git.distorted.org.uk Git - u/mdw/catacomb/blob - progs/pixie.c

   1 /* -*-c-*-
   2  *
   3  * Passphrase pixie for Catacomb
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include "config.h"
  31
  32 #include <assert.h>
  33 #include <ctype.h>
  34 #include <errno.h>
  35 #include <signal.h>
  36 #include <stdarg.h>
  37 #include <stddef.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <time.h>
  42
  43 #include <sys/types.h>
  44 #include <sys/time.h>
  45 #include <unistd.h>
  46 #include <sys/stat.h>
  47 #include <sys/wait.h>
  48 #include <pwd.h>
  49 #include <fcntl.h>
  50 #include <sys/ioctl.h>
  51 #include <termios.h>
  52 #include <syslog.h>
  53
  54 #include <sys/socket.h>
  55 #include <sys/un.h>
  56
  57 #include <mLib/alloc.h>
  58 #include <mLib/dstr.h>
  59 #include <mLib/fdflags.h>
  60 #include <mLib/mdwopt.h>
  61 #include <mLib/quis.h>
  62 #include <mLib/report.h>
  63 #include <mLib/sel.h>
  64 #include <mLib/selbuf.h>
  65 #include <mLib/sig.h>
  66 #include <mLib/str.h>
  67 #include <mLib/sub.h>
  68 #include <mLib/tv.h>
  69
  70 #include "arena.h"
  71 #include "lmem.h"
  72 #include "passphrase.h"
  73 #include "pixie.h"
  74
  75 /*----- Static variables --------------------------------------------------*/
  76
  77 static unsigned long timeout = 900;
  78 static sel_state sel;
  79 static unsigned verbose = 1;
  80 static const char *command = 0;
  81 static lmem lm;
  82 static unsigned flags = 0;
  83
  84 #define F_SYSLOG 1u
  85 #define F_FETCH 2u
  86 #define F_REPLACE 4u
  87
  88 /*----- Event logging -----------------------------------------------------*/
  89
  90 /* --- @pxlog@ --- *
  91  *
  92  * Arguments:   @const char *p@ = @printf@-style format string
  93  *              @...@ = extra arguments to fill in
  94  *
  95  * Returns:     ---
  96  *
  97  * Use:         Writes out a timestamped log message.
  98  */
  99
 100 static void PRINTF_LIKE(1, 2) pxlog(const char *p, ...)
 101 {
 102   dstr d = DSTR_INIT;
 103   va_list ap;
 104
 105   if (!(flags & F_SYSLOG)) {
 106     time_t t = time(0);
 107     struct tm *tm = localtime(&t);
 108     DENSURE(&d, 64);
 109     d.len += strftime(d.buf, d.sz, "%Y-%m-%d %H:%M:%S ", tm);
 110   }
 111   va_start(ap, p);
 112   dstr_vputf(&d, p, &ap);
 113   va_end(ap);
 114
 115   if (flags & F_SYSLOG)
 116     syslog(LOG_NOTICE, "%s", d.buf);
 117   else {
 118     DPUTC(&d, '\n');
 119     dstr_write(&d, stderr);
 120   }
 121   DDESTROY(&d);
 122 }
 123
 124 /*----- Passphrase management ---------------------------------------------*/
 125
 126 /* --- Data structures --- */
 127
 128 typedef struct phrase {
 129   struct phrase *next, *prev;
 130   char *tag;
 131   char *p;
 132   unsigned long t;
 133   sel_timer timer;
 134   unsigned f;
 135 } phrase;
 136
 137 /* --- Variables --- */
 138
 139 static phrase *p_head = 0, *p_tail = 0;
 140
 141 /* --- Utility macros --- */
 142
 143 #define P_LINKTAIL(p) do {                                              \
 144   (p)->next = 0;                                                        \
 145   (p)->prev = p_tail;                                                   \
 146   *(p_tail ? &p_tail->next : &p_head) = (p);                            \
 147   p_tail = (p);                                                         \
 148 } while (0)
 149
 150 #define P_UNLINK(p) do {                                                \
 151   *((p)->next ? &(p)->next->prev : &p_tail) = (p)->prev;                \
 152   *((p)->prev ? &(p)->prev->next : &p_head) = (p)->next;                \
 153 } while (0)
 154
 155 /* --- @p_free@ --- *
 156  *
 157  * Arguments:   @phrase *p@ = pointer to phrase block
 158  *
 159  * Returns:     ---
 160  *
 161  * Use:         Frees a phrase block.
