1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57 #include <openssl/asn1.h>
58
59 #include <string.h>
60
61 #include <openssl/err.h>
62 #include <openssl/mem.h>
63
64 #include "../internal.h"
65
66
ASN1_INTEGER_dup(const ASN1_INTEGER * x)67 ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
68 {
69 return M_ASN1_INTEGER_dup(x);
70 }
71
ASN1_INTEGER_cmp(const ASN1_INTEGER * x,const ASN1_INTEGER * y)72 int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
73 {
74 int neg, ret;
75 /* Compare signs */
76 neg = x->type & V_ASN1_NEG;
77 if (neg != (y->type & V_ASN1_NEG)) {
78 if (neg)
79 return -1;
80 else
81 return 1;
82 }
83
84 ret = ASN1_STRING_cmp(x, y);
85
86 if (neg)
87 return -ret;
88 else
89 return ret;
90 }
91
92 /*
93 * This converts an ASN1 INTEGER into its content encoding.
94 * The internal representation is an ASN1_STRING whose data is a big endian
95 * representation of the value, ignoring the sign. The sign is determined by
96 * the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
97 *
98 * Positive integers are no problem: they are almost the same as the DER
99 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
100 *
101 * Negative integers are a bit trickier...
102 * The DER representation of negative integers is in 2s complement form.
103 * The internal form is converted by complementing each octet and finally
104 * adding one to the result. This can be done less messily with a little trick.
105 * If the internal form has trailing zeroes then they will become FF by the
106 * complement and 0 by the add one (due to carry) so just copy as many trailing
107 * zeros to the destination as there are in the source. The carry will add one
108 * to the last none zero octet: so complement this octet and add one and finally
109 * complement any left over until you get to the start of the string.
110 *
111 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
112 * with 0xff. However if the first byte is 0x80 and one of the following bytes
113 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
114 * followed by optional zeros isn't padded.
115 */
116
i2c_ASN1_INTEGER(ASN1_INTEGER * a,unsigned char ** pp)117 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
118 {
119 int pad = 0, ret, i, neg;
120 unsigned char *p, *n, pb = 0;
121
122 if (a == NULL)
123 return (0);
124 neg = a->type & V_ASN1_NEG;
125 if (a->length == 0)
126 ret = 1;
127 else {
128 ret = a->length;
129 i = a->data[0];
130 if (ret == 1 && i == 0)
131 neg = 0;
132 if (!neg && (i > 127)) {
133 pad = 1;
134 pb = 0;
135 } else if (neg) {
136 if (i > 128) {
137 pad = 1;
138 pb = 0xFF;
139 } else if (i == 128) {
140 /*
141 * Special case: if any other bytes non zero we pad:
142 * otherwise we don't.
143 */
144 for (i = 1; i < a->length; i++)
145 if (a->data[i]) {
146 pad = 1;
147 pb = 0xFF;
148 break;
149 }
150 }
151 }
152 ret += pad;
153 }
154 if (pp == NULL)
155 return (ret);
156 p = *pp;
157
158 if (pad)
159 *(p++) = pb;
160 if (a->length == 0)
161 *(p++) = 0;
162 else if (!neg)
163 OPENSSL_memcpy(p, a->data, (unsigned int)a->length);
164 else {
165 /* Begin at the end of the encoding */
166 n = a->data + a->length - 1;
167 p += a->length - 1;
168 i = a->length;
169 /* Copy zeros to destination as long as source is zero */
170 while (!*n && i > 1) {
171 *(p--) = 0;
172 n--;
173 i--;
174 }
175 /* Complement and increment next octet */
176 *(p--) = ((*(n--)) ^ 0xff) + 1;
177 i--;
178 /* Complement any octets left */
179 for (; i > 0; i--)
180 *(p--) = *(n--) ^ 0xff;
181 }
182
183 *pp += ret;
184 return (ret);
185 }
186
187 /* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
188
c2i_ASN1_INTEGER(ASN1_INTEGER ** a,const unsigned char ** pp,long len)189 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
190 long len)
191 {
192 ASN1_INTEGER *ret = NULL;
193 const unsigned char *p, *pend;
194 unsigned char *to, *s;
195 int i;
196
197 if ((a == NULL) || ((*a) == NULL)) {
198 if ((ret = M_ASN1_INTEGER_new()) == NULL)
199 return (NULL);
200 ret->type = V_ASN1_INTEGER;
201 } else
202 ret = (*a);
203
204 p = *pp;
205 pend = p + len;
206
207 /*
208 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
209 * a missing NULL parameter.
