1 /* ====================================================================
2 * Copyright (c) 2008 The OpenSSL Project. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 *
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 *
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in
13 * the documentation and/or other materials provided with the
14 * distribution.
15 *
16 * 3. All advertising materials mentioning features or use of this
17 * software must display the following acknowledgment:
18 * "This product includes software developed by the OpenSSL Project
19 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
20 *
21 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
22 * endorse or promote products derived from this software without
23 * prior written permission. For written permission, please contact
24 * openssl-core@openssl.org.
25 *
26 * 5. Products derived from this software may not be called "OpenSSL"
27 * nor may "OpenSSL" appear in their names without prior written
28 * permission of the OpenSSL Project.
29 *
30 * 6. Redistributions of any form whatsoever must retain the following
31 * acknowledgment:
32 * "This product includes software developed by the OpenSSL Project
33 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
34 *
35 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
36 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
37 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
38 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
41 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
42 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
46 * OF THE POSSIBILITY OF SUCH DAMAGE.
47 * ==================================================================== */
48
49 #include <assert.h>
50 #include <string.h>
51
52 #include "internal.h"
53
54
55 #ifndef STRICT_ALIGNMENT
56 # define STRICT_ALIGNMENT 0
57 #endif
58
CRYPTO_cbc128_encrypt(const uint8_t * in,uint8_t * out,size_t len,const void * key,uint8_t ivec[16],block128_f block)59 void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
60 const void *key, uint8_t ivec[16],
61 block128_f block) {
62 size_t n;
63 const uint8_t *iv = ivec;
64
65 assert(key != NULL && ivec != NULL);
66 assert(len == 0 || (in != NULL && out != NULL));
67
68 if (STRICT_ALIGNMENT &&
69 ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
70 while (len >= 16) {
71 for (n = 0; n < 16; ++n) {
72 out[n] = in[n] ^ iv[n];
73 }
74 (*block)(out, out, key);
75 iv = out;
76 len -= 16;
77 in += 16;
78 out += 16;
79 }
80 } else {
81 while (len >= 16) {
82 for (n = 0; n < 16; n += sizeof(size_t)) {
83 *(size_t *)(out + n) = *(size_t *)(in + n) ^ *(size_t *)(iv + n);
84 }
85 (*block)(out, out, key);
86 iv = out;
87 len -= 16;
88 in += 16;
89 out += 16;
90 }
91 }
92
93 while (len) {
94 for (n = 0; n < 16 && n < len; ++n) {
95 out[n] = in[n] ^ iv[n];
96 }
97 for (; n < 16; ++n) {
98 out[n] = iv[n];
99 }
100 (*block)(out, out, key);
101 iv = out;
102 if (len <= 16) {
103 break;
104 }
105 len -= 16;
106 in += 16;
107 out += 16;
108 }
109
110 memcpy(ivec, iv, 16);
111 }
112
CRYPTO_cbc128_decrypt(const uint8_t * in,uint8_t * out,size_t len,const void * key,uint8_t ivec[16],block128_f block)113 void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
114 const void *key, uint8_t ivec[16],
115 block128_f block) {
116 size_t n;
117 union {
118 size_t t[16 / sizeof(size_t)];
119 uint8_t c[16];
120 } tmp;
121
122 assert(key != NULL && ivec != NULL);
123 assert(len == 0 || (in != NULL && out != NULL));
124
125 const uintptr_t inptr = (uintptr_t) in;
126 const uintptr_t outptr = (uintptr_t) out;
127 /* If |in| and |out| alias, |in| must be ahead. */
128 assert(inptr >= outptr || inptr + len <= outptr);
129
130 if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) {
131 /* If |out| is at least two blocks behind |in| or completely disjoint, there
132 * is no need to decrypt to a temporary block. */
133 const uint8_t *iv = ivec;
134
135 if (STRICT_ALIGNMENT &&
136 ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
137 while (len >= 16) {
138 (*block)(in, out, key);
139 for (n = 0; n < 16; ++n) {
140 out[n] ^= iv[n];
141 }
142 iv = in;
143 len -= 16;
144 in += 16;
145 out += 16;
146 }
147 } else if (16 % sizeof(size_t) == 0) { /* always true */
148 while (len >= 16) {
149 size_t *out_t = (size_t *)out, *iv_t = (size_t *)iv;
150
151 (*block)(in, out, key);
152 for (n = 0; n < 16 / sizeof(size_t); n++) {
153 out_t[n] ^= iv_t[n];
154 }
155 iv = in;
156 len -= 16;
157 in += 16;
158 out += 16;
159 }
160 }
161 memcpy(ivec, iv, 16);
162 } else {
163 /* |out| is less than two blocks behind |in|. Decrypting an input block
164 * directly to |out| would overwrite a ciphertext block before it is used as
165 * the next block's IV. Decrypt to a temporary block instead. */
166 if (STRICT_ALIGNMENT &&
167 ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
168 uint8_t c;
169 while (len >= 16) {
170 (*block)(in, tmp.c, key);
171 for (n = 0; n < 16; ++n) {
172 c = in[n];
173 out[n] = tmp.c[n] ^ ivec[n];
174 ivec[n] = c;
175 }
176 len -= 16;
177 in += 16;
178 out += 16;
179 }
180 } else if (16 % sizeof(size_t) == 0) { /* always true */
181 while (len >= 16) {
182 size_t c, *out_t = (size_t *)out, *ivec_t = (size_t *)ivec;
183 const size_t *in_t = (const size_t *)in;
184
185 (*block)(in, tmp.c, key);
186 for (n = 0; n < 16 / sizeof(size_t); n++) {
187 c = in_t[n];
188 out_t[n] = tmp.t[n] ^ ivec_t[n];
189 ivec_t[n] = c;
190 }
191 len -= 16;
192 in += 16;
193 out += 16;
194 }
195 }
196 }
197
198 while (len) {
199 uint8_t c;
200 (*block)(in, tmp.c, key);
201 for (n = 0; n < 16 && n < len; ++n) {
202 c = in[n];
203 out[n] = tmp.c[n] ^ ivec[n];
204 ivec[n] = c;
205 }
206 if (len <= 16) {
207 for (; n < 16; ++n) {
208 ivec[n] = in[n];
209 }
210 break;
211 }
212 len -= 16;
213 in += 16;
214 out += 16;
215 }
216 }
217