1 /* crypto/asn1/a_int.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to. The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 * notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 * notice, this list of conditions and the following disclaimer in the
30 * documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 * must display the following acknowledgement:
33 * "This product includes cryptographic software written by
34 * Eric Young (eay@cryptsoft.com)"
35 * The word 'cryptographic' can be left out if the rouines from the library
36 * being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 * the apps directory (application code) you must include an acknowledgement:
39 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed. i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59 #include <stdio.h>
60 #include "cryptlib.h"
61 #include <openssl/asn1.h>
62 #include <openssl/bn.h>
63
64 ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
65 { return M_ASN1_INTEGER_dup(x);}
66
67 int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
68 {
69 int neg, ret;
70 /* Compare signs */
71 neg = x->type & V_ASN1_NEG;
72 if (neg != (y->type & V_ASN1_NEG))
73 {
74 if (neg)
75 return -1;
76 else
77 return 1;
78 }
79
80 ret = ASN1_STRING_cmp(x, y);
81
82 if (neg)
83 return -ret;
84 else
85 return ret;
86 }
87
88
89 /*
90 * This converts an ASN1 INTEGER into its content encoding.
91 * The internal representation is an ASN1_STRING whose data is a big endian
92 * representation of the value, ignoring the sign. The sign is determined by
93 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
94 *
95 * Positive integers are no problem: they are almost the same as the DER
96 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
97 *
98 * Negative integers are a bit trickier...
99 * The DER representation of negative integers is in 2s complement form.
100 * The internal form is converted by complementing each octet and finally
101 * adding one to the result. This can be done less messily with a little trick.
102 * If the internal form has trailing zeroes then they will become FF by the
103 * complement and 0 by the add one (due to carry) so just copy as many trailing
104 * zeros to the destination as there are in the source. The carry will add one
105 * to the last none zero octet: so complement this octet and add one and finally
106 * complement any left over until you get to the start of the string.
107 *
108 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
109 * with 0xff. However if the first byte is 0x80 and one of the following bytes
110 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
111 * followed by optional zeros isn't padded.
112 */
113
114 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
115 {
116 int pad=0,ret,i,neg;
117 unsigned char *p,*n,pb=0;
118
119 if (a == NULL) return(0);
120 neg=a->type & V_ASN1_NEG;
121 if (a->length == 0)
122 ret=1;
123 else
124 {
125 ret=a->length;
126 i=a->data[0];
127 if (!neg && (i > 127)) {
128 pad=1;
129 pb=0;
130 } else if(neg) {
131 if(i>128) {
132 pad=1;
133 pb=0xFF;
134 } else if(i == 128) {
135 /*
136 * Special case: if any other bytes non zero we pad:
137 * otherwise we don't.
138 */
139 for(i = 1; i < a->length; i++) if(a->data[i]) {
140 pad=1;
141 pb=0xFF;
142 break;
143 }
144 }
145 }
146 ret+=pad;
147 }
148 if (pp == NULL) return(ret);
149 p= *pp;
150
151 if (pad) *(p++)=pb;
152 if (a->length == 0) *(p++)=0;
153 else if (!neg) memcpy(p,a->data,(unsigned int)a->length);
154 else {
155 /* Begin at the end of the encoding */
156 n=a->data + a->length - 1;
157 p += a->length - 1;
158 i = a->length;
159 /* Copy zeros to destination as long as source is zero */
160 while(!*n) {
161 *(p--) = 0;
162 n--;
163 i--;
164 }
165 /* Complement and increment next octet */
166 *(p--) = ((*(n--)) ^ 0xff) + 1;
167 i--;
168 /* Complement any octets left */
169 for(;i > 0; i--) *(p--) = *(n--) ^ 0xff;
170 }
171
172 *pp+=ret;
173 return(ret);
174 }
175
176 /* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
177
178 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
179 long len)
180 {
181 ASN1_INTEGER *ret=NULL;
182 const unsigned char *p, *pend;
183 unsigned char *to,*s;
184 int i;
185
186 if ((a == NULL) || ((*a) == NULL))
187 {
188 if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
189 ret->type=V_ASN1_INTEGER;
190 }
191 else
192 ret=(*a);
193
194 p= *pp;
195 pend = p + len;
196
197 /* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
198 * signifies a missing NULL parameter. */
199 s=(unsigned char *)OPENSSL_malloc((int)len+1);
200 if (s == NULL)
201 {
202 i=ERR_R_MALLOC_FAILURE;
203 goto err;
204 }
205 to=s;
206 if(!len) {
207 /* Strictly speaking this is an illegal INTEGER but we
208 * tolerate it.
