75 lines
2.3 KiB
C
75 lines
2.3 KiB
C
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/* Copyright (c) 2015, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#include <openssl/bn.h>
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#include <openssl/bytestring.h>
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#include <openssl/err.h>
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int BN_cbs2unsigned(CBS *cbs, BIGNUM *ret) {
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CBS child;
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if (!CBS_get_asn1(cbs, &child, CBS_ASN1_INTEGER) ||
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CBS_len(&child) == 0) {
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OPENSSL_PUT_ERROR(BN, BN_cbs2unsigned, BN_R_BAD_ENCODING);
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return 0;
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}
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if (CBS_data(&child)[0] & 0x80) {
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OPENSSL_PUT_ERROR(BN, BN_cbs2unsigned, BN_R_NEGATIVE_NUMBER);
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return 0;
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}
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/* INTEGERs must be minimal. */
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if (CBS_data(&child)[0] == 0x00 &&
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CBS_len(&child) > 1 &&
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!(CBS_data(&child)[1] & 0x80)) {
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OPENSSL_PUT_ERROR(BN, BN_cbs2unsigned, BN_R_BAD_ENCODING);
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return 0;
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}
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return BN_bin2bn(CBS_data(&child), CBS_len(&child), ret) != NULL;
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}
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int BN_bn2cbb(CBB *cbb, const BIGNUM *bn) {
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/* Negative numbers are unsupported. */
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if (BN_is_negative(bn)) {
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OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_NEGATIVE_NUMBER);
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return 0;
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}
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CBB child;
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if (!CBB_add_asn1(cbb, &child, CBS_ASN1_INTEGER)) {
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OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_ENCODE_ERROR);
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return 0;
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}
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/* The number must be padded with a leading zero if the high bit would
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* otherwise be set (or |bn| is zero). */
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if (BN_num_bits(bn) % 8 == 0 &&
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!CBB_add_u8(&child, 0x00)) {
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OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_ENCODE_ERROR);
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return 0;
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}
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uint8_t *out;
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if (!CBB_add_space(&child, &out, BN_num_bytes(bn))) {
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OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_ENCODE_ERROR);
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return 0;
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}
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BN_bn2bin(bn, out);
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if (!CBB_flush(cbb)) {
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OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_ENCODE_ERROR);
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return 0;
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}
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return 1;
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}
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