src/pinentry.c

   1 /*
   2     Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
   3     Ben Kibbey <bjk@luxsci.net>
   4
   5     This file is part of libpwmd.
   6
   7     Libpwmd 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 2 of the License, or
  10     (at your option) any later version.
  11
  12     Libpwmd 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 Libpwmd.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include <sys/types.h>
  25 #include <errno.h>
  26 #include <stdlib.h>
  27 #include <limits.h>
  28
  29 #ifdef HAVE_STRING_H
  30 #include <string.h>
  31 #endif
  32
  33 #include "pinentry.h"
  34 #include "misc.h"
  35
  36 #ifdef WITH_QUALITY
  37 #include <crack.h>
  38 #endif
  39
  40 static gpg_error_t set_pinentry_strings (pwm_t * pwm, pwmd_pinentry_t which);
  41
  42 static gpg_error_t
  43 launch_pinentry (pwm_t * pwm)
  44 {
  45   int rc;
  46   assuan_context_t ctx;
  47   int child_list[] = { -1 };
  48   const char *argv[10];
  49   const char **p = argv;
  50   static struct assuan_malloc_hooks mhooks = {
  51     pwmd_malloc, pwmd_realloc, pwmd_free
  52   };
  53
  54   update_pinentry_settings (pwm);
  55   if (!pwm->pinentry_display && !pwm->pinentry_tty)
  56     return GPG_ERR_ENOTTY;
  57
  58   *p++ = "pinentry";
  59   *p++ = pwm->pinentry_display ? "--display" : "--ttyname";
  60   *p++ = pwm->pinentry_display ? pwm->pinentry_display : pwm->pinentry_tty;
  61
  62   if (pwm->pinentry_lcctype)
  63     {
  64       *p++ = "--lc-ctype";
  65       *p++ = pwm->pinentry_lcctype;
  66     }
  67
  68   if (pwm->pinentry_lcmessages)
  69     {
  70       *p++ = "--lc-messages";
  71       *p++ = pwm->pinentry_lcmessages;
  72     }
  73
  74   *p = NULL;
  75
  76   if (!pwm->pinentry_display)
  77     {
  78       *p++ = "--ttytype";
  79       *p++ = pwm->pinentry_term ? pwm->pinentry_term : getenv ("TERM");
  80       *p = NULL;
  81     }
  82
  83   rc = assuan_new_ext (&ctx, GPG_ERR_SOURCE_PINENTRY, &mhooks, NULL, NULL);
  84   if (rc)
  85     return rc;
  86
  87   rc = assuan_pipe_connect (ctx,
  88                             pwm->pinentry_path ? pwm->
  89                             pinentry_path : PINENTRY_PATH, argv, child_list,
  90                             NULL, NULL, 0);
  91   if (rc)
  92     {
  93       assuan_release (ctx);
  94       return rc;
  95     }
  96
  97   pwm->pinentry_pid = assuan_get_pid (ctx);
  98   pwm->pctx = ctx;
  99   rc = set_pinentry_strings (pwm, 0);
 100   if (rc)
 101     _pinentry_disconnect (pwm);
 102
 103   return rc;
 104 }
 105
 106 static gpg_error_t
 107 pinentry_command (pwm_t * pwm, char **result, size_t * len, const char *cmd)
 108 {
 109   if (len)
 110     *len = 0;
 111
 112   if (result)
 113     *result = NULL;
 114
 115   if (!pwm->pctx)
 116     {
 117       gpg_error_t rc = launch_pinentry (pwm);
 118
 119       if (rc)
 120         return rc;
 121     }
 122
 123   return _assuan_command (pwm, pwm->pctx, result, len, cmd);
 124 }
 125
 126 #ifdef WITH_QUALITY
 127 static gpg_error_t
 128 quality_cb (void *data, const char *line)
 129 {
 130   pwm_t *pwm = data;
 131   int score = 0;
 132   char buf[5];
 133   const char *tmp;
 134
 135   if (strncmp (line, "QUALITY ", 8))
 136     return GPG_ERR_INV_ARG;
 137
 138   if (!(tmp = FascistCheck (line + 8, CRACKLIB_DICT)))
 139     return assuan_send_data (pwm->pctx, "100", 3);
 140
 141   if (!strcmp (tmp, N_("it is WAY too short")))
 142     score = 10;
 143   else if (!strcmp (tmp, N_("it is too short")))
 144     score = 20;
 145   else if (!strcmp (tmp, N_("it is all whitespace")))
 146     score = 25;
 147   else if (!strcmp (tmp, N_("it is based on your username")))
 148     score = 30;
 149   else
 150     if (!strcmp (tmp, N_("it does not contain enough DIFFERENT characters")))
 151     score = 35;
 152   else if (!strcmp (tmp, N_("it is based on a dictionary word")))
 153     score = 40;
 154   else if (!strcmp (tmp, N_("it is based upon your password entry")))
 155     score = 50;
 156   else if (!strcmp (tmp, N_("it's derived from your password entry")))
 157     score = 50;
 158   else if (!strcmp (tmp, N_("it is derived from your password entry")))
 159     score = 50;
 160   else if (!strcmp (tmp, N_("it is based on a (reversed) dictionary word")))
 161     score = 60;
 162   else if (!strcmp (tmp, N_("it is derivable from your password entry")))
 163     score = 70;
 164   else if (!strcmp (tmp, N_("it's derivable from your password entry")))
 165     score = 70;
 166   else if (!strcmp (tmp, N_("it looks like a National Insurance number.")))
