common/simple-pwquery.c

   1 /* simple-pwquery.c - A simple password query client for gpg-agent
   2  *      Copyright (C) 2002, 2004, 2007 Free Software Foundation, Inc.
   3  *
   4  * This file is part of GnuPG.
   5  *
   6  * GnuPG is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * GnuPG is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 /* This module is intended as a standalone client implementation to
  21    gpg-agent's GET_PASSPHRASE command.  In particular it does not use
  22    the Assuan library and can only cope with an already running
  23    gpg-agent.  Some stuff is configurable in the header file. */
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include <config.h>
  27 #endif
  28 #include <stdlib.h>
  29 #include <stddef.h>
  30 #include <string.h>
  31 #include <errno.h>
  32 #include <unistd.h>
  33 #ifdef HAVE_W32_SYSTEM
  34 #include <winsock2.h>
  35 #else
  36 #include <sys/socket.h>
  37 #include <sys/un.h>
  38 #endif
  39 #ifdef HAVE_LOCALE_H
  40 #include <locale.h>
  41 #endif
  42 #ifdef HAVE_W32_SYSTEM
  43 #include "../jnlib/w32-afunix.h"
  44 #endif
  45
  46
  47 #define SIMPLE_PWQUERY_IMPLEMENTATION 1
  48 #include "simple-pwquery.h"
  49
  50 #if defined(SPWQ_USE_LOGGING) && !defined(HAVE_JNLIB_LOGGING)
  51 # undef SPWQ_USE_LOGGING
  52 #endif
  53
  54 #ifndef _
  55 #define _(a) (a)
  56 #endif
  57
  58 #if !defined (hexdigitp) && !defined (xtoi_2)
  59 #define digitp(p)   (*(p) >= '0' && *(p) <= '9')
  60 #define hexdigitp(a) (digitp (a)                     \
  61                       || (*(a) >= 'A' && *(a) <= 'F')  \
  62                       || (*(a) >= 'a' && *(a) <= 'f'))
  63 #define xtoi_1(p)   (*(p) <= '9'? (*(p)- '0'): \
  64                      *(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
  65 #define xtoi_2(p)   ((xtoi_1(p) * 16) + xtoi_1((p)+1))
  66 #endif
  67
  68
  69 /* Name of the socket to be used if GPG_AGENT_INFO has not been
  70    set. No default socket is used if this is NULL.  */
  71 static char *default_gpg_agent_info;
  72
  73
  74
  75
  76 \f
  77
  78 #ifndef HAVE_STPCPY
  79 static char *
  80 my_stpcpy(char *a,const char *b)
  81 {
  82     while( *b )
  83         *a++ = *b++;
  84     *a = 0;
  85
  86     return (char*)a;
  87 }
  88 #define stpcpy(a,b)  my_stpcpy((a), (b))
  89 #endif
  90
  91
  92
  93 /* Write NBYTES of BUF to file descriptor FD. */
  94 static int
  95 writen (int fd, const void *buf, size_t nbytes)
  96 {
  97   size_t nleft = nbytes;
  98   int nwritten;
  99
 100   while (nleft > 0)
 101     {
 102 #ifdef HAVE_W32_SYSTEM
 103       nwritten = send (fd, buf, nleft, 0);
 104 #else
 105       nwritten = write (fd, buf, nleft);
 106 #endif
 107       if (nwritten < 0)
 108         {
 109           if (errno == EINTR)
 110             nwritten = 0;
 111           else {
 112 #ifdef SPWQ_USE_LOGGING
 113             log_error ("write failed: %s\n", strerror (errno));
 114 #endif
 115             return SPWQ_IO_ERROR;
 116           }
 117         }
 118       nleft -= nwritten;
 119       buf = (const char*)buf + nwritten;
 120     }
 121
 122   return 0;
 123 }
 124
 125
 126 /* Read an entire line and return number of bytes read. */
 127 static int
 128 readline (int fd, char *buf, size_t buflen)
 129 {
 130   size_t nleft = buflen;
 131   char *p;
 132   int nread = 0;
 133
 134   while (nleft > 0)
 135     {
 136 #ifdef HAVE_W32_SYSTEM
 137       int n = recv (fd, buf, nleft, 0);
 138 #else
 139       int n = read (fd, buf, nleft);
 140 #endif
 141       if (n < 0)
 142         {
 143           if (errno == EINTR)
 144             continue;
 145           return -(SPWQ_IO_ERROR);
 146         }
 147       else if (!n)
 148         {
 149           return -(SPWQ_PROTOCOL_ERROR); /* incomplete line */
 150         }
 151       p = buf;
 152       nleft -= n;
 153       buf += n;
 154       nread += n;
 155
 156       for (; n && *p != '\n'; n--, p++)
 157         ;
 158       if (n)
 159         {
 160           break; /* At least one full line available - that's enough.
