g10/decrypt.c

   1 /* decrypt.c - verify signed data
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 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 "errors.h"
  32 #include "iobuf.h"
  33 #include "keydb.h"
  34 #include "util.h"
  35 #include "main.h"
  36 #include "status.h"
  37 #include "i18n.h"
  38
  39
  40
  41 /****************
  42  * Assume that the input is an encrypted message and decrypt
  43  * (and if signed, verify the signature on) it.
  44  * This command differs from the default operation, as it never
  45  * writes to the filename which is included in the file and it
  46  * rejects files which don't begin with an encrypted message.
  47  */
  48
  49 int
  50 decrypt_message( const char *filename )
  51 {
  52     IOBUF fp;
  53     armor_filter_context_t *afx = NULL;
  54     progress_filter_context_t *pfx;
  55     int rc;
  56     int no_out = 0;
  57
  58     pfx = new_progress_context ();
  59
  60     /* Open the message file.  */
  61     fp = iobuf_open(filename);
  62     if (fp && is_secured_file (iobuf_get_fd (fp)))
  63       {
  64         iobuf_close (fp);
  65         fp = NULL;
  66         errno = EPERM;
  67       }
  68     if( !fp ) {
  69         rc = gpg_error_from_syserror ();
  70         log_error (_("can't open `%s': %s\n"), print_fname_stdin(filename),
  71                    gpg_strerror (rc));
  72         release_progress_context (pfx);
  73         return rc;
  74     }
  75
  76     handle_progress (pfx, fp, filename);
  77
  78     if( !opt.no_armor ) {
  79         if( use_armor_filter( fp ) ) {
  80             afx = new_armor_context ();
  81             push_armor_filter ( afx, fp );
  82         }
  83     }
  84
  85     if( !opt.outfile ) {
  86         no_out = 1;
  87         opt.outfile = "-";
  88     }
  89     rc = proc_encryption_packets( NULL, fp );
  90     if( no_out )
  91        opt.outfile = NULL;
  92     iobuf_close(fp);
  93     release_armor_context (afx);
  94     release_progress_context (pfx);
  95     return rc;
  96 }
  97
  98 void
  99 decrypt_messages(int nfiles, char *files[])
 100 {
 101   IOBUF fp;
 102   armor_filter_context_t *afx = NULL;
 103   progress_filter_context_t *pfx;
 104   char *p, *output = NULL;
 105   int rc=0,use_stdin=0;
 106   unsigned int lno=0;
 107
 108   if (opt.outfile)
 109     {
 110       log_error(_("--output doesn't work for this command\n"));
 111       return;
 112     }
 113
 114   pfx = new_progress_context ();
 115
 116   if(!nfiles)
 117     use_stdin=1;
 118
 119   for(;;)
 120     {
 121       char line[2048];
 122       char *filename=NULL;
 123
 124       if(use_stdin)
 125         {
 126           if(fgets(line, DIM(line), stdin))
 127             {
 128               lno++;
 129               if (!*line || line[strlen(line)-1] != '\n')
 130                 log_error("input line %u too long or missing LF\n", lno);
 131               else
 132                 {
 133                   line[strlen(line)-1] = '\0';
 134                   filename=line;
 135                 }
 136             }
 137         }
 138       else
 139         {
 140           if(nfiles)
 141             {
 142               filename=*files;
 143               nfiles--;
 144               files++;
 145             }
 146         }
 147
 148       if(filename==NULL)
 149         break;
 150
 151       print_file_status(STATUS_FILE_START, filename, 3);
 152       output = make_outfile_name(filename);
 153       if (!output)
 154         goto next_file;
 155       fp = iobuf_open(filename);
 156       if (fp)
 157         iobuf_ioctl (fp,3,1,NULL); /* disable fd caching */
 158       if (fp && is_secured_file (iobuf_get_fd (fp)))
 159         {
 160           iobuf_close (fp);
 161           fp = NULL;
 162           errno = EPERM;
 163         }
 164       if (!fp)
 165         {
 166           log_error(_("can't open `%s'\n"), print_fname_stdin(filename));
 167           goto next_file;
 168         }
 169
 170       handle_progress (pfx, fp, filename);
 171
 172       if (!opt.no_armor)
 173         {
 174           if (use_armor_filter(fp))
 175             {
 176               afx = new_armor_context ();
 177               push_armor_filter ( afx, fp );
 178             }
 179         }
 180       rc = proc_packets(NULL, fp);
 181       iobuf_close(fp);
 182       if (rc)
 183         log_error("%s: decryption failed: %s\n", print_fname_stdin(filename),
 184                   g10_errstr(rc));
 185       p = get_last_passphrase();
 186       set_next_passphrase(p);
 187       xfree (p);
 188
 189     next_file:
 190       /* Note that we emit file_done even after an error. */
 191       write_status( STATUS_FILE_DONE );
 192       xfree(output);
 193       reset_literals_seen();
 194     }
 195
 196   set_next_passphrase(NULL);
 197   release_armor_context (afx);
 198   release_progress_context (pfx);
 199 }