 167     score = 80;
 168   else if (!strcmp (tmp, N_("it is too simplistic/systematic")))
 169     score = 90;
 170   else
 171     score = 0;
 172
 173   snprintf (buf, sizeof (buf), "%i", score);
 174   return assuan_send_data (pwm->pctx, buf, strlen (buf));
 175 }
 176 #endif
 177
 178 static gpg_error_t
 179 set_pinentry_strings (pwm_t * pwm, pwmd_pinentry_t which)
 180 {
 181   char *tmp, *desc = NULL;
 182   gpg_error_t rc;
 183
 184   if (which != PWMD_PINENTRY_USER)
 185     {
 186       rc = pinentry_command (pwm, NULL, NULL, "SETERROR ");
 187       if (rc)
 188         return rc;
 189     }
 190
 191   tmp = pwmd_malloc (ASSUAN_LINELENGTH + 1);
 192   if (!tmp)
 193     return gpg_error_from_errno (ENOMEM);
 194
 195   if (!pwm->pinentry_prompt)
 196     {
 197       pwm->pinentry_prompt = pwmd_strdup (N_("Passphrase:"));
 198       if (!pwm->pinentry_prompt)
 199         {
 200           pwmd_free (tmp);
 201           return GPG_ERR_ENOMEM;
 202         }
 203     }
 204
 205   if (!pwm->pinentry_desc)
 206     {
 207       if (which == PWMD_PINENTRY_OPEN || which == PWMD_PINENTRY_OPEN_FAILED)
 208         desc =
 209           pwmd_strdup_printf (N_
 210                               ("A passphrase is required to unlock the secret key for the encrypted data file \"%s\". Please enter the passphrase below."),
 211                               pwm->filename);
 212       else if (which == PWMD_PINENTRY_SAVE
 213                || which == PWMD_PINENTRY_SAVE_FAILED)
 214         desc =
 215           pwmd_strdup_printf (N_
 216                               ("Please enter the passphrase to use to encrypt the data file \"%s\"."),
 217                               pwm->filename);
 218       else if (which == PWMD_PINENTRY_SAVE_CONFIRM)
 219         desc =
 220           pwmd_strdup_printf (N_
 221                               ("Please re-enter the passphrase for confirmation."),
 222                               pwm->filename);
 223
 224       if (!desc)
 225         {
 226           pwmd_free (tmp);
 227           return GPG_ERR_ENOMEM;
 228         }
 229     }
 230
 231   if (pwm->pinentry_desc)
 232     desc = pwm->pinentry_desc;
 233
 234   if (which == PWMD_PINENTRY_USER)
 235     {
 236       snprintf (tmp, ASSUAN_LINELENGTH, "SETERROR %s",
 237                 pwm->pinentry_error ? pwm->pinentry_error : "");
 238       rc = pinentry_command (pwm, NULL, NULL, tmp);
 239       if (rc)
 240         {
 241           pwmd_free (tmp);
 242           return rc;
 243         }
 244
 245       snprintf (tmp, ASSUAN_LINELENGTH, "SETDESC %s",
 246                 pwm->pinentry_desc ? pwm->pinentry_desc : "");
 247     }
 248   else
 249     {
 250       if (which == PWMD_PINENTRY_SAVE_FAILED
 251           || which == PWMD_PINENTRY_OPEN_FAILED)
 252         {
 253           if (which == PWMD_PINENTRY_SAVE_FAILED)
 254             snprintf (tmp, ASSUAN_LINELENGTH, "SETERROR %s",
 255                       N_("Passphrases do not match, try again."));
 256           else
 257             {
 258               if (pwm->pinentry_tries)
 259                 {
 260                   strcpy (tmp, "SETERROR ");
 261                   snprintf (tmp + strlen ("SETERROR "), ASSUAN_LINELENGTH,
 262                             N_("Bad passphrase (try %i of %i)"),
 263                             pwm->pinentry_try + 1, pwm->pinentry_tries);