 161                     This function is just a simple implementation, so
 162                     it is okay to forget about pending bytes.  */
 163         }
 164     }
 165
 166   return nread;
 167 }
 168
 169
 170 /* Send an option to the agent */
 171 static int
 172 agent_send_option (int fd, const char *name, const char *value)
 173 {
 174   char buf[200];
 175   int nread;
 176   char *line;
 177   int i;
 178
 179   line = spwq_malloc (7 + strlen (name) + 1 + strlen (value) + 2);
 180   if (!line)
 181     return SPWQ_OUT_OF_CORE;
 182   strcpy (stpcpy (stpcpy (stpcpy (
 183                      stpcpy (line, "OPTION "), name), "="), value), "\n");
 184   i = writen (fd, line, strlen (line));
 185   spwq_free (line);
 186   if (i)
 187     return i;
 188
 189   /* get response */
 190   nread = readline (fd, buf, DIM(buf)-1);
 191   if (nread < 0)
 192     return -nread;
 193   if (nread < 3)
 194     return SPWQ_PROTOCOL_ERROR;
 195
 196   if (buf[0] == 'O' && buf[1] == 'K' && (buf[2] == ' ' || buf[2] == '\n'))
 197     return 0; /* okay */
 198
 199   return SPWQ_ERR_RESPONSE;
 200 }
 201
 202
 203 /* Send all available options to the agent. */
 204 static int
 205 agent_send_all_options (int fd)
 206 {
 207   char *dft_display = NULL;
 208   char *dft_ttyname = NULL;
 209   char *dft_ttytype = NULL;
 210   int rc = 0;
 211
 212   dft_display = getenv ("DISPLAY");
 213   if (dft_display)
 214     {
 215       if ((rc = agent_send_option (fd, "display", dft_display)))
 216         return rc;
 217     }
 218
 219   dft_ttyname = getenv ("GPG_TTY");
 220 #ifndef HAVE_W32_SYSTEM
 221   if ((!dft_ttyname || !*dft_ttyname) && ttyname (0))
 222     dft_ttyname = ttyname (0);
 223 #endif
 224   if (dft_ttyname && *dft_ttyname)
 225     {
 226       if ((rc=agent_send_option (fd, "ttyname", dft_ttyname)))
 227         return rc;
 228     }
 229
 230   dft_ttytype = getenv ("TERM");
 231   if (dft_ttyname && dft_ttytype)
 232     {
 233       if ((rc = agent_send_option (fd, "ttytype", dft_ttytype)))
 234         return rc;
 235     }
 236
 237 #if defined(HAVE_SETLOCALE)
 238   {
 239     char *old_lc = NULL;
 240     char *dft_lc = NULL;
 241
 242 #if defined(LC_CTYPE)
 243     old_lc = setlocale (LC_CTYPE, NULL);
 244     if (old_lc)
 245       {
 246         char *p = spwq_malloc (strlen (old_lc)+1);
 247         if (!p)
 248           return SPWQ_OUT_OF_CORE;
 249         strcpy (p, old_lc);
 250         old_lc = p;
 251       }
 252     dft_lc = setlocale (LC_CTYPE, "");
 253     if (dft_ttyname && dft_lc)
 254       rc = agent_send_option (fd, "lc-ctype", dft_lc);
 255     if (old_lc)
 256       {
 257         setlocale (LC_CTYPE, old_lc);
 258         spwq_free (old_lc);
 259       }
 260     if (rc)
 261       return rc;
 262 #endif
 263
 264 #if defined(LC_MESSAGES)
 265     old_lc = setlocale (LC_MESSAGES, NULL);
 266     if (old_lc)
 267       {
 268         char *p = spwq_malloc (strlen (old_lc)+1);
 269         if (!p)
 270           return SPWQ_OUT_OF_CORE;
 271         strcpy (p, old_lc);
 272         old_lc = p;
 273       }
 274     dft_lc = setlocale (LC_MESSAGES, "");
 275     if (dft_ttyname && dft_lc)
 276       rc = agent_send_option (fd, "lc-messages", dft_lc);
 277     if (old_lc)
 278       {
 279         setlocale (LC_MESSAGES, old_lc);
 280         spwq_free (old_lc);
 281       }
 282     if (rc)
 283       return rc;
 284 #endif
 285   }
 286 #endif /*HAVE_SETLOCALE*/
 287
 288   return 0;
 289 }
 290
 291
 292
 293 /* Try to open a connection to the agent, send all options and return
 294    the file descriptor for the connection.  Return -1 in case of
