1/*
2 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10#include <stdio.h>
11#include "internal/cryptlib.h"
12#include "internal/numbers.h"
13#include <limits.h>
14#include <openssl/asn1.h>
15#include <openssl/bn.h>
16#include "asn1_local.h"
17
18ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
19{
20 return ASN1_STRING_dup(x);
21}
22
23int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
24{
25 int neg, ret;
26 /* Compare signs */
27 neg = x->type & V_ASN1_NEG;
28 if (neg != (y->type & V_ASN1_NEG)) {
29 if (neg)
30 return -1;
31 else
32 return 1;
33 }
34
35 ret = ASN1_STRING_cmp(x, y);
36
37 if (neg)
38 return -ret;
39 else
40 return ret;
41}
42
43/*-
44 * This converts a big endian buffer and sign into its content encoding.
45 * This is used for INTEGER and ENUMERATED types.
46 * The internal representation is an ASN1_STRING whose data is a big endian
47 * representation of the value, ignoring the sign. The sign is determined by
48 * the type: if type & V_ASN1_NEG is true it is negative, otherwise positive.
49 *
50 * Positive integers are no problem: they are almost the same as the DER
51 * encoding, except if the first byte is >= 0x80 we need to add a zero pad.
52 *
53 * Negative integers are a bit trickier...
54 * The DER representation of negative integers is in 2s complement form.
55 * The internal form is converted by complementing each octet and finally
56 * adding one to the result. This can be done less messily with a little trick.
57 * If the internal form has trailing zeroes then they will become FF by the
58 * complement and 0 by the add one (due to carry) so just copy as many trailing
59 * zeros to the destination as there are in the source. The carry will add one
60 * to the last none zero octet: so complement this octet and add one and finally
61 * complement any left over until you get to the start of the string.
62 *
63 * Padding is a little trickier too. If the first bytes is > 0x80 then we pad
64 * with 0xff. However if the first byte is 0x80 and one of the following bytes
65 * is non-zero we pad with 0xff. The reason for this distinction is that 0x80
66 * followed by optional zeros isn't padded.
67 */
68
69/*
70 * If |pad| is zero, the operation is effectively reduced to memcpy,
71 * and if |pad| is 0xff, then it performs two's complement, ~dst + 1.
72 * Note that in latter case sequence of zeros yields itself, and so
73 * does 0x80 followed by any number of zeros. These properties are
74 * used elsewhere below...
75 */
76static void twos_complement(unsigned char *dst, const unsigned char *src,
77 size_t len, unsigned char pad)
78{
79 unsigned int carry = pad & 1;
80
81 /* Begin at the end of the encoding */
82 dst += len;
83 src += len;
84 /* two's complement value: ~value + 1 */
85 while (len-- != 0) {
86 *(--dst) = (unsigned char)(carry += *(--src) ^ pad);
87 carry >>= 8;
88 }
89}
90
91static size_t i2c_ibuf(const unsigned char *b, size_t blen, int neg,
92 unsigned char **pp)
93{
94 unsigned int pad = 0;
95 size_t ret, i;
96 unsigned char *p, pb = 0;
97
98 if (b != NULL && blen) {
99 ret = blen;
100 i = b[0];
101 if (!neg && (i > 127)) {
102 pad = 1;
103 pb = 0;
104 } else if (neg) {
105 pb = 0xFF;
106 if (i > 128) {
107 pad = 1;
108 } else if (i == 128) {
109 /*
110 * Special case [of minimal negative for given length]:
111 * if any other bytes non zero we pad, otherwise we don't.
112 */
113 for (pad = 0, i = 1; i < blen; i++)
114 pad |= b[i];
115 pb = pad != 0 ? 0xffU : 0;
116 pad = pb & 1;
117 }
118 }
119 ret += pad;
120 } else {
121 ret = 1;
122 blen = 0; /* reduce '(b == NULL || blen == 0)' to '(blen == 0)' */
123 }
124
125 if (pp == NULL || (p = *pp) == NULL)
126 return ret;
127
128 /*
129 * This magically handles all corner cases, such as '(b == NULL ||
130 * blen == 0)', non-negative value, "negative" zero, 0x80 followed
131 * by any number of zeros...
