blob: 29e172d672120e0db916a3671ab2769db38b3f6a [file] [log] [blame]
/*
* Public Key layer for writing key files and structures
*
* Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
*
* This file is part of mbed TLS (https://polarssl.org)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if !defined(POLARSSL_CONFIG_FILE)
#include "polarssl/config.h"
#else
#include POLARSSL_CONFIG_FILE
#endif
#if defined(POLARSSL_PK_WRITE_C)
#include "polarssl/pk.h"
#include "polarssl/asn1write.h"
#include "polarssl/oid.h"
#include <string.h>
#if defined(POLARSSL_RSA_C)
#include "polarssl/rsa.h"
#endif
#if defined(POLARSSL_ECP_C)
#include "polarssl/ecp.h"
#endif
#if defined(POLARSSL_ECDSA_C)
#include "polarssl/ecdsa.h"
#endif
#if defined(POLARSSL_PEM_WRITE_C)
#include "polarssl/pem.h"
#endif
#if defined(POLARSSL_PLATFORM_C)
#include "polarssl/platform.h"
#else
#include <stdlib.h>
#define polarssl_malloc malloc
#define polarssl_free free
#endif
#if defined(POLARSSL_RSA_C)
/*
* RSAPublicKey ::= SEQUENCE {
* modulus INTEGER, -- n
* publicExponent INTEGER -- e
* }
*/
static int pk_write_rsa_pubkey( unsigned char **p, unsigned char *start,
rsa_context *rsa )
{
int ret;
size_t len = 0;
ASN1_CHK_ADD( len, asn1_write_mpi( p, start, &rsa->E ) );
ASN1_CHK_ADD( len, asn1_write_mpi( p, start, &rsa->N ) );
ASN1_CHK_ADD( len, asn1_write_len( p, start, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( p, start, ASN1_CONSTRUCTED |
ASN1_SEQUENCE ) );
return( (int) len );
}
#endif /* POLARSSL_RSA_C */
#if defined(POLARSSL_ECP_C)
/*
* EC public key is an EC point
*/
static int pk_write_ec_pubkey( unsigned char **p, unsigned char *start,
ecp_keypair *ec )
{
int ret;
size_t len = 0;
unsigned char buf[POLARSSL_ECP_MAX_PT_LEN];
if( ( ret = ecp_point_write_binary( &ec->grp, &ec->Q,
POLARSSL_ECP_PF_UNCOMPRESSED,
&len, buf, sizeof( buf ) ) ) != 0 )
{
return( ret );
}
if( *p - start < (int) len )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*p -= len;
memcpy( *p, buf, len );
return( (int) len );
}
/*
* ECParameters ::= CHOICE {
* namedCurve OBJECT IDENTIFIER
* }
*/
static int pk_write_ec_param( unsigned char **p, unsigned char *start,
ecp_keypair *ec )
{
int ret;
size_t len = 0;
const char *oid;
size_t oid_len;
if( ( ret = oid_get_oid_by_ec_grp( ec->grp.id, &oid, &oid_len ) ) != 0 )
return( ret );
ASN1_CHK_ADD( len, asn1_write_oid( p, start, oid, oid_len ) );
return( (int) len );
}
#endif /* POLARSSL_ECP_C */
int pk_write_pubkey( unsigned char **p, unsigned char *start,
const pk_context *key )
{
int ret;
size_t len = 0;
#if defined(POLARSSL_RSA_C)
if( pk_get_type( key ) == POLARSSL_PK_RSA )
ASN1_CHK_ADD( len, pk_write_rsa_pubkey( p, start, pk_rsa( *key ) ) );
else
#endif
#if defined(POLARSSL_ECP_C)
if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
ASN1_CHK_ADD( len, pk_write_ec_pubkey( p, start, pk_ec( *key ) ) );
else
#endif
return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
return( (int) len );
}
int pk_write_pubkey_der( pk_context *key, unsigned char *buf, size_t size )
{
int ret;
unsigned char *c;
size_t len = 0, par_len = 0, oid_len;
const char *oid;
c = buf + size;
ASN1_CHK_ADD( len, pk_write_pubkey( &c, buf, key ) );
if( c - buf < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
/*
* SubjectPublicKeyInfo ::= SEQUENCE {
* algorithm AlgorithmIdentifier,
* subjectPublicKey BIT STRING }
*/
*--c = 0;
len += 1;
ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_BIT_STRING ) );