 295    error. */
 296 static int
 297 agent_open (int *rfd)
 298 {
 299   int rc;
 300   int fd;
 301   char *infostr, *p;
 302   struct sockaddr_un client_addr;
 303   size_t len;
 304   int prot;
 305   char line[200];
 306   int nread;
 307
 308   *rfd = -1;
 309   infostr = getenv ( "GPG_AGENT_INFO" );
 310   if ( !infostr || !*infostr )
 311     infostr = default_gpg_agent_info;
 312   if ( !infostr || !*infostr )
 313     {
 314 #ifdef SPWQ_USE_LOGGING
 315       log_error (_("gpg-agent is not available in this session\n"));
 316 #endif
 317       return SPWQ_NO_AGENT;
 318     }
 319   p = spwq_malloc (strlen (infostr)+1);
 320   if (!p)
 321     return SPWQ_OUT_OF_CORE;
 322   strcpy (p, infostr);
 323   infostr = p;
 324
 325   if ( !(p = strchr ( infostr, PATHSEP_C)) || p == infostr
 326        || (p-infostr)+1 >= sizeof client_addr.sun_path )
 327     {
 328 #ifdef SPWQ_USE_LOGGING
 329       log_error ( _("malformed GPG_AGENT_INFO environment variable\n"));
 330 #endif
 331       return SPWQ_NO_AGENT;
 332     }
 333   *p++ = 0;
 334
 335   while (*p && *p != PATHSEP_C)
 336     p++;
 337   prot = *p? atoi (p+1) : 0;
 338   if ( prot != 1)
 339     {
 340 #ifdef SPWQ_USE_LOGGING
 341       log_error (_("gpg-agent protocol version %d is not supported\n"),prot);
 342 #endif
 343       return SPWQ_PROTOCOL_ERROR;
 344     }
 345
 346 #ifdef HAVE_W32_SYSTEM
 347   fd = _w32_sock_new (AF_UNIX, SOCK_STREAM, 0);
 348 #else
 349   fd = socket (AF_UNIX, SOCK_STREAM, 0);
 350 #endif
 351   if (fd == -1)
 352     {
 353 #ifdef SPWQ_USE_LOGGING
 354       log_error ("can't create socket: %s\n", strerror(errno) );
 355 #endif
 356       return SPWQ_SYS_ERROR;
 357     }
 358
 359   memset (&client_addr, 0, sizeof client_addr);
 360   client_addr.sun_family = AF_UNIX;
 361   strcpy (client_addr.sun_path, infostr);
 362   len = (offsetof (struct sockaddr_un, sun_path)
 363          + strlen(client_addr.sun_path) + 1);
 364
 365 #ifdef HAVE_W32_SYSTEM
 366   rc = _w32_sock_connect (fd, (struct sockaddr*)&client_addr, len );
 367 #else
 368   rc = connect (fd, (struct sockaddr*)&client_addr, len );
 369 #endif
 370   if (rc == -1)
 371     {
 372 #ifdef SPWQ_USE_LOGGING
 373       log_error ( _("can't connect to `%s': %s\n"), infostr, strerror (errno));
 374 #endif
 375       close (fd );
 376       return SPWQ_IO_ERROR;
 377     }
 378
 379   nread = readline (fd, line, DIM(line));
 380   if (nread < 3 || !(line[0] == 'O' && line[1] == 'K'
 381                      && (line[2] == '\n' || line[2] == ' ')) )
 382     {
 383 #ifdef SPWQ_USE_LOGGING
 384       log_error ( _("communication problem with gpg-agent\n"));
 385 #endif
 386       close (fd );
 387       return SPWQ_PROTOCOL_ERROR;
 388     }
 389
 390   rc = agent_send_all_options (fd);
 391   if (rc)
 392     {
 393 #ifdef SPWQ_USE_LOGGING
 394       log_error (_("problem setting the gpg-agent options\n"));
 395 #endif
 396       close (fd);
 397       return rc;
 398     }
 399
 400   *rfd = fd;
 401   return 0;
 402 }
 403
 404
 405 /* Copy text to BUFFER and escape as required.  Return a pointer to
 406    the end of the new buffer.  Note that BUFFER must be large enough
 407    to keep the entire text; allocataing it 3 times the size of TEXT
 408    is sufficient. */
 409 static char *
 410 copy_and_escape (char *buffer, const char *text)
 411 {
 412   int i;
 413   const unsigned char *s = (unsigned char *)text;
 414   char *p = buffer;
 415
 416
 417   for (i=0; s[i]; i++)
 418     {
 419       if (s[i] < ' ' || s[i] == '+')
 420         {
 421           sprintf (p, "%%%02X", s[i]);
