mirror of
git://git.gnupg.org/gnupg.git
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428 lines
9.1 KiB
C
428 lines
9.1 KiB
C
/* md.c - message digest dispatcher
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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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#define DEFINES_MD_HANDLE 1
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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 <errno.h>
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#include "util.h"
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#include "cipher.h"
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#include "errors.h"
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#include "dynload.h"
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#include "md5.h"
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#include "sha1.h"
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#include "rmd.h"
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/****************
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* This structure is used for the list of available algorithms
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* and for the list of algorithms in MD_HANDLE.
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*/
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struct md_digest_list_s {
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struct md_digest_list_s *next;
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const char *name;
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int algo;
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byte *asnoid;
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int asnlen;
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int mdlen;
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void (*init)( void *c );
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void (*write)( void *c, byte *buf, size_t nbytes );
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void (*final)( void *c );
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byte *(*read)( void *c );
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size_t contextsize; /* allocate this amount of context */
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char context[1];
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};
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static struct md_digest_list_s *digest_list;
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static struct md_digest_list_s *
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new_list_item( int algo,
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const char *(*get_info)( int, size_t*,byte**, int*, int*,
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void (**)(void*),
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void (**)(void*,byte*,size_t),
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void (**)(void*),byte *(**)(void*)) )
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{
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struct md_digest_list_s *r;
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r = m_alloc_clear( sizeof *r );
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r->algo = algo,
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r->name = (*get_info)( algo, &r->contextsize,
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&r->asnoid, &r->asnlen, &r->mdlen,
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&r->init, &r->write, &r->final, &r->read );
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if( !r->name ) {
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m_free(r);
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r = NULL;
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}
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return r;
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}
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/****************
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* Put the static entries into the table.
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*/
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static void
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setup_digest_list()
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{
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struct md_digest_list_s *r;
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r = new_list_item( DIGEST_ALGO_MD5, md5_get_info );
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if( r ) { r->next = digest_list; digest_list = r; }
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r = new_list_item( DIGEST_ALGO_RMD160, rmd160_get_info );
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if( r ) { r->next = digest_list; digest_list = r; }
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r = new_list_item( DIGEST_ALGO_SHA1, sha1_get_info );
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if( r ) { r->next = digest_list; digest_list = r; }
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}
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/****************
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* Try to load all modules and return true if new modules are available
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*/
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static int
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load_digest_modules()
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{
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static int done = 0;
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static int initialized = 0;
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struct md_digest_list_s *r;
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void *context = NULL;
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int algo;
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int any = 0;
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const char *(*get_info)( int, size_t*,byte**, int*, int*,
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void (**)(void*),
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void (**)(void*,byte*,size_t),
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void (**)(void*),byte *(**)(void*));
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if( !initialized ) {
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setup_digest_list(); /* load static modules on the first call */
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initialized = 1;
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return 1;
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}
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if( done )
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return 0;
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done = 1;
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while( enum_gnupgext_digests( &context, &algo, &get_info ) ) {
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for(r=digest_list; r; r = r->next )
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if( r->algo == algo )
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break;
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if( r ) {
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log_info("skipping digest %d: already loaded\n", algo );
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continue;
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}
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r = new_list_item( algo, get_info );
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if( ! r ) {
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log_info("skipping digest %d: no name\n", algo );
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continue;
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}
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/* put it into the list */
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if( g10_opt_verbose > 1 )
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log_info("loaded digest %d\n", algo);
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r->next = digest_list;
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digest_list = r;
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any = 1;
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}
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enum_gnupgext_digests( &context, NULL, NULL );
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return any;
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}
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/****************
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* Map a string to the digest algo
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*/
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int
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string_to_digest_algo( const char *string )
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{
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struct md_digest_list_s *r;
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do {
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for(r = digest_list; r; r = r->next )
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if( !stricmp( r->name, string ) )
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return r->algo;
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} while( !r && load_digest_modules() );
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return 0;
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}
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/****************
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* Map a digest algo to a string
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*/
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const char *
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digest_algo_to_string( int algo )
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{
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struct md_digest_list_s *r;
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do {
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for(r = digest_list; r; r = r->next )
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if( r->algo == algo )
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return r->name;
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} while( !r && load_digest_modules() );
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return NULL;
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}
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int
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check_digest_algo( int algo )
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{
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struct md_digest_list_s *r;
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do {
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for(r = digest_list; r; r = r->next )
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if( r->algo == algo )
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return 0;
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} while( !r && load_digest_modules() );
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return G10ERR_DIGEST_ALGO;
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}
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/****************
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* Open a message digest handle for use with algorithm ALGO.
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* More algorithms may be added by md_enable(). The initial algorithm
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* may be 0.
