mirror of git://git.gnupg.org/gnupg.git
313 lines
8.7 KiB
C
313 lines
8.7 KiB
C
/* seckey-cert.c - secret key certifucate packet handling
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* Copyright (C) 1998 Free Software Foundation, Inc.
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*
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* This file is part of GNUPG.
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*
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* GNUPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* GNUPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <assert.h>
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#include "util.h"
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#include "memory.h"
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#include "packet.h"
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#include "mpi.h"
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#include "keydb.h"
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#include "cipher.h"
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#include "main.h"
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#include "options.h"
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static int
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do_check( PKT_secret_cert *cert )
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{
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byte *buffer;
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u16 csum=0;
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int res;
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unsigned nbytes;
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if( cert->is_protected ) { /* remove the protection */
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DEK *dek = NULL;
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u32 keyid[2];
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CIPHER_HANDLE cipher_hd=NULL;
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PKT_secret_cert *save_cert;
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char save_iv[8];
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switch( cert->protect.algo ) {
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case CIPHER_ALGO_NONE: BUG(); break;
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case CIPHER_ALGO_BLOWFISH:
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case CIPHER_ALGO_CAST:
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keyid_from_skc( cert, keyid );
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if( cert->protect.s2k == 1 || cert->protect.s2k == 3 )
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dek = get_passphrase_hash( keyid, NULL,
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cert->protect.salt );
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else
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dek = get_passphrase_hash( keyid, NULL, NULL );
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cipher_hd = cipher_open( cert->protect.algo,
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CIPHER_MODE_AUTO_CFB, 1);
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cipher_setkey( cipher_hd, dek->key, dek->keylen );
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cipher_setiv( cipher_hd, NULL );
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m_free(dek); /* pw is in secure memory, so m_free() burns it */
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save_cert = copy_secret_cert( NULL, cert );
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memcpy(save_iv, cert->protect.iv, 8 );
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cipher_decrypt( cipher_hd, cert->protect.iv, cert->protect.iv, 8 );
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switch( cert->pubkey_algo ) {
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case PUBKEY_ALGO_ELGAMAL:
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buffer = mpi_get_secure_buffer( cert->d.elg.x, &nbytes, NULL );
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cipher_decrypt( cipher_hd, buffer, buffer, nbytes );
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mpi_set_buffer( cert->d.elg.x, buffer, nbytes, 0 );
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csum = checksum_mpi( cert->d.elg.x );
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m_free( buffer );
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break;
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case PUBKEY_ALGO_DSA:
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buffer = mpi_get_secure_buffer( cert->d.dsa.x, &nbytes, NULL );
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cipher_decrypt( cipher_hd, buffer, buffer, nbytes );
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mpi_set_buffer( cert->d.dsa.x, buffer, nbytes, 0 );
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csum = checksum_mpi( cert->d.dsa.x );
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m_free( buffer );
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break;
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#ifdef HAVE_RSA_CIPHER
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case PUBKEY_ALGO_RSA:
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csum = 0;
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#define X(a) do { \
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buffer = mpi_get_secure_buffer( cert->d.rsa.##a, \
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&nbytes, NULL ); \
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csum += checksum_u16( nbytes*8 ); \
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cipher_decrypt( cipher_hd, buffer, buffer, nbytes ); \
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csum += checksum( buffer, nbytes ); \
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mpi_set_buffer(cert->d.rsa.##a, buffer, nbytes, 0 ); \
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m_free( buffer ); \
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} while(0)
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X(d);
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X(p);
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X(q);
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X(u);
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#undef X
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break;
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#endif /* HAVE_RSA_CIPHER */
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default: BUG();
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}
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cipher_close( cipher_hd );
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/* now let's see whether we have used the right passphrase */
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if( csum != cert->csum ) {
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if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL ) {
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/* very bad kludge to work around an early bug */
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csum -= checksum_u16( mpi_get_nbits(cert->d.elg.x) );
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nbytes = mpi_get_nlimbs(cert->d.elg.x) * 4;
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csum += checksum_u16( nbytes*8 );
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if( !opt.batch && csum == cert->csum )
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log_info("Probably you have an old key - use "
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"\"--change-passphrase\" to convert.\n");
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}
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if( csum != cert->csum ) {
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copy_secret_cert( cert, save_cert );
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free_secret_cert( save_cert );
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memcpy( cert->protect.iv, save_iv, 8 );
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return G10ERR_BAD_PASS;
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}
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}
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switch( cert->pubkey_algo ) {
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case PUBKEY_ALGO_ELGAMAL:
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res = elg_check_secret_key( &cert->d.elg );
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break;
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case PUBKEY_ALGO_DSA:
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res = dsa_check_secret_key( &cert->d.dsa );
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break;
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#ifdef HAVE_RSA_CIPHER
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case PUBKEY_ALGO_RSA:
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res = rsa_check_secret_key( &cert->d.rsa );
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break;
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#endif
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default: BUG();
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}
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if( !res ) {
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copy_secret_cert( cert, save_cert );
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free_secret_cert( save_cert );
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memcpy( cert->protect.iv, save_iv, 8 );
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return G10ERR_BAD_PASS;
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}
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free_secret_cert( save_cert );
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cert->is_protected = 0;
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break;
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default:
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return G10ERR_CIPHER_ALGO; /* unsupported protection algorithm */
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}
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}
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else { /* not protected */
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switch( cert->pubkey_algo ) {
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case PUBKEY_ALGO_ELGAMAL:
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csum = checksum_mpi( cert->d.elg.x );
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break;
