g10/decrypt.c

   1 /* decrypt.c - decrypt and verify data
   2  * Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
   3  *               2007, 2009 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 "i18n.h"
  38
  39 /* Assume that the input is an encrypted message and decrypt
  40  * (and if signed, verify the signature on) it.
  41  * This command differs from the default operation, as it never
  42  * writes to the filename which is included in the file and it
  43  * rejects files which don't begin with an encrypted message.
  44  */
  45 int
  46 decrypt_message (const char *filename)
  47 {
  48   IOBUF fp;
  49   armor_filter_context_t *afx = NULL;
  50   progress_filter_context_t *pfx;
  51   int rc;
  52   int no_out = 0;
  53
  54   pfx = new_progress_context ();
  55
  56   /* Open the message file.  */
  57   fp = iobuf_open (filename);
  58   if (fp && is_secured_file (iobuf_get_fd (fp)))
  59     {
  60       iobuf_close (fp);
  61       fp = NULL;
  62       errno = EPERM;
  63     }
  64   if ( !fp )
  65     {
  66       rc = gpg_error_from_syserror ();
  67       log_error (_("can't open `%s': %s\n"), print_fname_stdin(filename),
  68                  gpg_strerror (rc));
  69       release_progress_context (pfx);
  70       return rc;
  71     }
  72
  73   handle_progress (pfx, fp, filename);
  74
  75   if ( !opt.no_armor )
  76     {
  77       if ( use_armor_filter( fp ) )
  78         {
  79           afx = new_armor_context ();
  80           push_armor_filter ( afx, fp );
  81         }
  82     }
  83
  84   if (!opt.outfile)
  85     {
  86       no_out = 1;
  87       opt.outfile = "-";
  88     }
  89   rc = proc_encryption_packets ( NULL, fp );
  90   if (no_out)
  91     opt.outfile = NULL;
  92
  93   iobuf_close (fp);
  94   release_armor_context (afx);
  95   release_progress_context (pfx);
  96   return rc;
  97 }
  98
  99
 100 void
 101 decrypt_messages (int nfiles, char *files[])
 102 {
 103   IOBUF fp;
 104   armor_filter_context_t *afx = NULL;
 105   progress_filter_context_t *pfx;
 106   char *p, *output = NULL;
 107   int rc=0,use_stdin=0;
 108   unsigned int lno=0;
 109
 110   if (opt.outfile)
 111     {
 112       log_error(_("--output doesn't work for this command\n"));
 113       return;
 114     }
 115
 116   pfx = new_progress_context ();
 117
 118   if(!nfiles)
 119     use_stdin=1;
 120
 121   for(;;)
 122     {
 123       char line[2048];
 124       char *filename=NULL;
 125
 126       if(use_stdin)
 127         {
 128           if(fgets(line, DIM(line), stdin))
 129             {
 130               lno++;
 131               if (!*line || line[strlen(line)-1] != '\n')
 132                 log_error("input line %u too long or missing LF\n", lno);
 133               else
 134                 {
 135                   line[strlen(line)-1] = '\0';
 136                   filename=line;
 137                 }
 138             }
 139         }
 140       else
 141         {
 142           if(nfiles)
 143             {
 144               filename=*files;
 145               nfiles--;
 146               files++;
 147             }
 148         }
 149
 150       if(filename==NULL)
 151         break;
 152
 153       print_file_status(STATUS_FILE_START, filename, 3);
 154       output = make_outfile_name(filename);
 155       if (!output)
 156         goto next_file;
 157       fp = iobuf_open(filename);
 158       if (fp)
 159         iobuf_ioctl (fp,3,1,NULL); /* disable fd caching */
 160       if (fp && is_secured_file (iobuf_get_fd (fp)))
 161         {
 162           iobuf_close (fp);
 163           fp = NULL;
 164           errno = EPERM;
 165         }
 166       if (!fp)
 167         {
 168           log_error(_("can't open `%s'\n"), print_fname_stdin(filename));
 169           goto next_file;
 170         }
 171
 172       handle_progress (pfx, fp, filename);
 173
 174       if (!opt.no_armor)
 175         {
 176           if (use_armor_filter(fp))
 177             {
 178               afx = new_armor_context ();
 179               push_armor_filter ( afx, fp );
 180             }
 181         }
 182       rc = proc_packets(NULL, fp);
 183       iobuf_close(fp);
 184       if (rc)
 185         log_error("%s: decryption failed: %s\n", print_fname_stdin(filename),
 186                   g10_errstr(rc));
 187       p = get_last_passphrase();
 188       set_next_passphrase(p);
 189       xfree (p);
 190
 191     next_file:
 192       /* Note that we emit file_done even after an error. */
 193       write_status( STATUS_FILE_DONE );
 194       xfree(output);
 195       reset_literals_seen();
 196     }
 197
 198   set_next_passphrase(NULL);
 199   release_armor_context (afx);
 200   release_progress_context (pfx);
 201 }