mirror of
git://git.gnupg.org/gnupg.git
synced 2024-11-10 21:38:50 +01:00
324 lines
8.6 KiB
C
324 lines
8.6 KiB
C
/* seckey-cert.c - secret key certifucate packet handling
|
|
* Copyright (c) 1997 by Werner Koch (dd9jn)
|
|
*
|
|
* This file is part of G10.
|
|
*
|
|
* G10 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.
|
|
*
|
|
* G10 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
|
|
*/
|
|
|
|
#include <config.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <assert.h>
|
|
#include "util.h"
|
|
#include "memory.h"
|
|
#include "packet.h"
|
|
#include "mpi.h"
|
|
#include "keydb.h"
|
|
#include "cipher.h"
|
|
|
|
#if BLOWFISH_BLOCKSIZE != 8
|
|
#error unsupportted blocksize
|
|
#endif
|
|
|
|
static u16
|
|
checksum_u16( unsigned n )
|
|
{
|
|
u16 a;
|
|
|
|
a = (n >> 8) & 0xff;
|
|
a |= n & 0xff;
|
|
return a;
|
|
}
|
|
|
|
static u16
|
|
checksum( byte *p, unsigned n )
|
|
{
|
|
u16 a;
|
|
|
|
for(a=0; n; n-- )
|
|
a += *p++;
|
|
return a;
|
|
}
|
|
|
|
|
|
|
|
static int
|
|
check_elg( PKT_secret_cert *cert )
|
|
{
|
|
byte *buffer;
|
|
u16 csum=0;
|
|
int res;
|
|
unsigned nbytes;
|
|
u32 keyid[2];
|
|
ELG_secret_key skey;
|
|
char save_iv[8];
|
|
|
|
if( cert->d.elg.is_protected ) { /* remove the protection */
|
|
DEK *dek = NULL;
|
|
MPI test_x;
|
|
BLOWFISH_context *blowfish_ctx=NULL;
|
|
|
|
switch( cert->d.elg.protect_algo ) {
|
|
case CIPHER_ALGO_NONE: BUG(); break;
|
|
case CIPHER_ALGO_BLOWFISH:
|
|
keyid_from_skc( cert, keyid );
|
|
dek = get_passphrase_hash( keyid, NULL );
|
|
blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx );
|
|
blowfish_setkey( blowfish_ctx, dek->key, dek->keylen );
|
|
m_free(dek); /* pw is in secure memory, so m_free() burns it */
|
|
blowfish_setiv( blowfish_ctx, NULL );
|
|
memcpy(save_iv, cert->d.elg.protect.blowfish.iv, 8 );
|
|
blowfish_decode_cfb( blowfish_ctx,
|
|
cert->d.elg.protect.blowfish.iv,
|
|
cert->d.elg.protect.blowfish.iv, 8 );
|
|
buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
|
|
csum = checksum_u16( nbytes*8 );
|
|
blowfish_decode_cfb( blowfish_ctx, buffer, buffer, nbytes );
|
|
csum += checksum( buffer, nbytes );
|
|
test_x = mpi_alloc_secure( mpi_get_nlimbs(cert->d.elg.x) );
|
|
mpi_set_buffer( test_x, buffer, nbytes, 0 );
|
|
m_free( buffer );
|
|
m_free( blowfish_ctx );
|
|
/* now let's see wether we have used the right passphrase */
|
|
if( csum != cert->d.elg.csum ) {
|
|
mpi_free(test_x);
|
|
memcpy( cert->d.elg.protect.blowfish.iv, save_iv, 8 );
|
|
return G10ERR_BAD_PASS;
|
|
}
|
|
|
|
skey.p = cert->d.elg.p;
|
|
skey.g = cert->d.elg.g;
|
|
skey.y = cert->d.elg.y;
|
|
skey.x = test_x;
|
|
res = elg_check_secret_key( &skey );
|
|
memset( &skey, 0, sizeof skey );
|
|
if( !res ) {
|
|
mpi_free(test_x);
|
|
memcpy( cert->d.elg.protect.blowfish.iv, save_iv, 8 );
|
|
return G10ERR_BAD_PASS;
|
|
}
|
|
mpi_set(cert->d.elg.x, test_x);
|
|
mpi_free(test_x);
|
|
cert->d.elg.is_protected = 0;
