88 lines
2.3 KiB
C
88 lines
2.3 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
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/* SPDX-License-Identifier: Unlicense */
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#include "tomcrypt_private.h"
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#ifdef LTC_MDH
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int dh_import_pkcs8_asn1(ltc_asn1_list *alg_id, ltc_asn1_list *priv_key, dh_key *key)
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{
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int err;
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LTC_ARGCHK(key != NULL);
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if (!alg_id->child ||
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!LTC_ASN1_IS_TYPE(alg_id->child->next, LTC_ASN1_SEQUENCE) ||
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!LTC_ASN1_IS_TYPE(alg_id->child->next->child, LTC_ASN1_INTEGER) ||
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!LTC_ASN1_IS_TYPE(alg_id->child->next->child->next, LTC_ASN1_INTEGER)) {
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return CRYPT_PK_INVALID_TYPE;
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}
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if ((err = dh_init(key)) != CRYPT_OK) {
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return err;
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}
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if ((err = ltc_mp_copy(alg_id->child->next->child->data, key->prime)) != CRYPT_OK) {
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goto error;
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}
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if ((err = ltc_mp_copy(alg_id->child->next->child->next->data, key->base)) != CRYPT_OK) {
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goto error;
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}
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if ((err = der_decode_integer(priv_key->data, priv_key->size, key->x)) != CRYPT_OK) {
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goto error;
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}
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/* compute public key: y = (base ^ x) mod prime */
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if ((err = ltc_mp_exptmod(key->base, key->x, key->prime, key->y)) != CRYPT_OK) {
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goto error;
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}
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/* check public key */
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if ((err = dh_check_pubkey(key)) != CRYPT_OK) {
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goto error;
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}
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key->type = PK_PRIVATE;
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return CRYPT_OK;
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error:
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dh_free(key);
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return err;
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}
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/**
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Import a DH key in PKCS#8 format
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@param in The packet to import from
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@param inlen It's length (octets)
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@param pw_ctx The password context when decrypting the private key
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@param key [out] Destination for newly imported key
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@return CRYPT_OK if successful, on error all allocated memory is freed automatically
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*/
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int dh_import_pkcs8(const unsigned char *in, unsigned long inlen,
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const password_ctx *pw_ctx, dh_key *key)
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{
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int err;
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ltc_asn1_list *l = NULL;
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ltc_asn1_list *alg_id, *priv_key;
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enum ltc_oid_id pka;
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LTC_ARGCHK(in != NULL);
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if ((err = pkcs8_decode_flexi(in, inlen, pw_ctx, &l)) != CRYPT_OK) {
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return err;
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}
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if ((err = pkcs8_get_children(l, &pka, &alg_id, &priv_key)) != CRYPT_OK) {
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goto LBL_DER_FREE;
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}
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if (pka != LTC_OID_DH) {
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err = CRYPT_INVALID_PACKET;
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goto LBL_DER_FREE;
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}
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err = dh_import_pkcs8_asn1(alg_id, priv_key, key);
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LBL_DER_FREE:
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der_free_sequence_flexi(l);
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return err;
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}
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#endif /* LTC_MDH */
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