2 * Copyright 1995-2017 The OpenSSL Project Authors. All Rights Reserved.
4 * Licensed under the OpenSSL license (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
11 #include "internal/cryptlib.h"
12 #include "internal/numbers.h"
14 #include <openssl/asn1.h>
15 #include <openssl/bn.h>
16 #include "asn1_locl.h"
18 ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
20 return ASN1_STRING_dup(x);
23 int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
27 neg = x->type & V_ASN1_NEG;
28 if (neg != (y->type & V_ASN1_NEG)) {
35 ret = ASN1_STRING_cmp(x, y);
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.
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.
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.
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.
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...
76 static void twos_complement(unsigned char *dst, const unsigned char *src,
77 size_t len, unsigned char pad)
79 unsigned int carry = pad & 1;
81 /* Begin at the end of the encoding */
84 /* two's complement value: ~value + 1 */
86 *(--dst) = (unsigned char)(carry += *(--src) ^ pad);
91 static size_t i2c_ibuf(const unsigned char *b, size_t blen, int neg,
96 unsigned char *p, pb = 0;
98 if (b != NULL && blen) {
101 if (!neg && (i > 127)) {
108 } else if (i == 128) {
110 * Special case [of minimal negative for given length]:
111 * if any other bytes non zero we pad, otherwise we don't.
113 for (pad = 0, i = 1; i < blen; i++)
115 pb = pad != 0 ? 0xffU : 0;
122 blen = 0; /* reduce '(b == NULL || blen == 0)' to '(blen == 0)' */
125 if (pp == NULL || (p = *pp) == NULL)
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...
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);
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.
148 static size_t c2i_ibuf(unsigned char *b, int *pneg,
149 const unsigned char *p, size_t plen)
152 /* Zero content length is illegal */
154 ASN1err(ASN1_F_C2I_IBUF, ASN1_R_ILLEGAL_ZERO_CONTENT);
160 /* Handle common case where length is 1 octet separately */
164 b[0] = (p[0] ^ 0xFF) + 1;
174 } else if (p[0] == 0xFF) {
178 * Special case [of "one less minimal negative" for given length]:
179 * if any other bytes non zero it was padded, otherwise not.
181 for (pad = 0, i = 1; i < plen; i++)
183 pad = pad != 0 ? 1 : 0;
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);
196 twos_complement(b, p, plen, neg ? 0xffU : 0);
201 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
203 return i2c_ibuf(a->data, a->length, a->type & V_ASN1_NEG, pp);
206 /* Convert big endian buffer into uint64_t, return 0 on error */
207 static int asn1_get_uint64(uint64_t *pr, const unsigned char *b, size_t blen)
212 if (blen > sizeof(*pr)) {
213 ASN1err(ASN1_F_ASN1_GET_UINT64, ASN1_R_TOO_LARGE);
218 for (r = 0, i = 0; i < blen; i++) {
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.
231 static size_t asn1_put_uint64(unsigned char b[sizeof(uint64_t)], uint64_t r)
233 size_t off = sizeof(uint64_t);
236 b[--off] = (unsigned char)r;
243 * Absolute value of INT64_MIN: we can't just use -INT64_MIN as gcc produces
246 #define ABS_INT64_MIN ((uint64_t)INT64_MAX + (-(INT64_MIN + INT64_MAX)))
