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/* der2rsa.c
*
* Decoding of keys in PKCS#1 format.
*/
/* nettle, low-level cryptographics library
*
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*
* The nettle library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The nettle library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the nettle library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#if HAVE_CONFIG_H
# include "config.h"
#endif
#include "rsa.h"
#include "bignum.h"
#include "asn1.h"
#define GET(i, x, l) \
(asn1_der_iterator_next((i)) == ASN1_ITERATOR_PRIMITIVE \
&& (i)->type == ASN1_INTEGER \
&& asn1_der_get_bignum((i), (x), (l)) \
&& mpz_sgn((x)) > 0)
int
rsa_public_key_from_der_iterator(struct rsa_public_key *pub,
unsigned limit,
struct asn1_der_iterator *i)
{
/* RSAPublicKey ::= SEQUENCE {
modulus INTEGER, -- n
publicExponent INTEGER -- e
}
*/
return (i->type == ASN1_SEQUENCE
&& asn1_der_decode_constructed_last(i) == ASN1_ITERATOR_PRIMITIVE
&& asn1_der_get_bignum(i, pub->n, limit)
&& mpz_sgn(pub->n) > 0
&& GET(i, pub->e, limit)
&& asn1_der_iterator_next(i) == ASN1_ITERATOR_END
&& rsa_public_key_prepare(pub));
}
int
rsa_private_key_from_der_iterator(struct rsa_public_key *pub,
struct rsa_private_key *priv,
unsigned limit,
struct asn1_der_iterator *i)
{
/* RSAPrivateKey ::= SEQUENCE {
version Version,
modulus INTEGER, -- n
publicExponent INTEGER, -- e
privateExponent INTEGER, -- d
prime1 INTEGER, -- p
prime2 INTEGER, -- q
exponent1 INTEGER, -- d mod (p-1)
exponent2 INTEGER, -- d mod (q-1)
coefficient INTEGER, -- (inverse of q) mod p
otherPrimeInfos OtherPrimeInfos OPTIONAL
}
*/
uint32_t version;
if (i->type != ASN1_SEQUENCE)
return 0;
if (asn1_der_decode_constructed_last(i) == ASN1_ITERATOR_PRIMITIVE
&& i->type == ASN1_INTEGER
&& asn1_der_get_uint32(i, &version)
&& version <= 1
&& GET(i, pub->n, limit)
&& GET(i, pub->e, limit)
&& rsa_public_key_prepare(pub)
&& GET(i, priv->d, limit)
&& GET(i, priv->p, limit)
&& GET(i, priv->q, limit)
&& GET(i, priv->a, limit)
&& GET(i, priv->b, limit)
&& GET(i, priv->c, limit)
&& rsa_private_key_prepare(priv))
{
if (version == 1)
{
/* otherPrimeInfos must be present. We ignore the contents */
if (!(asn1_der_iterator_next(i) == ASN1_ITERATOR_CONSTRUCTED
&& i->type == ASN1_SEQUENCE))
return 0;
}
return (asn1_der_iterator_next(i) == ASN1_ITERATOR_END);
}
return 0;
}
int
rsa_keypair_from_der(struct rsa_public_key *pub,
struct rsa_private_key *priv,
unsigned limit,
unsigned length, const uint8_t *data)
{
struct asn1_der_iterator i;
enum asn1_iterator_result res;
res = asn1_der_iterator_first(&i, length, data);
if (res != ASN1_ITERATOR_CONSTRUCTED)
return 0;
if (priv)
return rsa_private_key_from_der_iterator(pub, priv, limit, &i);
else
return rsa_public_key_from_der_iterator(pub, limit, &i);
}