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/* Copyright (c) 2015, Google Inc.
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
#include <openssl/bn.h>
#include <openssl/bytestring.h>
#include <openssl/err.h>
int BN_cbs2unsigned(CBS *cbs, BIGNUM *ret) {
CBS child;
if (!CBS_get_asn1(cbs, &child, CBS_ASN1_INTEGER) ||
CBS_len(&child) == 0) {
OPENSSL_PUT_ERROR(BN, BN_R_BAD_ENCODING);
return 0;
}
if (CBS_data(&child)[0] & 0x80) {
OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
return 0;
}
/* INTEGERs must be minimal. */
if (CBS_data(&child)[0] == 0x00 &&
CBS_len(&child) > 1 &&
!(CBS_data(&child)[1] & 0x80)) {
OPENSSL_PUT_ERROR(BN, BN_R_BAD_ENCODING);
return 0;
}
return BN_bin2bn(CBS_data(&child), CBS_len(&child), ret) != NULL;
}
int BN_cbs2unsigned_buggy(CBS *cbs, BIGNUM *ret) {
CBS child;
if (!CBS_get_asn1(cbs, &child, CBS_ASN1_INTEGER) ||
CBS_len(&child) == 0) {
OPENSSL_PUT_ERROR(BN, BN_R_BAD_ENCODING);
return 0;
}
/* This function intentionally does not reject negative numbers or non-minimal
* encodings. Estonian IDs issued between September 2014 to September 2015 are
* broken. See https://crbug.com/532048 and https://crbug.com/534766.
*
* TODO(davidben): Remove this code and callers in March 2016. */
return BN_bin2bn(CBS_data(&child), CBS_len(&child), ret) != NULL;
}
int BN_bn2cbb(CBB *cbb, const BIGNUM *bn) {
/* Negative numbers are unsupported. */
if (BN_is_negative(bn)) {
OPENSSL_PUT_ERROR(BN, BN_R_NEGATIVE_NUMBER);
return 0;
}
CBB child;
if (!CBB_add_asn1(cbb, &child, CBS_ASN1_INTEGER)) {
OPENSSL_PUT_ERROR(BN, BN_R_ENCODE_ERROR);
return 0;
}
/* The number must be padded with a leading zero if the high bit would
* otherwise be set (or |bn| is zero). */
if (BN_num_bits(bn) % 8 == 0 &&
!CBB_add_u8(&child, 0x00)) {
OPENSSL_PUT_ERROR(BN, BN_R_ENCODE_ERROR);
return 0;
}
uint8_t *out;
if (!CBB_add_space(&child, &out, BN_num_bytes(bn))) {
OPENSSL_PUT_ERROR(BN, BN_R_ENCODE_ERROR);
return 0;
}
BN_bn2bin(bn, out);
if (!CBB_flush(cbb)) {
OPENSSL_PUT_ERROR(BN, BN_R_ENCODE_ERROR);
return 0;
}
return 1;
}
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