 162  */
 163
 164 static void p_free(phrase *p)
 165 {
 166   if (p->t)
 167     sel_rmtimer(&p->timer);
 168   xfree(p->tag);
 169   l_free(&lm, p->p);
 170   P_UNLINK(p);
 171   DESTROY(p);
 172 }
 173
 174 /* --- @p_timer@ --- *
 175  *
 176  * Arguments:   @struct timeval *tv@ = current time
 177  *              @void *p@ = pointer to phrase
 178  *
 179  * Returns:     ---
 180  *
 181  * Use:         Expires a passphrase.
 182  */
 183
 184 static void p_timer(struct timeval *tv, void *p)
 185 {
 186   phrase *pp = p;
 187   if (verbose)
 188     pxlog("expiring passphrase `%s'", pp->tag);
 189   p_free(pp);
 190 }
 191
 192 /* --- @p_alloc@ --- *
 193  *
 194  * Arguments:   @size_t sz@ = amount of memory required
 195  *
 196  * Returns:     Pointer to allocated memory, or null.
 197  *
 198  * Use:         Allocates some locked memory, flushing old passphrases if
 199  *              there's not enough space.
 200  */
 201
 202 static void *p_alloc(size_t sz)
 203 {
 204   for (;;) {
 205     char *p;
 206     if ((p = l_alloc(&lm, sz)) != 0)
 207       return (p);
 208     if (!p_head)
 209       return (0);
 210     if (verbose) {
 211       pxlog("flushing passphrase `%s' to free up needed space",
 212             p_head->tag);
 213     }
 214     p_free(p_head);
 215   }
 216 }
 217
 218 /* --- @p_find@ --- *
 219  *
 220  * Arguments:   @const char *tag@ = pointer to tag to find
 221  *
 222  * Returns:     Pointer to passphrase block, or null.
 223  *
 224  * Use:         Finds a passphrase with a given tag.
 225  */
 226
 227 static phrase *p_find(const char *tag)
 228 {
 229   phrase *p;
 230
 231   for (p = p_head; p; p = p->next) {
 232     if (strcmp(p->tag, tag) == 0) {
 233       if (p->t) {
 234         struct timeval tv;
 235         sel_rmtimer(&p->timer);
 236         gettimeofday(&tv, 0);
 237         tv.tv_sec += p->t;
 238         sel_addtimer(&sel, &p->timer, &tv, p_timer, p);
 239       }
 240       P_UNLINK(p);
 241       P_LINKTAIL(p);
 242       return (p);
 243     }
 244   }
 245   return (0);
 246 }
 247
 248 /* --- @p_add@ --- *
 249  *
 250  * Arguments:   @const char *tag@ = pointer to tag string
 251  *              @const char *p@ = pointer to passphrase
 252  *              @unsigned long t@ = expiry timeout
 253  *
 254  * Returns:     Pointer to newly-added passphrase.
 255  *
 256  * Use:         Adds a new passphrase.  The tag must not already exist.
 257  */
 258
 259 static phrase *p_add(const char *tag, const char *p, unsigned long t)
 260 {
 261   size_t sz = strlen(p) + 1;
 262   char *l = p_alloc(sz);
 263   phrase *pp;
 264
 265   /* --- Make sure the locked memory was allocated --- */
 266
 267   if (!l)
 268     return (0);
 269
 270   /* --- Fill in some other bits of the block --- */
 271
 272   pp = CREATE(phrase);
 273   memcpy(l, p, sz);
 274   pp->p = l;
 275   pp->tag = xstrdup(tag);
 276   pp->f = 0;
 277
 278   /* --- Set the timer --- */
 279
 280   pp->t = t;
 281   if (t) {
 282     struct timeval tv;
 283     gettimeofday(&tv, 0);
 284     tv.tv_sec += t;
 285     sel_addtimer(&sel, &pp->timer, &tv, p_timer, pp);
 286   }
 287
 288   /* --- Link the block into the chain --- */
 289
 290   P_LINKTAIL(pp);
 291   return (pp);
 292 }
 293
 294 /* --- @p_flush@ --- *
 295  *
 296  * Arguments:   @const char *tag@ = pointer to tag string, or zero for all
 297  *
 298  * Returns:     ---
 299  *
 300  * Use:         Immediately flushes either a single phrase or all of them.
