138 lines
4.6 KiB
C
138 lines
4.6 KiB
C
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
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*
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* LibTomCrypt is a library that provides various cryptographic
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* algorithms in a highly modular and flexible manner.
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*
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* The library is free for all purposes without any express
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* guarantee it works.
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*/
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#include "tomcrypt.h"
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/**
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@file dsa_import.c
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DSA implementation, import a DSA key, Tom St Denis
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*/
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#ifdef LTC_MDSA
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/**
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Import a DSA key
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@param in The binary packet to import from
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@param inlen The length of the binary packet
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@param key [out] Where to store the imported key
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@return CRYPT_OK if successful, upon error this function will free all allocated memory
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*/
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int dsa_import(const unsigned char *in, unsigned long inlen, dsa_key *key)
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{
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int err;
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unsigned long zero = 0;
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unsigned char* tmpbuf = NULL;
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unsigned char flags[1];
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LTC_ARGCHK(in != NULL);
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LTC_ARGCHK(key != NULL);
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LTC_ARGCHK(ltc_mp.name != NULL);
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/* init key */
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if (mp_init_multi(&key->p, &key->g, &key->q, &key->x, &key->y, NULL) != CRYPT_OK) {
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return CRYPT_MEM;
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}
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/* try to match the old libtomcrypt format */
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err = der_decode_sequence_multi(in, inlen, LTC_ASN1_BIT_STRING, 1UL, flags,
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LTC_ASN1_EOL, 0UL, NULL);
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if (err == CRYPT_OK || err == CRYPT_PK_INVALID_SIZE) {
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/* private key */
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if (flags[0]) {
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if ((err = der_decode_sequence_multi(in, inlen,
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LTC_ASN1_BIT_STRING, 1UL, flags,
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LTC_ASN1_INTEGER, 1UL, key->g,
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LTC_ASN1_INTEGER, 1UL, key->p,
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LTC_ASN1_INTEGER, 1UL, key->q,
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LTC_ASN1_INTEGER, 1UL, key->y,
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LTC_ASN1_INTEGER, 1UL, key->x,
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LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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key->type = PK_PRIVATE;
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goto LBL_OK;
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}
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/* public key */
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else {
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if ((err = der_decode_sequence_multi(in, inlen,
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LTC_ASN1_BIT_STRING, 1UL, flags,
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LTC_ASN1_INTEGER, 1UL, key->g,
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LTC_ASN1_INTEGER, 1UL, key->p,
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LTC_ASN1_INTEGER, 1UL, key->q,
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LTC_ASN1_INTEGER, 1UL, key->y,
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LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
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goto LBL_ERR;
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}
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key->type = PK_PUBLIC;
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goto LBL_OK;
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}
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}
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/* get key type */
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if ((err = der_decode_sequence_multi(in, inlen,
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LTC_ASN1_SHORT_INTEGER, 1UL, &zero,
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LTC_ASN1_INTEGER, 1UL, key->p,
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LTC_ASN1_INTEGER, 1UL, key->q,
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LTC_ASN1_INTEGER, 1UL, key->g,
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LTC_ASN1_INTEGER, 1UL, key->y,
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LTC_ASN1_INTEGER, 1UL, key->x,
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LTC_ASN1_EOL, 0UL, NULL)) == CRYPT_OK) {
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key->type = PK_PRIVATE;
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} else { /* public */
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ltc_asn1_list params[3];
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unsigned long tmpbuf_len = LTC_DER_MAX_PUBKEY_SIZE*8;
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LTC_SET_ASN1(params, 0, LTC_ASN1_INTEGER, key->p, 1UL);
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LTC_SET_ASN1(params, 1, LTC_ASN1_INTEGER, key->q, 1UL);
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LTC_SET_ASN1(params, 2, LTC_ASN1_INTEGER, key->g, 1UL);
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tmpbuf = XCALLOC(1, tmpbuf_len);
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if (tmpbuf == NULL) {
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err = CRYPT_MEM;
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goto LBL_ERR;
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}
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err = der_decode_subject_public_key_info(in, inlen, PKA_DSA,
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tmpbuf, &tmpbuf_len,
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LTC_ASN1_SEQUENCE, params, 3);
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if (err != CRYPT_OK) {
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XFREE(tmpbuf);
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goto LBL_ERR;
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}
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if ((err=der_decode_integer(tmpbuf, tmpbuf_len, key->y)) != CRYPT_OK) {
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XFREE(tmpbuf);
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goto LBL_ERR;
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}
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XFREE(tmpbuf);
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key->type = PK_PUBLIC;
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}
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LBL_OK:
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key->qord = mp_unsigned_bin_size(key->q);
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if (key->qord >= LTC_MDSA_MAX_GROUP || key->qord <= 15 ||
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(unsigned long)key->qord >= mp_unsigned_bin_size(key->p) || (mp_unsigned_bin_size(key->p) - key->qord) >= LTC_MDSA_DELTA) {
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err = CRYPT_INVALID_PACKET;
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goto LBL_ERR;
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}
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return CRYPT_OK;
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LBL_ERR:
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dsa_free(key);
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return err;
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}
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#endif
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/* ref: $Format:%D$ */
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/* git commit: $Format:%H$ */
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/* commit time: $Format:%ai$ */
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