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       log_debug ( "a='%s'\n", infostr);
 331       log_debug ( "a='%s'\n", strchr ( infostr, PATHSEP_C));
 332       log_debug ( "a=%td\n", (p-infostr));
 333 #endif
 334       return SPWQ_NO_AGENT;
 335     }
 336   *p++ = 0;
 337
 338   while (*p && *p != PATHSEP_C)
 339     p++;
 340   prot = *p? atoi (p+1) : 0;
 341   if ( prot != 1)
 342     {
 343 #ifdef SPWQ_USE_LOGGING
 344       log_error (_("gpg-agent protocol version %d is not supported\n"),prot);
 345 #endif
 346       return SPWQ_PROTOCOL_ERROR;
 347     }
 348
 349 #ifdef HAVE_W32_SYSTEM
 350   fd = _w32_sock_new (AF_UNIX, SOCK_STREAM, 0);
 351 #else
 352   fd = socket (AF_UNIX, SOCK_STREAM, 0);
 353 #endif
 354   if (fd == -1)
 355     {
 356 #ifdef SPWQ_USE_LOGGING
 357       log_error ("can't create socket: %s\n", strerror(errno) );
 358 #endif
 359       return SPWQ_SYS_ERROR;
 360     }
 361
 362   memset (&client_addr, 0, sizeof client_addr);
 363   client_addr.sun_family = AF_UNIX;
 364   strcpy (client_addr.sun_path, infostr);
 365   len = (offsetof (struct sockaddr_un, sun_path)
 366          + strlen(client_addr.sun_path) + 1);
 367
 368 #ifdef HAVE_W32_SYSTEM
 369   rc = _w32_sock_connect (fd, (struct sockaddr*)&client_addr, len );
 370 #else
 371   rc = connect (fd, (struct sockaddr*)&client_addr, len );
 372 #endif
 373   if (rc == -1)
 374     {
 375 #ifdef SPWQ_USE_LOGGING
 376       log_error ( _("can't connect to `%s': %s\n"), infostr, strerror (errno));
 377 #endif
 378       close (fd );
 379       return SPWQ_IO_ERROR;
 380     }
 381
 382   nread = readline (fd, line, DIM(line));
 383   if (nread < 3 || !(line[0] == 'O' && line[1] == 'K'
 384                      && (line[2] == '\n' || line[2] == ' ')) )
 385     {
 386 #ifdef SPWQ_USE_LOGGING
 387       log_error ( _("communication problem with gpg-agent\n"));
 388 #endif
 389       close (fd );
 390       return SPWQ_PROTOCOL_ERROR;
 391     }
 392
 393   rc = agent_send_all_options (fd);
 394   if (rc)
 395     {
 396 #ifdef SPWQ_USE_LOGGING
 397       log_error (_("problem setting the gpg-agent options\n"));
 398 #endif
 399       close (fd);
 400       return rc;
 401     }
 402
 403   *rfd = fd;
 404   return 0;
 405 }
 406
 407
 408 /* Copy text to BUFFER and escape as required.  Return a pointer to
 409    the end of the new buffer.  Note that BUFFER must be large enough
 410    to keep the entire text; allocataing it 3 times the size of TEXT
 411    is sufficient. */
 412 static char *
 413 copy_and_escape (char *buffer, const char *text)
 414 {
 415   int i;
 416   const unsigned char *s = (unsigned char *)text;
 417   char *p = buffer;
 418
 419
 420   for (i=0; s[i]; i++)
 421     {
 422       if (s[i] < ' ' || s[i] == '+')
 423         {
 424           sprintf (p, "%%%02X", s[i]);
 425           p += 3;
 426         }
 427       else if (s[i] == ' ')
 428         *p++ = '+';
 429       else
 430         *p++ = s[i];
 431     }
 432   return p;
 433 }
 434
 435
 436 /* Set the name of the default socket to NAME.  */
 437 int
 438 simple_pw_set_socket (const char *name)
 439 {
 440   spwq_free (default_gpg_agent_info);
 441   if (name)
 442     {
 443       default_gpg_agent_info = spwq_malloc (strlen (name) + 4 + 1);
 444       if (!default_gpg_agent_info)
 445         return SPWQ_OUT_OF_CORE;
 446       /* We don't know the PID thus we use 0.  */
 447       strcpy (stpcpy (default_gpg_agent_info, name),
 448               PATHSEP_S "0" PATHSEP_S "1");
 449     }
 450   else
 451     default_gpg_agent_info = NULL;
 452
 453   return 0;