248 /* signed version of asn1_get_uint64 */
249 static int asn1_get_int64(int64_t *pr, const unsigned char *b, size_t blen,
253 if (asn1_get_uint64(&r, b, blen) == 0)
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. */
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);
265 ASN1err(ASN1_F_ASN1_GET_INT64, ASN1_R_TOO_SMALL);
269 if (r <= INT64_MAX) {
272 ASN1err(ASN1_F_ASN1_GET_INT64, ASN1_R_TOO_LARGE);
279 /* Convert ASN1 INTEGER content octets to ASN1_INTEGER structure */
280 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
283 ASN1_INTEGER *ret = NULL;
287 r = c2i_ibuf(NULL, NULL, *pp, len);
292 if ((a == NULL) || ((*a) == NULL)) {
293 ret = ASN1_INTEGER_new();
296 ret->type = V_ASN1_INTEGER;
300 if (ASN1_STRING_set(ret, NULL, r) == 0)
303 c2i_ibuf(ret->data, &neg, *pp, len);
306 ret->type |= V_ASN1_NEG;
313 ASN1err(ASN1_F_C2I_ASN1_INTEGER, ERR_R_MALLOC_FAILURE);
314 if ((a == NULL) || (*a != ret))
315 ASN1_INTEGER_free(ret);
319 static int asn1_string_get_int64(int64_t *pr, const ASN1_STRING *a, int itype)
322 ASN1err(ASN1_F_ASN1_STRING_GET_INT64, ERR_R_PASSED_NULL_PARAMETER);
325 if ((a->type & ~V_ASN1_NEG) != itype) {
326 ASN1err(ASN1_F_ASN1_STRING_GET_INT64, ASN1_R_WRONG_INTEGER_TYPE);
329 return asn1_get_int64(pr, a->data, a->length, a->type & V_ASN1_NEG);
332 static int asn1_string_set_int64(ASN1_STRING *a, int64_t r, int itype)
334 unsigned char tbuf[sizeof(r)];
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;
347 off = asn1_put_uint64(tbuf, r);
348 a->type &= ~V_ASN1_NEG;
350 return ASN1_STRING_set(a, tbuf + off, sizeof(tbuf) - off);
353 static int asn1_string_get_uint64(uint64_t *pr, const ASN1_STRING *a,
357 ASN1err(ASN1_F_ASN1_STRING_GET_UINT64, ERR_R_PASSED_NULL_PARAMETER);
360 if ((a->type & ~V_ASN1_NEG) != itype) {
361 ASN1err(ASN1_F_ASN1_STRING_GET_UINT64, ASN1_R_WRONG_INTEGER_TYPE);
364 if (a->type & V_ASN1_NEG) {
365 ASN1err(ASN1_F_ASN1_STRING_GET_UINT64, ASN1_R_ILLEGAL_NEGATIVE_VALUE);
368 return asn1_get_uint64(pr, a->data, a->length);
371 static int asn1_string_set_uint64(ASN1_STRING *a, uint64_t r, int itype)
373 unsigned char tbuf[sizeof(r)];
377 off = asn1_put_uint64(tbuf, r);
378 return ASN1_STRING_set(a, tbuf + off, sizeof(tbuf) - off);
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).
387 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
390 ASN1_INTEGER *ret = NULL;
391 const unsigned char *p;
394 int inf, tag, xclass;
397 if ((a == NULL) || ((*a) == NULL)) {
398 if ((ret = ASN1_INTEGER_new()) == NULL)
400 ret->type = V_ASN1_INTEGER;
405 inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
407 i = ASN1_R_BAD_OBJECT_HEADER;
411 if (tag != V_ASN1_INTEGER) {
412 i = ASN1_R_EXPECTING_AN_INTEGER;
417 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
418 * a missing NULL parameter.
420 s = OPENSSL_malloc((int)len + 1);
422 i = ERR_R_MALLOC_FAILURE;
425 ret->type = V_ASN1_INTEGER;
427 if ((*p == 0) && (len != 1)) {
431 memcpy(s, p, (int)len);
435 OPENSSL_free(ret->data);
437 ret->length = (int)len;
443 ASN1err(ASN1_F_D2I_ASN1_UINTEGER, i);
444 if ((a == NULL) || (*a != ret))
445 ASN1_INTEGER_free(ret);
449 static ASN1_STRING *bn_to_asn1_string(const BIGNUM *bn, ASN1_STRING *ai,
