Add Chacha20-Poly1305, AES128-GCM and AES256-GCM support (#93) * Add Chacha20-Poly1305 authenticated encryption * Add general AEAD approach. * Add [email protected] algo using LibTomCrypt chacha and poly1305 routines. Chacha20-Poly1305 is generally faster than AES256 on CPU w/o dedicated AES instructions, having the same key size. Compiling in will add ~5,5kB to binary size on x86-64. function old new delta chacha_crypt - 1397 +1397 _poly1305_block - 608 +608 poly1305_done - 595 +595 dropbear_chachapoly_crypt - 457 +457 .rodata 26976 27392 +416 poly1305_process - 290 +290 poly1305_init - 221 +221 chacha_setup - 218 +218 encrypt_packet 1068 1270 +202 dropbear_chachapoly_getlength - 147 +147 decrypt_packet 756 897 +141 chacha_ivctr64 - 137 +137 read_packet 543 637 +94 dropbear_chachapoly_start - 94 +94 read_kex_algos 792 880 +88 chacha_keystream - 69 +69 dropbear_mode_chachapoly - 48 +48 sshciphers 280 320 +40 dropbear_mode_none 24 48 +24 dropbear_mode_ctr 24 48 +24 dropbear_mode_cbc 24 48 +24 dropbear_chachapoly_mac - 24 +24 dropbear_chachapoly - 24 +24 gen_new_keys 848 854 +6 ------------------------------------------------------------------------------ (add/remove: 14/0 grow/shrink: 10/0 up/down: 5388/0) Total: 5388 bytes * Add AES128-GCM and AES256-GCM authenticated encryption * Add general AES-GCM mode. * Add [email protected] and [email protected] algo using LibTomCrypt gcm routines. AES-GCM is combination of AES CTR mode and GHASH, slower than AES-CTR on CPU w/o dedicated AES/GHASH instructions therefore disabled by default. Compiling in will add ~6kB to binary size on x86-64. function old new delta gcm_process - 1060 +1060 .rodata 26976 27808 +832 gcm_gf_mult - 820 +820 gcm_add_aad - 660 +660 gcm_shift_table - 512 +512 gcm_done - 471 +471 gcm_add_iv - 384 +384 gcm_init - 347 +347 dropbear_gcm_crypt - 309 +309 encrypt_packet 1068 1270 +202 decrypt_packet 756 897 +141 gcm_reset - 118 +118 read_packet 543 637 +94 read_kex_algos 792 880 +88 sshciphers 280 360 +80 gcm_mult_h - 80 +80 dropbear_gcm_start - 62 +62 dropbear_mode_gcm - 48 +48 dropbear_mode_none 24 48 +24 dropbear_mode_ctr 24 48 +24 dropbear_mode_cbc 24 48 +24 dropbear_ghash - 24 +24 dropbear_gcm_getlength - 24 +24 gen_new_keys 848 854 +6 ------------------------------------------------------------------------------ (add/remove: 14/0 grow/shrink: 10/0 up/down: 6434/0) Total: 6434 bytes

/*
 * Dropbear - a SSH2 server
 * 
 * Copyright (c) 2002,2003 Matt Johnston
 * 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 "includes.h"
#include "runopts.h"
#include "signkey.h"
#include "buffer.h"
#include "dbutil.h"
#include "auth.h"
#include "algo.h"
#include "dbrandom.h"

runopts opts; /* GLOBAL */

/* returns success or failure, and the keytype in *type. If we want
 * to restrict the type, type can contain a type to return */
int readhostkey(const char * filename, sign_key * hostkey, 
	enum signkey_type *type) {

	int ret = DROPBEAR_FAILURE;
	buffer *buf;

	buf = buf_new(MAX_PRIVKEY_SIZE);

	if (buf_readfile(buf, filename) == DROPBEAR_FAILURE) {
		goto out;
	}
	buf_setpos(buf, 0);

	addrandom(buf_getptr(buf, buf->len), buf->len);

	if (buf_get_priv_key(buf, hostkey, type) == DROPBEAR_FAILURE) {
		goto out;
	}

	ret = DROPBEAR_SUCCESS;
out:

	buf_burn(buf);
	buf_free(buf);
	return ret;
}

#if DROPBEAR_USER_ALGO_LIST
void
parse_ciphers_macs()
{
	if (opts.cipher_list)
	{
		if (strcmp(opts.cipher_list, "help") == 0)
		{
			char *ciphers = algolist_string(sshciphers);
			dropbear_log(LOG_INFO, "Available ciphers:\n%s\n", ciphers);
			m_free(ciphers);
			dropbear_exit(".");
		}

		if (strcmp(opts.cipher_list, "none") == 0)
		{
			/* Encryption is required during authentication */
			opts.cipher_list = "none,aes128-ctr";
		}

		if (check_user_algos(opts.cipher_list, sshciphers, "cipher") == 0)
		{
			dropbear_exit("No valid ciphers specified for '-c'");
		}
	}

	if (opts.mac_list)
	{
		if (strcmp(opts.mac_list, "help") == 0)
		{
			char *macs = algolist_string(sshhashes);
			dropbear_log(LOG_INFO, "Available MACs:\n%s\n", macs);
			m_free(macs);
			dropbear_exit(".");
		}

		if (check_user_algos(opts.mac_list, sshhashes, "MAC") == 0)
		{
			dropbear_exit("No valid MACs specified for '-m'");
		}
	}
}
#endif

void print_version() {
	fprintf(stderr, "Dropbear v%s\n", DROPBEAR_VERSION);
}