g10/verify.c

   1 /* verify.c - Verify signed data
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2004, 2005, 2006,
   3  *               2007 Free Software Foundation, Inc.
   4  *
   5  * This file is part of GnuPG.
   6  *
   7  * GnuPG is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 3 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * GnuPG is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  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
  28 #include "gpg.h"
  29 #include "options.h"
  30 #include "packet.h"
  31 #include "status.h"
  32 #include "iobuf.h"
  33 #include "keydb.h"
  34 #include "util.h"
  35 #include "main.h"
  36 #include "status.h"
  37 #include "filter.h"
  38 #include "ttyio.h"
  39 #include "i18n.h"
  40
  41
  42
  43 /****************
  44  * Assume that the input is a signature and verify it without
  45  * generating any output.  With no arguments, the signature packet
  46  * is read from stdin (it may be a detached signature when not
  47  * used in batch mode). If only a sigfile is given, it may be a complete
  48  * signature or a detached signature in which case the signed stuff
  49  * is expected from stdin. With more than 1 argument, the first should
  50  * be a detached signature and the remaining files are the signed stuff.
  51  */
  52
  53 int
  54 verify_signatures( int nfiles, char **files )
  55 {
  56     IOBUF fp;
  57     armor_filter_context_t *afx = NULL;
  58     progress_filter_context_t *pfx = new_progress_context ();
  59     const char *sigfile;
  60     int i, rc;
  61     strlist_t sl;
  62
  63     /* Decide whether we should handle a detached or a normal signature,
  64      * which is needed so that the code later can hash the correct data and
  65      * not have a normal signature act as detached signature and ignoring the
  66      * indended signed material from the 2nd file or stdin.
  67      * 1. gpg <file        - normal
  68      * 2. gpg file         - normal (or detached)
  69      * 3. gpg file <file2  - detached
  70      * 4. gpg file file2   - detached
  71      * The question is how decide between case 2 and 3?  The only way
  72      * we can do it is by reading one byte from stdin and then unget
  73      * it; the problem here is that we may be reading from the
  74      * terminal (which could be detected using isatty() but won't work
  75      * when under contol of a pty using program (e.g. expect)) and
  76      * might get us in trouble when stdin is used for another purpose
  77      * (--passphrase-fd 0).  So we have to break with the behaviour
  78      * prior to gpg 1.0.4 by assuming that case 3 is a normal
  79      * signature (where file2 is ignored and require for a detached
  80      * signature to indicate signed material comes from stdin by using
  81      * case 4 with a file2 of "-".
  82      *
  83      * Actually we don't have to change anything here but can handle
  84      * that all quite easily in mainproc.c
  85      */
  86
  87     sigfile = nfiles? *files : NULL;
  88
  89     /* open the signature file */
  90     fp = iobuf_open(sigfile);
  91     if (fp && is_secured_file (iobuf_get_fd (fp)))
  92       {
  93         iobuf_close (fp);
  94         fp = NULL;
  95         errno = EPERM;
  96       }
  97     if( !fp ) {
  98         rc = gpg_error_from_syserror ();
  99         log_error(_("can't open `%s': %s\n"),
 100                   print_fname_stdin(sigfile), strerror (errno));
 101         goto leave;
 102     }
 103     handle_progress (pfx, fp, sigfile);
 104
 105     if ( !opt.no_armor && use_armor_filter( fp ) )
 106       {
 107         afx = new_armor_context ();
 108         push_armor_filter (afx, fp);
 109       }
 110
 111     sl = NULL;
 112     for(i=nfiles-1 ; i > 0 ; i-- )
 113         add_to_strlist( &sl, files[i] );
 114     rc = proc_signature_packets( NULL, fp, sl, sigfile );
 115     free_strlist(sl);
 116     iobuf_close(fp);
 117     if( (afx && afx->no_openpgp_data && rc == -1) || rc == G10ERR_NO_DATA ) {
 118         log_error(_("the signature could not be verified.\n"
 119                    "Please remember that the signature file (.sig or .asc)\n"
 120                    "should be the first file given on the command line.\n") );
 121         rc = 0;
 122     }
 123
 124  leave:
 125     release_armor_context (afx);
 126     release_progress_context (pfx);
 127     return rc;