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case PUBKEY_ALGO_DSA:
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csum = checksum_mpi( cert->d.dsa.x );
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break;
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#ifdef HAVE_RSA_CIPHER
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case PUBKEY_ALGO_RSA:
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csum =0;
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buffer = mpi_get_buffer( cert->d.rsa.rsa_d, &nbytes, NULL );
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csum += checksum_u16( nbytes*8 );
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csum += checksum( buffer, nbytes );
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m_free( buffer );
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buffer = mpi_get_buffer( cert->d.rsa.rsa_p, &nbytes, NULL );
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csum += checksum_u16( nbytes*8 );
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csum += checksum( buffer, nbytes );
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m_free( buffer );
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buffer = mpi_get_buffer( cert->d.rsa.rsa_q, &nbytes, NULL );
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csum += checksum_u16( nbytes*8 );
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csum += checksum( buffer, nbytes );
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m_free( buffer );
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buffer = mpi_get_buffer( cert->d.rsa.rsa_u, &nbytes, NULL );
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csum += checksum_u16( nbytes*8 );
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csum += checksum( buffer, nbytes );
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m_free( buffer );
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break;
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#endif
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default: BUG();
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}
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if( csum != cert->csum ) {
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if( cert->pubkey_algo == PUBKEY_ALGO_ELGAMAL ) {
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/* very bad kludge to work around an early bug */
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csum -= checksum_u16( mpi_get_nbits(cert->d.elg.x) );
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nbytes = mpi_get_nlimbs(cert->d.elg.x) * 4;
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csum += checksum_u16( nbytes*8 );
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if( !opt.batch && csum == cert->csum )
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log_info("Probably you have an old key - use "
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"\"--change-passphrase\" to convert.\n");
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}
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if( csum != cert->csum )
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return G10ERR_CHECKSUM;
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}
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}
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return 0;
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}
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/****************
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* Check the secret key certificate
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* Ask up to 3 times for a correct passphrase
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*/
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int
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check_secret_key( PKT_secret_cert *cert )
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{
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int rc = G10ERR_BAD_PASS;
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int i;
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for(i=0; i < 3 && rc == G10ERR_BAD_PASS; i++ ) {
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if( i )
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log_error("Invalid passphrase; please try again ...\n");
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switch( cert->pubkey_algo ) {
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case PUBKEY_ALGO_ELGAMAL:
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case PUBKEY_ALGO_DSA:
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rc = do_check( cert );
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break;
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default: rc = G10ERR_PUBKEY_ALGO;
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}
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if( get_passphrase_fd() != -1 )
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break;
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}
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return rc;
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}
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/****************
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* check whether the secret key is protected.
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* Returns: 0 not protected, -1 on error or the protection algorithm
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*/
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int
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is_secret_key_protected( PKT_secret_cert *cert )
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{
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return cert->is_protected? cert->protect.algo : 0;
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}
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static int
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do_protect( void (*fnc)(CIPHER_HANDLE, byte *, byte *, unsigned),
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CIPHER_HANDLE fnc_hd, PKT_secret_cert *cert )
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{
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byte *buffer;
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unsigned nbytes;
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switch( cert->pubkey_algo ) {
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case PUBKEY_ALGO_ELGAMAL:
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/* recalculate the checksum, so that --change-passphrase
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* can be used to convert from the faulty to the correct one
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* wk 06.04.98:
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* fixme: remove this some time in the future.
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*/
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cert->csum = checksum_mpi( cert->d.elg.x );
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buffer = mpi_get_buffer( cert->d.elg.x, &nbytes, NULL );
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(*fnc)( fnc_hd, buffer, buffer, nbytes );
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mpi_set_buffer( cert->d.elg.x, buffer, nbytes, 0 );
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m_free( buffer );
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break;
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case PUBKEY_ALGO_DSA:
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buffer = mpi_get_buffer( cert->d.dsa.x, &nbytes, NULL );
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(*fnc)( fnc_hd, buffer, buffer, nbytes );
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mpi_set_buffer( cert->d.dsa.x, buffer, nbytes, 0 );
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m_free( buffer );
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break;
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default: return G10ERR_PUBKEY_ALGO;
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}
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return 0;
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}
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/****************
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* Protect the secret key certificate with the passphrase from DEK
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*/
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int
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protect_secret_key( PKT_secret_cert *cert, DEK *dek )
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{
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int rc=0;
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if( !dek )
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return 0;
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if( !cert->is_protected ) { /* okay, apply the protection */
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CIPHER_HANDLE cipher_hd=NULL;
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switch( cert->protect.algo ) {
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case CIPHER_ALGO_NONE: BUG(); break;
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case CIPHER_ALGO_BLOWFISH:
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case CIPHER_ALGO_CAST:
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cipher_hd = cipher_open( cert->protect.algo,
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CIPHER_MODE_AUTO_CFB, 1 );
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cipher_setkey( cipher_hd, dek->key, dek->keylen );
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cipher_setiv( cipher_hd, NULL );
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cipher_encrypt( cipher_hd, cert->protect.iv, cert->protect.iv, 8 );
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if( !do_protect( &cipher_encrypt, cipher_hd, cert ) )
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cert->is_protected = 1;
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cipher_close( cipher_hd );
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break;
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default:
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rc = G10ERR_CIPHER_ALGO; /* unsupport protection algorithm */
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break;
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}
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}
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return rc;
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}
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