&dropbear_sha1, 1},
#endif
#ifdef DROPBEAR_MD5_HMAC
{"hmac-md5", 0, (void*)&dropbear_md5, 1},
#endif
{NULL, 0, NULL, 0}
};
algo_type sshcompress[] = {
{"none", DROPBEAR_COMP_NONE, NULL, 1},
#ifndef DISABLE_ZLIB
{"zlib", DROPBEAR_COMP_ZLIB, NULL, 1},
#endif
{NULL, 0, NULL, 0}
};
algo_type sshhostkey[] = {
#ifdef DROPBEAR_RSA
{"ssh-rsa", DROPBEAR_SIGNKEY_RSA, NULL, 1},
#endif
#ifdef DROPBEAR_DSS
{"ssh-dss", DROPBEAR_SIGNKEY_DSS, NULL, 1},
#endif
{NULL, 0, NULL, 0}
};
algo_type sshkex[] = {
{"diffie-hellman-group1-sha1", DROPBEAR_KEX_DH_GROUP1, NULL, 1},
{NULL, 0, NULL, 0}
};
/* Register the compiled in ciphers.
* This should be run before using any of the ciphers/hashes */
void crypto_init() {
const struct ltc_cipher_descriptor *regciphers[] = {
#ifdef DROPBEAR_AES_CBC
&aes_desc,
#endif
#ifdef DROPBEAR_BLOWFISH_CBC
&blowfish_desc,
#endif
#ifdef DROPBEAR_TWOFISH_CBC
&twofish_desc,
#endif
#ifdef DROPBEAR_3DES_CBC
&des3_desc,
#endif
NULL
};
const struct ltc_hash_descriptor *reghashes[] = {
/* we need sha1 for hostkey stuff regardless */
&sha1_desc,
#ifdef DROPBEAR_MD5_HMAC
&md5_desc,
#endif
NULL
};
int i;
for (i = 0; regciphers[i] != NULL; i++) {
if (register_cipher(regciphers[i]) == -1) {
dropbear_exit("error registering crypto");
}
}
for (i = 0; reghashes[i] != NULL; i++) {
if (register_hash(reghashes[i]) == -1) {
dropbear_exit("error registering crypto");
}
}
}
/* algolen specifies the length of algo, algos is our local list to match
* against.
* Returns DROPBEAR_SUCCESS if we have a match for algo, DROPBEAR_FAILURE
* otherwise */
int have_algo(char* algo, size_t algolen, algo_type algos[]) {
int i;
for (i = 0; algos[i].name != NULL; i++) {
if (strlen(algos[i].name) == algolen
&& (strncmp(algos[i].name, algo, algolen) == 0)) {
return DROPBEAR_SUCCESS;
}
}
return DROPBEAR_FAILURE;
}
/* Output a comma separated list of algorithms to a buffer */
void buf_put_algolist(buffer * buf, algo_type localalgos[]) {
unsigned int i, len;
unsigned int donefirst = 0;
buffer *algolist = NULL;
algolist = buf_new(100);
for (i = 0; localalgos[i].name != NULL; i++) {
if (localalgos[i].usable) {
if (donefirst)
buf_putbyte(algolist, ',');
donefirst = 1;
len = strlen(localalgos[i].name);
buf_putbytes(algolist, localalgos[i].name, len);
}
}
buf_putstring(buf, algolist->data, algolist->len);
buf_free(algolist);
}
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