210 */
211 s = (unsigned char *)OPENSSL_malloc((int)len + 1);
212 if (s == NULL) {
213 i = ERR_R_MALLOC_FAILURE;
214 goto err;
215 }
216 to = s;
217 if (!len) {
218 /*
219 * Strictly speaking this is an illegal INTEGER but we tolerate it.
220 */
221 ret->type = V_ASN1_INTEGER;
222 } else if (*p & 0x80) { /* a negative number */
223 ret->type = V_ASN1_NEG_INTEGER;
224 if ((*p == 0xff) && (len != 1)) {
225 p++;
226 len--;
227 }
228 i = len;
229 p += i - 1;
230 to += i - 1;
231 while ((!*p) && i) {
232 *(to--) = 0;
233 i--;
234 p--;
235 }
236 /*
237 * Special case: if all zeros then the number will be of the form FF
238 * followed by n zero bytes: this corresponds to 1 followed by n zero
239 * bytes. We've already written n zeros so we just append an extra
240 * one and set the first byte to a 1. This is treated separately
241 * because it is the only case where the number of bytes is larger
242 * than len.
243 */
244 if (!i) {
245 *s = 1;
246 s[len] = 0;
247 len++;
248 } else {
249 *(to--) = (*(p--) ^ 0xff) + 1;
250 i--;
251 for (; i > 0; i--)
252 *(to--) = *(p--) ^ 0xff;
253 }
254 } else {
255 ret->type = V_ASN1_INTEGER;
256 if ((*p == 0) && (len != 1)) {
257 p++;
258 len--;
259 }
260 OPENSSL_memcpy(s, p, (int)len);
261 }
262
263 if (ret->data != NULL)
264 OPENSSL_free(ret->data);
265 ret->data = s;
266 ret->length = (int)len;
267 if (a != NULL)
268 (*a) = ret;
269 *pp = pend;
270 return (ret);
271 err:
272 OPENSSL_PUT_ERROR(ASN1, i);
273 if ((ret != NULL) && ((a == NULL) || (*a != ret)))
274 M_ASN1_INTEGER_free(ret);
275 return (NULL);
276 }
277
278 /*
279 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1
280 * integers: some broken software can encode a positive INTEGER with its MSB
281 * set as negative (it doesn't add a padding zero).
282 */
283
d2i_ASN1_UINTEGER(ASN1_INTEGER ** a,const unsigned char ** pp,long length)284 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
285 long length)
286 {
287 ASN1_INTEGER *ret = NULL;
288 const unsigned char *p;
289 unsigned char *s;
290 long len;
291 int inf, tag, xclass;
292 int i;
293
294 if ((a == NULL) || ((*a) == NULL)) {
295 if ((ret = M_ASN1_INTEGER_new()) == NULL)
296 return (NULL);
297 ret->type = V_ASN1_INTEGER;
298 } else
299 ret = (*a);
300
301 p = *pp;
302 inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
303 if (inf & 0x80) {
304 i = ASN1_R_BAD_OBJECT_HEADER;
305 goto err;
306 }
307
308 if (tag != V_ASN1_INTEGER) {
309 i = ASN1_R_EXPECTING_AN_INTEGER;
310 goto err;
311 }
312
313 /*
314 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
315 * a missing NULL parameter.
