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 /* Same as decrypt_message but takes a file descriptor for input and
 101    output.  */
 102 gpg_error_t
 103 decrypt_message_fd (int input_fd, int output_fd)
 104 {
 105   gpg_error_t err;
 106   IOBUF fp;
 107   armor_filter_context_t *afx = NULL;
 108   progress_filter_context_t *pfx;
 109
 110   if (opt.outfp)
 111     return gpg_error (GPG_ERR_BUG);
 112
 113   pfx = new_progress_context ();
 114
 115   /* Open the message file.  */
 116   fp = iobuf_open_fd_or_name (input_fd, NULL, "rb");
 117   if (fp && is_secured_file (iobuf_get_fd (fp)))
 118     {
 119       iobuf_close (fp);
 120       fp = NULL;
 121       errno = EPERM;
 122     }
 123   if (!fp)
 124     {
 125       char xname[64];
 126
 127       err = gpg_error_from_syserror ();
 128       snprintf (xname, sizeof xname, "[fd %d]", input_fd);
 129       log_error (_("can't open `%s': %s\n"), xname, gpg_strerror (err));
 130       release_progress_context (pfx);
 131       return err;
 132     }
 133
 134   opt.outfp = fdopen (dup (output_fd), "wb");
 135   if (!opt.outfp)
 136     {
 137       char xname[64];
 138
 139       err = gpg_error_from_syserror ();
 140       snprintf (xname, sizeof xname, "[fd %d]", output_fd);
 141       log_error (_("can't open `%s': %s\n"), xname, gpg_strerror (err));
 142       iobuf_close (fp);
 143       release_progress_context (pfx);
 144       return err;
 145     }
 146
 147   if (!opt.no_armor)
 148     {
 149       if (use_armor_filter (fp))
 150         {
 151           afx = new_armor_context ();
 152           push_armor_filter ( afx, fp );
 153         }
 154     }
 155
 156   err = proc_encryption_packets ( NULL, fp );
 157
 158   iobuf_close (fp);
 159   fclose (opt.outfp);
 160   opt.outfp = NULL;
 161   release_armor_context (afx);
 162   release_progress_context (pfx);
 163   return err;
 164 }
 165
 166
 167 void
 168 decrypt_messages (int nfiles, char *files[])
 169 {
 170   IOBUF fp;
 171   armor_filter_context_t *afx = NULL;
 172   progress_filter_context_t *pfx;
 173   char *p, *output = NULL;
 174   int rc=0,use_stdin=0;
 175   unsigned int lno=0;
 176
 177   if (opt.outfile)
 178     {
 179       log_error(_("--output doesn't work for this command\n"));
 180       return;
 181     }
 182
 183   pfx = new_progress_context ();
 184
 185   if(!nfiles)
 186     use_stdin=1;
 187
 188   for(;;)
 189     {
 190       char line[2048];
 191       char *filename=NULL;
 192
 193       if(use_stdin)
 194         {
 195           if(fgets(line, DIM(line), stdin))
 196             {
 197               lno++;
 198               if (!*line || line[strlen(line)-1] != '\n')
 199                 log_error("input line %u too long or missing LF\n", lno);
 200               else
 201                 {
 202                   line[strlen(line)-1] = '\0';
 203                   filename=line;
 204                 }
 205             }
 206         }
 207       else
 208         {
 209           if(nfiles)
 210             {
 211               filename=*files;
 212               nfiles--;
 213               files++;
 214             }
 215         }
 216
 217       if(filename==NULL)
 218         break;
 219
 220       print_file_status(STATUS_FILE_START, filename, 3);
 221       output = make_outfile_name(filename);
 222       if (!output)
 223         goto next_file;
 224       fp = iobuf_open(filename);
 225       if (fp)
 226         iobuf_ioctl (fp,3,1,NULL); /* disable fd caching */
 227       if (fp && is_secured_file (iobuf_get_fd (fp)))
 228         {
 229           iobuf_close (fp);
 230           fp = NULL;
 231           errno = EPERM;
 232         }
 233       if (!fp)
 234         {
 235           log_error(_("can't open `%s'\n"), print_fname_stdin(filename));
 236           goto next_file;
 237         }
 238
 239       handle_progress (pfx, fp, filename);
 240
 241       if (!opt.no_armor)
 242         {
 243           if (use_armor_filter(fp))
 244             {
 245               afx = new_armor_context ();
 246               push_armor_filter ( afx, fp );
 247             }
 248         }
 249       rc = proc_packets(NULL, fp);
 250       iobuf_close(fp);
 251       if (rc)
 252         log_error("%s: decryption failed: %s\n", print_fname_stdin(filename),
 253                   g10_errstr(rc));
 254       p = get_last_passphrase();
 255       set_next_passphrase(p);
 256       xfree (p);
 257
 258     next_file:
 259       /* Note that we emit file_done even after an error. */
 260       write_status( STATUS_FILE_DONE );
 261       xfree(output);
 262       reset_literals_seen();
 263     }
 264
 265   set_next_passphrase(NULL);
 266   release_armor_context (afx);
 267   release_progress_context (pfx);
 268 }