diff options
Diffstat (limited to 'cipher/md.c')
| -rw-r--r-- | cipher/md.c | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/cipher/md.c b/cipher/md.c new file mode 100644 index 000000000..49728638b --- /dev/null +++ b/cipher/md.c @@ -0,0 +1,524 @@ +/* md.c - message digest dispatcher + * Copyright (C) 1998, 1999 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 <assert.h> +#include "util.h" +#include "cipher.h" +#include "errors.h" +#include "dynload.h" +#include "rmd.h" + + +/**************** + * This structure is used for the list of available algorithms + * and for the list of algorithms in MD_HANDLE. + */ +struct md_digest_list_s { + struct md_digest_list_s *next; + const char *name; + int algo; + byte *asnoid; + int asnlen; + int mdlen; + void (*init)( void *c ); + void (*write)( void *c, byte *buf, size_t nbytes ); + void (*final)( void *c ); + byte *(*read)( void *c ); + size_t contextsize; /* allocate this amount of context */ + PROPERLY_ALIGNED_TYPE context; +}; + +static struct md_digest_list_s *digest_list; + + +static struct md_digest_list_s * +new_list_item( int algo, + const char *(*get_info)( int, size_t*,byte**, int*, int*, + void (**)(void*), + void (**)(void*,byte*,size_t), + void (**)(void*),byte *(**)(void*)) ) +{ + struct md_digest_list_s *r; + + r = m_alloc_clear( sizeof *r ); + r->algo = algo, + r->name = (*get_info)( algo, &r->contextsize, + &r->asnoid, &r->asnlen, &r->mdlen, + &r->init, &r->write, &r->final, &r->read ); + if( !r->name ) { + m_free(r); + r = NULL; + } + return r; +} + + + +/**************** + * Try to load the modules with the requeste algorithm + * and return true if new modules are available + * If req_alog is -1 try to load all digest algorithms. + */ +static int +load_digest_module( int req_algo ) +{ + static int initialized = 0; + static u32 checked_algos[256/32]; + static int checked_all = 0; + struct md_digest_list_s *r; + void *context = NULL; + int algo; + int any = 0; + const char *(*get_info)( int, size_t*,byte**, int*, int*, + void (**)(void*), + void (**)(void*,byte*,size_t), + void (**)(void*),byte *(**)(void*)); + + if( !initialized ) { + cipher_modules_constructor(); + initialized = 1; + } + algo = req_algo; + if( algo > 255 || !algo ) + return 0; /* algorithm number too high (does not fit into out bitmap)*/ + if( checked_all ) + return 0; /* already called with -1 */ + if( algo < 0 ) + checked_all = 1; + else if( (checked_algos[algo/32] & (1 << (algo%32))) ) + return 0; /* already checked and not found */ + else + checked_algos[algo/32] |= (1 << (algo%32)); + + while( enum_gnupgext_digests( &context, &algo, &get_info ) ) { + if( req_algo != -1 && algo != req_algo ) + continue; + for(r=digest_list; r; r = r->next ) + if( r->algo == algo ) + break; + if( r ) { + log_info("skipping digest %d: already loaded\n", algo ); + continue; + } + r = new_list_item( algo, get_info ); + if( ! r ) { + log_info("skipping digest %d: no name\n", algo ); + continue; + } + /* put it into the list */ + if( g10_opt_verbose > 1 ) + log_info("loaded digest %d\n", algo); + r->next = digest_list; + digest_list = r; + any = 1; + if( req_algo != -1 ) + break; + } + enum_gnupgext_digests( &context, NULL, NULL ); + return any; +} + + + +/**************** + * Map a string to the digest algo + */ +int +string_to_digest_algo( const char *string ) +{ + struct md_digest_list_s *r; + + do { + for(r = digest_list; r; r = r->next ) + if( !ascii_strcasecmp( r->name, string ) ) + return r->algo; + } while( !r && load_digest_module(-1) ); + return 0; +} + + +/**************** + * Map a