|
|
break;
|
|
|
|
default:
|
|
return G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */
|
|
}
|
|
}
|
|
else { /* not protected */
|
|
buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
|
|
csum = checksum_u16( nbytes*8 );
|
|
csum += checksum( buffer, nbytes );
|
|
m_free( buffer );
|
|
if( csum != cert->d.elg.csum )
|
|
return G10ERR_CHECKSUM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
protect_elg( PKT_secret_cert *cert, DEK *dek )
|
|
{
|
|
byte *buffer;
|
|
unsigned nbytes;
|
|
|
|
if( !cert->d.elg.is_protected ) { /* add the protection */
|
|
BLOWFISH_context *blowfish_ctx=NULL;
|
|
|
|
switch( cert->d.elg.protect_algo ) {
|
|
case CIPHER_ALGO_NONE: BUG(); break;
|
|
case CIPHER_ALGO_BLOWFISH:
|
|
blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx );
|
|
blowfish_setkey( blowfish_ctx, dek->key, dek->keylen );
|
|
blowfish_setiv( blowfish_ctx, NULL );
|
|
blowfish_encode_cfb( blowfish_ctx,
|
|
cert->d.elg.protect.blowfish.iv,
|
|
cert->d.elg.protect.blowfish.iv, 8 );
|
|
buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
|
|
blowfish_encode_cfb( blowfish_ctx, buffer, buffer, nbytes );
|
|
mpi_set_buffer( cert->d.elg.x, buffer, nbytes, 0 );
|
|
m_free( buffer );
|
|
m_free( blowfish_ctx );
|
|
cert->d.elg.is_protected = 1;
|
|
break;
|
|
|
|
default:
|
|
return G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
#ifdef HAVE_RSA_CIPHER
|
|
static int
|
|
check_rsa( PKT_secret_cert *cert )
|
|
{
|
|
byte *buffer;
|
|
u16 csum=0;
|
|
int res;
|
|
unsigned nbytes;
|
|
u32 keyid[2];
|
|
RSA_secret_key skey;
|
|
|
|
if( cert->d.rsa.is_protected ) { /* remove the protection */
|
|
DEK *dek = NULL;
|
|
BLOWFISH_context *blowfish_ctx=NULL;
|
|
|
|
switch( cert->d.rsa.protect_algo ) {
|
|
/* FIXME: use test variables to check for the correct key */
|
|
case CIPHER_ALGO_NONE: BUG(); break;
|
|
case CIPHER_ALGO_BLOWFISH:
|
|
keyid_from_skc( cert, keyid );
|
|
dek = get_passphrase_hash( keyid, NULL );
|
|
blowfish_ctx = m_alloc_secure( sizeof *blowfish_ctx );
|
|
blowfish_setkey( blowfish_ctx, dek->key, dek->keylen );
|
|
m_free(dek); /* pw is in secure memory, so m_free() burns it */
|
|
blowfish_setiv( blowfish_ctx, NULL );
|
|
blowfish_decode_cfb( blowfish_ctx,
|
|
cert->d.rsa.protect.blowfish.iv,
|
|
cert->d.rsa.protect.blowfish.iv, 8 );
|
|
csum = 0;
|
|
#define X(a) do { \
|
|
buffer = mpi_get_buffer( cert->d.rsa.rsa_##a, &nbytes, NULL );\
|
|
csum += checksum_u16( nbytes*8 ); \
|
|
blowfish_decode_cfb( blowfish_ctx, buffer, buffer, nbytes ); \
|
|
csum += checksum( buffer, nbytes ); \
|
|
mpi_set_buffer(cert->d.rsa.rsa_##a, buffer, nbytes, 0 ); \
|
|
m_free( buffer ); \
|
|
} while(0)
|
|
X(d);
|
|
X(p);
|
|
X(q);
|
|
X(u);
|
|
#undef X
|
|
cert->d.rsa.is_protected = 0;
|
|
m_free( blowfish_ctx );
|
|
/* now let's see wether we have used the right passphrase */
|
|
if( csum != cert->d.rsa.csum )
|
|
return G10ERR_BAD_PASS;
|
|
|
|