316 */
317 s = (unsigned char *)OPENSSL_malloc((int)len + 1);
318 if (s == NULL) {
319 i = ERR_R_MALLOC_FAILURE;
320 goto err;
321 }
322 ret->type = V_ASN1_INTEGER;
323 if (len) {
324 if ((*p == 0) && (len != 1)) {
325 p++;
326 len--;
327 }
328 OPENSSL_memcpy(s, p, (int)len);
329 p += len;
330 }
331
332 if (ret->data != NULL)
333 OPENSSL_free(ret->data);
334 ret->data = s;
335 ret->length = (int)len;
336 if (a != NULL)
337 (*a) = ret;
338 *pp = p;
339 return (ret);
340 err:
341 OPENSSL_PUT_ERROR(ASN1, i);
342 if ((ret != NULL) && ((a == NULL) || (*a != ret)))
343 M_ASN1_INTEGER_free(ret);
344 return (NULL);
345 }
346
ASN1_INTEGER_set(ASN1_INTEGER * a,long v)347 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
348 {
349 int j, k;
350 unsigned int i;
351 unsigned char buf[sizeof(long) + 1];
352 long d;
353
354 a->type = V_ASN1_INTEGER;
355 if (a->length < (int)(sizeof(long) + 1)) {
356 if (a->data != NULL)
357 OPENSSL_free(a->data);
358 if ((a->data =
359 (unsigned char *)OPENSSL_malloc(sizeof(long) + 1)) != NULL)
360 OPENSSL_memset((char *)a->data, 0, sizeof(long) + 1);
361 }
362 if (a->data == NULL) {
363 OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
364 return (0);
365 }
366 d = v;
367 if (d < 0) {
368 d = -d;
369 a->type = V_ASN1_NEG_INTEGER;
370 }
371
372 for (i = 0; i < sizeof(long); i++) {
373 if (d == 0)
374 break;
375 buf[i] = (int)d & 0xff;
376 d >>= 8;
377 }
378 j = 0;
379 for (k = i - 1; k >= 0; k--)
380 a->data[j++] = buf[k];
381 a->length = j;
382 return (1);
383 }
384
ASN1_INTEGER_get(const ASN1_INTEGER * a)385 long ASN1_INTEGER_get(const ASN1_INTEGER *a)
386 {
387 int neg = 0, i;
388 long r = 0;
389
390 if (a == NULL)
391 return (0L);
392 i = a->type;
393 if (i == V_ASN1_NEG_INTEGER)
394 neg = 1;
395 else if (i != V_ASN1_INTEGER)
396 return -1;
397
398 if (a->length > (int)sizeof(long)) {
399 /* hmm... a bit ugly, return all ones */
400 return -1;
401 }
402 if (a->data == NULL)
403 return 0;
404
405 for (i = 0; i < a->length; i++) {
406 r <<= 8;
407 r |= (unsigned char)a->data[i];
408 }
409 if (neg)
410 r = -r;
411 return (r);
412 }
413
BN_to_ASN1_INTEGER(const BIGNUM * bn,ASN1_INTEGER * ai)414 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
415 {
416 ASN1_INTEGER *ret;
417 int len, j;
418
419 if (ai == NULL)
420 ret = M_ASN1_INTEGER_new();
421 else
422 ret = ai;
423 if (ret == NULL) {
424 OPENSSL_PUT_ERROR(ASN1, ASN1_R_NESTED_ASN1_ERROR);
425 goto err;
426 }
427 if (BN_is_negative(bn) && !BN_is_zero(bn))
428 ret->type = V_ASN1_NEG_INTEGER;
429 else
430 ret->type = V_ASN1_INTEGER;
431 j = BN_num_bits(bn);
432 len = ((j == 0) ? 0 : ((j / 8) + 1));
433 if (ret->length < len + 4) {
434 unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4);
435 if (!new_data) {
436 OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
437 goto err;
438 }
439 ret->data = new_data;
440 }
441 ret->length = BN_bn2bin(bn, ret->data);
442 /* Correct zero case */
443 if (!ret->length) {
444 ret->data[0] = 0;
445 ret->length = 1;
446 }
447 return (ret);
448 err:
449 if (ret != ai)
450 M_ASN1_INTEGER_free(ret);
451 return (NULL);
452 }
453
ASN1_INTEGER_to_BN(const ASN1_INTEGER * ai,BIGNUM * bn)454 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
455 {
456 BIGNUM *ret;
457
458 if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL)
459 OPENSSL_PUT_ERROR(ASN1, ASN1_R_BN_LIB);
460 else if (ai->type == V_ASN1_NEG_INTEGER)
461 BN_set_negative(ret, 1);
462 return (ret);
463 }
464