/* * 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} */ /* NOTE: if keysize > 2*SHA1_HASH_SIZE, code such as hashkeys() needs revisiting */ #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[] = { #ifndef DISABLE_ZLIB {"zlib", DROPBEAR_COMP_ZLIB, NULL, 1}, #endif {"none", DROPBEAR_COMP_NONE, NULL, 1}, {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); }