1 /*
2 * Copyright (C) 1998,1999,2000,2001 Nikos Mavroyanopoulos
3 *
4 * This library is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU Library General Public License as published
6 * by the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
18 */
19
20 #include <libdefs.h>
21 #include <mcrypt_modules.h>
22
23 #define _init_mcrypt ncfb_LTX__init_mcrypt
24 #define _mcrypt_set_state ncfb_LTX__mcrypt_set_state
25 #define _mcrypt_get_state ncfb_LTX__mcrypt_get_state
26 #define _end_mcrypt ncfb_LTX__end_mcrypt
27 #define _mcrypt ncfb_LTX__mcrypt
28 #define _mdecrypt ncfb_LTX__mdecrypt
29 #define _has_iv ncfb_LTX__has_iv
30 #define _is_block_mode ncfb_LTX__is_block_mode
31 #define _is_block_algorithm_mode ncfb_LTX__is_block_algorithm_mode
32 #define _mcrypt_get_modes_name ncfb_LTX__mcrypt_get_modes_name
33 #define _mcrypt_mode_get_size ncfb_LTX__mcrypt_mode_get_size
34 #define _mcrypt_mode_version ncfb_LTX__mcrypt_mode_version
35
36 typedef struct ncfb_buf {
37 byte* enc_s_register;
38 byte* s_register;
39 int s_register_pos;
40 int blocksize;
41 } nCFB_BUFFER;
42
43 /* nCFB MODE */
44
_init_mcrypt(nCFB_BUFFER * buf,void * key,int lenofkey,void * IV,int size)45 int _init_mcrypt( nCFB_BUFFER* buf, void *key, int lenofkey, void *IV, int size)
46 {
47 buf->enc_s_register = buf->s_register = NULL;
48 buf->s_register_pos = 0;
49
50 buf->blocksize = size;
51
52 /* For cfb */
53 buf->enc_s_register=malloc( size);
54 if (buf->enc_s_register==NULL) goto freeall;
55
56 buf->s_register=malloc( size);
57 if (buf->s_register==NULL) goto freeall;
58
59 if (IV!=NULL) {
60 memcpy(buf->enc_s_register, IV, size);
61 memcpy(buf->s_register, IV, size);
62 } else {
63 memset(buf->enc_s_register, 0, size);
64 memset(buf->s_register, 0, size);
65 }
66
67 /* End ncfb */
68
69 return 0;
70 freeall:
71 free(buf->enc_s_register);
72 free(buf->s_register);
73 return -1;
74 }
75
_mcrypt_set_state(nCFB_BUFFER * buf,byte * IV,int size)76 int _mcrypt_set_state( nCFB_BUFFER* buf, byte *IV, int size)
77 {
78 buf->s_register_pos = IV[0];
79 memcpy(buf->enc_s_register, &IV[1], size-1);
80 memcpy(buf->s_register, &IV[1], size-1);
81
82 return 0;
83 }
84
_mcrypt_get_state(nCFB_BUFFER * buf,byte * IV,int * size)85 int _mcrypt_get_state( nCFB_BUFFER* buf, byte *IV, int *size)
86 {
87 if (*size < buf->blocksize + 1) {
88 *size = buf->blocksize + 1;
89 return -1;
90 }
91 *size = buf->blocksize + 1;
92
93 IV[0] = buf->s_register_pos;
94 memcpy( &IV[1], buf->s_register, buf->blocksize);
95
96 return 0;
97 }
98
_end_mcrypt(nCFB_BUFFER * buf)99 void _end_mcrypt( nCFB_BUFFER* buf) {
100 free(buf->enc_s_register);
101 free(buf->s_register);
102 }
103
104 inline static
xor_stuff_en(nCFB_BUFFER * buf,void * akey,void (* func)(void *,void *),byte * plain,int blocksize,int xor_size)105 void xor_stuff_en( nCFB_BUFFER *buf, void* akey, void (*func)(void*,void*), byte* plain, int blocksize, int xor_size)
106 {
107 void (*_mcrypt_block_encrypt) (void *, void *);
108
109 _mcrypt_block_encrypt = func;
110
111 if (xor_size == blocksize) {
112 if (buf->s_register_pos == 0) {
113
