common-algo.c - third_party/dropbear - Git at Google

 /*
  * 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*/

 static int void_cipher(const unsigned char* in, unsigned char* out,
 		unsigned long len, void *cipher_state) {
 	if (in != out) {
 		memmove(out, in, len);
 	}
 	return CRYPT_OK;
 }

 static int void_start(int cipher, const unsigned char *IV,
 			const unsigned char *key,
 			int keylen, int num_rounds, void *cipher_state) {
 	return CRYPT_OK;
 }

 /* 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
 static const struct dropbear_cipher dropbear_aes256 =
 	{&aes_desc, 32, 16};
 #endif
 #ifdef DROPBEAR_AES128
 static const struct dropbear_cipher dropbear_aes128 =
 	{&aes_desc, 16, 16};
 #endif
 #ifdef DROPBEAR_BLOWFISH
 static const struct dropbear_cipher dropbear_blowfish =
 	{&blowfish_desc, 16, 8};
 #endif
 #ifdef DROPBEAR_TWOFISH256
 static const struct dropbear_cipher dropbear_twofish256 =
 	{&twofish_desc, 32, 16};
 #endif
 #ifdef DROPBEAR_TWOFISH128
 static const struct dropbear_cipher dropbear_twofish128 =
 	{&twofish_desc, 16, 16};
 #endif
 #ifdef DROPBEAR_3DES
 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};

 /* A few void* s are required to silence warnings
  * about the symmetric_CBC vs symmetric_CTR cipher_state pointer */
 const struct dropbear_cipher_mode dropbear_mode_cbc =
 	{(void*)cbc_start, (void*)cbc_encrypt, (void*)cbc_decrypt};
 const struct dropbear_cipher_mode dropbear_mode_none =
 	{void_start, void_cipher, void_cipher};
 #ifdef DROPBEAR_ENABLE_CTR_MODE
 /* a wrapper to make ctr_start and cbc_start look the same */
 static int dropbear_big_endian_ctr_start(int cipher,
 		const unsigned char *IV,
 		const unsigned char *key, int keylen,
 		int num_rounds, symmetric_CTR *ctr) {
 	return ctr_start(cipher, IV, key, keylen, num_rounds, CTR_COUNTER_BIG_ENDIAN, ctr);
 }
 const struct dropbear_cipher_mode dropbear_mode_ctr =
 	{(void*)dropbear_big_endian_ctr_start, (void*)ctr_encrypt, (void*)ctr_decrypt};
 #endif

 /* 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.
  * The ordering here is important for the client - the first mode
  * that is also supported by the server will get used. */

 algo_type sshciphers[] = {
 #ifdef DROPBEAR_ENABLE_CTR_MODE
 #ifdef DROPBEAR_AES128
 	{"aes128-ctr", 0, &dropbear_aes128, 1, &dropbear_mode_ctr},
 #endif
 #ifdef DROPBEAR_3DES
 	{"3des-ctr", 0, &dropbear_3des, 1, &dropbear_mode_ctr},
 #endif
 #ifdef DROPBEAR_AES256
 	{"aes256-ctr", 0, &dropbear_aes256, 1, &dropbear_mode_ctr},
 #endif
 #endif /* DROPBEAR_ENABLE_CTR_MODE */

 /* CBC modes are always enabled */
 #ifdef DROPBEAR_AES128
 	{"aes128-cbc", 0, &dropbear_aes128, 1, &dropbear_mode_cbc},
 #endif
 #ifdef DROPBEAR_3DES
 	{"3des-cbc", 0, &dropbear_3des, 1, &dropbear_mode_cbc},
 #endif
 #ifdef DROPBEAR_AES256
 	{"aes256-cbc", 0, &dropbear_aes256, 1, &dropbear_mode_cbc},
 #endif
 #ifdef DROPBEAR_TWOFISH256
 	{"twofish256-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc},
 	{"twofish-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc},
 #endif
 #ifdef DROPBEAR_TWOFISH128
 	{"twofish128-cbc", 0, &dropbear_twofish128, 1, &dropbear_mode_cbc},
 #endif
 #ifdef DROPBEAR_BLOWFISH
 	{"blowfish-cbc", 0, &dropbear_blowfish, 1, &dropbear_mode_cbc},
 #endif
 	{NULL, 0, NULL, 0, NULL}
 };

 algo_type sshhashes[] = {
 #ifdef DROPBEAR_SHA1_96_HMAC
 	{"hmac-sha1-96", 0, &dropbear_sha1_96, 1, NULL},
 #endif
 #ifdef DROPBEAR_SHA1_HMAC
 	{"hmac-sha1", 0, &dropbear_sha1, 1, NULL},
 #endif
 #ifdef DROPBEAR_MD5_HMAC
 	{"hmac-md5", 0, &dropbear_md5, 1, NULL},
 #endif
 	{NULL, 0, NULL, 0, NULL}
 };