 422           p += 3;
 423         }
 424       else if (s[i] == ' ')
 425         *p++ = '+';
 426       else
 427         *p++ = s[i];
 428     }
 429   return p;
 430 }
 431
 432
 433 /* Set the name of the default socket to NAME.  */
 434 int
 435 simple_pw_set_socket (const char *name)
 436 {
 437   spwq_free (default_gpg_agent_info);
 438   if (name)
 439     {
 440       default_gpg_agent_info = spwq_malloc (strlen (name) + 4 + 1);
 441       if (!default_gpg_agent_info)
 442         return SPWQ_OUT_OF_CORE;
 443       /* We don't know the PID thus we use 0.  */
 444       strcpy (stpcpy (default_gpg_agent_info, name),
 445               PATHSEP_S "0" PATHSEP_S "1");
 446     }
 447   else
 448     default_gpg_agent_info = NULL;
 449
 450   return 0;
 451 }
 452
 453
 454 /* Ask the gpg-agent for a passphrase and present the user with a
 455    DESCRIPTION, a PROMPT and optionally with a TRYAGAIN extra text.
 456    If a CACHEID is not NULL it is used to locate the passphrase in in
 457    the cache and store it under this ID.  If OPT_CHECK is true
 458    gpg-agent is asked to apply some checks on the passphrase security.
 459    If ERRORCODE is not NULL it should point a variable receiving an
 460    errorcode; this error code might be 0 if the user canceled the
 461    operation.  The function returns NULL to indicate an error.  */
 462 char *
 463 simple_pwquery (const char *cacheid,
 464                 const char *tryagain,
 465                 const char *prompt,
 466                 const char *description,
 467                 int opt_check,
 468                 int *errorcode)
 469 {
 470   int fd = -1;
 471   int nread;
 472   char *result = NULL;
 473   char *pw = NULL;
 474   char *p;
 475   int rc, i;
 476
 477   rc = agent_open (&fd);
 478   if (rc)
 479     goto leave;
 480
 481   if (!cacheid)
 482     cacheid = "X";
 483   if (!tryagain)
 484     tryagain = "X";
 485   if (!prompt)
 486     prompt = "X";
 487   if (!description)
 488     description = "X";
 489
 490   {
 491     char *line;
 492     /* We allocate 3 times the needed space so that there is enough
 493        space for escaping. */
 494     line = spwq_malloc (15 + 10
 495                         + 3*strlen (cacheid) + 1
 496                         + 3*strlen (tryagain) + 1
 497                         + 3*strlen (prompt) + 1
 498                         + 3*strlen (description) + 1
 499                         + 2);
 500     if (!line)
 501       {
 502         rc = SPWQ_OUT_OF_CORE;
 503         goto leave;
 504       }
 505     strcpy (line, "GET_PASSPHRASE ");
 506     p = line+15;
 507     if (opt_check)
 508       p = stpcpy (p, "--check ");
 509     p = copy_and_escape (p, cacheid);
 510     *p++ = ' ';
 511     p = copy_and_escape (p, tryagain);
 512     *p++ = ' ';
 513     p = copy_and_escape (p, prompt);
 514     *p++ = ' ';
 515     p = copy_and_escape (p, description);
 516     *p++ = '\n';
 517     rc = writen (fd, line, p - line);
 518     spwq_free (line);
 519     if (rc)
 520       goto leave;
 521   }
 522
 523   /* get response */
 524   pw = spwq_secure_malloc (500);
 525   nread = readline (fd, pw, 499);
 526   if (nread < 0)
 527     {
 528       rc = -nread;
 529       goto leave;
 530     }
 531   if (nread < 3)
 532     {
 533       rc = SPWQ_PROTOCOL_ERROR;
 534       goto leave;
 535     }
 536
 537   if (pw[0] == 'O' && pw[1] == 'K' && pw[2] == ' ')
 538     { /* we got a passphrase - convert it back from hex */
 539       size_t pwlen = 0;
 540
 541       for (i=3; i < nread && hexdigitp (pw+i); i+=2)
 542         pw[pwlen++] = xtoi_2 (pw+i);
