diff options
Diffstat (limited to 'crypto/bn/bn_asn1.c')
-rw-r--r-- | crypto/bn/bn_asn1.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/crypto/bn/bn_asn1.c b/crypto/bn/bn_asn1.c new file mode 100644 index 00000000..81e7b897 --- /dev/null +++ b/crypto/bn/bn_asn1.c @@ -0,0 +1,74 @@ +/* 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_cbs2unsigned, BN_R_BAD_ENCODING); + return 0; + } + if (CBS_data(&child)[0] & 0x80) { + OPENSSL_PUT_ERROR(BN, BN_cbs2unsigned, 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_cbs2unsigned, BN_R_BAD_ENCODING); + return 0; + } + 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_bn2cbb, BN_R_NEGATIVE_NUMBER); + return 0; + } + + CBB child; + if (!CBB_add_asn1(cbb, &child, CBS_ASN1_INTEGER)) { + OPENSSL_PUT_ERROR(BN, BN_bn2cbb, 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_bn2cbb, BN_R_ENCODE_ERROR); + return 0; + } + + uint8_t *out; + if (!CBB_add_space(&child, &out, BN_num_bytes(bn))) { + OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_ENCODE_ERROR); + return 0; + } + BN_bn2bin(bn, out); + if (!CBB_flush(cbb)) { + OPENSSL_PUT_ERROR(BN, BN_bn2cbb, BN_R_ENCODE_ERROR); + return 0; + } + return 1; +} |