209 */
210 ret->type=V_ASN1_INTEGER;
211 } else if (*p & 0x80) /* a negative number */
212 {
213 ret->type=V_ASN1_NEG_INTEGER;
214 if ((*p == 0xff) && (len != 1)) {
215 p++;
216 len--;
217 }
218 i = len;
219 p += i - 1;
220 to += i - 1;
221 while((!*p) && i) {
222 *(to--) = 0;
223 i--;
224 p--;
225 }
226 /* Special case: if all zeros then the number will be of
227 * the form FF followed by n zero bytes: this corresponds to
228 * 1 followed by n zero bytes. We've already written n zeros
229 * so we just append an extra one and set the first byte to
230 * a 1. This is treated separately because it is the only case
231 * where the number of bytes is larger than len.
232 */
233 if(!i) {
234 *s = 1;
235 s[len] = 0;
236 len++;
237 } else {
238 *(to--) = (*(p--) ^ 0xff) + 1;
239 i--;
240 for(;i > 0; i--) *(to--) = *(p--) ^ 0xff;
241 }
242 } else {
243 ret->type=V_ASN1_INTEGER;
244 if ((*p == 0) && (len != 1))
245 {
246 p++;
247 len--;
248 }
249 memcpy(s,p,(int)len);
250 }
251
252 if (ret->data != NULL) OPENSSL_free(ret->data);
253 ret->data=s;
254 ret->length=(int)len;
255 if (a != NULL) (*a)=ret;
256 *pp=pend;
257 return(ret);
258 err:
259 ASN1err(ASN1_F_C2I_ASN1_INTEGER,i);
260 if ((ret != NULL) && ((a == NULL) || (*a != ret)))
261 M_ASN1_INTEGER_free(ret);
262 return(NULL);
263 }
264
265
266 /* This is a version of d2i_ASN1_INTEGER that ignores the sign bit of
267 * ASN1 integers: some broken software can encode a positive INTEGER
268 * with its MSB set as negative (it doesn't add a padding zero).
269 */
270
271 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
272 long length)
273 {
274 ASN1_INTEGER *ret=NULL;
275 const unsigned char *p;
276 unsigned char *s;
277 long len;
278 int inf,tag,xclass;
279 int i;
280
281 if ((a == NULL) || ((*a) == NULL))
282 {
283 if ((ret=M_ASN1_INTEGER_new()) == NULL) return(NULL);
284 ret->type=V_ASN1_INTEGER;
285 }
286 else
287 ret=(*a);
288
289 p= *pp;
290 inf=ASN1_get_object(&p,&len,&tag,&xclass,length);
291 if (inf & 0x80)
292 {
293 i=ASN1_R_BAD_OBJECT_HEADER;
294 goto err;
295 }
296
297 if (tag != V_ASN1_INTEGER)
298 {
299 i=ASN1_R_EXPECTING_AN_INTEGER;
300 goto err;
301 }
302
303 /* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it
304 * signifies a missing NULL parameter. */
305 s=(unsigned char *)OPENSSL_malloc((int)len+1);
306 if (s == NULL)
307 {
308 i=ERR_R_MALLOC_FAILURE;
309 goto err;
310 }
311 ret->type=V_ASN1_INTEGER;
312 if(len) {
313 if ((*p == 0) && (len != 1))
314 {
315 p++;
316 len--;
317 }
318 memcpy(s,p,(int)len);
319 p+=len;
320 }
321
322 if (ret->data != NULL) OPENSSL_free(ret->data);
323 ret->data=s;
324 ret->length=(int)len;
325 if (a != NULL) (*a)=ret;
326 *pp=p;
327 return(ret);
328 err:
329 ASN1err(ASN1_F_D2I_ASN1_UINTEGER,i);
