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Diffstat (limited to 'cipher-3des1.c')
| -rw-r--r-- | cipher-3des1.c | 171 |
1 files changed, 171 insertions, 0 deletions
diff --git a/cipher-3des1.c b/cipher-3des1.c new file mode 100644 index 00000000..f9a35239 --- /dev/null +++ b/cipher-3des1.c @@ -0,0 +1,171 @@ +/* + * Copyright (c) 2003 Markus Friedl. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "includes.h" +RCSID("$OpenBSD: cipher-3des1.c,v 1.1 2003/05/15 03:08:29 markus Exp $"); + +#include <openssl/evp.h> +#include "xmalloc.h" +#include "log.h" + +/* + * This is used by SSH1: + * + * What kind of triple DES are these 2 routines? + * + * Why is there a redundant initialization vector? + * + * If only iv3 was used, then, this would till effect have been + * outer-cbc. However, there is also a private iv1 == iv2 which + * perhaps makes differential analysis easier. On the other hand, the + * private iv1 probably makes the CRC-32 attack ineffective. This is a + * result of that there is no longer any known iv1 to use when + * choosing the X block. + */ +struct ssh1_3des_ctx +{ + EVP_CIPHER_CTX k1, k2, k3; +}; + +const EVP_CIPHER * evp_ssh1_3des(void); +void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); + +static int +ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, + int enc) +{ + struct ssh1_3des_ctx *c; + u_char *k1, *k2, *k3; + + 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) + return (1); + if (enc == -1) + enc = ctx->encrypt; + k1 = k2 = k3 = (u_char *) key; + k2 += 8; + if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) { + if (enc) + k3 += 16; + else + k1 += 16; + } + EVP_CIPHER_CTX_init(&c->k1); + EVP_CIPHER_CTX_init(&c->k2); + EVP_CIPHER_CTX_init(&c->k3); +#ifdef SSH_OLD_EVP + EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc); + EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc); + EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc); +#else + if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 || + EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 || + EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) { + memset(c, 0, sizeof(*c)); + xfree(c); + EVP_CIPHER_CTX_set_app_data(ctx, NULL); + return (0); + } +#endif + return (1); +} + +static int +ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len) +{ + struct ssh1_3des_ctx *c; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { + error("ssh1_3des_cbc: no context"); + return (0); + } +#ifdef SSH_OLD_EVP + EVP_Cipher(&c->k1, dest, (u_char *)src, len); + EVP_Cipher(&c->k2, dest, dest, len); + EVP_Cipher(&c->k3, dest, dest, len); +#else + if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 || + EVP_Cipher(&c->k2, dest, dest, len) == 0 || + EVP_Cipher(&c->k3, dest, dest, len) == 0) + return (0); +#endif + return (1); +} + +static int +ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx) +{ + struct ssh1_3des_ctx *c; + + if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { + memset(c, 0, sizeof(*c)); + xfree(c); + EVP_CIPHER_CTX_set_app_data(ctx, NULL); + } + return (1); +} + +void +ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len) +{ + struct ssh1_3des_ctx *c; + + if (len != 24) + fatal("%s: bad 3des iv length: %d", __func__, len); + if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL) + fatal("%s: no 3des context", __func__); + if (doset) { + debug3("%s: Installed 3DES IV", __func__); + memcpy(c->k1.iv, iv, 8); + memcpy(c->k2.iv, iv + 8, 8); + memcpy(c->k3.iv, iv + 16, 8); + } else { + debug3("%s: Copying 3DES IV", __func__); + memcpy(iv, c->k1.iv, 8); + memcpy(iv + 8, c->k2.iv, 8); + memcpy(iv + 16, c->k3.iv, 8); + } +} + +const EVP_CIPHER * +evp_ssh1_3des(void) +{ + static EVP_CIPHER ssh1_3des; + + memset(&ssh1_3des, 0, sizeof(EVP_CIPHER)); + ssh1_3des.nid = NID_undef; + ssh1_3des.block_size = 8; + ssh1_3des.iv_len = 0; + ssh1_3des.key_len = 16; + ssh1_3des.init = ssh1_3des_init; + ssh1_3des.cleanup = ssh1_3des_cleanup; + ssh1_3des.do_cipher = ssh1_3des_cbc; +#ifndef SSH_OLD_EVP + ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH; +#endif + return (&ssh1_3des); +} |