 454 }
 455
 456
 457 /* Ask the gpg-agent for a passphrase and present the user with a
 458    DESCRIPTION, a PROMPT and optionally with a TRYAGAIN extra text.
 459    If a CACHEID is not NULL it is used to locate the passphrase in in
 460    the cache and store it under this ID.  If OPT_CHECK is true
 461    gpg-agent is asked to apply some checks on the passphrase security.
 462    If ERRORCODE is not NULL it should point a variable receiving an
 463    errorcode; this error code might be 0 if the user canceled the
 464    operation.  The function returns NULL to indicate an error.  */
 465 char *
 466 simple_pwquery (const char *cacheid,
 467                 const char *tryagain,
 468                 const char *prompt,
 469                 const char *description,
 470                 int opt_check,
 471                 int *errorcode)
 472 {
 473   int fd = -1;
 474   int nread;
 475   char *result = NULL;
 476   char *pw = NULL;
 477   char *p;
 478   int rc, i;
 479
 480   rc = agent_open (&fd);
 481   if (rc)
 482     goto leave;
 483
 484   if (!cacheid)
 485     cacheid = "X";
 486   if (!tryagain)
 487     tryagain = "X";
 488   if (!prompt)
 489     prompt = "X";
 490   if (!description)
 491     description = "X";
 492
 493   {
 494     char *line;
 495     /* We allocate 3 times the needed space so that there is enough
 496        space for escaping. */
 497     line = spwq_malloc (15 + 10
 498                         + 3*strlen (cacheid) + 1
 499                         + 3*strlen (tryagain) + 1
 500                         + 3*strlen (prompt) + 1
 501                         + 3*strlen (description) + 1
 502                         + 2);
 503     if (!line)
 504       {
 505         rc = SPWQ_OUT_OF_CORE;
 506         goto leave;
 507       }
 508     strcpy (line, "GET_PASSPHRASE ");
 509     p = line+15;
 510     if (opt_check)
 511       p = stpcpy (p, "--check ");
 512     p = copy_and_escape (p, cacheid);
 513     *p++ = ' ';
 514     p = copy_and_escape (p, tryagain);
 515     *p++ = ' ';
 516     p = copy_and_escape (p, prompt);
 517     *p++ = ' ';
 518     p = copy_and_escape (p, description);
 519     *p++ = '\n';
 520     rc = writen (fd, line, p - line);
 521     spwq_free (line);
 522     if (rc)
 523       goto leave;
 524   }
 525
 526   /* get response */
 527   pw = spwq_secure_malloc (500);
 528   nread = readline (fd, pw, 499);
 529   if (nread < 0)
 530     {
 531       rc = -nread;
 532       goto leave;
 533     }
 534   if (nread < 3)
 535     {
 536       rc = SPWQ_PROTOCOL_ERROR;
 537       goto leave;
 538     }
 539
 540   if (pw[0] == 'O' && pw[1] == 'K' && pw[2] == ' ')
 541     { /* we got a passphrase - convert it back from hex */
 542       size_t pwlen = 0;
 543
 544       for (i=3; i < nread && hexdigitp (pw+i); i+=2)
 545         pw[pwlen++] = xtoi_2 (pw+i);
 546       pw[pwlen] = 0; /* make a C String */
 547       result = pw;
 548       pw = NULL;
 549     }
 550   else if ((nread > 7 && !memcmp (pw, "ERR 111", 7)
 551             && (pw[7] == ' ' || pw[7] == '\n') )
 552            || ((nread > 4 && !memcmp (pw, "ERR ", 4)
 553                 && (strtoul (pw+4, NULL, 0) & 0xffff) == 99)) )
 554     {