114 memcpy(buf->enc_s_register, buf->s_register, blocksize);
115
116 _mcrypt_block_encrypt(akey, buf->enc_s_register);
117
118 memxor( plain, buf->enc_s_register, blocksize);
119
120 memcpy(buf->s_register, plain, blocksize);
121
122 } else {
123 int size = blocksize - buf->s_register_pos;
124
125 memxor( plain, &buf->enc_s_register[buf->s_register_pos],
126 size);
127
128 memcpy(buf->enc_s_register, buf->s_register, blocksize);
129
130 _mcrypt_block_encrypt(akey, buf->enc_s_register);
131
132 memxor( &plain[size], buf->enc_s_register,
133 buf->s_register_pos);
134
135 memcpy( &buf->s_register[size],
136 plain, buf->s_register_pos);
137
138 /* buf->s_register_pos remains the same */
139 }
140 } else { /* xor_size != blocksize */
141 if (buf->s_register_pos == 0) {
142 memcpy(buf->enc_s_register, buf->s_register, blocksize);
143
144 _mcrypt_block_encrypt(akey, buf->enc_s_register);
145
146 memxor( plain, buf->enc_s_register, xor_size);
147
148 memcpy(buf->s_register, plain, xor_size);
149
150 buf->s_register_pos = xor_size;
151 } else {
152 int size = blocksize - buf->s_register_pos;
153 int min_size = size < xor_size ? size: xor_size;
154
155 memxor( plain, &buf->enc_s_register[buf->s_register_pos],
156 min_size);
157
158 memcpy( &buf->s_register[buf->s_register_pos], plain, min_size);
159
160 buf->s_register_pos += min_size;
161
162 if (min_size >= xor_size)
163 return;
164
165 memcpy(buf->enc_s_register, buf->s_register, blocksize);
166
167 _mcrypt_block_encrypt(akey, buf->enc_s_register);
168
169 memxor( &plain[min_size], buf->s_register,
170 xor_size - min_size);
171
172 buf->s_register_pos = xor_size - min_size;
173
174 memcpy(buf->s_register, plain, xor_size - min_size);
175 }
176
177 }
178 return;
179 }
180
181 inline static
xor_stuff_de(nCFB_BUFFER * buf,void * akey,void (* func)(void *,void *),byte * cipher,int blocksize,int xor_size)182 void xor_stuff_de( nCFB_BUFFER *buf, void* akey, void (*func)(void*,void*), byte* cipher, int blocksize, int xor_size)
183 {
184 void (*_mcrypt_block_encrypt) (void *, void *);
185
186 _mcrypt_block_encrypt = func;
187
188 if (xor_size == blocksize) {
189 if (buf->s_register_pos == 0) {
190
191 memcpy(buf->enc_s_register, buf->s_register, blocksize);
192
193 _mcrypt_block_encrypt(akey, buf->enc_s_register);
194
195 memcpy(buf->s_register, cipher, blocksize);
196
197 memxor( cipher, buf->enc_s_register, blocksize);
198
199
200 } else {
201 int size = blocksize - buf->s_register_pos;
202
203 memxor( cipher, &buf->enc_s_register[buf->s_register_pos],
204 size);
205
206 memcpy(buf->enc_s_register, buf->s_register, blocksize);
207
208 _mcrypt_block_encrypt(akey, buf->enc_s_register);
209
210 memcpy( &buf->s_register[size],
211 cipher, buf->s_register_pos);
212
213 memxor( &cipher[size], buf->enc_s_register,
214 buf->s_register_pos);
215
216
217 /* buf->s_register_pos remains the same */
218 }
219 } else { /* xor_size != blocksize */
220 if (buf->s_register_pos == 0) {
221 memcpy(buf->enc_s_register, buf->s_register, blocksize);
222
223 _mcrypt_block_encrypt(akey, buf->enc_s_register);
224
