1 /* $OpenBSD: cipher-3des1.c,v 1.12 2015/01/14 10:24:42 markus Exp $ */ 2 /* 3 * Copyright (c) 2003 Markus Friedl. All rights reserved. 4 * 5 * Permission to use, copy, modify, and distribute this software for any 6 * purpose with or without fee is hereby granted, provided that the above 7 * copyright notice and this permission notice appear in all copies. 8 * 9 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 10 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 11 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 12 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 13 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 14 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 15 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 16 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 17 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 18 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 19 */ 20 21 #include "includes.h" 22 23 #include <sys/types.h> 24 #include <string.h> 25 #include <openssl/evp.h> 26 27 #include "ssherr.h" 28 29 /* 30 * This is used by SSH1: 31 * 32 * What kind of triple DES are these 2 routines? 33 * 34 * Why is there a redundant initialization vector? 35 * 36 * If only iv3 was used, then, this would till effect have been 37 * outer-cbc. However, there is also a private iv1 == iv2 which 38 * perhaps makes differential analysis easier. On the other hand, the 39 * private iv1 probably makes the CRC-32 attack ineffective. This is a 40 * result of that there is no longer any known iv1 to use when 41 * choosing the X block. 42 */ 43 struct ssh1_3des_ctx 44 { 45 EVP_CIPHER_CTX k1, k2, k3; 46 }; 47 48 const EVP_CIPHER * evp_ssh1_3des(void); 49 int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); 50 51 static int 52 ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, 53 int enc) 54 { 55 struct ssh1_3des_ctx *c; 56 u_char *k1, *k2, *k3; 57 58 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { 59 if ((c = calloc(1, sizeof(*c))) == NULL) 60 return 0; 61 EVP_CIPHER_CTX_set_app_data(ctx, c); 62 } 63 if (key == NULL) 64 return 1; 65 if (enc == -1) 66 enc = ctx->encrypt; 67 k1 = k2 = k3 = (u_char *) key; 68 k2 += 8; 69 if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) { 70 if (enc) 71 k3 += 16; 72 else 73 k1 += 16; 74 } 75 EVP_CIPHER_CTX_init(&c->k1); 76 EVP_CIPHER_CTX_init(&c->k2); 77 EVP_CIPHER_CTX_init(&c->k3); 78 if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 || 79 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 || 80 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) { 81 explicit_bzero(c, sizeof(*c)); 82 free(c); 83 EVP_CIPHER_CTX_set_app_data(ctx, NULL); 84 return 0; 85 } 86 return 1; 87 } 88 89 static int 90 ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, size_t len) 91 { 92 struct ssh1_3des_ctx *c; 93 94 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) 95 return 0; 96 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 || 97 EVP_Cipher(&c->k2, dest, dest, len) == 0 || 98 EVP_Cipher(&c->k3, dest, dest, len) == 0) 99 return 0; 100 return 1; 101 } 102 103 static int 104 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx) 105 { 106 struct ssh1_3des_ctx *c; 107 108 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { 109 EVP_CIPHER_CTX_cleanup(&c->k1); 110 EVP_CIPHER_CTX_cleanup(&c->k2); 111 EVP_CIPHER_CTX_cleanup(&c->k3); 112 explicit_bzero(c, sizeof(*c)); 113 free(c); 114 EVP_CIPHER_CTX_set_app_data(ctx, NULL); 115 } 116 return 1; 117 } 118 119 int 120 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len) 121 { 122 struct ssh1_3des_ctx *c; 123 124 if (len != 24) 125 return SSH_ERR_INVALID_ARGUMENT; 126 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL) 127 return SSH_ERR_INTERNAL_ERROR; 128 if (doset) { 129 memcpy(c->k1.iv, iv, 8); 130 memcpy(c->k2.iv, iv + 8, 8); 131 memcpy(c->k3.iv, iv + 16, 8); 132 } else { 133 memcpy(iv, c->k1.iv, 8); 134 memcpy(iv + 8, c->k2.iv, 8); 135 memcpy(iv + 16, c->k3.iv, 8); 136 } 137 return 0; 138 } 139 140 const EVP_CIPHER * 141 evp_ssh1_3des(void) 142 { 143 static EVP_CIPHER ssh1_3des; 144 145 memset(&ssh1_3des, 0, sizeof(ssh1_3des)); 146 ssh1_3des.nid = NID_undef; 147 ssh1_3des.block_size = 8; 148 ssh1_3des.iv_len = 0; 149 ssh1_3des.key_len = 16; 150 ssh1_3des.init = ssh1_3des_init; 151 ssh1_3des.cleanup = ssh1_3des_cleanup; 152 ssh1_3des.do_cipher = ssh1_3des_cbc; 153 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH; 154 return &ssh1_3des; 155 } 156
