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
CRYPTO_cbc128_encrypt(const uint8_t * in,uint8_t * out,size_t len,const void * key,uint8_t ivec[16],block128_f block)55 void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
56 const void *key, uint8_t ivec[16],
57 block128_f block) {
58 size_t n;
59 const uint8_t *iv = ivec;
60
61 assert(key != NULL && ivec != NULL);
62 assert(len == 0 || (in != NULL && out != NULL));
63
64 if (STRICT_ALIGNMENT &&
65 ((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) !=
66 0) {
67 while (len >= 16) {
68 for (n = 0; n < 16; ++n) {
69 out[n] = in[n] ^ iv[n];
70 }
71 (*block)(out, out, key);
72 iv = out;
73 len -= 16;
74 in += 16;
75 out += 16;
76 }
77 } else {
78 while (len >= 16) {
79 for (n = 0; n < 16; n += sizeof(size_t)) {
80 store_word_le(out + n, load_word_le(in + n) ^ load_word_le(iv + n));
81 }
82 (*block)(out, out, key);
83 iv = out;
84 len -= 16;
85 in += 16;
86 out += 16;
87 }
88 }
89
90 while (len) {
91 for (n = 0; n < 16 && n < len; ++n) {
92 out[n] = in[n] ^ iv[n];
93 }
94 for (; n < 16; ++n) {
95 out[n] = iv[n];
96 }
97 (*block)(out, out, key);
98 iv = out;
99 if (len <= 16) {
100 break;
101 }
102 len -= 16;
103 in += 16;
104 out += 16;
105 }
106
107 OPENSSL_memcpy(ivec, iv, 16);
108 }
109
CRYPTO_cbc128_decrypt(const uint8_t * in,uint8_t * out,size_t len,const void * key,uint8_t ivec[16],block128_f block)110 void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
111 const void *key, uint8_t ivec[16],
112 block128_f block) {
113 size_t n;
114 union {
115 size_t t[16 / sizeof(size_t)];
116 uint8_t c[16];
117 } tmp;
118
119 assert(key != NULL && ivec != NULL);
120 assert(len == 0 || (in != NULL && out != NULL));
121
122 const uintptr_t inptr = (uintptr_t) in;
123 const uintptr_t outptr = (uintptr_t) out;
124 // If |in| and |out| alias, |in| must be ahead.
125 assert(inptr >= outptr || inptr + len <= outptr);
126
127 if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) {
128 // If |out| is at least two blocks behind |in| or completely disjoint, there
129 // is no need to decrypt to a temporary block.
130 const uint8_t *iv = ivec;
131
132 if (STRICT_ALIGNMENT &&
133 ((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) !=
134 0) {
135 while (len >= 16) {
136 (*block)(in, out, key);
137 for (n = 0; n < 16; ++n) {
138 out[n] ^= iv[n];
139 }
140 iv = in;
141 len -= 16;
142 in += 16;
143 out += 16;
144 }
145 } else if (16 % sizeof(size_t) == 0) { // always true
146 while (len >= 16) {
147 (*block)(in, out, key);
148 for (n = 0; n < 16; n += sizeof(size_t)) {
149 store_word_le(out + n, load_word_le(out + n) ^ load_word_le(iv + n));
150 }
151 iv = in;
152 len -= 16;
153 in += 16;
154 out += 16;
155 }
156 }
157 OPENSSL_memcpy(ivec, iv, 16);
158 } else {
159 // |out| is less than two blocks behind |in|. Decrypting an input block
160 // directly to |out| would overwrite a ciphertext block before it is used as
161 // the next block's IV. Decrypt to a temporary block instead.
162 if (STRICT_ALIGNMENT &&
163 ((uintptr_t)in | (uintptr_t)out | (uintptr_t)ivec) % sizeof(size_t) !=
164 0) {
165 uint8_t c;
166 while (len >= 16) {
167 (*block)(in, tmp.c, key);
168 for (n = 0; n < 16; ++n) {
169 c = in[n];
170 out[n] = tmp.c[n] ^ ivec[n];
171 ivec[n] = c;
172 }
173 len -= 16;
174 in += 16;
175 out += 16;
176 }
177 } else if (16 % sizeof(size_t) == 0) { // always true
178 while (len >= 16) {
179 (*block)(in, tmp.c, key);
180 for (n = 0; n < 16; n += sizeof(size_t)) {
181 size_t c = load_word_le(in + n);
182 store_word_le(out + n,
183 tmp.t[n / sizeof(size_t)] ^ load_word_le(ivec + n));
184 store_word_le(ivec + n, c);
185 }
186 len -= 16;
187 in += 16;
188 out += 16;
189 }
190 }
191 }
192
193 while (len) {
194 uint8_t c;
195 (*block)(in, tmp.c, key);
196 for (n = 0; n < 16 && n < len; ++n) {
197 c = in[n];
198 out[n] = tmp.c[n] ^ ivec[n];
199 ivec[n] = c;
200 }
201 if (len <= 16) {
202 for (; n < 16; ++n) {
203 ivec[n] = in[n];
204 }
205 break;
206 }
207 len -= 16;
208 in += 16;
209 out += 16;
210 }
211 }
212