 #ifndef DISABLE_ZLIB
 algo_type ssh_compress[] = {
 	{"zlib", DROPBEAR_COMP_ZLIB, NULL, 1, NULL},
 	{"zlib@openssh.com", DROPBEAR_COMP_ZLIB_DELAY, NULL, 1, NULL},
 	{"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
 	{NULL, 0, NULL, 0, NULL}
 };
 #endif

 algo_type ssh_nocompress[] = {
 	{"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
 	{NULL, 0, NULL, 0, NULL}
 };

 algo_type sshhostkey[] = {
 #ifdef DROPBEAR_RSA
 	{"ssh-rsa", DROPBEAR_SIGNKEY_RSA, NULL, 1, NULL},
 #endif
 #ifdef DROPBEAR_DSS
 	{"ssh-dss", DROPBEAR_SIGNKEY_DSS, NULL, 1, NULL},
 #endif
 	{NULL, 0, NULL, 0, NULL}
 };

 algo_type sshkex[] = {
 	{"diffie-hellman-group1-sha1", DROPBEAR_KEX_DH_GROUP1, NULL, 1, NULL},
 	{"diffie-hellman-group14-sha1", DROPBEAR_KEX_DH_GROUP14, NULL, 1, NULL},
 	{NULL, 0, NULL, 0, NULL}
 };


 /* 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
 		&aes_desc,
 #endif
 #ifdef DROPBEAR_BLOWFISH
 		&blowfish_desc,
 #endif
 #ifdef DROPBEAR_TWOFISH
 		&twofish_desc,
 #endif
 #ifdef DROPBEAR_3DES
 		&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(160);
 	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);
 }
	/*
	* 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*/

	static int void_cipher(const unsigned char* in, unsigned char* out,
	unsigned long len, void *cipher_state) {
	if (in != out) {
	memmove(out, in, len);
	}
	return CRYPT_OK;
	}

	static int void_start(int cipher, const unsigned char *IV,
	const unsigned char *key,
	int keylen, int num_rounds, void *cipher_state) {
	return CRYPT_OK;
	}

	/* 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
	static const struct dropbear_cipher dropbear_aes256 =
	{&aes_desc, 32, 16};
	#endif
	#ifdef DROPBEAR_AES128
	static const struct dropbear_cipher dropbear_aes128 =
	{&aes_desc, 16, 16};
	#endif
	#ifdef DROPBEAR_BLOWFISH
	static const struct dropbear_cipher dropbear_blowfish =
	{&blowfish_desc, 16, 8};
	#endif
	#ifdef DROPBEAR_TWOFISH256
	static const struct dropbear_cipher dropbear_twofish256 =
	{&twofish_desc, 32, 16};
	#endif
	#ifdef DROPBEAR_TWOFISH128
	static const struct dropbear_cipher dropbear_twofish128 =
	{&twofish_desc, 16, 16};
	#endif
	#ifdef DROPBEAR_3DES
	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};

	/* A few void* s are required to silence warnings
	* about the symmetric_CBC vs symmetric_CTR cipher_state pointer */
	const struct dropbear_cipher_mode dropbear_mode_cbc =
	{(void)cbc_start, (void)cbc_encrypt, (void*)cbc_decrypt};
	const struct dropbear_cipher_mode dropbear_mode_none =
	{void_start, void_cipher, void_cipher};
	#ifdef DROPBEAR_ENABLE_CTR_MODE
	/* a wrapper to make ctr_start and cbc_start look the same */
	static int dropbear_big_endian_ctr_start(int cipher,
	const unsigned char *IV,
	const unsigned char *key, int keylen,
	int num_rounds, symmetric_CTR *ctr) {
	return ctr_start(cipher, IV, key, keylen, num_rounds, CTR_COUNTER_BIG_ENDIAN, ctr);
	}
	const struct dropbear_cipher_mode dropbear_mode_ctr =
	{(void)dropbear_big_endian_ctr_start, (void)ctr_encrypt, (void*)ctr_decrypt};
	#endif