if( ( ret = oid_get_oid_by_pk_alg( pk_get_type( key ),
&oid, &oid_len ) ) != 0 )
{
return( ret );
}
#if defined(POLARSSL_ECP_C)
if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
{
ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, pk_ec( *key ) ) );
}
#endif
ASN1_CHK_ADD( len, asn1_write_algorithm_identifier( &c, buf, oid, oid_len,
par_len ) );
ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED |
ASN1_SEQUENCE ) );
return( (int) len );
}
int pk_write_key_der( pk_context *key, unsigned char *buf, size_t size )
{
int ret;
unsigned char *c = buf + size;
size_t len = 0;
#if defined(POLARSSL_RSA_C)
if( pk_get_type( key ) == POLARSSL_PK_RSA )
{
rsa_context *rsa = pk_rsa( *key );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->QP ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->DQ ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->DP ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->Q ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->P ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->D ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->E ) );
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &rsa->N ) );
ASN1_CHK_ADD( len, asn1_write_int( &c, buf, 0 ) );
ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED |
ASN1_SEQUENCE ) );
}
else
#endif /* POLARSSL_RSA_C */
#if defined(POLARSSL_ECP_C)
if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
{
ecp_keypair *ec = pk_ec( *key );
size_t pub_len = 0, par_len = 0;
/*
* RFC 5915, or SEC1 Appendix C.4
*
* ECPrivateKey ::= SEQUENCE {
* version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
* privateKey OCTET STRING,
* parameters [0] ECParameters {{ NamedCurve }} OPTIONAL,
* publicKey [1] BIT STRING OPTIONAL
* }
*/
/* publicKey */
ASN1_CHK_ADD( pub_len, pk_write_ec_pubkey( &c, buf, ec ) );
if( c - buf < 1 )
return( POLARSSL_ERR_ASN1_BUF_TOO_SMALL );
*--c = 0;
pub_len += 1;
ASN1_CHK_ADD( pub_len, asn1_write_len( &c, buf, pub_len ) );
ASN1_CHK_ADD( pub_len, asn1_write_tag( &c, buf, ASN1_BIT_STRING ) );
ASN1_CHK_ADD( pub_len, asn1_write_len( &c, buf, pub_len ) );
ASN1_CHK_ADD( pub_len, asn1_write_tag( &c, buf,
ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 1 ) );
len += pub_len;
/* parameters */
ASN1_CHK_ADD( par_len, pk_write_ec_param( &c, buf, ec ) );
ASN1_CHK_ADD( par_len, asn1_write_len( &c, buf, par_len ) );
ASN1_CHK_ADD( par_len, asn1_write_tag( &c, buf,
ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 0 ) );
len += par_len;
/* privateKey: write as MPI then fix tag */
ASN1_CHK_ADD( len, asn1_write_mpi( &c, buf, &ec->d ) );
*c = ASN1_OCTET_STRING;
/* version */
ASN1_CHK_ADD( len, asn1_write_int( &c, buf, 1 ) );
ASN1_CHK_ADD( len, asn1_write_len( &c, buf, len ) );
ASN1_CHK_ADD( len, asn1_write_tag( &c, buf, ASN1_CONSTRUCTED |
ASN1_SEQUENCE ) );
}
else
#endif /* POLARSSL_ECP_C */
return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
return( (int) len );
}
#if defined(POLARSSL_PEM_WRITE_C)
#define PEM_BEGIN_PUBLIC_KEY "-----BEGIN PUBLIC KEY-----\n"
#define PEM_END_PUBLIC_KEY "-----END PUBLIC KEY-----\n"
#define PEM_BEGIN_PRIVATE_KEY_RSA "-----BEGIN RSA PRIVATE KEY-----\n"
#define PEM_END_PRIVATE_KEY_RSA "-----END RSA PRIVATE KEY-----\n"
#define PEM_BEGIN_PRIVATE_KEY_EC "-----BEGIN EC PRIVATE KEY-----\n"
#define PEM_END_PRIVATE_KEY_EC "-----END EC PRIVATE KEY-----\n"
/*
* Max sizes of key per types. Shown as tag + len (+ content).
