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 #ifdef WITH_SSH1 24 25 #include <sys/types.h> 26 #include <string.h> 27 #include <openssl/evp.h> 28 29 #include "ssherr.h" 30 31 /* 32 * This is used by SSH1: 33 * 34 * What kind of triple DES are these 2 routines? 35 * 36 * Why is there a redundant initialization vector? 37 * 38 * If only iv3 was used, then, this would till effect have been 39 * outer-cbc. However, there is also a private iv1 == iv2 which 40 * perhaps makes differential analysis easier. On the other hand, the 41 * private iv1 probably makes the CRC-32 attack ineffective. This is a 42 * result of that there is no longer any known iv1 to use when 43 * choosing the X block. 44 */ 45 struct ssh1_3des_ctx 46 { 47 EVP_CIPHER_CTX k1, k2, k3; 48 }; 49 50 const EVP_CIPHER * evp_ssh1_3des(void); 51 int ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int); 52 53 static int 54 ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv, 55 int enc) 56 { 57 struct ssh1_3des_ctx *c; 58 u_char *k1, *k2, *k3; 59 60 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) { 61 if ((c = calloc(1, sizeof(*c))) == NULL) 62 return 0; 63 EVP_CIPHER_CTX_set_app_data(ctx, c); 64 } 65 if (key == NULL) 66 return 1; 67 if (enc == -1) 68 enc = ctx->encrypt; 69 k1 = k2 = k3 = (u_char *) key; 70 k2 += 8; 71 if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) { 72 if (enc) 73 k3 += 16; 74 else 75 k1 += 16; 76 } 77 EVP_CIPHER_CTX_init(&c->k1); 78 EVP_CIPHER_CTX_init(&c->k2); 79 EVP_CIPHER_CTX_init(&c->k3); 80 if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 || 81 EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 || 82 EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) { 83 explicit_bzero(c, sizeof(*c)); 84 free(c); 85 EVP_CIPHER_CTX_set_app_data(ctx, NULL); 86 return 0; 87 } 88 return 1; 89 } 90 91 static int 92 ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, size_t len) 93 { 94 struct ssh1_3des_ctx *c; 95 96 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) 97 return 0; 98 if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 || 99 EVP_Cipher(&c->k2, dest, dest, len) == 0 || 100 EVP_Cipher(&c->k3, dest, dest, len) == 0) 101 return 0; 102 return 1; 103 } 104 105 static int 106 ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx) 107 { 108 struct ssh1_3des_ctx *c; 109 110 if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) { 111 EVP_CIPHER_CTX_cleanup(&c->k1); 112 EVP_CIPHER_CTX_cleanup(&c->k2); 113 EVP_CIPHER_CTX_cleanup(&c->k3); 114 explicit_bzero(c, sizeof(*c)); 115 free(c); 116 EVP_CIPHER_CTX_set_app_data(ctx, NULL); 117 } 118 return 1; 119 } 120 121 int 122 ssh1_3des_iv(EVP_CIPHER_CTX *evp, int doset, u_char *iv, int len) 123 { 124 struct ssh1_3des_ctx *c; 125 126 if (len != 24) 127 return SSH_ERR_INVALID_ARGUMENT; 128 if ((c = EVP_CIPHER_CTX_get_app_data(evp)) == NULL) 129 return SSH_ERR_INTERNAL_ERROR; 130 if (doset) { 131 memcpy(c->k1.iv, iv, 8); 132 memcpy(c->k2.iv, iv + 8, 8); 133 memcpy(c->k3.iv, iv + 16, 8); 134 } else { 135 memcpy(iv, c->k1.iv, 8); 136 memcpy(iv + 8, c->k2.iv, 8); 137 memcpy(iv + 16, c->k3.iv, 8); 138 } 139 return 0; 140 } 141 142 const EVP_CIPHER * 143 evp_ssh1_3des(void) 144 { 145 static EVP_CIPHER ssh1_3des; 146 147 memset(&ssh1_3des, 0, sizeof(ssh1_3des)); 148 ssh1_3des.nid = NID_undef; 149 ssh1_3des.block_size = 8; 150 ssh1_3des.iv_len = 0; 151 ssh1_3des.key_len = 16; 152 ssh1_3des.init = ssh1_3des_init; 153 ssh1_3des.cleanup = ssh1_3des_cleanup; 154 ssh1_3des.do_cipher = ssh1_3des_cbc; 155 ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH; 156 return &ssh1_3des; 157 } 158 #endif /* WITH_SSH1 */ 159