132 */
133 *p = pb;
134 p += pad; /* yes, p[0] can be written twice, but it's little
135 * price to pay for eliminated branches */
136 twos_complement(p, b, blen, pb);
137
138 *pp += ret;
139 return ret;
140}
141
142/*
143 * convert content octets into a big endian buffer. Returns the length
144 * of buffer or 0 on error: for malformed INTEGER. If output buffer is
145 * NULL just return length.
146 */
147
148static size_t c2i_ibuf(unsigned char *b, int *pneg,
149 const unsigned char *p, size_t plen)
150{
151 int neg, pad;
152 /* Zero content length is illegal */
153 if (plen == 0) {
154 ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_ZERO_CONTENT);
155 return 0;
156 }
157 neg = p[0] & 0x80;
158 if (pneg)
159 *pneg = neg;
160 /* Handle common case where length is 1 octet separately */
161 if (plen == 1) {
162 if (b != NULL) {
163 if (neg)
164 b[0] = (p[0] ^ 0xFF) + 1;
165 else
166 b[0] = p[0];
167 }
168 return 1;
169 }
170
171 pad = 0;
172 if (p[0] == 0) {
173 pad = 1;
174 } else if (p[0] == 0xFF) {
175 size_t i;
176
177 /*
178 * Special case [of "one less minimal negative" for given length]:
179 * if any other bytes non zero it was padded, otherwise not.
180 */
181 for (pad = 0, i = 1; i < plen; i++)
182 pad |= p[i];
183 pad = pad != 0 ? 1 : 0;
184 }
185 /* reject illegal padding: first two octets MSB can't match */
186 if (pad && (neg == (p[1] & 0x80))) {
187 ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_PADDING);
188 return 0;
189 }
190
191 /* skip over pad */
192 p += pad;
193 plen -= pad;
194
195 if (b != NULL)
196 twos_complement(b, p, plen, neg ? 0xffU : 0);
197
198 return plen;
199}
200
201int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
202{
203 return i2c_ibuf(a->data, a->length, a->type & V_ASN1_NEG, pp);
204}
205
206/* Convert big endian buffer into uint64_t, return 0 on error */
207static int asn1_get_uint64(uint64_t *pr, const unsigned char *b, size_t blen)
208{
209 size_t i;
210 uint64_t r;
211
212 if (blen > sizeof(*pr)) {
213 ASN1err(ASN1_F_ASN1_GET_UINT64, ASN1_R_TOO_LARGE);
214 return 0;
215 }
216 if (b == NULL)
217 return 0;
218 for (r = 0, i = 0; i < blen; i++) {
219 r <<= 8;
220 r |= b[i];
221 }
222 *pr = r;
223 return 1;
224}
225
226/*
227 * Write uint64_t to big endian buffer and return offset to first
228 * written octet. In other words it returns offset in range from 0
229 * to 7, with 0 denoting 8 written octets and 7 - one.
230 */
231static size_t asn1_put_uint64(unsigned char b[sizeof(uint64_t)], uint64_t r)
232{
233 size_t off = sizeof(uint64_t);
234
235 do {
236 b[--off] = (unsigned char)r;
237 } while (r >>= 8);
238
239 return off;
240}
241
242/*
243 * Absolute value of INT64_MIN: we can't just use -INT64_MIN as gcc produces
244 * overflow warnings.
245 */
246#define ABS_INT64_MIN ((uint64_t)INT64_MAX + (-(INT64_MIN + INT64_MAX)))
247
248/* signed version of asn1_get_uint64 */
249static int asn1_get_int64(int64_t *pr, const unsigned char *b, size_t blen,
250 int neg)
251{
252 uint64_t r;
253 if (asn1_get_uint64(&r, b, blen) == 0)
254 return 0;
255 if (neg) {
256 if (r <= INT64_MAX) {
257 /* Most significant bit is guaranteed to be clear, negation
258 * is guaranteed to be meaningful in platform-neutral sense. */
259 *pr = -(int64_t)r;
260 } else if (r == ABS_INT64_MIN) {
261 /* This never happens if INT64_MAX == ABS_INT64_MIN, e.g.