*/
#if defined(POLARSSL_RSA_C)
/*
* RSA public keys:
* SubjectPublicKeyInfo ::= SEQUENCE { 1 + 3
* algorithm AlgorithmIdentifier, 1 + 1 (sequence)
* + 1 + 1 + 9 (rsa oid)
* + 1 + 1 (params null)
* subjectPublicKey BIT STRING } 1 + 3 + (1 + below)
* RSAPublicKey ::= SEQUENCE { 1 + 3
* modulus INTEGER, -- n 1 + 3 + MPI_MAX + 1
* publicExponent INTEGER -- e 1 + 3 + MPI_MAX + 1
* }
*/
#define RSA_PUB_DER_MAX_BYTES 38 + 2 * POLARSSL_MPI_MAX_SIZE
/*
* RSA private keys:
* RSAPrivateKey ::= SEQUENCE { 1 + 3
* version Version, 1 + 1 + 1
* modulus INTEGER, 1 + 3 + MPI_MAX + 1
* publicExponent INTEGER, 1 + 3 + MPI_MAX + 1
* privateExponent INTEGER, 1 + 3 + MPI_MAX + 1
* prime1 INTEGER, 1 + 3 + MPI_MAX / 2 + 1
* prime2 INTEGER, 1 + 3 + MPI_MAX / 2 + 1
* exponent1 INTEGER, 1 + 3 + MPI_MAX / 2 + 1
* exponent2 INTEGER, 1 + 3 + MPI_MAX / 2 + 1
* coefficient INTEGER, 1 + 3 + MPI_MAX / 2 + 1
* otherPrimeInfos OtherPrimeInfos OPTIONAL 0 (not supported)
* }
*/
#define MPI_MAX_SIZE_2 POLARSSL_MPI_MAX_SIZE / 2 + \
POLARSSL_MPI_MAX_SIZE % 2
#define RSA_PRV_DER_MAX_BYTES 47 + 3 * POLARSSL_MPI_MAX_SIZE \
+ 5 * MPI_MAX_SIZE_2
#else /* POLARSSL_RSA_C */
#define RSA_PUB_DER_MAX_BYTES 0
#define RSA_PRV_DER_MAX_BYTES 0
#endif /* POLARSSL_RSA_C */
#if defined(POLARSSL_ECP_C)
/*
* EC public keys:
* SubjectPublicKeyInfo ::= SEQUENCE { 1 + 2
* algorithm AlgorithmIdentifier, 1 + 1 (sequence)
* + 1 + 1 + 7 (ec oid)
* + 1 + 1 + 9 (namedCurve oid)
* subjectPublicKey BIT STRING 1 + 2 + 1 [1]
* + 1 (point format) [1]
* + 2 * ECP_MAX (coords) [1]
* }
*/
#define ECP_PUB_DER_MAX_BYTES 30 + 2 * POLARSSL_ECP_MAX_BYTES
/*
* EC private keys:
* ECPrivateKey ::= SEQUENCE { 1 + 2
* version INTEGER , 1 + 1 + 1
* privateKey OCTET STRING, 1 + 1 + ECP_MAX
* parameters [0] ECParameters OPTIONAL, 1 + 1 + (1 + 1 + 9)
* publicKey [1] BIT STRING OPTIONAL 1 + 2 + [1] above
* }
*/
#define ECP_PRV_DER_MAX_BYTES 29 + 3 * POLARSSL_ECP_MAX_BYTES
#else /* POLARSSL_ECP_C */
#define ECP_PUB_DER_MAX_BYTES 0
#define ECP_PRV_DER_MAX_BYTES 0
#endif /* POLARSSL_ECP_C */
#define PUB_DER_MAX_BYTES RSA_PUB_DER_MAX_BYTES > ECP_PUB_DER_MAX_BYTES ? \
RSA_PUB_DER_MAX_BYTES : ECP_PUB_DER_MAX_BYTES
#define PRV_DER_MAX_BYTES RSA_PRV_DER_MAX_BYTES > ECP_PRV_DER_MAX_BYTES ? \
RSA_PRV_DER_MAX_BYTES : ECP_PRV_DER_MAX_BYTES
int pk_write_pubkey_pem( pk_context *key, unsigned char *buf, size_t size )
{
int ret;
unsigned char output_buf[PUB_DER_MAX_BYTES];
size_t olen = 0;
if( ( ret = pk_write_pubkey_der( key, output_buf,
sizeof(output_buf) ) ) < 0 )
{
return( ret );
}
if( ( ret = pem_write_buffer( PEM_BEGIN_PUBLIC_KEY, PEM_END_PUBLIC_KEY,
output_buf + sizeof(output_buf) - ret,
ret, buf, size, &olen ) ) != 0 )
{
return( ret );
}
return( 0 );
}
int pk_write_key_pem( pk_context *key, unsigned char *buf, size_t size )
{
int ret;
unsigned char output_buf[PRV_DER_MAX_BYTES];
const char *begin, *end;
size_t olen = 0;
if( ( ret = pk_write_key_der( key, output_buf, sizeof(output_buf) ) ) < 0 )
return( ret );
#if defined(POLARSSL_RSA_C)
if( pk_get_type( key ) == POLARSSL_PK_RSA )
{
begin = PEM_BEGIN_PRIVATE_KEY_RSA;
end = PEM_END_PRIVATE_KEY_RSA;
}
else
#endif
#if defined(POLARSSL_ECP_C)
if( pk_get_type( key ) == POLARSSL_PK_ECKEY )
{
begin = PEM_BEGIN_PRIVATE_KEY_EC;
end = PEM_END_PRIVATE_KEY_EC;
}
else
#endif
return( POLARSSL_ERR_PK_FEATURE_UNAVAILABLE );
if( ( ret = pem_write_buffer( begin, end,
output_buf + sizeof(output_buf) - ret,
ret, buf, size, &olen ) ) != 0 )
{
return( ret );
}
return( 0 );
}
#endif /* POLARSSL_PEM_WRITE_C */
#endif /* POLARSSL_PK_WRITE_C */