456 ret = ASN1_STRING_type_new(atype);
463 ASN1err(ASN1_F_BN_TO_ASN1_STRING, ERR_R_NESTED_ASN1_ERROR);
467 if (BN_is_negative(bn) && !BN_is_zero(bn))
468 ret->type |= V_ASN1_NEG_INTEGER;
470 len = BN_num_bytes(bn);
475 if (ASN1_STRING_set(ret, NULL, len) == 0) {
476 ASN1err(ASN1_F_BN_TO_ASN1_STRING, ERR_R_MALLOC_FAILURE);
480 /* Correct zero case */
484 len = BN_bn2bin(bn, ret->data);
489 ASN1_INTEGER_free(ret);
493 static BIGNUM *asn1_string_to_bn(const ASN1_INTEGER *ai, BIGNUM *bn,
498 if ((ai->type & ~V_ASN1_NEG) != itype) {
499 ASN1err(ASN1_F_ASN1_STRING_TO_BN, ASN1_R_WRONG_INTEGER_TYPE);
503 ret = BN_bin2bn(ai->data, ai->length, bn);
505 ASN1err(ASN1_F_ASN1_STRING_TO_BN, ASN1_R_BN_LIB);
508 if (ai->type & V_ASN1_NEG)
509 BN_set_negative(ret, 1);
513 int ASN1_INTEGER_get_int64(int64_t *pr, const ASN1_INTEGER *a)
515 return asn1_string_get_int64(pr, a, V_ASN1_INTEGER);
518 int ASN1_INTEGER_set_int64(ASN1_INTEGER *a, int64_t r)
520 return asn1_string_set_int64(a, r, V_ASN1_INTEGER);
523 int ASN1_INTEGER_get_uint64(uint64_t *pr, const ASN1_INTEGER *a)
525 return asn1_string_get_uint64(pr, a, V_ASN1_INTEGER);
528 int ASN1_INTEGER_set_uint64(ASN1_INTEGER *a, uint64_t r)
530 return asn1_string_set_uint64(a, r, V_ASN1_INTEGER);
533 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
535 return ASN1_INTEGER_set_int64(a, v);
538 long ASN1_INTEGER_get(const ASN1_INTEGER *a)
544 i = ASN1_INTEGER_get_int64(&r, a);
547 if (r > LONG_MAX || r < LONG_MIN)
552 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
554 return bn_to_asn1_string(bn, ai, V_ASN1_INTEGER);
557 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
559 return asn1_string_to_bn(ai, bn, V_ASN1_INTEGER);
562 int ASN1_ENUMERATED_get_int64(int64_t *pr, const ASN1_ENUMERATED *a)
564 return asn1_string_get_int64(pr, a, V_ASN1_ENUMERATED);
567 int ASN1_ENUMERATED_set_int64(ASN1_ENUMERATED *a, int64_t r)
569 return asn1_string_set_int64(a, r, V_ASN1_ENUMERATED);
572 int ASN1_ENUMERATED_set(ASN1_ENUMERATED *a, long v)
574 return ASN1_ENUMERATED_set_int64(a, v);
577 long ASN1_ENUMERATED_get(const ASN1_ENUMERATED *a)
583 if ((a->type & ~V_ASN1_NEG) != V_ASN1_ENUMERATED)
585 if (a->length > (int)sizeof(long))
587 i = ASN1_ENUMERATED_get_int64(&r, a);
590 if (r > LONG_MAX || r < LONG_MIN)
595 ASN1_ENUMERATED *BN_to_ASN1_ENUMERATED(const BIGNUM *bn, ASN1_ENUMERATED *ai)
597 return bn_to_asn1_string(bn, ai, V_ASN1_ENUMERATED);
600 BIGNUM *ASN1_ENUMERATED_to_BN(const ASN1_ENUMERATED *ai, BIGNUM *bn)
602 return asn1_string_to_bn(ai, bn, V_ASN1_ENUMERATED);
605 /* Internal functions used by x_int64.c */
606 int c2i_uint64_int(uint64_t *ret, int *neg, const unsigned char **pp, long len)
608 unsigned char buf[sizeof(uint64_t)];
611 buflen = c2i_ibuf(NULL, NULL, *pp, len);
614 if (buflen > sizeof(uint64_t)) {
615 ASN1err(ASN1_F_C2I_UINT64_INT, ASN1_R_TOO_LARGE);
618 (void)c2i_ibuf(buf, neg, *pp, len);
619 return asn1_get_uint64(ret, buf, buflen);
622 int i2c_uint64_int(unsigned char *p, uint64_t r, int neg)
624 unsigned char buf[sizeof(uint64_t)];
627 off = asn1_put_uint64(buf, r);
628 return i2c_ibuf(buf + off, sizeof(buf) - off, neg, &p);