 555       /* 111 is the old Assuan code for canceled which might still
 556          be in use by old installations. 99 is GPG_ERR_CANCELED as
 557          used by modern gpg-agents; 0xffff is used to mask out the
 558          error source.  */
 559 #ifdef SPWQ_USE_LOGGING
 560       log_info (_("canceled by user\n") );
 561 #endif
 562       *errorcode = 0; /* Special error code to indicate Cancel. */
 563     }
 564   else if (nread > 4 && !memcmp (pw, "ERR ", 4))
 565     {
 566       switch ( (strtoul (pw+4, NULL, 0) & 0xffff) )
 567         {
 568         case 85: rc = SPWQ_NO_PIN_ENTRY;  break;
 569         default: rc = SPWQ_GENERAL_ERROR; break;
 570         }
 571     }
 572   else
 573     {
 574 #ifdef SPWQ_USE_LOGGING
 575       log_error (_("problem with the agent\n"));
 576 #endif
 577       rc = SPWQ_ERR_RESPONSE;
 578     }
 579
 580  leave:
 581   if (errorcode)
 582     *errorcode = rc;
 583   if (fd != -1)
 584     close (fd);
 585   if (pw)
 586     spwq_secure_free (pw);
 587   return result;
 588 }
 589
 590
 591 /* Ask the gpg-agent to clear the passphrase for the cache ID CACHEID.  */
 592 int
 593 simple_pwclear (const char *cacheid)
 594 {
 595   char line[500];
 596   char *p;
 597
 598   /* We need not more than 50 characters for the command and the
 599      terminating nul.  */
 600   if (strlen (cacheid) * 3 > sizeof (line) - 50)
 601     return SPWQ_PROTOCOL_ERROR;
 602
 603   strcpy (line, "CLEAR_PASSPHRASE ");
 604   p = line + 17;
 605   p = copy_and_escape (p, cacheid);
 606   *p++ = '\n';
 607   *p++ = '\0';
 608
 609   return simple_query (line);
 610 }
 611
 612
 613 /* Perform the simple query QUERY (which must be new-line and 0
 614    terminated) and return the error code.  */
 615 int
 616 simple_query (const char *query)
 617 {
 618   int fd = -1;
 619   int nread;
 620   char response[500];
 621   int rc;
 622
 623   rc = agent_open (&fd);
 624   if (rc)
 625     goto leave;
 626
 627   rc = writen (fd, query, strlen (query));
 628   if (rc)
 629     goto leave;
 630
 631   /* get response */
 632   nread = readline (fd, response, 499);
 633   if (nread < 0)
 634     {
 635       rc = -nread;
 636       goto leave;
 637     }
 638   if (nread < 3)
 639     {
 640       rc = SPWQ_PROTOCOL_ERROR;
 641       goto leave;
 642     }
 643
 644   if (response[0] == 'O' && response[1] == 'K')
 645     /* OK, do nothing.  */;
 646   else if ((nread > 7 && !memcmp (response, "ERR 111", 7)
 647             && (response[7] == ' ' || response[7] == '\n') )
 648            || ((nread > 4 && !memcmp (response, "ERR ", 4)
 649                 && (strtoul (response+4, NULL, 0) & 0xffff) == 99)) )
 650     {
 651       /* 111 is the old Assuan code for canceled which might still
 652          be in use by old installations. 99 is GPG_ERR_CANCELED as
 653          used by modern gpg-agents; 0xffff is used to mask out the
 654          error source.  */
 655 #ifdef SPWQ_USE_LOGGING
 656       log_info (_("canceled by user\n") );
 657 #endif
 658     }
 659   else
 660     {
 661 #ifdef SPWQ_USE_LOGGING
 662       log_error (_("problem with the agent\n"));
 663 #endif
 664       rc = SPWQ_ERR_RESPONSE;
 665     }
 666
 667  leave:
 668   if (fd != -1)
 669     close (fd);
 670   return rc;
 671 }