gnupg/cipher/md.c

/* md.c  -  message digest dispatcher
 *	Copyright (C) 1998 Free Software Foundation, Inc.
 *
 * This file is part of GNUPG.
 *
 * GNUPG 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.
 *
 * GNUPG 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 <errno.h>
#include "util.h"
#include "cipher.h"
#include "errors.h"



/* Note: the first string is the one used by ascii armor */
static struct { const char *name; int algo;} digest_names[] = {
    { "MD5",           DIGEST_ALGO_MD5    },
    { "SHA1",          DIGEST_ALGO_SHA1   },
    { "SHA-1",         DIGEST_ALGO_SHA1   },
    { "RIPEMD160",     DIGEST_ALGO_RMD160 },
    { "RMD160",        DIGEST_ALGO_RMD160 },
    { "RMD-160",       DIGEST_ALGO_RMD160 },
    { "RIPE-MD-160",   DIGEST_ALGO_RMD160 },
    {NULL} };




/****************
 * Map a string to the digest algo
 */
int
string_to_digest_algo( const char *string )
{
    int i;
    const char *s;

    for(i=0; (s=digest_names[i].name); i++ )
	if( !stricmp( s, string ) )
	    return digest_names[i].algo;
    return 0;
}


/****************
 * Map a digest algo to a string
 */
const char *
digest_algo_to_string( int algo )
{
    int i;

    for(i=0; digest_names[i].name; i++ )
	if( digest_names[i].algo == algo )
	    return digest_names[i].name;
    return NULL;
}


int
check_digest_algo( int algo )
{
    switch( algo ) {
      case DIGEST_ALGO_MD5:
      case DIGEST_ALGO_RMD160:
      case DIGEST_ALGO_SHA1:
	return 0;
      default:
	return G10ERR_DIGEST_ALGO;
    }
}







/****************
 * Open a message digest handle for use with algorithm ALGO.
 * More algorithms may be added by md_enable(). The initial algorithm
 * may be 0.
 */
MD_HANDLE
md_open( int algo, int secure )
{
    MD_HANDLE hd;

    hd = secure ? m_alloc_secure_clear( sizeof *hd )
		: m_alloc_clear( sizeof *hd );
    hd->secure = secure;
    if( algo )
	md_enable( hd, algo );
    fast_random_poll();
    return hd;
}

void
md_enable( MD_HANDLE h, int algo )
{
    if( algo == DIGEST_ALGO_MD5 ) {
	if( !h->use_md5 )
	    md5_init( &h->md5 );
	h->use_md5 = 1;
    }
    else if( algo == DIGEST_ALGO_RMD160 ) {
	if( !h->use_rmd160 )
	    rmd160_init( &h->rmd160 );
	h->use_rmd160 = 1;
    }
    else if( algo == DIGEST_ALGO_SHA1 ) {
	if( !h->use_sha1 )
	    sha1_init( &h->sha1 );
	h->use_sha1 = 1;
    }
    else
	log_bug("md_enable(%d)", algo );
}


MD_HANDLE
md_copy( MD_HANDLE a )
{
    MD_HANDLE b;

    b = a->secure ? m_alloc_secure( sizeof *b )
		  : m_alloc( sizeof *b );
    memcpy( b, a, sizeof *a );
    return b;
}


void
md_close(MD_HANDLE a)
{
    if( !a )
	return;
    if( a->debug )
	md_stop_debug(a);
    m_free(a);
}


void
md_write( MD_HANDLE a, byte *inbuf, size_t inlen)
{
    if( a->debug ) {
	if( a->bufcount && fwrite(a->buffer, a->bufcount, 1, a->debug ) != 1 )
	    BUG();
	if( inlen && fwrite(inbuf, inlen, 1, a->debug ) != 1 )
	    BUG();
    }
    if( a->use_rmd160 ) {
	rmd160_write( &a->rmd160, a->buffer, a->bufcount );
	rmd160_write( &a->rmd160, inbuf, inlen	);
    }
    if( a->use_sha1 ) {
	sha1_write( &a->sha1, a->buffer, a->bufcount );
	sha1_write( &a->sha1, inbuf, inlen  );
    }
    if( a->use_md5 ) {
	md5_write( &a->md5, a->buffer, a->bufcount );
	md5_write( &a->md5, inbuf, inlen  );
    }
    a->bufcount = 0;
}



void
md_final(MD_HANDLE a)
{
    if( a->bufcount )
	md_write( a, NULL, 0 );
    if( a->use_rmd160 )
	rmd160_final( &a->rmd160 );
    if( a->use_sha1 )
	sha1_final( &a->sha1 );
    if( a->use_md5 )
	md5_final( &a->md5 );
}


