2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
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
11 #include "internal/cryptlib.h"
12 #include "internal/numbers.h"
14 #include <openssl/asn1.h>
15 #include <openssl/bn.h>
16 #include "asn1_local.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 * if len == 0 then src/dst could be NULL, and this would be undefined
90 /* two's complement value: ~value + 1 */
92 *(--dst) = (unsigned char)(carry += *(--src) ^ pad);
97 static size_t i2c_ibuf(const unsigned char *b, size_t blen, int neg,
100 unsigned int pad = 0;
102 unsigned char *p, pb = 0;
104 if (b != NULL && blen) {
107 if (!neg && (i > 127)) {
114 } else if (i == 128) {
116 * Special case [of minimal negative for given length]:
117 * if any other bytes non zero we pad, otherwise we don't.
119 for (pad = 0, i = 1; i < blen; i++)
121 pb = pad != 0 ? 0xffU : 0;
128 blen = 0; /* reduce '(b == NULL || blen == 0)' to '(blen == 0)' */
131 if (pp == NULL || (p = *pp) == NULL)
135 * This magically handles all corner cases, such as '(b == NULL ||
136 * blen == 0)', non-negative value, "negative" zero, 0x80 followed
137 * by any number of zeros...
140 p += pad; /* yes, p[0] can be written twice, but it's little
141 * price to pay for eliminated branches */
142 twos_complement(p, b, blen, pb);
149 * convert content octets into a big endian buffer. Returns the length
150 * of buffer or 0 on error: for malformed INTEGER. If output buffer is
151 * NULL just return length.
154 static size_t c2i_ibuf(unsigned char *b, int *pneg,
155 const unsigned char *p, size_t plen)
158 /* Zero content length is illegal */
160 ERR_raise(ERR_LIB_ASN1, ASN1_R_ILLEGAL_ZERO_CONTENT);
166 /* Handle common case where length is 1 octet separately */
170 b[0] = (p[0] ^ 0xFF) + 1;
180 } else if (p[0] == 0xFF) {
184 * Special case [of "one less minimal negative" for given length]:
185 * if any other bytes non zero it was padded, otherwise not.
187 for (pad = 0, i = 1; i < plen; i++)
189 pad = pad != 0 ? 1 : 0;
191 /* reject illegal padding: first two octets MSB can't match */
192 if (pad && (neg == (p[1] & 0x80))) {
193 ERR_raise(ERR_LIB_ASN1, ASN1_R_ILLEGAL_PADDING);
202 twos_complement(b, p, plen, neg ? 0xffU : 0);
207 int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp)
209 return i2c_ibuf(a->data, a->length, a->type & V_ASN1_NEG, pp);
212 /* Convert big endian buffer into uint64_t, return 0 on error */
213 static int asn1_get_uint64(uint64_t *pr, const unsigned char *b, size_t blen)
218 if (blen > sizeof(*pr)) {
219 ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LARGE);
224 for (r = 0, i = 0; i < blen; i++) {
233 * Write uint64_t to big endian buffer and return offset to first
234 * written octet. In other words it returns offset in range from 0
235 * to 7, with 0 denoting 8 written octets and 7 - one.
237 static size_t asn1_put_uint64(unsigned char b[sizeof(uint64_t)], uint64_t r)
239 size_t off = sizeof(uint64_t);
242 b[--off] = (unsigned char)r;
249 * Absolute value of INT64_MIN: we can't just use -INT64_MIN as gcc produces
252 #define ABS_INT64_MIN ((uint64_t)INT64_MAX + (-(INT64_MIN + INT64_MAX)))
254 /* signed version of asn1_get_uint64 */
255 static int asn1_get_int64(int64_t *pr, const unsigned char *b, size_t blen,
259 if (asn1_get_uint64(&r, b, blen) == 0)
262 if (r <= INT64_MAX) {
263 /* Most significant bit is guaranteed to be clear, negation
264 * is guaranteed to be meaningful in platform-neutral sense. */
266 } else if (r == ABS_INT64_MIN) {
267 /* This never happens if INT64_MAX == ABS_INT64_MIN, e.g.
