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 <openssl/type_check.h>
50
51 #include <assert.h>
52 #include <string.h>
53
54 #include "internal.h"
55
56
57 OPENSSL_COMPILE_ASSERT((16 % sizeof(size_t)) == 0, bad_size_t_size_cfb);
58
CRYPTO_cfb128_encrypt(const uint8_t * in,uint8_t * out,size_t len,const void * key,uint8_t ivec[16],unsigned * num,int enc,block128_f block)59 void CRYPTO_cfb128_encrypt(const uint8_t *in, uint8_t *out, size_t len,
60 const void *key, uint8_t ivec[16], unsigned *num,
61 int enc, block128_f block) {
62 size_t l = 0;
63
64 assert(in && out && key && ivec && num);
65
66 unsigned n = *num;
67
68 if (enc) {
69 while (n && len) {
70 *(out++) = ivec[n] ^= *(in++);
71 --len;
72 n = (n + 1) % 16;
73 }
74 #if STRICT_ALIGNMENT
75 if (((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
76 while (l < len) {
77 if (n == 0) {
78 (*block)(ivec, ivec, key);
79 }
80 out[l] = ivec[n] ^= in[l];
81 ++l;
82 n = (n + 1) % 16;
83 }
84 *num = n;
85 return;
86 }
87 #endif
88 while (len >= 16) {
89 (*block)(ivec, ivec, key);
90 for (; n < 16; n += sizeof(size_t)) {
91 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^= *(size_t *)(in + n);
92 }
93 len -= 16;
94 out += 16;
95 in += 16;
96 n = 0;
97 }
98 if (len) {
99 (*block)(ivec, ivec, key);
100 while (len--) {
101 out[n] = ivec[n] ^= in[n];
102 ++n;
103 }
104 }
105 *num = n;
106 return;
107 } else {
108 while (n && len) {
109 uint8_t c;
110 *(out++) = ivec[n] ^ (c = *(in++));
111 ivec[n] = c;
112 --len;
113 n = (n + 1) % 16;
114 }
115 if (STRICT_ALIGNMENT && ((size_t)in | (size_t)out | (size_t)ivec) % sizeof(size_t) != 0) {
116 while (l < len) {
117 unsigned char c;
118 if (n == 0) {
119 (*block)(ivec, ivec, key);
120 }
121 out[l] = ivec[n] ^ (c = in[l]);
122 ivec[n] = c;
123 ++l;
124 n = (n + 1) % 16;
125 }
126 *num = n;
127 return;
128 }
129 while (len >= 16) {
130 (*block)(ivec, ivec, key);
131 for (; n < 16; n += sizeof(size_t)) {
132 size_t t = *(size_t *)(in + n);
133 *(size_t *)(out + n) = *(size_t *)(ivec + n) ^ t;
134 *(size_t *)(ivec + n) = t;
135 }
136 len -= 16;
137 out += 16;
138 in += 16;
139 n = 0;
140 }
141 if (len) {
142 (*block)(ivec, ivec, key);
143 while (len--) {
144 uint8_t c;
145 out[n] = ivec[n] ^ (c = in[n]);
146 ivec[n] = c;
147 ++n;
148 }
149 }
150 *num = n;
151 return;
152 }
153 }
154
155
156 /* This expects a single block of size nbits for both in and out. Note that
157 it corrupts any extra bits in the last byte of out */
cfbr_encrypt_block(const uint8_t * in,uint8_t * out,unsigned nbits,const void * key,uint8_t ivec[16],int enc,block128_f block)158 static void cfbr_encrypt_block(const uint8_t *in, uint8_t *out, unsigned nbits,
159 const void *key, uint8_t ivec[16], int enc,
160 block128_f block) {
161 int n, rem, num;
162 uint8_t ovec[16 * 2 + 1]; /* +1 because we dererefence (but don't use) one
163 byte off the end */
164
165 if (nbits <= 0 || nbits > 128) {
166 return;
167 }
168
169 /* fill in the first half of the new IV with the current IV */
170 OPENSSL_memcpy(ovec, ivec, 16);
171 /* construct the new IV */
172 (*block)(ivec, ivec, key);
173 num = (nbits + 7) / 8;
174 if (enc) {
175 /* encrypt the input */
176 for (n = 0; n < num; ++n) {
177 out[n] = (ovec[16 + n] = in[n] ^ ivec[n]);
178 }
179 } else {
180 /* decrypt the input */
181 for (n = 0; n < num; ++n) {
182 out[n] = (ovec[16 + n] = in[n]) ^ ivec[n];
183 }
184 }
185 /* shift ovec left... */
186 rem = nbits % 8;
187 num = nbits / 8;
188 if (rem == 0) {
189 OPENSSL_memcpy(ivec, ovec + num, 16);
190 } else {
191 for (n = 0; n < 16; ++n) {
192 ivec[n] = ovec[n + num] << rem | ovec[n + num + 1] >> (8 - rem);
193 }
194 }
195
196 /* it is not necessary to cleanse ovec, since the IV is not secret */
197 }
198
199 /* N.B. This expects the input to be packed, MS bit first */
CRYPTO_cfb128_1_encrypt(const uint8_t * in,uint8_t * out,size_t bits,const void * key,uint8_t ivec[16],unsigned * num,int enc,block128_f block)200 void CRYPTO_cfb128_1_encrypt(const uint8_t *in, uint8_t *out, size_t bits,
201 const void *key, uint8_t ivec[16], unsigned *num,
202 int enc, block128_f block) {
203 size_t n;
204 uint8_t c[1], d[1];
205
206 assert(in && out && key && ivec && num);
207 assert(*num == 0);
208
209 for (n = 0; n < bits; ++n) {
210 c[0] = (in[n / 8] & (1 << (7 - n % 8))) ? 0x80 : 0;
211 cfbr_encrypt_block(c, d, 1, key, ivec, enc, block);
212 out[n / 8] = (out[n / 8] & ~(1 << (unsigned int)(7 - n % 8))) |
213 ((d[0] & 0x80) >> (unsigned int)(n % 8));
214 }
215 }
216
CRYPTO_cfb128_8_encrypt(const unsigned char * in,unsigned char * out,size_t length,const void * key,unsigned char ivec[16],unsigned * num,int enc,block128_f block)217 void CRYPTO_cfb128_8_encrypt(const unsigned char *in, unsigned char *out,
218 size_t length, const void *key,
219 unsigned char ivec[16], unsigned *num, int enc,
220 block128_f block) {
221 size_t n;
222
223 assert(in && out && key && ivec && num);
224 assert(*num == 0);
225
226 for (n = 0; n < length; ++n) {
227 cfbr_encrypt_block(&in[n], &out[n], 8, key, ivec, enc, block);
228 }
229 }
230
231