ref: bfe9da47cfa2f51ebef78c59332b5ba2deba306d
dir: /third_party/boringssl/src/crypto/asn1/a_int.c/
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/asn1.h>
#include <string.h>
#include <limits.h>
#include <openssl/err.h>
#include <openssl/mem.h>
#include "../internal.h"
ASN1_INTEGER *ASN1_INTEGER_dup(const ASN1_INTEGER *x)
{
return ASN1_STRING_dup(x);
}
int ASN1_INTEGER_cmp(const ASN1_INTEGER *x, const ASN1_INTEGER *y)
{
int neg, ret;
/* Compare signs */
neg = x->type & V_ASN1_NEG;
if (neg != (y->type & V_ASN1_NEG)) {
if (neg)
return -1;
else
return 1;
}
ret = ASN1_STRING_cmp(x, y);
if (neg)
return -ret;
else
return ret;
}
/*
* This converts an ASN1 INTEGER into its content encoding.
* The internal representation is an ASN1_STRING whose data is a big endian
* representation of the value, ignoring the sign. The sign is determined by
* the type: V_ASN1_INTEGER for positive and V_ASN1_NEG_INTEGER for negative.
*
* Positive integers are no problem: they are almost the same as the DER
* encoding, except if the first byte is >= 0x80 we need to add a zero pad.
*
* Negative integers are a bit trickier...
* The DER representation of negative integers is in 2s complement form.
* The internal form is converted by complementing each octet and finally
* adding one to the result. This can be done less messily with a little trick.
* If the internal form has trailing zeroes then they will become FF by the
* complement and 0 by the add one (due to carry) so just copy as many trailing
* zeros to the destination as there are in the source. The carry will add one
* to the last none zero octet: so complement this octet and add one and finally
* complement any left over until you get to the start of the string.
*
* Padding is a little trickier too. If the first bytes is > 0x80 then we pad
* with 0xff. However if the first byte is 0x80 and one of the following bytes
* is non-zero we pad with 0xff. The reason for this distinction is that 0x80
* followed by optional zeros isn't padded.
*/
int i2c_ASN1_INTEGER(const ASN1_INTEGER *a, unsigned char **pp)
{
int pad = 0, ret, i, neg;
unsigned char *p, *n, pb = 0;
if (a == NULL)
return (0);
neg = a->type & V_ASN1_NEG;
if (a->length == 0)
ret = 1;
else {
ret = a->length;
i = a->data[0];
if (ret == 1 && i == 0)
neg = 0;
if (!neg && (i > 127)) {
pad = 1;
pb = 0;
} else if (neg) {
if (i > 128) {
pad = 1;
pb = 0xFF;
} else if (i == 128) {
/*
* Special case: if any other bytes non zero we pad:
* otherwise we don't.
*/
for (i = 1; i < a->length; i++)
if (a->data[i]) {
pad = 1;
pb = 0xFF;
break;
}
}
}
ret += pad;
}
if (pp == NULL)
return (ret);
p = *pp;
if (pad)
*(p++) = pb;
if (a->length == 0)
*(p++) = 0;
else if (!neg)
OPENSSL_memcpy(p, a->data, (unsigned int)a->length);
else {
/* Begin at the end of the encoding */
n = a->data + a->length - 1;
p += a->length - 1;
i = a->length;
/* Copy zeros to destination as long as source is zero */
while (!*n && i > 1) {
*(p--) = 0;
n--;
i--;
}
/* Complement and increment next octet */
*(p--) = ((*(n--)) ^ 0xff) + 1;
i--;
/* Complement any octets left */
for (; i > 0; i--)
*(p--) = *(n--) ^ 0xff;
}
*pp += ret;
return (ret);
}
/* Convert just ASN1 INTEGER content octets to ASN1_INTEGER structure */
ASN1_INTEGER *c2i_ASN1_INTEGER(ASN1_INTEGER **a, const unsigned char **pp,
long len)
{
ASN1_INTEGER *ret = NULL;
const unsigned char *p, *pend;
unsigned char *to, *s;
int i;
/*
* This function can handle lengths up to INT_MAX - 1, but the rest of the
* legacy ASN.1 code mixes integer types, so avoid exposing it to
* ASN1_INTEGERS with larger lengths.
*/
if (len < 0 || len > INT_MAX / 2) {
OPENSSL_PUT_ERROR(ASN1, ASN1_R_TOO_LONG);
return NULL;
}
if ((a == NULL) || ((*a) == NULL)) {
if ((ret = ASN1_INTEGER_new()) == NULL)
return (NULL);
ret->type = V_ASN1_INTEGER;
} else
ret = (*a);
p = *pp;
pend = p + len;
/*
* We must OPENSSL_malloc stuff, even for 0 bytes otherwise it signifies
* a missing NULL parameter.
*/
s = (unsigned char *)OPENSSL_malloc((int)len + 1);
if (s == NULL) {
i = ERR_R_MALLOC_FAILURE;
goto err;
}
to = s;
if (!len) {
/*
* Strictly speaking this is an illegal INTEGER but we tolerate it.