330 if ((ret != NULL) && ((a == NULL) || (*a != ret)))
331 M_ASN1_INTEGER_free(ret);
332 return(NULL);
333 }
334
335 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
336 {
337 int j,k;
338 unsigned int i;
339 unsigned char buf[sizeof(long)+1];
340 long d;
341
342 a->type=V_ASN1_INTEGER;
343 if (a->length < (int)(sizeof(long)+1))
344 {
345 if (a->data != NULL)
346 OPENSSL_free(a->data);
347 if ((a->data=(unsigned char *)OPENSSL_malloc(sizeof(long)+1)) != NULL)
348 memset((char *)a->data,0,sizeof(long)+1);
349 }
350 if (a->data == NULL)
351 {
352 ASN1err(ASN1_F_ASN1_INTEGER_SET,ERR_R_MALLOC_FAILURE);
353 return(0);
354 }
355 d=v;
356 if (d < 0)
357 {
358 d= -d;
359 a->type=V_ASN1_NEG_INTEGER;
360 }
361
362 for (i=0; i<sizeof(long); i++)
363 {
364 if (d == 0) break;
365 buf[i]=(int)d&0xff;
366 d>>=8;
367 }
368 j=0;
369 for (k=i-1; k >=0; k--)
370 a->data[j++]=buf[k];
371 a->length=j;
372 return(1);
373 }
374
375 long ASN1_INTEGER_get(const ASN1_INTEGER *a)
376 {
377 int neg=0,i;
378 long r=0;
379
380 if (a == NULL) return(0L);
381 i=a->type;
382 if (i == V_ASN1_NEG_INTEGER)
383 neg=1;
384 else if (i != V_ASN1_INTEGER)
385 return -1;
386
387 if (a->length > (int)sizeof(long))
388 {
389 /* hmm... a bit ugly, return all ones */
390 return -1;
391 }
392 if (a->data == NULL)
393 return 0;
394
395 for (i=0; i<a->length; i++)
396 {
397 r<<=8;
398 r|=(unsigned char)a->data[i];
399 }
400 if (neg) r= -r;
401 return(r);
402 }
403
404 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
405 {
406 ASN1_INTEGER *ret;
407 int len,j;
408
409 if (ai == NULL)
410 ret=M_ASN1_INTEGER_new();
411 else
412 ret=ai;
413 if (ret == NULL)
414 {
415 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_NESTED_ASN1_ERROR);
416 goto err;
417 }
418 if (BN_is_negative(bn))
419 ret->type = V_ASN1_NEG_INTEGER;
420 else ret->type=V_ASN1_INTEGER;
421 j=BN_num_bits(bn);
422 len=((j == 0)?0:((j/8)+1));
423 if (ret->length < len+4)
424 {
425 unsigned char *new_data=OPENSSL_realloc(ret->data, len+4);
426 if (!new_data)
427 {
428 ASN1err(ASN1_F_BN_TO_ASN1_INTEGER,ERR_R_MALLOC_FAILURE);
429 goto err;
430 }
431 ret->data=new_data;
432 }
433 ret->length=BN_bn2bin(bn,ret->data);
434 /* Correct zero case */
435 if(!ret->length)
436 {
437 ret->data[0] = 0;
438 ret->length = 1;
439 }
440 return(ret);
441 err:
442 if (ret != ai) M_ASN1_INTEGER_free(ret);
443 return(NULL);
444 }
445
446 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
447 {
448 BIGNUM *ret;
449
450 if ((ret=BN_bin2bn(ai->data,ai->length,bn)) == NULL)
451 ASN1err(ASN1_F_ASN1_INTEGER_TO_BN,ASN1_R_BN_LIB);
452 else if(ai->type == V_ASN1_NEG_INTEGER)
453 BN_set_negative(ret, 1);
454 return(ret);
455 }
456
457 IMPLEMENT_STACK_OF(ASN1_INTEGER)
458 IMPLEMENT_ASN1_SET_OF(ASN1_INTEGER)