262 * on ones'-complement system. */
263 *pr = (int64_t)(0 - r);
264 } else {
265 ASN1err(ASN1_F_ASN1_GET_INT64, ASN1_R_TOO_SMALL);
266 return 0;
267 }
268 } else {
269 if (r <= INT64_MAX) {
270 *pr = (int64_t)r;
271 } else {
272 ASN1err(ASN1_F_ASN1_GET_INT64, ASN1_R_TOO_LARGE);
273 return 0;
274 }
275 }
276 return 1;
277}
278
279/* Convert ASN1 INTEGER content octets to ASN1_INTEGER structure */
280ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
281 long len)
282{
283 ASN1_INTEGER *ret = NULL;
284 size_t r;
285 int neg;
286
287 r = c2i_ibuf(NULL, NULL, *pp, len);
288
289 if (r == 0)
290 return NULL;
291
292 if ((a == NULL) || ((*a) == NULL)) {
293 ret = ASN1_INTEGER_new();
294 if (ret == NULL)
295 return NULL;
296 ret->type = V_ASN1_INTEGER;
297 } else
298 ret = *a;
299
300 if (ASN1_STRING_set(ret, NULL, r) == 0)
301 goto err;
302
303 c2i_ibuf(ret->data, &neg, *pp, len);
304
305 if (neg)
306 ret->type |= V_ASN1_NEG;
307
308 *pp += len;
309 if (a != NULL)
310 (*a) = ret;
311 return ret;
312 err:
313 ASN1err(ASN1_F_C2I_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
314 if ((a == NULL) || (*a != ret))
315 ASN1_INTEGER_free(ret);
316 return NULL;
317}
318
319static int asn1_string_get_int64(int64_t *pr, const ASN1_STRING *a, int itype)
320{
321 if (a == NULL) {
322 ASN1err(ASN1_F_ASN1_STRING_GET_INT64, ERR_R_PASSED_NULL_PARAMETER);
323 return 0;
324 }
325 if ((a->type & ~V_ASN1_NEG) != itype) {
326 ASN1err(ASN1_F_ASN1_STRING_GET_INT64, ASN1_R_WRONG_INTEGER_TYPE);
327 return 0;
328 }
329 return asn1_get_int64(pr, a->data, a->length, a->type & V_ASN1_NEG);
330}
331
332static int asn1_string_set_int64(ASN1_STRING *a, int64_t r, int itype)
333{
334 unsigned char tbuf[sizeof(r)];
335 size_t off;
336
337 a->type = itype;
338 if (r < 0) {
339 /* Most obvious '-r' triggers undefined behaviour for most
340 * common INT64_MIN. Even though below '0 - (uint64_t)r' can
341 * appear two's-complement centric, it does produce correct/
342 * expected result even on one's-complement. This is because
343 * cast to unsigned has to change bit pattern... */
344 off = asn1_put_uint64(tbuf, 0 - (uint64_t)r);
345 a->type |= V_ASN1_NEG;
346 } else {
347 off = asn1_put_uint64(tbuf, r);
348 a->type &= ~V_ASN1_NEG;
349 }
350 return ASN1_STRING_set(a, tbuf + off, sizeof(tbuf) - off);
351}
352
353static int asn1_string_get_uint64(uint64_t *pr, const ASN1_STRING *a,
354 int itype)
355{
356 if (a == NULL) {
357 ASN1err(ASN1_F_ASN1_STRING_GET_UINT64, ERR_R_PASSED_NULL_PARAMETER);
358 return 0;
359 }
360 if ((a->type & ~V_ASN1_NEG) != itype) {
361 ASN1err(ASN1_F_ASN1_STRING_GET_UINT64, ASN1_R_WRONG_INTEGER_TYPE);
362 return 0;
363 }
364 if (a->type & V_ASN1_NEG) {
365 ASN1err(ASN1_F_ASN1_STRING_GET_UINT64, ASN1_R_ILLEGAL_NEGATIVE_VALUE);
366 return 0;
367 }
368 return asn1_get_uint64(pr, a->data, a->length);
369}
370
371static int asn1_string_set_uint64(ASN1_STRING *a, uint64_t r, int itype)
372{
373 unsigned char tbuf[sizeof(r)];
374 size_t off;
375
376 a->type = itype;
377 off = asn1_put_uint64(tbuf, r);
378 return ASN1_STRING_set(a, tbuf + off, sizeof(tbuf) - off);
379}
380
381/*
382 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1
383 * integers: some broken software can encode a positive INTEGER with its MSB
384 * set as negative (it doesn't add a padding zero).
