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
_krb5_evp_schedule(krb5_context context,struct _krb5_key_type * kt,struct _krb5_key_data * kd)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 key->ectx = EVP_CIPHER_CTX_new();
45 key->dctx = EVP_CIPHER_CTX_new();
46 if (key->ectx == NULL || key->dctx == NULL)
47 krb5_abort(context, ENOMEM, "malloc failed");
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
_krb5_evp_cleanup(krb5_context context,struct _krb5_key_data * kd)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_free(key->ectx);
58 EVP_CIPHER_CTX_free(key->dctx);
59 }
60
61 krb5_error_code
_krb5_evp_encrypt(krb5_context context,struct _krb5_key_data * key,void * data,size_t len,krb5_boolean encryptp,int usage,void * ivec)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
_krb5_evp_encrypt_cts(krb5_context context,struct _krb5_key_data * key,void * data,size_t len,krb5_boolean encryptp,int usage,void * ivec)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 unsigned 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 unsigned 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