1 /* $OpenBSD: cbc128.c,v 1.5 2022/01/22 00:45:17 inoguchi Exp $ */
2 /* ====================================================================
3  * Copyright (c) 2008 The OpenSSL Project.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  *
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  *
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in
14  *    the documentation and/or other materials provided with the
15  *    distribution.
16  *
17  * 3. All advertising materials mentioning features or use of this
18  *    software must display the following acknowledgment:
19  *    "This product includes software developed by the OpenSSL Project
20  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
21  *
22  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23  *    endorse or promote products derived from this software without
24  *    prior written permission. For written permission, please contact
25  *    openssl-core@openssl.org.
26  *
27  * 5. Products derived from this software may not be called "OpenSSL"
28  *    nor may "OpenSSL" appear in their names without prior written
29  *    permission of the OpenSSL Project.
30  *
31  * 6. Redistributions of any form whatsoever must retain the following
32  *    acknowledgment:
33  *    "This product includes software developed by the OpenSSL Project
34  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
35  *
36  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
40  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47  * OF THE POSSIBILITY OF SUCH DAMAGE.
48  * ====================================================================
49  *
50  */
51 
52 #include <openssl/crypto.h>
53 #include "modes_lcl.h"
54 #include <string.h>
55 
56 #ifndef MODES_DEBUG
57 # ifndef NDEBUG
58 #  define NDEBUG
59 # endif
60 #endif
61 
62 #undef STRICT_ALIGNMENT
63 #ifdef __STRICT_ALIGNMENT
64 #define STRICT_ALIGNMENT 1
65 #else
66 #define STRICT_ALIGNMENT 0
67 #endif
68 
69 void CRYPTO_cbc128_encrypt(const unsigned char *in, unsigned char *out,
70 			size_t len, const void *key,
71 			unsigned char ivec[16], block128_f block)
72 {
73 	size_t n;
74 	const unsigned char *iv = ivec;
75 
76 #if !defined(OPENSSL_SMALL_FOOTPRINT)
77 	if (STRICT_ALIGNMENT &&
78 	    ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) {
79 		while (len>=16) {
80 			for(n=0; n<16; ++n)
81 				out[n] = in[n] ^ iv[n];
82 			(*block)(out, out, key);
83 			iv = out;
84 			len -= 16;
85 			in  += 16;
86 			out += 16;
87 		}
88 	} else {
89 		while (len>=16) {
90 			for(n=0; n<16; n+=sizeof(size_t))
91 				*(size_t*)(out+n) =
92 				*(size_t*)(in+n) ^ *(size_t*)(iv+n);
93 			(*block)(out, out, key);
94 			iv = out;
95 			len -= 16;
96 			in  += 16;
97 			out += 16;
98 		}
99 	}
100 #endif
101 	while (len) {
102 		for(n=0; n<16 && n<len; ++n)
103 			out[n] = in[n] ^ iv[n];
104 		for(; n<16; ++n)
105 			out[n] = iv[n];
106 		(*block)(out, out, key);
107 		iv = out;
108 		if (len<=16) break;
109 		len -= 16;
110 		in  += 16;
111 		out += 16;
112 	}
113 	memmove(ivec,iv,16);
114 }
115 
116 void CRYPTO_cbc128_decrypt(const unsigned char *in, unsigned char *out,
117 			size_t len, const void *key,
118 			unsigned char ivec[16], block128_f block)
119 {
120 	size_t n;
121 	union { size_t t[16/sizeof(size_t)]; unsigned char c[16]; } tmp;
122 
123 #if !defined(OPENSSL_SMALL_FOOTPRINT)
124 	if (in != out) {
125 		const unsigned char *iv = ivec;
126 
127 		if (STRICT_ALIGNMENT &&
128 		    ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) {
129 			while (len>=16) {
130 				(*block)(in, out, key);
131 				for(n=0; n<16; ++n)
132 					out[n] ^= iv[n];
133 				iv = in;
134 				len -= 16;
135 				in  += 16;
136 				out += 16;
137 			}
138 		} else if (16%sizeof(size_t) == 0) { /* always true */
139 			while (len>=16) {
140 				size_t *out_t=(size_t *)out, *iv_t=(size_t *)iv;
141 
142 				(*block)(in, out, key);
143 				for(n=0; n<16/sizeof(size_t); n++)
144 					out_t[n] ^= iv_t[n];
145 				iv = in;
146 				len -= 16;
147 				in  += 16;
148 				out += 16;
149 			}
150 		}
151 		memmove(ivec,iv,16);
152 	} else {
153 		if (STRICT_ALIGNMENT &&
154 		    ((size_t)in|(size_t)out|(size_t)ivec)%sizeof(size_t) != 0) {
155 			unsigned char c;
156 			while (len>=16) {
157 				(*block)(in, tmp.c, key);
158 				for(n=0; n<16; ++n) {
159 					c = in[n];
160 					out[n] = tmp.c[n] ^ ivec[n];
161 					ivec[n] = c;
162 				}
163 				len -= 16;
164 				in  += 16;
165 				out += 16;
166 			}
167 		} else if (16%sizeof(size_t) == 0) { /* always true */
168 			while (len>=16) {
169 				size_t c, *out_t=(size_t *)out, *ivec_t=(size_t *)ivec;
170 				const size_t *in_t=(const size_t *)in;
171 
172 				(*block)(in, tmp.c, key);
173 				for(n=0; n<16/sizeof(size_t); n++) {
174 					c = in_t[n];
175 					out_t[n] = tmp.t[n] ^ ivec_t[n];
176 					ivec_t[n] = c;
177 				}
178 				len -= 16;
179 				in  += 16;
180 				out += 16;
181 			}
182 		}
183 	}
184 #endif
185 	while (len) {
186 		unsigned char c;
187 		(*block)(in, tmp.c, key);
188 		for(n=0; n<16 && n<len; ++n) {
189 			c = in[n];
190 			out[n] = tmp.c[n] ^ ivec[n];
191 			ivec[n] = c;
192 		}
193 		if (len<=16) {
194 			for (; n<16; ++n)
195 				ivec[n] = in[n];
196 			break;
197 		}
198 		len -= 16;
199 		in  += 16;
200 		out += 16;
201 	}
202 }
203