 301  */
 302
 303 static void p_flush(const char *tag)
 304 {
 305   phrase *p;
 306
 307   if (!tag && verbose > 1)
 308     pxlog("flushing all passphrases");
 309   p = p_head;
 310   while (p) {
 311     phrase *pp = p->next;
 312     if (!tag)
 313       p_free(p);
 314     else if (strcmp(p->tag, tag) == 0) {
 315       if (verbose > 1)
 316         pxlog("flushing passphrase `%s'", tag);
 317       p_free(p);
 318       break;
 319     }
 320     p = pp;
 321   }
 322 }
 323
 324 /*----- Reading passphrases -----------------------------------------------*/
 325
 326 /* --- @p_request@ --- *
 327  *
 328  * Arguments:   @const char *msg@ = message string
 329  *              @const char *tag@ = pointer to tag string
 330  *              @char *buf@ = pointer to (locked) buffer
 331  *              @size_t sz@ = size of buffer
 332  *
 333  * Returns:     Zero if all went well, nonzero otherwise.
 334  *
 335  * Use:         Requests a passphrase from the user.
 336  */
 337
 338 static int p_request(const char *msg, const char *tag, char *buf, size_t sz)
 339 {
 340   /* --- If there's a passphrase-fetching command, run it --- */
 341
 342   if (command) {
 343     dstr d = DSTR_INIT;
 344     const char *p;
 345     int fd[2];
 346     pid_t kid;
 347     int r;
 348     int rc;
 349
 350     /* --- Substitute the prompt string into the command --- */
 351
 352     p = command;
 353     for (;;) {
 354       const char *q = strchr(p, '%');
 355       if (!q || !q[1]) {
 356         DPUTS(&d, p);
 357         break;
 358       }
 359       DPUTM(&d, p, q - p);
 360       p = q + 1;
 361       switch (*p) {
 362         case 'm':
 363           DPUTS(&d, msg);
 364           break;
 365         case 't':
 366           DPUTS(&d, tag);
 367           break;
 368         default:
 369           DPUTC(&d, '%');
 370           DPUTC(&d, *p);
 371           break;
 372       }
 373       p++;
 374     }
 375     DPUTZ(&d);
 376
 377     /* --- Create a pipe and start a child process --- */
 378
 379     if (pipe(fd))
 380       goto fail_1;
 381     if ((kid = fork()) < 0)
 382       goto fail_2;
 383
 384     /* --- Child process --- */
 385
 386     fflush(0);
 387     if (kid == 0) {
 388       if (dup2(fd[1], STDOUT_FILENO) < 0)
 389         _exit(127);
 390       close(fd[0]);
 391       execl("/bin/sh", "sh", "-c", d.buf, (char *)0);
 392       _exit(127);
 393     }
 394
 395     /* --- Read the data back into my buffer --- */
 396
 397     close(fd[1]);
 398     if ((r = read(fd[0], buf, sz - 1)) >= 0) {
 399       char *q = memchr(buf, '\n', r);
 400       if (!q)
 401         q = buf + r;
 402       *q = 0;
 403     }
 404     close(fd[0]);
 405     waitpid(kid, &rc, 0);
 406     dstr_destroy(&d);
 407     if (r < 0 || rc != 0)
 408       goto fail_0;
 409     goto ok;
 410
 411     /* --- Tidy up when things go wrong --- */
 412
 413   fail_2:
 414     close(fd[0]);
 415     close(fd[1]);
 416   fail_1:
 417     dstr_destroy(&d);
 418   fail_0:
 419     return (-1);
 420   }
 421
 422   /* --- Read a passphrase from the terminal --- *
 423    *
 424    * Use the standard Catacomb passphrase-reading function, so it'll read the
 425    * passphrase from a file descriptor or something if the appropriate
 426    * environment variable is set.
 427    */
 428
 429   {
 430     dstr d = DSTR_INIT;
 431     int rc;
 432     dstr_putf(&d, "%s %s: ", msg, tag);
 433     rc = pixie_getpass(d.buf, buf, sz);
 434     dstr_destroy(&d);
 435     if (rc)
 436       return (rc);
 437     goto ok;
 438   }
 439
 440   /* --- Sort out the buffer --- *
 441    *
 442    * Strip leading spaces.
 443    */
 444
 445 ok: {
 446     char *p = buf;
 447     size_t len;
 448     while (isspace((unsigned char)*p))
 449       p++;
 450     len = strlen(p);
 451     memmove(buf, p, len);
 452     p[len] = 0;
 453   }
 454
 455   /* --- Done --- */
 456
 457   return (0);
 458 }
 459
 460 /* --- @p_get@ --- *
 461  *
 462  * Arguments:   @const char **q@ = where to store the result
 463  *              @const char *tag@ = pointer to tag string
 464  *              @unsigned mode@ = reading mode (verify?)
