Mercurial > dropbear
diff gcm.c @ 1672:3a97f14c0235
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
author | Vladislav Grishenko <themiron@users.noreply.github.com> |
---|---|
date | Mon, 25 May 2020 20:50:25 +0500 |
parents | |
children | 5b701bf529aa |
line wrap: on
line diff
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/gcm.c Mon May 25 20:50:25 2020 +0500 @@ -0,0 +1,120 @@ +/* + * Dropbear SSH + * + * Copyright (c) 2002,2003 Matt Johnston + * Copyright (c) 2020 by Vladislav Grishenko + * 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 "algo.h" +#include "dbutil.h" +#include "gcm.h" + +#if DROPBEAR_ENABLE_GCM_MODE + +#define GHASH_LEN 16 + +static const struct dropbear_hash dropbear_ghash = + {NULL, 0, GHASH_LEN}; + +static int dropbear_gcm_start(int cipher, const unsigned char *IV, + const unsigned char *key, int keylen, + int UNUSED(num_rounds), dropbear_gcm_state *state) { + int err; + + TRACE2(("enter dropbear_gcm_start")) + + if ((err = gcm_init(&state->gcm, cipher, key, keylen)) != CRYPT_OK) { + return err; + } + memcpy(state->iv, IV, GCM_NONCE_LEN); + + TRACE2(("leave dropbear_gcm_start")) + return CRYPT_OK; +} + +static int dropbear_gcm_crypt(unsigned int UNUSED(seq), + const unsigned char *in, unsigned char *out, + unsigned long len, unsigned long taglen, + dropbear_gcm_state *state, int direction) { + unsigned char *iv, tag[GHASH_LEN]; + int i, err; + + TRACE2(("enter dropbear_gcm_crypt")) + + if (len < 4 || taglen != GHASH_LEN) { + return CRYPT_ERROR; + } + + gcm_reset(&state->gcm); + + if ((err = gcm_add_iv(&state->gcm, + state->iv, GCM_NONCE_LEN)) != CRYPT_OK) { + return err; + } + + if ((err = gcm_add_aad(&state->gcm, in, 4)) != CRYPT_OK) { + return err; + } + + if ((err = gcm_process(&state->gcm, (unsigned char *) in + 4, + len - 4, out + 4, direction)) != CRYPT_OK) { + return err; + } + + if (direction == LTC_ENCRYPT) { + gcm_done(&state->gcm, out + len, &taglen); + } else { + gcm_done(&state->gcm, tag, &taglen); + if (constant_time_memcmp(in + len, tag, taglen) != 0) { + return CRYPT_ERROR; + } + } + + /* increment invocation counter */ + iv = state->iv + GCM_IVFIX_LEN; + for (i = GCM_IVCTR_LEN - 1; i >= 0 && ++iv[i] == 0; i--); + + TRACE2(("leave dropbear_gcm_crypt")) + return CRYPT_OK; +} + +static int dropbear_gcm_getlength(unsigned int UNUSED(seq), + const unsigned char *in, unsigned int *outlen, + unsigned long len, dropbear_gcm_state* UNUSED(state)) { + TRACE2(("enter dropbear_gcm_parse")) + + if (len < 4) { + return CRYPT_ERROR; + } + + LOAD32H(*outlen, in); + + TRACE2(("leave dropbear_gcm_parse")) + return CRYPT_OK; +} + +const struct dropbear_cipher_mode dropbear_mode_gcm = + {(void *)dropbear_gcm_start, NULL, NULL, + (void *)dropbear_gcm_crypt, + (void *)dropbear_gcm_getlength, &dropbear_ghash}; + +#endif /* DROPBEAR_ENABLE_GCM_MODE */