g10/verify.c

   1 /* verify.c - verify signed data
   2  * Copyright (C) 1998, 1999, 2000, 2001 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  19  */
  20
  21 #include <config.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <errno.h>
  26 #include <assert.h>
  27 #include <unistd.h> /* for isatty() */
  28
  29 #include "options.h"
  30 #include "packet.h"
  31 #include "errors.h"
  32 #include "iobuf.h"
  33 #include "keydb.h"
  34 #include "memory.h"
  35 #include "util.h"
  36 #include "main.h"
  37 #include "status.h"
  38 #include "filter.h"
  39 #include "ttyio.h"
  40 #include "i18n.h"
  41
  42
  43
  44 /****************
  45  * Assume that the input is a signature and verify it without
  46  * generating any output.  With no arguments, the signature packet
  47  * is read from stdin (it may be a detached signature when not
  48  * used in batch mode). If only a sigfile is given, it may be a complete
  49  * signature or a detached signature in which case the signed stuff
  50  * is expected from stdin. With more than 1 argument, the first should
  51  * be a detached signature and the remaining files are the signed stuff.
  52  */
  53
  54 int
  55 verify_signatures( int nfiles, char **files )
  56 {
  57     iobuf_t fp;
  58     armor_filter_context_t afx;
  59     progress_filter_context_t pfx;
  60     const char *sigfile;
  61     int i, rc;
  62     STRLIST sl;
  63
  64     memset( &afx, 0, sizeof afx);
  65     /* decide whether we should handle a detached or a normal signature,
  66      * which is needed so that the code later can hash the correct data and
  67      * not have a normal signature act as detached signature and ignoring the
  68      * indended signed material from the 2nd file or stdin.
  69      * 1. gpg <file        - normal
  70      * 2. gpg file         - normal (or detached)
  71      * 3. gpg file <file2  - detached
  72      * 4. gpg file file2   - detached
  73      * The question is how decide between case 2 and 3?  The only way
  74      * we can do it is by reading one byte from stdin and the unget
  75      * it; the problem here is that we may be reading from the
  76      * terminal (which could be detected using isatty() but won't work
  77      * when under contol of a pty using program (e.g. expect)) and
  78      * might get us in trouble when stdin is used for another purpose
  79      * (--passphrase-fd 0).  So we have to break with the behaviour
  80      * prior to gpg 1.0.4 by assuming that case 3 is a normal
  81      * signature (where file2 is ignored and require for a detached
  82      * signature to indicate signed material comes from stdin by using
  83      * case 4 with a file2 of "-".
  84      *
  85      * Actually we don't have to change anything here but can handle
  86      * that all quite easily in mainproc.c
  87      */
  88
  89
  90     sigfile = nfiles? *files : NULL;
  91
  92     /* open the signature file */
  93     fp = iobuf_open(sigfile);
  94     if( !fp ) {
  95         rc = gpg_error_from_errno (errno);
  96         log_error(_("can't open `%s': %s\n"),
  97                   print_fname_stdin(sigfile), strerror (errno));
  98         return rc;
  99     }
 100     handle_progress (&pfx, fp, sigfile);
 101
 102     if( !opt.no_armor && use_armor_filter( fp ) )
 103         iobuf_push_filter( fp, armor_filter, &afx );
 104
 105     sl = NULL;
 106     for(i=1 ; i < nfiles; i++ )
 107         add_to_strlist( &sl, files[i] );
 108     rc = proc_signature_packets( NULL, fp, sl, sigfile );
 109     free_strlist(sl);
 110     iobuf_close(fp);
 111     if( afx.no_openpgp_data && rc == -1 ) {
 112         log_error(_("the signature could not be verified.\n"
 113                    "Please remember that the signature file (.sig or .asc)\n"
 114                    "should be the first file given on the command line.\n") );
 115         rc = 0;
 116     }
 117
 118     return rc;
 119 }
 120
 121
 122 void
 123 print_file_status( int status, const char *name, int what )
 124 {
 125     char *p = xmalloc (strlen(name)+10);
 126     sprintf(p, "%d %s", what, name );
 127     write_status_text( status, p );
 128     xfree (p);
 129 }
 130
 131
 132 static int
 133 verify_one_file( const char *name )
 134 {
 135     iobuf_t fp;
 136     armor_filter_context_t afx;
 137     progress_filter_context_t pfx;
 138     int rc;
 139
 140     print_file_status( STATUS_FILE_START, name, 1 );
 141     fp = iobuf_open(name);
 142     if( !fp ) {
 143         rc = gpg_error_from_errno (errno);
 144         log_error(_("can't open `%s': %s\n"),
 145                   print_fname_stdin(name), strerror (errno));
 146         print_file_status( STATUS_FILE_ERROR, name, 1 );
 147         return rc;
 148     }
 149     handle_progress (&pfx, fp, name);
 150
 151     if( !opt.no_armor ) {
 152         if( use_armor_filter( fp ) ) {
 153             memset( &afx, 0, sizeof afx);
 154             iobuf_push_filter( fp, armor_filter, &afx );
 155         }
 156     }
 157
 158     rc = proc_signature_packets( NULL, fp, NULL, name );
 159     iobuf_close(fp);
 160     write_status( STATUS_FILE_DONE );
 161     return rc;
 162 }
 163
 164 /****************
 165  * Verify each file given in the files array or read the names of the
 166  * files from stdin.
 167  * Note:  This function can not handle detached signatures.
 168  */
 169 int
 170 verify_files( int nfiles, char **files )
 171 {
 172     int i;
 173
 174     if( !nfiles ) { /* read the filenames from stdin */
 175         char line[2048];
 176         unsigned int lno = 0;
 177
 178         while( fgets(line, DIM(line), stdin) ) {
 179             lno++;
 180             if( !*line || line[strlen(line)-1] != '\n' ) {
 181                 log_error(_("input line %u too long or missing LF\n"), lno );
 182                 return GPG_ERR_GENERAL;
 183             }
 184             /* This code does not work on MSDOS but how cares there are
 185              * also no script languages available.  We don't strip any
 186              * spaces, so that we can process nearly all filenames */
 187             line[strlen(line)-1] = 0;
 188             verify_one_file( line );
 189         }
 190
 191     }
 192     else {  /* take filenames from the array */
 193         for(i=0; i < nfiles; i++ )
 194             verify_one_file( files[i] );
 195     }
 196     return 0;
 197 }