225 memcpy(buf->s_register, cipher, xor_size);
226
227 memxor( cipher, buf->enc_s_register, xor_size);
228
229
230 buf->s_register_pos = xor_size;
231 } else {
232 int size = blocksize - buf->s_register_pos;
233 int min_size = size < xor_size ? size: xor_size;
234
235 memxor( cipher, &buf->enc_s_register[buf->s_register_pos],
236 min_size);
237
238 memcpy( &buf->s_register[buf->s_register_pos], cipher, min_size);
239
240 buf->s_register_pos += min_size;
241
242 if (min_size >= xor_size)
243 return;
244
245 memcpy(buf->enc_s_register, buf->s_register, blocksize);
246
247 _mcrypt_block_encrypt(akey, buf->enc_s_register);
248
249 memcpy(buf->s_register, cipher, xor_size - min_size);
250
251 memxor( &cipher[min_size], buf->s_register,
252 xor_size - min_size);
253
254 buf->s_register_pos = xor_size - min_size;
255
256 }
257
258 }
259 return;
260 }
261
262
_mcrypt(nCFB_BUFFER * buf,void * plaintext,int len,int blocksize,void * akey,void (* func)(void *,void *),void (* func2)(void *,void *))263 int _mcrypt( nCFB_BUFFER* buf,void *plaintext, int len, int blocksize, void* akey, void (*func)(void*,void*), void (*func2)(void*,void*))
264 { /* plaintext is n*blocksize bytes (nbit cfb) */
265 byte* plain;
266 int i, j=0;
267 void (*_mcrypt_block_encrypt) (void *, void *);
268 int modlen;
269
270 _mcrypt_block_encrypt = func;
271
272 plain = plaintext;
273 for (j = 0; j < len / blocksize; j++) {
274 xor_stuff_en( buf, akey, func, plain, blocksize, blocksize);
275
276 plain += blocksize;
277
278 }
279 modlen = len % blocksize;
280 if (modlen > 0) {
281 xor_stuff_en( buf, akey, func, plain, blocksize, modlen);
282 }
283
284 return 0;
285 }
286
287
_mdecrypt(nCFB_BUFFER * buf,void * plaintext,int len,int blocksize,void * akey,void (* func)(void *,void *),void (* func2)(void *,void *))288 int _mdecrypt( nCFB_BUFFER* buf,void *plaintext, int len, int blocksize, void* akey, void (*func)(void*,void*), void (*func2)(void*,void*))
289 { /* plaintext is n*blocksize bytes (nbit cfb) */
290 byte* plain;
291 int i, j=0;
292 void (*_mcrypt_block_encrypt) (void *, void *);
293 int modlen;
294
295 _mcrypt_block_encrypt = func;
296
297 plain = plaintext;
298 for (j = 0; j < len / blocksize; j++) {
299 xor_stuff_de( buf, akey, func, plain, blocksize, blocksize);
300
301 plain += blocksize;
302
303 }
304 modlen = len % blocksize;
305 if (modlen > 0) {
306 xor_stuff_de( buf, akey, func, plain, blocksize, modlen);
307 }
308
309 return 0;
310 }
311
312
_has_iv()313 int _has_iv() { return 1; }
_is_block_mode()314 int _is_block_mode() { return 0; }
_is_block_algorithm_mode()315 int _is_block_algorithm_mode() { return 1; }
_mcrypt_get_modes_name()316 const char *_mcrypt_get_modes_name() { return "nCFB";}
_mcrypt_mode_get_size()317 int _mcrypt_mode_get_size () {return sizeof(nCFB_BUFFER);}
318
319
_mcrypt_mode_version()320 word32 _mcrypt_mode_version() {
321 return 20020307;
322 }
323
324 #ifdef WIN32
325 # ifdef USE_LTDL
main(void)326 WIN32DLL_DEFINE int main (void)
327 {
328 /* empty main function to avoid linker error (see cygwin FAQ) */
329 }
330 # endif
331 #endif
332