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/* LibTomCrypt, modular cryptographic library -- Tom St Denis
*
* LibTomCrypt is a library that provides various cryptographic
* algorithms in a highly modular and flexible manner.
*
* The library is free for all purposes without any express
* guarantee it works.
*
* Tom St Denis, tomstdenis@gmail.com, http://libtomcrypt.com
*/
#include "tomcrypt.h"
/**
@file rsa_import.c
Import a PKCS RSA key, Tom St Denis
*/
#ifdef MRSA
/**
Import an RSAPublicKey or RSAPrivateKey [two-prime only, only support >= 1024-bit keys, defined in PKCS #1 v2.1]
@param in The packet to import from
@param inlen It's length (octets)
@param key [out] Destination for newly imported key
@return CRYPT_OK if successful, upon error allocated memory is freed
*/
int rsa_import(const unsigned char *in, unsigned long inlen, rsa_key *key)
{
int err;
void *zero;
unsigned char *tmpbuf;
unsigned long t, x, y, z, tmpoid[16];
ltc_asn1_list ssl_pubkey_hashoid[2];
ltc_asn1_list ssl_pubkey[2];
LTC_ARGCHK(in != NULL);
LTC_ARGCHK(key != NULL);
LTC_ARGCHK(ltc_mp.name != NULL);
/* init key */
if ((err = mp_init_multi(&key->e, &key->d, &key->N, &key->dQ,
&key->dP, &key->qP, &key->p, &key->q, NULL)) != CRYPT_OK) {
return err;
}
/* see if the OpenSSL DER format RSA public key will work */
tmpbuf = XCALLOC(1, MAX_RSA_SIZE*8);
if (tmpbuf == NULL) {
err = CRYPT_MEM;
goto LBL_ERR;
}
/* this includes the internal hash ID and optional params (NULL in this case) */
LTC_SET_ASN1(ssl_pubkey_hashoid, 0, LTC_ASN1_OBJECT_IDENTIFIER, tmpoid, sizeof(tmpoid)/sizeof(tmpoid[0]));
LTC_SET_ASN1(ssl_pubkey_hashoid, 1, LTC_ASN1_NULL, NULL, 0);
/* the actual format of the SSL DER key is odd, it stores a RSAPublicKey in a **BIT** string ... so we have to extract it
then proceed to convert bit to octet
*/
LTC_SET_ASN1(ssl_pubkey, 0, LTC_ASN1_SEQUENCE, &ssl_pubkey_hashoid, 2);
LTC_SET_ASN1(ssl_pubkey, 1, LTC_ASN1_BIT_STRING, tmpbuf, MAX_RSA_SIZE*8);
if (der_decode_sequence(in, inlen,
ssl_pubkey, 2UL) == CRYPT_OK) {
/* ok now we have to reassemble the BIT STRING to an OCTET STRING. Thanks OpenSSL... */
for (t = y = z = x = 0; x < ssl_pubkey[1].size; x++) {
y = (y << 1) | tmpbuf[x];
if (++z == 8) {
tmpbuf[t++] = (unsigned char)y;
y = 0;
z = 0;
}
}
/* now it should be SEQUENCE { INTEGER, INTEGER } */
if ((err = der_decode_sequence_multi(tmpbuf, t,
LTC_ASN1_INTEGER, 1UL, key->N,
LTC_ASN1_INTEGER, 1UL, key->e,
LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
XFREE(tmpbuf);
goto LBL_ERR;
}
XFREE(tmpbuf);
key->type = PK_PUBLIC;
return CRYPT_OK;
}
XFREE(tmpbuf);
/* not SSL public key, try to match against PKCS #1 standards */
if ((err = der_decode_sequence_multi(in, inlen,
LTC_ASN1_INTEGER, 1UL, key->N,
LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
goto LBL_ERR;
}
if (mp_cmp_d(key->N, 0) == LTC_MP_EQ) {
if ((err = mp_init(&zero)) != CRYPT_OK) {
goto LBL_ERR;
}
/* it's a private key */
if ((err = der_decode_sequence_multi(in, inlen,
LTC_ASN1_INTEGER, 1UL, zero,
LTC_ASN1_INTEGER, 1UL, key->N,
LTC_ASN1_INTEGER, 1UL, key->e,
LTC_ASN1_INTEGER, 1UL, key->d,
LTC_ASN1_INTEGER, 1UL, key->p,
LTC_ASN1_INTEGER, 1UL, key->q,
LTC_ASN1_INTEGER, 1UL, key->dP,
LTC_ASN1_INTEGER, 1UL, key->dQ,
LTC_ASN1_INTEGER, 1UL, key->qP,
LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
mp_clear(zero);
goto LBL_ERR;
}
mp_clear(zero);
key->type = PK_PRIVATE;
} else if (mp_cmp_d(key->N, 1) == LTC_MP_EQ) {
/* we don't support multi-prime RSA */
err = CRYPT_PK_INVALID_TYPE;
goto LBL_ERR;
} else {
/* it's a public key and we lack e */
if ((err = der_decode_sequence_multi(in, inlen,
LTC_ASN1_INTEGER, 1UL, key->N,
LTC_ASN1_INTEGER, 1UL, key->e,
LTC_ASN1_EOL, 0UL, NULL)) != CRYPT_OK) {
goto LBL_ERR;
}
key->type = PK_PUBLIC;
}
return CRYPT_OK;
LBL_ERR:
mp_clear_multi(key->d, key->e, key->N, key->dQ, key->dP, key->qP, key->p, key->q, NULL);
return err;
}
#endif /* MRSA */
/* $Source: /cvs/libtom/libtomcrypt/src/pk/rsa/rsa_import.c,v $ */
/* $Revision: 1.21 $ */
/* $Date: 2006/12/04 22:23:27 $ */
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