/****************
 * if ALGO is null get the digest for the used algo (which should be only one)
 */
byte *
md_read( MD_HANDLE a, int algo )
{
    if( !algo ) {
	if( a->use_rmd160 )
	    return rmd160_read( &a->rmd160 );
	if( a->use_sha1 )
	    return sha1_read( &a->sha1 );
	if( a->use_md5 )
	    return md5_read( &a->md5 );
    }
    else {
	if( algo == DIGEST_ALGO_RMD160 )
	    return rmd160_read( &a->rmd160 );
	if( algo == DIGEST_ALGO_SHA1 )
	    return sha1_read( &a->sha1 );
	if( algo == DIGEST_ALGO_MD5 )
	    return md5_read( &a->md5 );
    }
    BUG();
}

int
md_get_algo( MD_HANDLE a )
{
    if( a->use_rmd160 )
	return DIGEST_ALGO_RMD160;
    if( a->use_sha1 )
	return DIGEST_ALGO_SHA1;
    if( a->use_md5 )
	return DIGEST_ALGO_MD5;
    return 0;
}

/****************
 * Return the length of the digest
 */
int
md_digest_length( int algo )
{
    switch( algo ) {
      case DIGEST_ALGO_RMD160:
      case DIGEST_ALGO_SHA1:
	return 20;
      default:
	return 16;
    }
}


/* fixme: put the oids in a table and add a mode to enumerate the OIDs
 * to make g10/sig-check.c more portable */
const byte *
md_asn_oid( int algo, size_t *asnlen, size_t *mdlen )
{
    size_t alen;
    byte *p;

    if( algo == DIGEST_ALGO_MD5 ) {
	static byte asn[18] = /* Object ID is 1.2.840.113549.2.5 */
		    { 0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a, 0x86,0x48,
		      0x86, 0xf7, 0x0d, 0x02, 0x05, 0x05, 0x00, 0x04, 0x10 };
	alen = DIM(asn); p = asn;
    }
    else if( algo == DIGEST_ALGO_RMD160 ) {
	static byte asn[15] = /* Object ID is 1.3.36.3.2.1 */
	  { 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x24, 0x03,
	    0x02, 0x01, 0x05, 0x00, 0x04, 0x14 };
	alen = DIM(asn); p = asn;
    }
    else if( algo == DIGEST_ALGO_TIGER ) {
	/* 40: SEQUENCE {
	 * 12:	 SEQUENCE {
	 *  8:	   OCTET STRING   :54 49 47 45 52 31 39 32
	 *  0:	   NULL
	 *   :	   }
	 * 24:	 OCTET STRING
	 *   :	 }
	 *
	 * By replacing the 5th byte (0x04) with 0x16 we would have;
	 *	  8:	 IA5String 'TIGER192'
	 */
	static byte asn[18] =
		    { 0x30, 0x28, 0x30, 0x0c, 0x04, 0x08, 0x54, 0x49, 0x47,
		      0x45, 0x52, 0x31, 0x39, 0x32, 0x05, 0x00, 0x04, 0x18 };
	alen = DIM(asn); p = asn;
    }
    else if( algo == DIGEST_ALGO_SHA1 ) {
	static byte asn[15] = /* Object ID is 1.3.14.3.2.26 */
		    { 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03,
		      0x02, 0x1a, 0x05, 0x00, 0x04, 0x14 };
	alen = DIM(asn); p = asn;
    }
    else
	log_bug("md_asn_oid(%d)", algo );

    if( asnlen )
	*asnlen = alen;
    if( mdlen )
	*mdlen = p[alen-1];
    return p;
}


void
md_start_debug( MD_HANDLE md, const char *suffix )
{
    static int index=0;
    char buf[25];

    if( md->debug ) {
	log_debug("Oops: md debug already started\n");
	return;
    }
    index++;
    sprintf(buf, "dbgmd-%05d.%.10s", index, suffix );
    md->debug = fopen(buf, "w");
    if( !md->debug )
	log_debug("md debug: can't open %s\n", buf );
}

void
md_stop_debug( MD_HANDLE md )
{
    if( md->debug ) {
	fclose(md->debug);
	md->debug = NULL;
    }
}