385 */
386
387ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
388 long length)
389{
390 ASN1_INTEGER *ret = NULL;
391 const unsigned char *p;
392 unsigned char *s;
393 long len;
394 int inf, tag, xclass;
395 int i;
396
397 if ((a == NULL) || ((*a) == NULL)) {
398 if ((ret = ASN1_INTEGER_new()) == NULL)
399 return NULL;
400 ret->type = V_ASN1_INTEGER;
401 } else
402 ret = (*a);
403
404 p = *pp;
405 inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
406 if (inf & 0x80) {
407 i = ASN1_R_BAD_OBJECT_HEADER;
408 goto err;
409 }
410
411 if (tag != V_ASN1_INTEGER) {
412 i = ASN1_R_EXPECTING_AN_INTEGER;
413 goto err;
414 }
415
416 /*
417 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
418 * a missing NULL parameter.
419 */
420 s = OPENSSL_malloc((int)len + 1);
421 if (s == NULL) {
422 i = ERR_R_MALLOC_FAILURE;
423 goto err;
424 }
425 ret->type = V_ASN1_INTEGER;
426 if (len) {
427 if ((*p == 0) && (len != 1)) {
428 p++;
429 len--;
430 }
431 memcpy(s, p, (int)len);
432 p += len;
433 }
434
435 OPENSSL_free(ret->data);
436 ret->data = s;
437 ret->length = (int)len;
438 if (a != NULL)
439 (*a) = ret;
440 *pp = p;
441 return ret;
442 err:
443 ASN1err(ASN1_F_D2I_ASN1_UINTEGER, i);
444 if ((a == NULL) || (*a != ret))
445 ASN1_INTEGER_free(ret);
446 return NULL;
447}
448
449static ASN1_STRING *bn_to_asn1_string(const BIGNUM *bn, ASN1_STRING *ai,
450 int atype)
451{
452 ASN1_INTEGER *ret;
453 int len;
454
455 if (ai == NULL) {
456 ret = ASN1_STRING_type_new(atype);
457 } else {
458 ret = ai;
459 ret->type = atype;
460 }
461
462 if (ret == NULL) {
463 ASN1err(ASN1_F_BN_TO_ASN1_STRING, ERR_R_NESTED_ASN1_ERROR);
464 goto err;
465 }
466
467 if (BN_is_negative(bn) && !BN_is_zero(bn))
468 ret->type |= V_ASN1_NEG_INTEGER;
469
470 len = BN_num_bytes(bn);
471
472 if (len == 0)
473 len = 1;
474
475 if (ASN1_STRING_set(ret, NULL, len) == 0) {
476 ASN1err(ASN1_F_BN_TO_ASN1_STRING, ERR_R_MALLOC_FAILURE);
477 goto err;
478 }
479
480 /* Correct zero case */
481 if (BN_is_zero(bn))
482 ret->data[0] = 0;
483 else
484 len = BN_bn2bin(bn, ret->data);
485 ret->length = len;
486 return ret;
487 err:
488 if (ret != ai)
489 ASN1_INTEGER_free(ret);
490 return NULL;
491}
492
493static BIGNUM *asn1_string_to_bn(const ASN1_INTEGER *ai, BIGNUM *bn,
494 int itype)
495{
496 BIGNUM *ret;
497
498 if ((ai->type & ~V_ASN1_NEG) != itype) {
499 ASN1err(ASN1_F_ASN1_STRING_TO_BN, ASN1_R_WRONG_INTEGER_TYPE);
500 return NULL;
501 }
502
503 ret = BN_bin2bn(ai->data, ai->length, bn);
504 if (ret == NULL) {
505 ASN1err(ASN1_F_ASN1_STRING_TO_BN, ASN1_R_BN_LIB);
506 return NULL;
507 }
508 if (ai->type & V_ASN1_NEG)
509 BN_set_negative(ret, 1);
510 return ret;
511}
512
513int ASN1_INTEGER_get_int64(int64_t *pr, const ASN1_INTEGER *a)
514{
515 return asn1_string_get_int64(pr, a, V_ASN1_INTEGER);
516}
517
