You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
146 lines
3.6 KiB
146 lines
3.6 KiB
/* $OpenBSD: cipher-ctr.c,v 1.11 2010/10/01 23:05:32 djm Exp $ */ |
|
/* |
|
* Copyright (c) 2003 Markus Friedl <markus@openbsd.org> |
|
* |
|
* Permission to use, copy, modify, and distribute this software for any |
|
* purpose with or without fee is hereby granted, provided that the above |
|
* copyright notice and this permission notice appear in all copies. |
|
* |
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES |
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF |
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR |
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES |
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN |
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF |
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. |
|
*/ |
|
#include "includes.h" |
|
|
|
#if defined(WITH_OPENSSL) && !defined(OPENSSL_HAVE_EVPCTR) |
|
#include <sys/types.h> |
|
|
|
#include <stdarg.h> |
|
#include <string.h> |
|
|
|
#include <openssl/evp.h> |
|
|
|
#include "xmalloc.h" |
|
#include "log.h" |
|
|
|
/* compatibility with old or broken OpenSSL versions */ |
|
#include "openbsd-compat/openssl-compat.h" |
|
|
|
#ifndef USE_BUILTIN_RIJNDAEL |
|
#include <openssl/aes.h> |
|
#endif |
|
|
|
struct ssh_aes_ctr_ctx |
|
{ |
|
AES_KEY aes_ctx; |
|
u_char aes_counter[AES_BLOCK_SIZE]; |
|
}; |
|
|
|
/* |
|
* increment counter 'ctr', |
|
* the counter is of size 'len' bytes and stored in network-byte-order. |
|
* (LSB at ctr[len-1], MSB at ctr[0]) |
|
*/ |
|
static void |
|
ssh_ctr_inc(u_char *ctr, size_t len) |
|
{ |
|
int i; |
|
|
|
for (i = len - 1; i >= 0; i--) |
|
if (++ctr[i]) /* continue on overflow */ |
|
return; |
|
} |
|
|
|
static int |
|
ssh_aes_ctr(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, |
|
LIBCRYPTO_EVP_INL_TYPE len) |
|
{ |
|
struct ssh_aes_ctr_ctx *c; |
|
size_t n = 0; |
|
u_char buf[AES_BLOCK_SIZE]; |
|
|
|
if (len == 0) |
|
return (1); |
|
if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) |
|
return (0); |
|
|
|
while ((len--) > 0) { |
|
if (n == 0) { |
|
AES_encrypt(c->aes_counter, buf, &c->aes_ctx); |
|
ssh_ctr_inc(c->aes_counter, AES_BLOCK_SIZE); |
|
} |
|
*(dest++) = *(src++) ^ buf[n]; |
|
n = (n + 1) % AES_BLOCK_SIZE; |
|
} |
|
return (1); |
|
} |
|
|
|
static int |
|
ssh_aes_ctr_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, |
|
int enc) |
|
{ |
|
struct ssh_aes_ctr_ctx *c; |
|
|
|
if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { |
|
c = xmalloc(sizeof(*c)); |
|
EVP_CIPHER_CTX_set_app_data(ctx, c); |
|
} |
|
if (key != NULL) |
|
AES_set_encrypt_key(key, EVP_CIPHER_CTX_key_length(ctx) * 8, |
|
&c->aes_ctx); |
|
if (iv != NULL) |
|
memcpy(c->aes_counter, iv, AES_BLOCK_SIZE); |
|
return (1); |
|
} |
|
|
|
static int |
|
ssh_aes_ctr_cleanup(EVP_CIPHER_CTX *ctx) |
|
{ |
|
struct ssh_aes_ctr_ctx *c; |
|
|
|
if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { |
|
memset(c, 0, sizeof(*c)); |
|
free(c); |
|
EVP_CIPHER_CTX_set_app_data(ctx, NULL); |
|
} |
|
return (1); |
|
} |
|
|
|
void |
|
ssh_aes_ctr_iv(EVP_CIPHER_CTX *evp, int doset, u_char * iv, size_t len) |
|
{ |
|
struct ssh_aes_ctr_ctx *c; |
|
|
|
if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL) |
|
fatal("ssh_aes_ctr_iv: no context"); |
|
if (doset) |
|
memcpy(c->aes_counter, iv, len); |
|
else |
|
memcpy(iv, c->aes_counter, len); |
|
} |
|
|
|
const EVP_CIPHER * |
|
evp_aes_128_ctr(void) |
|
{ |
|
static EVP_CIPHER aes_ctr; |
|
|
|
memset(&aes_ctr, 0, sizeof(EVP_CIPHER)); |
|
aes_ctr.nid = NID_undef; |
|
aes_ctr.block_size = AES_BLOCK_SIZE; |
|
aes_ctr.iv_len = AES_BLOCK_SIZE; |
|
aes_ctr.key_len = 16; |
|
aes_ctr.init = ssh_aes_ctr_init; |
|
aes_ctr.cleanup = ssh_aes_ctr_cleanup; |
|
aes_ctr.do_cipher = ssh_aes_ctr; |
|
#ifndef SSH_OLD_EVP |
|
aes_ctr.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | |
|
EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV; |
|
#endif |
|
return (&aes_ctr); |
|
} |
|
|
|
#endif /* defined(WITH_OPENSSL) && !defined(OPENSSL_HAVE_EVPCTR) */
|
|
|