 543       pw[pwlen] = 0; /* make a C String */
 544       result = pw;
 545       pw = NULL;
 546     }
 547   else if ((nread > 7 && !memcmp (pw, "ERR 111", 7)
 548             && (pw[7] == ' ' || pw[7] == '\n') )
 549            || ((nread > 4 && !memcmp (pw, "ERR ", 4)
 550                 && (strtoul (pw+4, NULL, 0) & 0xffff) == 99)) )
 551     {
 552       /* 111 is the old Assuan code for canceled which might still
 553          be in use by old installations. 99 is GPG_ERR_CANCELED as
 554          used by modern gpg-agents; 0xffff is used to mask out the
 555          error source.  */
 556 #ifdef SPWQ_USE_LOGGING
 557       log_info (_("canceled by user\n") );
 558 #endif
 559       *errorcode = 0; /* Special error code to indicate Cancel. */
 560     }
 561   else if (nread > 4 && !memcmp (pw, "ERR ", 4))
 562     {
 563       switch ( (strtoul (pw+4, NULL, 0) & 0xffff) )
 564         {
 565         case 85: rc = SPWQ_NO_PIN_ENTRY;  break;
 566         default: rc = SPWQ_GENERAL_ERROR; break;
 567         }
 568     }
 569   else
 570     {
 571 #ifdef SPWQ_USE_LOGGING
 572       log_error (_("problem with the agent\n"));
 573 #endif
 574       rc = SPWQ_ERR_RESPONSE;
 575     }
 576
 577  leave:
 578   if (errorcode)
 579     *errorcode = rc;
 580   if (fd != -1)
 581     close (fd);
 582   if (pw)
 583     spwq_secure_free (pw);
 584   return result;
 585 }
 586
 587
 588 /* Ask the gpg-agent to clear the passphrase for the cache ID CACHEID.  */
 589 int
 590 simple_pwclear (const char *cacheid)
 591 {
 592   char line[500];
 593   char *p;
 594
 595   /* We need not more than 50 characters for the command and the
 596      terminating nul.  */
 597   if (strlen (cacheid) * 3 > sizeof (line) - 50)
 598     return SPWQ_PROTOCOL_ERROR;
 599
 600   strcpy (line, "CLEAR_PASSPHRASE ");
 601   p = line + 17;
 602   p = copy_and_escape (p, cacheid);
 603   *p++ = '\n';
 604   *p++ = '\0';
 605
 606   return simple_query (line);
 607 }
 608
 609
 610 /* Perform the simple query QUERY (which must be new-line and 0
 611    terminated) and return the error code.  */
 612 int
 613 simple_query (const char *query)
 614 {
 615   int fd = -1;
 616   int nread;
 617   char response[500];
 618   int rc;
 619
 620   rc = agent_open (&fd);
 621   if (rc)
 622     goto leave;
 623
 624   rc = writen (fd, query, strlen (query));
 625   if (rc)
 626     goto leave;
 627
 628   /* get response */
 629   nread = readline (fd, response, 499);
 630   if (nread < 0)
 631     {
 632       rc = -nread;
 633       goto leave;
 634     }
 635   if (nread < 3)
 636     {
 637       rc = SPWQ_PROTOCOL_ERROR;
 638       goto leave;
 639     }
 640
 641   if (response[0] == 'O' && response[1] == 'K')
 642     /* OK, do nothing.  */;
 643   else if ((nread > 7 && !memcmp (response, "ERR 111", 7)
 644             && (response[7] == ' ' || response[7] == '\n') )
 645            || ((nread > 4 && !memcmp (response, "ERR ", 4)
 646                 && (strtoul (response+4, NULL, 0) & 0xffff) == 99)) )
 647     {
 648       /* 111 is the old Assuan code for canceled which might still
 649          be in use by old installations. 99 is GPG_ERR_CANCELED as
 650          used by modern gpg-agents; 0xffff is used to mask out the
 651          error source.  */
 652 #ifdef SPWQ_USE_LOGGING
 653       log_info (_("canceled by user\n") );
 654 #endif
 655     }
 656   else
 657     {
 658 #ifdef SPWQ_USE_LOGGING
 659       log_error (_("problem with the agent\n"));
 660 #endif
 661       rc = SPWQ_ERR_RESPONSE;
 662     }
 663
 664  leave:
 665   if (fd != -1)
 666     close (fd);
 667   return rc;
 668 }