 128 }
 129
 130
 131
 132 void
 133 print_file_status( int status, const char *name, int what )
 134 {
 135     char *p = xmalloc(strlen(name)+10);
 136     sprintf(p, "%d %s", what, name );
 137     write_status_text( status, p );
 138     xfree(p);
 139 }
 140
 141
 142 static int
 143 verify_one_file( const char *name )
 144 {
 145     IOBUF fp;
 146     armor_filter_context_t *afx = NULL;
 147     progress_filter_context_t *pfx = new_progress_context ();
 148     int rc;
 149
 150     print_file_status( STATUS_FILE_START, name, 1 );
 151     fp = iobuf_open(name);
 152     if (fp)
 153       iobuf_ioctl (fp,3,1,NULL); /* disable fd caching */
 154     if (fp && is_secured_file (iobuf_get_fd (fp)))
 155       {
 156         iobuf_close (fp);
 157         fp = NULL;
 158         errno = EPERM;
 159       }
 160     if( !fp ) {
 161         rc = gpg_error_from_syserror ();
 162         log_error(_("can't open `%s': %s\n"),
 163                   print_fname_stdin(name), strerror (errno));
 164         print_file_status( STATUS_FILE_ERROR, name, 1 );
 165         goto leave;
 166     }
 167     handle_progress (pfx, fp, name);
 168
 169     if( !opt.no_armor ) {
 170         if( use_armor_filter( fp ) ) {
 171             afx = new_armor_context ();
 172             push_armor_filter (afx, fp);
 173         }
 174     }
 175
 176     rc = proc_signature_packets( NULL, fp, NULL, name );
 177     iobuf_close(fp);
 178     write_status( STATUS_FILE_DONE );
 179
 180     reset_literals_seen();
 181
 182  leave:
 183     release_armor_context (afx);
 184     release_progress_context (pfx);
 185     return rc;
 186 }
 187
 188 /****************
 189  * Verify each file given in the files array or read the names of the
 190  * files from stdin.
 191  * Note:  This function can not handle detached signatures.
 192  */
 193 int
 194 verify_files( int nfiles, char **files )
 195 {
 196     int i;
 197
 198     if( !nfiles ) { /* read the filenames from stdin */
 199         char line[2048];
 200         unsigned int lno = 0;
 201
 202         while( fgets(line, DIM(line), stdin) ) {
 203             lno++;
 204             if( !*line || line[strlen(line)-1] != '\n' ) {
 205                 log_error(_("input line %u too long or missing LF\n"), lno );
 206                 return G10ERR_GENERAL;
 207             }
 208             /* This code does not work on MSDOS but how cares there are
 209              * also no script languages available.  We don't strip any
 210              * spaces, so that we can process nearly all filenames */
 211             line[strlen(line)-1] = 0;
 212             verify_one_file( line );
 213         }
 214
 215     }
 216     else {  /* take filenames from the array */
 217         for(i=0; i < nfiles; i++ )
 218             verify_one_file( files[i] );
 219     }
 220     return 0;
 221 }
 222
 223
 224
 225
 226 /* Perform a verify operation.  To verify detached signatures, DATA_FD
 227    shall be the descriptor of the signed data; for regular signatures
 228    it needs to be -1.  If OUT_FP is not NULL and DATA_FD is not -1 the
 229    the signed material gets written that stream.
 230
 231    FIXME: OUTFP is not yet implemented.
 232 */
 233 int
 234 gpg_verify (ctrl_t ctrl, int sig_fd, int data_fd, FILE *out_fp)
 235 {
 236   int rc;
 237   iobuf_t fp;
 238   armor_filter_context_t *afx = NULL;
 239   progress_filter_context_t *pfx = new_progress_context ();
 240
 241   (void)ctrl;
 242   (void)out_fp;
 243
 244   fp = iobuf_fdopen (sig_fd, "rb");
 245   if (fp && is_secured_file (sig_fd))
 246     {
 247       fp = NULL;
 248       errno = EPERM;
 249     }
 250   if ( !fp )
 251     {
 252       rc = gpg_error_from_syserror ();
 253       log_error (_("can't open fd %d: %s\n"), sig_fd, strerror (errno));
 254       goto leave;
 255     }
 256
 257   handle_progress (pfx, fp, NULL);
 258
 259   if ( !opt.no_armor && use_armor_filter (fp) )
 260     {
 261       afx = new_armor_context ();
 262       push_armor_filter (afx, fp);
 263     }
 264
 265   rc = proc_signature_packets_by_fd ( NULL, fp, data_fd );
 266
 267   if ( afx && afx->no_openpgp_data
 268        && (rc == -1 || gpg_err_code (rc) == GPG_ERR_EOF) )
 269     rc = gpg_error (GPG_ERR_NO_DATA);
 270
 271  leave:
 272   if (fp)
 273     iobuf_close (fp);
 274   release_progress_context (pfx);
 275   release_armor_context (afx);
 276   return rc;
 277 }
 278