*/
ret->type = V_ASN1_INTEGER;
} else if (*p & 0x80) { /* a negative number */
ret->type = V_ASN1_NEG_INTEGER;
if ((*p == 0xff) && (len != 1)) {
p++;
len--;
}
i = len;
p += i - 1;
to += i - 1;
while ((!*p) && i) {
*(to--) = 0;
i--;
p--;
}
/*
* Special case: if all zeros then the number will be of the form FF
* followed by n zero bytes: this corresponds to 1 followed by n zero
* bytes. We've already written n zeros so we just append an extra
* one and set the first byte to a 1. This is treated separately
* because it is the only case where the number of bytes is larger
* than len.
*/
if (!i) {
*s = 1;
s[len] = 0;
len++;
} else {
*(to--) = (*(p--) ^ 0xff) + 1;
i--;
for (; i > 0; i--)
*(to--) = *(p--) ^ 0xff;
}
} else {
ret->type = V_ASN1_INTEGER;
if ((*p == 0) && (len != 1)) {
p++;
len--;
}
OPENSSL_memcpy(s, p, (int)len);
}
if (ret->data != NULL)
OPENSSL_free(ret->data);
ret->data = s;
ret->length = (int)len;
if (a != NULL)
(*a) = ret;
*pp = pend;
return (ret);
err:
OPENSSL_PUT_ERROR(ASN1, i);
if ((ret != NULL) && ((a == NULL) || (*a != ret)))
ASN1_INTEGER_free(ret);
return (NULL);
}
int ASN1_INTEGER_set(ASN1_INTEGER *a, long v)
{
if (v >= 0) {
return ASN1_INTEGER_set_uint64(a, (uint64_t) v);
}
if (!ASN1_INTEGER_set_uint64(a, 0 - (uint64_t) v)) {
return 0;
}
a->type = V_ASN1_NEG_INTEGER;
return 1;
}
int ASN1_INTEGER_set_uint64(ASN1_INTEGER *out, uint64_t v)
{
uint8_t *const newdata = OPENSSL_malloc(sizeof(uint64_t));
if (newdata == NULL) {
OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
return 0;
}
OPENSSL_free(out->data);
out->data = newdata;
v = CRYPTO_bswap8(v);
memcpy(out->data, &v, sizeof(v));
out->type = V_ASN1_INTEGER;
size_t leading_zeros;
for (leading_zeros = 0; leading_zeros < sizeof(uint64_t) - 1;
leading_zeros++) {
if (out->data[leading_zeros] != 0) {
break;
}
}
out->length = sizeof(uint64_t) - leading_zeros;
OPENSSL_memmove(out->data, out->data + leading_zeros, out->length);
return 1;
}
long ASN1_INTEGER_get(const ASN1_INTEGER *a)
{
int neg = 0, i;
if (a == NULL)
return (0L);
i = a->type;
if (i == V_ASN1_NEG_INTEGER)
neg = 1;
else if (i != V_ASN1_INTEGER)
return -1;
OPENSSL_STATIC_ASSERT(sizeof(uint64_t) >= sizeof(long),
"long larger than uint64_t");
if (a->length > (int)sizeof(uint64_t)) {
/* hmm... a bit ugly, return all ones */
return -1;
}
uint64_t r64 = 0;
if (a->data != NULL) {
for (i = 0; i < a->length; i++) {
r64 <<= 8;
r64 |= (unsigned char)a->data[i];
}
if (r64 > LONG_MAX) {
return -1;
}
}
long r = (long) r64;
if (neg)
r = -r;
return r;
}
ASN1_INTEGER *BN_to_ASN1_INTEGER(const BIGNUM *bn, ASN1_INTEGER *ai)
{
ASN1_INTEGER *ret;
int len, j;
if (ai == NULL)
ret = ASN1_INTEGER_new();
else
ret = ai;
if (ret == NULL) {
OPENSSL_PUT_ERROR(ASN1, ASN1_R_NESTED_ASN1_ERROR);
goto err;
}
if (BN_is_negative(bn) && !BN_is_zero(bn))
ret->type = V_ASN1_NEG_INTEGER;
else
ret->type = V_ASN1_INTEGER;
j = BN_num_bits(bn);
len = ((j == 0) ? 0 : ((j / 8) + 1));
if (ret->length < len + 4) {
unsigned char *new_data = OPENSSL_realloc(ret->data, len + 4);
if (!new_data) {
OPENSSL_PUT_ERROR(ASN1, ERR_R_MALLOC_FAILURE);
goto err;
}
ret->data = new_data;
}
ret->length = BN_bn2bin(bn, ret->data);
/* Correct zero case */
if (!ret->length) {
ret->data[0] = 0;
ret->length = 1;
}
return (ret);
err:
if (ret != ai)
ASN1_INTEGER_free(ret);
return (NULL);
}
BIGNUM *ASN1_INTEGER_to_BN(const ASN1_INTEGER *ai, BIGNUM *bn)
{
BIGNUM *ret;
if ((ret = BN_bin2bn(ai->data, ai->length, bn)) == NULL)
OPENSSL_PUT_ERROR(ASN1, ASN1_R_BN_LIB);
else if (ai->type == V_ASN1_NEG_INTEGER)
BN_set_negative(ret, 1);
return (ret);
}