digest algo to a string + */ +const char * +digest_algo_to_string( int algo ) +{ + struct md_digest_list_s *r; + + do { + for(r = digest_list; r; r = r->next ) + if( r->algo == algo ) + return r->name; + } while( !r && load_digest_module( algo ) ); + return NULL; +} + + +int +check_digest_algo( int algo ) +{ + struct md_digest_list_s *r; + + do { + for(r = digest_list; r; r = r->next ) + if( r->algo == algo ) + return 0; + } while( !r && load_digest_module(algo) ); + 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; + int bufsize; + + if( secure ) { + bufsize = 512 - sizeof( *hd ); + hd = m_alloc_secure_clear( sizeof *hd + bufsize ); + } + else { + bufsize = 1024 - sizeof( *hd ); + hd = m_alloc_clear( sizeof *hd + bufsize ); + } + + hd->bufsize = bufsize+1; /* hd has already one byte allocated */ + hd->secure = secure; + if( algo ) + md_enable( hd, algo ); + fast_random_poll(); + return hd; +} + +void +md_enable( MD_HANDLE h, int algo ) +{ + struct md_digest_list_s *r, *ac; + + for( ac=h->list; ac; ac = ac->next ) + if( ac->algo == algo ) + return ; /* already enabled */ + /* find the algorithm */ + do { + for(r = digest_list; r; r = r->next ) + if( r->algo == algo ) + break; + } while( !r && load_digest_module( algo ) ); + if( !r ) { + log_error("md_enable: algorithm %d not available\n", algo ); + return; + } + /* and allocate a new list entry */ + ac = h->secure? m_alloc_secure( sizeof *ac + r->contextsize + - sizeof(r->context) ) + : m_alloc( sizeof *ac + r->contextsize + - sizeof(r->context) ); + *ac = *r; + ac->next = h->list; + h->list = ac; + /* and init this instance */ + (*ac->init)( &ac->context.c ); +} + + +MD_HANDLE +md_copy( MD_HANDLE a ) +{ + MD_HANDLE b; + struct md_digest_list_s *ar, *br; + + if( a->bufcount ) + md_write( a, NULL, 0 ); + b = a->secure ? m_alloc_secure( sizeof *b + a->bufsize - 1 ) + : m_alloc( sizeof *b + a->bufsize - 1 ); + memcpy( b, a, sizeof *a + a->bufsize - 1 ); + b->list = NULL; + b->debug = NULL; + /* and now copy the complete list of algorithms */ + /* I know that the copied list is reversed, but that doesn't matter */ + for( ar=a->list; ar; ar = ar->next ) { + br = a->secure ? m_alloc_secure( sizeof *br + ar->contextsize + - sizeof(ar->context) ) + : m_alloc( sizeof *br + ar->contextsize + - sizeof(ar->context) ); + memcpy( br, ar, sizeof(*br) + ar->contextsize + - sizeof(ar->context) ); + br->next = b->list; + b->list = br; + } + + if( a->debug ) + md_start_debug( b, "unknown" ); + return b; +} + + +/**************** + * Reset all contexts and discard any buffered stuff. This may be used + * instead of a md_close(); md_open(). + */ +void +md_reset( MD_HANDLE a ) +{ + struct md_digest_list_s *r; + + a->bufcount = a->finalized = 0; + for( r=a->list; r; r = r->next ) { + memset( r->context.c, 0, r->contextsize ); + (*r->init)( &r->context.c ); + } +} + + +void +md_close(MD_HANDLE a) +{ + struct md_digest_list_s *r, *r2; + + if( !a ) + return; + if( a->debug ) + md_stop_debug(a); + for(r=a->list; r; r = r2 ) { + r2 = r->next; + m_free(r); + } + m_free(a); +} + + +void +md_write( MD_HANDLE a, const byte *inbuf, size_t inlen) +{ + struct md_digest_list_s *r; + + 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(); + } + for(r=a->list; r; r = r->next ) { + (*r->write)( &r->context.c, a->buffer, a->bufcount ); + /* Fixme: all ->write fnc should take a const byte* */ + (*r->write)( &r->context.c, (byte*)inbuf, inlen ); + } + a->bufcount = 0; +} + + + +void +md_final(MD_HANDLE a) +{ + struct md_digest_list_s *r; + + if( a->finalized ) + return; + + if( a->bufcount ) + md_write( a, NULL, 0 ); + + for(r=a->list; r; r = r->next ) { + (*r->final)( &r->context.c ); + } + a->finalized = 1; +} + + +/**************** + * if ALGO is null get the digest for the used algo (which should be only one) + */ +byte * +md_read( MD_HANDLE a, int algo ) +{ + struct md_digest_list_s *r; + + if( !algo ) { /* return the first algorithm */ + if( (r=a->list) ) { + if( r->next ) + log_debug("more than algorithm in md_read(0)\n"); + return (*r->read)( &r->context.c ); + } + } + else { + for(r=a->list; r; r = r->next ) + if( r->algo == algo ) + return (*r->read)( &r->context.c ); + } + BUG(); + return NULL; +} + + +/**************** + * This function combines md_final and md_read but keeps the context + * intact. This function can be used to calculate intermediate + * digests. The digest is copied into buffer and the digestlength is + * returned. If buffer is NULL only the needed size for buffer is returned. + * buflen gives the max size of buffer. If the buffer is too shourt to + * hold the complete digest, the buffer is filled with as many bytes are + * possible and this value is returned. + */ +int +md_digest( MD_HANDLE a, int algo, byte *buffer, int buflen ) +{ + struct md_digest_list_s *r = NULL; + char *context; + char *digest; + + if( a->bufcount ) + md_write( a, NULL, 0 ); + + if( !algo ) { /* return digest for the first algorithm */ + if( (r=a->list) && r->next ) + log_debug("more than algorithm in md_digest(0)\n"); + } + else { + for(r=a->list; r; r = r->next ) + if( r->algo == algo ) + break; + } + if( !r ) + BUG(); + + if( !buffer ) + return r->mdlen; + + /* I don't want to change the interface, so I simply work on a copy + * the context (extra overhead - should be fixed)*/ + context = a->secure ? m_alloc_secure( r->contextsize ) + : m_alloc( r->contextsize ); + memcpy( context, r->context.c, r->contextsize ); + (*r->final)( context ); + digest = (*r->read)( context ); + + if( buflen > r->mdlen ) + buflen = r->mdlen; + memcpy( buffer, digest, buflen ); + + m_free(context); + return buflen; +} + + +int +md_get_algo( MD_HANDLE a ) +{ + struct md_digest_list_s *r; + + if( (r=a->list) ) { + if( r->next ) + log_error("WARNING: more than algorithm in md_get_algo()\n"); + return r->algo; + } + return 0; +} + +/**************** + * Return the length of the digest + */ +int +md_digest_length( int algo ) +{ + struct md_digest_list_s *r; + + do { + for(r = digest_list; r; r = r->next ) { + if( r->algo == algo ) + return r->mdlen; + } + } while( !r && load_digest_module( algo ) ); + log_error("WARNING: no length for md algo %d\n", algo); + return 0; +} + + +/* Hmmm: 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 ) +{ + struct md_digest_list_s *r; + + do { + for(r = digest_list; r; r = r->next ) { + if( r->algo == algo ) { + if( asnlen ) + *asnlen = r->asnlen; + if( mdlen ) + *mdlen = r->mdlen; + return r->asnoid; + } + } + } while( !r && load_digest_module( algo ) ); + log_bug("no asn for md algo %d\n", algo); + return NULL; +} + + +void +md_start_debug( MD_HANDLE md, const char *suffix ) +{ + static int idx=0; + char buf[25]; + + if( md->debug ) { + log_debug("Oops: md debug already started\n"); + return; + } + idx++; + sprintf(buf, "dbgmd-%05d" EXTSEP_S "%.10s", idx, 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 ) { + if( md->bufcount ) + md_write( md, NULL, 0 ); + fclose(md->debug); + md->debug = NULL; + } + #ifdef HAVE_U64_TYPEDEF + { /* a kludge to pull in the __muldi3 for Solaris */ + volatile u32 a = (u32)(ulong)md; + volatile u64 b = 42; + volatile u64 c; + c = a * b; + } + #endif +} + |