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 * [email protected].
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 #include "../../internal.h"
54
55
CRYPTO_cbc128_encrypt(const uint8_t * in,uint8_t * out,size_t len,const AES_KEY * key,uint8_t ivec[16],block128_f block)56 void CRYPTO_cbc128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
57 const AES_KEY *key, uint8_t ivec[16],
58 block128_f block) {
59 assert(key != NULL && ivec != NULL);
60 if (len == 0) {
61 // Avoid |ivec| == |iv| in the |memcpy| below, which is not legal in C.
62 return;
63 }
64
65 assert(in != NULL && out != NULL);
66 size_t n;
67 const uint8_t *iv = ivec;
68 while (len >= 16) {
69 CRYPTO_xor16(out, in, iv);
70 (*block)(out, out, key);
71 iv = out;
72 len -= 16;
73 in += 16;
74 out += 16;
75 }
76
77 while (len) {
78 for (n = 0; n < 16 && n < len; ++n) {
79 out[n] = in[n] ^ iv[n];
80 }
81 for (; n < 16; ++n) {
82 out[n] = iv[n];
83 }
84 (*block)(out, out, key);
85 iv = out;
86 if (len <= 16) {
87 break;
88 }
89 len -= 16;
90 in += 16;
91 out += 16;
92 }
93
94 OPENSSL_memcpy(ivec, iv, 16);
95 }
96
CRYPTO_cbc128_decrypt(const uint8_t * in,uint8_t * out,size_t len,const AES_KEY * key,uint8_t ivec[16],block128_f block)97 void CRYPTO_cbc128_decrypt(const uint8_t *in, uint8_t *out, size_t len,
98 const AES_KEY *key, uint8_t ivec[16],
99 block128_f block) {
100 assert(key != NULL && ivec != NULL);
101 if (len == 0) {
102 // Avoid |ivec| == |iv| in the |memcpy| below, which is not legal in C.
103 return;
104 }
105
106 assert(in != NULL && out != NULL);
107
108 const uintptr_t inptr = (uintptr_t) in;
109 const uintptr_t outptr = (uintptr_t) out;
110 // If |in| and |out| alias, |in| must be ahead.
111 assert(inptr >= outptr || inptr + len <= outptr);
112
113 size_t n;
114 alignas(16) uint8_t tmp[16];
115 if ((inptr >= 32 && outptr <= inptr - 32) || inptr < outptr) {
116 // If |out| is at least two blocks behind |in| or completely disjoint, there
117 // is no need to decrypt to a temporary block.
118 const uint8_t *iv = ivec;
119 while (len >= 16) {
120 (*block)(in, out, key);
121 CRYPTO_xor16(out, out, iv);
122 iv = in;
123 len -= 16;
124 in += 16;
125 out += 16;
126 }
127 OPENSSL_memcpy(ivec, iv, 16);
128 } else {
129 static_assert(16 % sizeof(crypto_word_t) == 0,
130 "block cannot be evenly divided into words");
131
132 while (len >= 16) {
133 (*block)(in, tmp, key);
134 for (n = 0; n < 16; n += sizeof(crypto_word_t)) {
135 crypto_word_t c = CRYPTO_load_word_le(in + n);
136 CRYPTO_store_word_le(out + n, CRYPTO_load_word_le(tmp + n) ^
137 CRYPTO_load_word_le(ivec + n));
138 CRYPTO_store_word_le(ivec + n, c);
139 }
140 len -= 16;
141 in += 16;
142 out += 16;
143 }
144 }
145
146 while (len) {
147 uint8_t c;
148 (*block)(in, tmp, key);
149 for (n = 0; n < 16 && n < len; ++n) {
150 c = in[n];
151 out[n] = tmp[n] ^ ivec[n];
152 ivec[n] = c;
153 }
154 if (len <= 16) {
155 for (; n < 16; ++n) {
156 ivec[n] = in[n];
157 }
158 break;
159 }
160 len -= 16;
161 in += 16;
162 out += 16;
163 }
164 }
165