skey.d = cert->d.rsa.rsa_d;
|
|
skey.p = cert->d.rsa.rsa_p;
|
|
skey.q = cert->d.rsa.rsa_q;
|
|
skey.u = cert->d.rsa.rsa_u;
|
|
res = rsa_check_secret_key( &skey );
|
|
memset( &skey, 0, sizeof skey );
|
|
if( !res )
|
|
return G10ERR_BAD_PASS;
|
|
break;
|
|
|
|
default:
|
|
return G10ERR_CIPHER_ALGO; /* unsupported protection algorithm */
|
|
}
|
|
}
|
|
else { /* not protected */
|
|
csum =0;
|
|
buffer = mpi_get_buffer( cert->d.rsa.rsa_d, &nbytes, NULL );
|
|
csum += checksum_u16( nbytes*8 );
|
|
csum += checksum( buffer, nbytes );
|
|
m_free( buffer );
|
|
buffer = mpi_get_buffer( cert->d.rsa.rsa_p, &nbytes, NULL );
|
|
csum += checksum_u16( nbytes*8 );
|
|
csum += checksum( buffer, nbytes );
|
|
m_free( buffer );
|
|
buffer = mpi_get_buffer( cert->d.rsa.rsa_q, &nbytes, NULL );
|
|
csum += checksum_u16( nbytes*8 );
|
|
csum += checksum( buffer, nbytes );
|
|
m_free( buffer );
|
|
buffer = mpi_get_buffer( cert->d.rsa.rsa_u, &nbytes, NULL );
|
|
csum += checksum_u16( nbytes*8 );
|
|
csum += checksum( buffer, nbytes );
|
|
m_free( buffer );
|
|
if( csum != cert->d.rsa.csum )
|
|
return G10ERR_CHECKSUM;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
#endif /*HAVE_RSA_CIPHER*/
|
|
|
|
|
|
|
|
|
|
/****************
|
|
* Check the secret key certificate
|
|
* Ask up to 3 time for a correct passphrase
|
|
*/
|
|
int
|
|
check_secret_key( PKT_secret_cert *cert )
|
|
{
|
|
int rc = G10ERR_BAD_PASS;
|
|
int i;
|
|
|
|
for(i=0; i < 3 && rc == G10ERR_BAD_PASS; i++ ) {
|
|
if( i )
|
|
log_error("Invalid passphrase; please try again ...\n");
|
|
if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
|
|
rc = check_elg( cert );
|
|
#ifdef HAVE_RSA_CIPHER
|
|
else if( cert->pubkey_algo == PUBKEY_ALGO_RSA )
|
|
rc = check_rsa( cert );
|
|
#endif
|
|
else
|
|
rc = G10ERR_PUBKEY_ALGO;
|
|
if( get_passphrase_fd() != -1 )
|
|
break;
|
|
}
|
|
return rc;
|
|
}
|
|
|
|
/****************
|
|
* check wether the secret key is protected.
|
|
* Returns: 0 not protected, -1 on error or the protection algorithm
|
|
*/
|
|
int
|
|
is_secret_key_protected( PKT_secret_cert *cert )
|
|
{
|
|
if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
|
|
return cert->d.elg.is_protected? cert->d.elg.protect_algo : 0;
|
|
#ifdef HAVE_RSA_CIPHER
|
|
else if( cert->pubkey_algo == PUBKEY_ALGO_RSA )
|
|
return cert->d.rsa.is_protected? cert->d.rsa.protect_algo : 0;
|
|
#endif
|
|
else
|
|
return -1; /* unsupported */
|
|
}
|
|
|
|
|
|
/****************
|
|
* Protect the secret key certificate with the passphrase from DEK
|
|
*/
|
|
int
|
|
protect_secret_key( PKT_secret_cert *cert, DEK *dek )
|
|
{
|
|
if( !dek )
|
|
return 0;
|
|
|
|
if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL )
|
|
return protect_elg( cert, dek );
|
|
#ifdef 0 /* noy yet implemented */
|
|
else if( cert->pubkey_algo == PUBKEY_ALGO_RSA )
|
|
return protect_rsa( cert, dek );
|
|
#endif
|
|
else
|
|
return G10ERR_PUBKEY_ALGO;
|
|
}
|
|
|