	/* 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.
	* The ordering here is important for the client - the first mode
	* that is also supported by the server will get used. */

	algo_type sshciphers[] = {
	#ifdef DROPBEAR_ENABLE_CTR_MODE
	#ifdef DROPBEAR_AES128
	{"aes128-ctr", 0, &dropbear_aes128, 1, &dropbear_mode_ctr},
	#endif
	#ifdef DROPBEAR_3DES
	{"3des-ctr", 0, &dropbear_3des, 1, &dropbear_mode_ctr},
	#endif
	#ifdef DROPBEAR_AES256
	{"aes256-ctr", 0, &dropbear_aes256, 1, &dropbear_mode_ctr},
	#endif
	#endif /* DROPBEAR_ENABLE_CTR_MODE */

	/* CBC modes are always enabled */
	#ifdef DROPBEAR_AES128
	{"aes128-cbc", 0, &dropbear_aes128, 1, &dropbear_mode_cbc},
	#endif
	#ifdef DROPBEAR_3DES
	{"3des-cbc", 0, &dropbear_3des, 1, &dropbear_mode_cbc},
	#endif
	#ifdef DROPBEAR_AES256
	{"aes256-cbc", 0, &dropbear_aes256, 1, &dropbear_mode_cbc},
	#endif
	#ifdef DROPBEAR_TWOFISH256
	{"twofish256-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc},
	{"twofish-cbc", 0, &dropbear_twofish256, 1, &dropbear_mode_cbc},
	#endif
	#ifdef DROPBEAR_TWOFISH128
	{"twofish128-cbc", 0, &dropbear_twofish128, 1, &dropbear_mode_cbc},
	#endif
	#ifdef DROPBEAR_BLOWFISH
	{"blowfish-cbc", 0, &dropbear_blowfish, 1, &dropbear_mode_cbc},
	#endif
	{NULL, 0, NULL, 0, NULL}
	};

	algo_type sshhashes[] = {
	#ifdef DROPBEAR_SHA1_96_HMAC
	{"hmac-sha1-96", 0, &dropbear_sha1_96, 1, NULL},
	#endif
	#ifdef DROPBEAR_SHA1_HMAC
	{"hmac-sha1", 0, &dropbear_sha1, 1, NULL},
	#endif
	#ifdef DROPBEAR_MD5_HMAC
	{"hmac-md5", 0, &dropbear_md5, 1, NULL},
	#endif
	{NULL, 0, NULL, 0, NULL}
	};

	#ifndef DISABLE_ZLIB
	algo_type ssh_compress[] = {
	{"zlib", DROPBEAR_COMP_ZLIB, NULL, 1, NULL},
	{"zlib@openssh.com", DROPBEAR_COMP_ZLIB_DELAY, NULL, 1, NULL},
	{"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
	{NULL, 0, NULL, 0, NULL}
	};
	#endif

	algo_type ssh_nocompress[] = {
	{"none", DROPBEAR_COMP_NONE, NULL, 1, NULL},
	{NULL, 0, NULL, 0, NULL}
	};

	algo_type sshhostkey[] = {
	#ifdef DROPBEAR_RSA
	{"ssh-rsa", DROPBEAR_SIGNKEY_RSA, NULL, 1, NULL},
	#endif
	#ifdef DROPBEAR_DSS
	{"ssh-dss", DROPBEAR_SIGNKEY_DSS, NULL, 1, NULL},
	#endif
	{NULL, 0, NULL, 0, NULL}
	};

	algo_type sshkex[] = {
	{"diffie-hellman-group1-sha1", DROPBEAR_KEX_DH_GROUP1, NULL, 1, NULL},
	{"diffie-hellman-group14-sha1", DROPBEAR_KEX_DH_GROUP14, NULL, 1, NULL},
	{NULL, 0, NULL, 0, NULL}
	};


	/* 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
	&aes_desc,
	#endif
	#ifdef DROPBEAR_BLOWFISH
	&blowfish_desc,
	#endif
	#ifdef DROPBEAR_TWOFISH
	&twofish_desc,
	#endif
	#ifdef DROPBEAR_3DES
	&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(160);
	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);
	}