 264                 }
 265               else
 266                 snprintf (tmp, ASSUAN_LINELENGTH, "SETERROR %s",
 267                           N_("Bad passphrase, try again"));
 268             }
 269
 270           rc = pinentry_command (pwm, NULL, NULL, tmp);
 271           if (rc)
 272             {
 273               pwmd_free (tmp);
 274               return rc;
 275             }
 276         }
 277
 278       snprintf (tmp, ASSUAN_LINELENGTH, "SETDESC %s", desc);
 279
 280       if (pwm->pinentry_desc != desc)
 281         pwmd_free (desc);
 282     }
 283
 284   rc = pinentry_command (pwm, NULL, NULL, tmp);
 285   if (rc)
 286     {
 287       pwmd_free (tmp);
 288       return rc;
 289     }
 290
 291   snprintf (tmp, ASSUAN_LINELENGTH, "SETPROMPT %s", pwm->pinentry_prompt);
 292   rc = pinentry_command (pwm, NULL, NULL, tmp);
 293   pwmd_free (tmp);
 294
 295 #ifdef WITH_QUALITY
 296   if (!rc && (which == PWMD_PINENTRY_SAVE ||
 297               which == PWMD_PINENTRY_SAVE_FAILED))
 298     {
 299       rc = pinentry_command (pwm, NULL, NULL, "SETQUALITYBAR");
 300       if (!rc)
 301         {
 302           pwm->_inquire_func = quality_cb;
 303           pwm->_inquire_data = pwm;
 304         }
 305     }
 306 #endif
 307
 308   if (pwm->pinentry_timeout >= 0)
 309     {
 310       char buf[32];
 311
 312       snprintf(buf, sizeof(buf), "SETTIMEOUT %i", pwm->pinentry_timeout);
 313       rc = pinentry_command(pwm, NULL, NULL, buf);
 314     }
 315
 316   return rc;
 317 }
 318
 319 void
 320 _pinentry_disconnect (pwm_t * pwm)
 321 {
 322   if (pwm->pctx)
 323     assuan_release (pwm->pctx);
 324
 325   pwm->pctx = NULL;
 326   pwm->pinentry_pid = -1;
 327 }
 328
 329 gpg_error_t
 330 _getpin (pwm_t * pwm, char **result, size_t * len, pwmd_pinentry_t which)
 331 {
 332   gpg_error_t rc = set_pinentry_strings (pwm, which);
 333
 334   if (rc)
 335     {
 336       _pinentry_disconnect (pwm);
 337       return rc;
 338     }
 339
 340   rc = pinentry_command (pwm, result, len,
 341                          which == PWMD_PINENTRY_CONFIRM ? "CONFIRM" : "GETPIN");
 342   if (rc)
 343     {
 344       _pinentry_disconnect (pwm);
 345
 346       /* This lets PWMD_OPTION_PINENTRY_TIMEOUT work. Note that it is not
 347        * thread safe do to the global variables. */
 348       if (gpg_err_code (rc) == GPG_ERR_EOF)
 349         rc = GPG_ERR_CANCELED;
 350     }
 351   else if (which != PWMD_PINENTRY_CONFIRM && len && result)
 352     {
 353       if (*len)
 354         *len = strlen (*result);        // remove the null byte
 355       else
 356         {
 357           *result = pwmd_malloc (1);
 358           *(*result) = 0;
 359           *len = 1;
 360         }
 361     }
 362
 363   return rc;
 364 }
 365
 366 gpg_error_t
 367 _pwmd_getpin (pwm_t * pwm, const char *filename, char **result,
 368               size_t * len, pwmd_pinentry_t which)
 369 {
 370   gpg_error_t rc;
 371   char *p;
 372
 373   if (!pwm)
 374     return GPG_ERR_INV_ARG;
 375
 376   p = pwm->filename;
 377   if (which == PWMD_PINENTRY_CLOSE)
 378     {
 379       _pinentry_disconnect (pwm);
 380       return 0;
 381     }
 382
 383   if (!result && which != PWMD_PINENTRY_CONFIRM)
 384     return GPG_ERR_INV_ARG;
 385
 386   pwm->filename = (char *) filename;
 387   rc = _getpin (pwm, result, len, which);
 388   pwm->filename = p;
 389   return rc;
 390 }