1 /* $NetBSD: crypto-evp.c,v 1.1.1.1 2011/04/13 18:15:32 elric Exp $ */ 2 3 /* 4 * Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan 5 * (Royal Institute of Technology, Stockholm, Sweden). 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * 3. Neither the name of the Institute nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include "krb5_locl.h" 37 38 void 39 _krb5_evp_schedule(krb5_context context, 40 struct _krb5_key_type *kt, 41 struct _krb5_key_data *kd) 42 { 43 struct _krb5_evp_schedule *key = kd->schedule->data; 44 const EVP_CIPHER *c = (*kt->evp)(); 45 46 EVP_CIPHER_CTX_init(&key->ectx); 47 EVP_CIPHER_CTX_init(&key->dctx); 48 49 EVP_CipherInit_ex(&key->ectx, c, NULL, kd->key->keyvalue.data, NULL, 1); 50 EVP_CipherInit_ex(&key->dctx, c, NULL, kd->key->keyvalue.data, NULL, 0); 51 } 52 53 void 54 _krb5_evp_cleanup(krb5_context context, struct _krb5_key_data *kd) 55 { 56 struct _krb5_evp_schedule *key = kd->schedule->data; 57 EVP_CIPHER_CTX_cleanup(&key->ectx); 58 EVP_CIPHER_CTX_cleanup(&key->dctx); 59 } 60 61 krb5_error_code 62 _krb5_evp_encrypt(krb5_context context, 63 struct _krb5_key_data *key, 64 void *data, 65 size_t len, 66 krb5_boolean encryptp, 67 int usage, 68 void *ivec) 69 { 70 struct _krb5_evp_schedule *ctx = key->schedule->data; 71 EVP_CIPHER_CTX *c; 72 c = encryptp ? &ctx->ectx : &ctx->dctx; 73 if (ivec == NULL) { 74 /* alloca ? */ 75 size_t len2 = EVP_CIPHER_CTX_iv_length(c); 76 void *loiv = malloc(len2); 77 if (loiv == NULL) { 78 krb5_clear_error_message(context); 79 return ENOMEM; 80 } 81 memset(loiv, 0, len2); 82 EVP_CipherInit_ex(c, NULL, NULL, NULL, loiv, -1); 83 free(loiv); 84 } else 85 EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1); 86 EVP_Cipher(c, data, data, len); 87 return 0; 88 } 89 90 static const unsigned char zero_ivec[EVP_MAX_BLOCK_LENGTH] = { 0 }; 91 92 krb5_error_code 93 _krb5_evp_encrypt_cts(krb5_context context, 94 struct _krb5_key_data *key, 95 void *data, 96 size_t len, 97 krb5_boolean encryptp, 98 int usage, 99 void *ivec) 100 { 101 size_t i, blocksize; 102 struct _krb5_evp_schedule *ctx = key->schedule->data; 103 char tmp[EVP_MAX_BLOCK_LENGTH], ivec2[EVP_MAX_BLOCK_LENGTH]; 104 EVP_CIPHER_CTX *c; 105 unsigned char *p; 106 107 c = encryptp ? &ctx->ectx : &ctx->dctx; 108 109 blocksize = EVP_CIPHER_CTX_block_size(c); 110 111 if (len < blocksize) { 112 krb5_set_error_message(context, EINVAL, 113 "message block too short"); 114 return EINVAL; 115 } else if (len == blocksize) { 116 EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1); 117 EVP_Cipher(c, data, data, len); 118 return 0; 119 } 120 121 if (ivec) 122 EVP_CipherInit_ex(c, NULL, NULL, NULL, ivec, -1); 123 else 124 EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1); 125 126 if (encryptp) { 127 128 p = data; 129 i = ((len - 1) / blocksize) * blocksize; 130 EVP_Cipher(c, p, p, i); 131 p += i - blocksize; 132 len -= i; 133 memcpy(ivec2, p, blocksize); 134 135 for (i = 0; i < len; i++) 136 tmp[i] = p[i + blocksize] ^ ivec2[i]; 137 for (; i < blocksize; i++) 138 tmp[i] = 0 ^ ivec2[i]; 139 140 EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1); 141 EVP_Cipher(c, p, tmp, blocksize); 142 143 memcpy(p + blocksize, ivec2, len); 144 if (ivec) 145 memcpy(ivec, p, blocksize); 146 } else { 147 char tmp2[EVP_MAX_BLOCK_LENGTH], tmp3[EVP_MAX_BLOCK_LENGTH]; 148 149 p = data; 150 if (len > blocksize * 2) { 151 /* remove last two blocks and round up, decrypt this with cbc, then do cts dance */ 152 i = ((((len - blocksize * 2) + blocksize - 1) / blocksize) * blocksize); 153 memcpy(ivec2, p + i - blocksize, blocksize); 154 EVP_Cipher(c, p, p, i); 155 p += i; 156 len -= i + blocksize; 157 } else { 158 if (ivec) 159 memcpy(ivec2, ivec, blocksize); 160 else 161 memcpy(ivec2, zero_ivec, blocksize); 162 len -= blocksize; 163 } 164 165 memcpy(tmp, p, blocksize); 166 EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1); 167 EVP_Cipher(c, tmp2, p, blocksize); 168 169 memcpy(tmp3, p + blocksize, len); 170 memcpy(tmp3 + len, tmp2 + len, blocksize - len); /* xor 0 */ 171 172 for (i = 0; i < len; i++) 173 p[i + blocksize] = tmp2[i] ^ tmp3[i]; 174 175 EVP_CipherInit_ex(c, NULL, NULL, NULL, zero_ivec, -1); 176 EVP_Cipher(c, p, tmp3, blocksize); 177 178 for (i = 0; i < blocksize; i++) 179 p[i] ^= ivec2[i]; 180 if (ivec) 181 memcpy(ivec, tmp, blocksize); 182 } 183 return 0; 184 } 185