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*/
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MD_HANDLE
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md_open( int algo, int secure )
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{
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MD_HANDLE hd;
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hd = secure ? m_alloc_secure_clear( sizeof *hd )
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: m_alloc_clear( sizeof *hd );
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hd->secure = secure;
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if( algo )
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md_enable( hd, algo );
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fast_random_poll();
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return hd;
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}
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void
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md_enable( MD_HANDLE h, int algo )
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{
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struct md_digest_list_s *r, *ac;
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for( ac=h->list; ac; ac = ac->next )
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if( ac->algo == algo )
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return ; /* already enabled */
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/* find the algorithm */
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do {
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for(r = digest_list; r; r = r->next )
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if( r->algo == algo )
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break;
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} while( !r && load_digest_modules() );
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if( !r ) {
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log_error("md_enable: algorithm %d not available\n", algo );
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return;
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}
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/* and allocate a new list entry */
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ac = h->secure? m_alloc_secure( sizeof *ac + r->contextsize )
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: m_alloc( sizeof *ac + r->contextsize );
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*ac = *r;
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ac->next = h->list;
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h->list = ac;
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/* and init this instance */
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(*ac->init)( &ac->context );
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}
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MD_HANDLE
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md_copy( MD_HANDLE a )
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{
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MD_HANDLE b;
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struct md_digest_list_s *ar, *br;
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b = a->secure ? m_alloc_secure( sizeof *b )
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: m_alloc( sizeof *b );
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memcpy( b, a, sizeof *a );
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b->list = NULL;
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/* and now copy the compelte list of algorithms */
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/* I know that the copied list is reversed, but that doesn't matter */
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for( ar=a->list; ar; ar = ar->next ) {
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br = a->secure ? m_alloc_secure( sizeof *br + ar->contextsize )
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: m_alloc( sizeof *br + ar->contextsize );
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memcpy( br, ar, sizeof(*br) + ar->contextsize );
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br->next = b->list;
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b->list = br;
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}
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return b;
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}
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void
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md_close(MD_HANDLE a)
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{
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struct md_digest_list_s *r, *r2;
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if( !a )
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return;
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if( a->debug )
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md_stop_debug(a);
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for(r=a->list; r; r = r2 ) {
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r2 = r->next;
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m_free(r);
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}
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m_free(a);
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}
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void
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md_write( MD_HANDLE a, byte *inbuf, size_t inlen)
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{
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struct md_digest_list_s *r;
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if( a->debug ) {
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if( a->bufcount && fwrite(a->buffer, a->bufcount, 1, a->debug ) != 1 )
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BUG();
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if( inlen && fwrite(inbuf, inlen, 1, a->debug ) != 1 )
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BUG();
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}
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for(r=a->list; r; r = r->next ) {
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(*r->write)( &r->context, a->buffer, a->bufcount );
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(*r->write)( &r->context, inbuf, inlen );
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}
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a->bufcount = 0;
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}
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void
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md_final(MD_HANDLE a)
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{
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struct md_digest_list_s *r;
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if( a->bufcount )
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md_write( a, NULL, 0 );
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for(r=a->list; r; r = r->next ) {
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(*r->final)( &r->context );
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}
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}
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/****************
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* if ALGO is null get the digest for the used algo (which should be only one)
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*/
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byte *
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md_read( MD_HANDLE a, int algo )
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{
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struct md_digest_list_s *r;
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if( !algo ) { /* return the first algorithm */
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if( (r=a->list) ) {
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if( r->next )
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log_error("warning: more than algorithm in md_read(0)\n");
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return (*r->read)( &r->context );
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}
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}
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else {
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for(r=a->list; r; r = r->next )
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if( r->algo == algo )
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return (*r->read)( &r->context );
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}
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BUG();
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return NULL;
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}
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int
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md_get_algo( MD_HANDLE a )
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{
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struct md_digest_list_s *r;
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if( (r=a->list) ) {
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if( r->next )
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log_error("warning: more than algorithm in md_get_algo()\n");
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return r->algo;
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}
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return 0;
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}
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/****************
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* Return the length of the digest
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*/
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int
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md_digest_length( int algo )
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{
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struct md_digest_list_s *r;
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do {
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for(r = digest_list; r; r = r->next ) {
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if( r->algo == algo )
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return r->mdlen;
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}
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} while( !r && load_digest_modules() );
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log_error("warning: no length for md algo %d\n", algo);
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return 0;
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}
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/* fixme: add a mode to enumerate the OIDs
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* to make g10/sig-check.c more portable */
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const byte *
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md_asn_oid( int algo, size_t *asnlen, size_t *mdlen )
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{
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struct md_digest_list_s *r;
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do {
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for(r = digest_list; r; r = r->next ) {
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if( r->algo == algo ) {
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if( asnlen )
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*asnlen = r->asnlen;
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if( mdlen )
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*mdlen = r->mdlen;
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return r->asnoid;
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}
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}
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} while( !r && load_digest_modules() );
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log_bug("warning: no asn for md algo %d\n", algo);
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return NULL;
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}
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void
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md_start_debug( MD_HANDLE md, const char *suffix )
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{
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static int index=0;
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char buf[25];
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if( md->debug ) {
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log_debug("Oops: md debug already started\n");
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return;
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}
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index++;
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sprintf(buf, "dbgmd-%05d.%.10s", index, suffix );
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md->debug = fopen(buf, "w");
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if( !md->debug )
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log_debug("md debug: can't open %s\n", buf );
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}
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void
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md_stop_debug( MD_HANDLE md )
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{
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if( md->debug ) {
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fclose(md->debug);
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md->debug = NULL;
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}
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}
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