518int ASN1_INTEGER_set_int64(ASN1_INTEGER *a, int64_t r)
519{
520 return asn1_string_set_int64(a, r, V_ASN1_INTEGER);
521}
522
523int ASN1_INTEGER_get_uint64(uint64_t *pr, const ASN1_INTEGER *a)
524{
525 return asn1_string_get_uint64(pr, a, V_ASN1_INTEGER);
526}
527
528int ASN1_INTEGER_set_uint64(ASN1_INTEGER *a, uint64_t r)
529{
530 return asn1_string_set_uint64(a, r, V_ASN1_INTEGER);
531}
532
533int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
534{
535 return ASN1_INTEGER_set_int64(a, v);
536}
537
538long ASN1_INTEGER_get(const ASN1_INTEGER *a)
539{
540 int i;
541 int64_t r;
542 if (a == NULL)
543 return 0;
544 i = ASN1_INTEGER_get_int64(&r, a);
545 if (i == 0)
546 return -1;
547 if (r > LONG_MAX || r < LONG_MIN)
548 return -1;
549 return (long)r;
550}
551
552ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
553{
554 return bn_to_asn1_string(bn, ai, V_ASN1_INTEGER);
555}
556
557BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
558{
559 return asn1_string_to_bn(ai, bn, V_ASN1_INTEGER);
560}
561
562int ASN1_ENUMERATED_get_int64(int64_t *pr, const ASN1_ENUMERATED *a)
563{
564 return asn1_string_get_int64(pr, a, V_ASN1_ENUMERATED);
565}
566
567int ASN1_ENUMERATED_set_int64(ASN1_ENUMERATED *a, int64_t r)
568{
569 return asn1_string_set_int64(a, r, V_ASN1_ENUMERATED);
570}
571
572int ASN1_ENUMERATED_set(ASN1_ENUMERATED *a, long v)
573{
574 return ASN1_ENUMERATED_set_int64(a, v);
575}
576
577long ASN1_ENUMERATED_get(const ASN1_ENUMERATED *a)
578{
579 int i;
580 int64_t r;
581 if (a == NULL)
582 return 0;
583 if ((a->type & ~V_ASN1_NEG) != V_ASN1_ENUMERATED)
584 return -1;
585 if (a->length > (int)sizeof(long))
586 return 0xffffffffL;
587 i = ASN1_ENUMERATED_get_int64(&r, a);
588 if (i == 0)
589 return -1;
590 if (r > LONG_MAX || r < LONG_MIN)
591 return -1;
592 return (long)r;
593}
594
595ASN1_ENUMERATED *BN_to_ASN1_ENUMERATED(const BIGNUM *bn, ASN1_ENUMERATED *ai)
596{
597 return bn_to_asn1_string(bn, ai, V_ASN1_ENUMERATED);
598}
599
600BIGNUM *ASN1_ENUMERATED_to_BN(const ASN1_ENUMERATED *ai, BIGNUM *bn)
601{
602 return asn1_string_to_bn(ai, bn, V_ASN1_ENUMERATED);
603}
604
605/* Internal functions used by x_int64.c */
606int c2i_uint64_int(uint64_t *ret, int *neg, const unsigned char **pp, long len)
607{
608 unsigned char buf[sizeof(uint64_t)];
609 size_t buflen;
610
611 buflen = c2i_ibuf(NULL, NULL, *pp, len);
612 if (buflen == 0)
613 return 0;
614 if (buflen > sizeof(uint64_t)) {
615 ASN1err(ASN1_F_C2I_UINT64_INT, ASN1_R_TOO_LARGE);
616 return 0;
617 }
618 (void)c2i_ibuf(buf, neg, *pp, len);
619 return asn1_get_uint64(ret, buf, buflen);
620}
621
622int i2c_uint64_int(unsigned char *p, uint64_t r, int neg)
623{
624 unsigned char buf[sizeof(uint64_t)];
625 size_t off;
626
627 off = asn1_put_uint64(buf, r);
628 return i2c_ibuf(buf + off, sizeof(buf) - off, neg, &p);
629}
630
631