268 * on ones'-complement system. */
269 *pr = (int64_t)(0 - r);
271 ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_SMALL);
275 if (r <= INT64_MAX) {
278 ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LARGE);
285 /* Convert ASN1 INTEGER content octets to ASN1_INTEGER structure */
286 ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
289 ASN1_INTEGER *ret = NULL;
293 r = c2i_ibuf(NULL, NULL, *pp, len);
298 if ((a == NULL) || ((*a) == NULL)) {
299 ret = ASN1_INTEGER_new();
302 ret->type = V_ASN1_INTEGER;
306 if (ASN1_STRING_set(ret, NULL, r) == 0)
309 c2i_ibuf(ret->data, &neg, *pp, len);
312 ret->type |= V_ASN1_NEG;
319 ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
320 if ((a == NULL) || (*a != ret))
321 ASN1_INTEGER_free(ret);
325 static int asn1_string_get_int64(int64_t *pr, const ASN1_STRING *a, int itype)
328 ERR_raise(ERR_LIB_ASN1, ERR_R_PASSED_NULL_PARAMETER);
331 if ((a->type & ~V_ASN1_NEG) != itype) {
332 ERR_raise(ERR_LIB_ASN1, ASN1_R_WRONG_INTEGER_TYPE);
335 return asn1_get_int64(pr, a->data, a->length, a->type & V_ASN1_NEG);
338 static int asn1_string_set_int64(ASN1_STRING *a, int64_t r, int itype)
340 unsigned char tbuf[sizeof(r)];
345 /* Most obvious '-r' triggers undefined behaviour for most
346 * common INT64_MIN. Even though below '0 - (uint64_t)r' can
347 * appear two's-complement centric, it does produce correct/
348 * expected result even on one's-complement. This is because
349 * cast to unsigned has to change bit pattern... */
350 off = asn1_put_uint64(tbuf, 0 - (uint64_t)r);
351 a->type |= V_ASN1_NEG;
353 off = asn1_put_uint64(tbuf, r);
354 a->type &= ~V_ASN1_NEG;
356 return ASN1_STRING_set(a, tbuf + off, sizeof(tbuf) - off);
359 static int asn1_string_get_uint64(uint64_t *pr, const ASN1_STRING *a,
363 ERR_raise(ERR_LIB_ASN1, ERR_R_PASSED_NULL_PARAMETER);
366 if ((a->type & ~V_ASN1_NEG) != itype) {
367 ERR_raise(ERR_LIB_ASN1, ASN1_R_WRONG_INTEGER_TYPE);
370 if (a->type & V_ASN1_NEG) {
371 ERR_raise(ERR_LIB_ASN1, ASN1_R_ILLEGAL_NEGATIVE_VALUE);
374 return asn1_get_uint64(pr, a->data, a->length);
377 static int asn1_string_set_uint64(ASN1_STRING *a, uint64_t r, int itype)
379 unsigned char tbuf[sizeof(r)];
383 off = asn1_put_uint64(tbuf, r);
384 return ASN1_STRING_set(a, tbuf + off, sizeof(tbuf) - off);
388 * This is a version of d2i_ASN1_INTEGER that ignores the sign bit of ASN1
389 * integers: some broken software can encode a positive INTEGER with its MSB
390 * set as negative (it doesn't add a padding zero).
393 ASN1_INTEGER *d2i_ASN1_UINTEGER(ASN1_INTEGER **a, const unsigned char **pp,
396 ASN1_INTEGER *ret = NULL;
397 const unsigned char *p;
400 int inf, tag, xclass;
403 if ((a == NULL) || ((*a) == NULL)) {
404 if ((ret = ASN1_INTEGER_new()) == NULL)
406 ret->type = V_ASN1_INTEGER;
411 inf = ASN1_get_object(&p, &len, &tag, &xclass, length);
413 i = ASN1_R_BAD_OBJECT_HEADER;
417 if (tag != V_ASN1_INTEGER) {
418 i = ASN1_R_EXPECTING_AN_INTEGER;
423 * We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
424 * a missing NULL parameter.
