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