426 s = OPENSSL_malloc((int)len + 1);
428 i = ERR_R_MALLOC_FAILURE;
431 ret->type = V_ASN1_INTEGER;
433 if ((*p == 0) && (len != 1)) {
437 memcpy(s, p, (int)len);
441 OPENSSL_free(ret->data);
443 ret->length = (int)len;
449 ERR_raise(ERR_LIB_ASN1, i);
450 if ((a == NULL) || (*a != ret))
451 ASN1_INTEGER_free(ret);
455 static ASN1_STRING *bn_to_asn1_string(const BIGNUM *bn, ASN1_STRING *ai,
462 ret = ASN1_STRING_type_new(atype);
469 ERR_raise(ERR_LIB_ASN1, ERR_R_NESTED_ASN1_ERROR);
473 if (BN_is_negative(bn) && !BN_is_zero(bn))
474 ret->type |= V_ASN1_NEG_INTEGER;
476 len = BN_num_bytes(bn);
481 if (ASN1_STRING_set(ret, NULL, len) == 0) {
482 ERR_raise(ERR_LIB_ASN1, ERR_R_MALLOC_FAILURE);
486 /* Correct zero case */
490 len = BN_bn2bin(bn, ret->data);
495 ASN1_INTEGER_free(ret);
499 static BIGNUM *asn1_string_to_bn(const ASN1_INTEGER *ai, BIGNUM *bn,
504 if ((ai->type & ~V_ASN1_NEG) != itype) {
505 ERR_raise(ERR_LIB_ASN1, ASN1_R_WRONG_INTEGER_TYPE);
509 ret = BN_bin2bn(ai->data, ai->length, bn);
511 ERR_raise(ERR_LIB_ASN1, ASN1_R_BN_LIB);
514 if (ai->type & V_ASN1_NEG)
515 BN_set_negative(ret, 1);
519 int ASN1_INTEGER_get_int64(int64_t *pr, const ASN1_INTEGER *a)
521 return asn1_string_get_int64(pr, a, V_ASN1_INTEGER);
524 int ASN1_INTEGER_set_int64(ASN1_INTEGER *a, int64_t r)
526 return asn1_string_set_int64(a, r, V_ASN1_INTEGER);
529 int ASN1_INTEGER_get_uint64(uint64_t *pr, const ASN1_INTEGER *a)
531 return asn1_string_get_uint64(pr, a, V_ASN1_INTEGER);
534 int ASN1_INTEGER_set_uint64(ASN1_INTEGER *a, uint64_t r)
536 return asn1_string_set_uint64(a, r, V_ASN1_INTEGER);
539 int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
541 return ASN1_INTEGER_set_int64(a, v);
544 long ASN1_INTEGER_get(const ASN1_INTEGER *a)
550 i = ASN1_INTEGER_get_int64(&r, a);
553 if (r > LONG_MAX || r < LONG_MIN)
558 ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
560 return bn_to_asn1_string(bn, ai, V_ASN1_INTEGER);
563 BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
565 return asn1_string_to_bn(ai, bn, V_ASN1_INTEGER);
568 int ASN1_ENUMERATED_get_int64(int64_t *pr, const ASN1_ENUMERATED *a)
570 return asn1_string_get_int64(pr, a, V_ASN1_ENUMERATED);
573 int ASN1_ENUMERATED_set_int64(ASN1_ENUMERATED *a, int64_t r)
575 return asn1_string_set_int64(a, r, V_ASN1_ENUMERATED);
578 int ASN1_ENUMERATED_set(ASN1_ENUMERATED *a, long v)
580 return ASN1_ENUMERATED_set_int64(a, v);
583 long ASN1_ENUMERATED_get(const ASN1_ENUMERATED *a)
589 if ((a->type & ~V_ASN1_NEG) != V_ASN1_ENUMERATED)
591 if (a->length > (int)sizeof(long))
593 i = ASN1_ENUMERATED_get_int64(&r, a);
596 if (r > LONG_MAX || r < LONG_MIN)
601 ASN1_ENUMERATED *BN_to_ASN1_ENUMERATED(const BIGNUM *bn, ASN1_ENUMERATED *ai)
603 return bn_to_asn1_string(bn, ai, V_ASN1_ENUMERATED);
606 BIGNUM *ASN1_ENUMERATED_to_BN(const ASN1_ENUMERATED *ai, BIGNUM *bn)
608 return asn1_string_to_bn(ai, bn, V_ASN1_ENUMERATED);
611 /* Internal functions used by x_int64.c */
612 int c2i_uint64_int(uint64_t *ret, int *neg, const unsigned char **pp, long len)
614 unsigned char buf[sizeof(uint64_t)];
617 buflen = c2i_ibuf(NULL, NULL, *pp, len);
620 if (buflen > sizeof(uint64_t)) {
621 ERR_raise(ERR_LIB_ASN1, ASN1_R_TOO_LARGE);
624 (void)c2i_ibuf(buf, neg, *pp, len);
625 return asn1_get_uint64(ret, buf, buflen);
628 int i2c_uint64_int(unsigned char *p, uint64_t r, int neg)
630 unsigned char buf[sizeof(uint64_t)];
633 off = asn1_put_uint64(buf, r);
634 return i2c_ibuf(buf + off, sizeof(buf) - off, neg, &p);