 465  *              @time_t exp@ = expiry time suggestion
 466  *
 467  * Returns:     Zero if successful, @-1@ on a read failure, or @+1@ if the
 468  *              passphrase is missing and there is no fetcher.  (This will
 469  *              always happen if there is no fetcher and @mode@ is
 470  *              @PMODE_VERIFY@.
 471  *
 472  * Use:         Reads a passphrase from somewhere.
 473  */
 474
 475 static int p_get(const char **q, const char *tag, unsigned mode, time_t exp)
 476 {
 477 #define LBUFSZ 1024
 478
 479   phrase *p;
 480   char *pp = 0;
 481
 482   /* --- Write a log message --- */
 483
 484   if (verbose > 1)
 485     pxlog("passphrase `%s' requested", tag);
 486
 487   /* --- If there is no fetcher, life is simpler --- */
 488
 489   if (!(flags & F_FETCH)) {
 490     if (mode == PMODE_VERIFY)
 491       return (+1);
 492     if ((p = p_find(tag)) == 0)
 493       return (+1);
 494     *q = p->p;
 495     return (0);
 496   }
 497
 498   /* --- Try to find the phrase --- */
 499
 500   if (mode == PMODE_VERIFY)
 501     p_flush(tag);
 502   if (mode == PMODE_VERIFY || (p = p_find(tag)) == 0) {
 503     if ((pp = p_alloc(LBUFSZ)) == 0)
 504       goto fail;
 505     if (p_request(mode == PMODE_READ ? "Passphrase" : "New passphrase",
 506                   tag, pp, LBUFSZ) < 0)
 507       goto fail;
 508     p = p_add(tag, pp, exp);
 509     if (!p)
 510       goto fail;
 511   }
 512
 513   /* --- If verification is requested, verify the passphrase --- */
 514
 515   if (mode == PMODE_VERIFY) {
 516     if (!pp && (pp = p_alloc(LBUFSZ)) == 0)
 517       goto fail;
 518     if (p_request("Verify passphrase", tag, pp, LBUFSZ) < 0)
 519       goto fail;
 520     if (strcmp(pp, p->p) != 0) {
 521       if (verbose)
 522         pxlog("passphrases for `%s' don't match", tag);
 523       p_free(p);
 524       goto fail;
 525     }
 526   }
 527
 528   /* --- Tidy up and return the passphrase --- */
 529
 530   if (pp) {
 531     memset(pp, 0, LBUFSZ);
 532     l_free(&lm, pp);
 533   }
 534   *q = p->p;
 535   return (0);
 536
 537   /* --- Tidy up if things went wrong --- */
 538
 539 fail:
 540   if (pp) {
 541     memset(pp, 0, LBUFSZ);
 542     l_free(&lm, pp);
 543   }
 544   return (-1);
 545
 546 #undef LBUFSZ
 547 }
 548
 549 /*----- Server command parsing --------------------------------------------*/
 550
 551 /* --- Data structures --- */
 552
 553 typedef struct pixserv {
 554   selbuf b;
 555   int fd;
 556   sel_timer timer;
 557   unsigned f;
 558 } pixserv;
 559
 560 #define px_stdin 1u
 561
 562 #define PIXSERV_TIMEOUT 30
 563
 564 /* --- @pixserv_expire@ --- *
 565  *
 566  * Arguments:   @struct timeval *tv@ = pointer to current time
 567  *              @void *p@ = pointer to server block
 568  *
 569  * Returns:     ---
 570  *
 571  * Use:         Expires a pixie connection if the remote end decides he's not
 572  *              interested any more.
 573  */
 574
 575 static void pixserv_expire(struct timeval *tv, void *p)
 576 {
 577   pixserv *px = p;
 578   if (px->fd != px->b.reader.fd)
 579     close(px->fd);
 580   selbuf_destroy(&px->b);
 581   close(px->b.reader.fd);
 582   DESTROY(px);
 583 }
 584
 585 /* --- @pixserv_write@ --- *
 586  *
 587  * Arguments:   @pixserv *px@ = pointer to server block
 588  *              @const char *p@ = pointer to skeleton string
 589  *              @...@ = other arguments to fill in
 590  *
 591  * Returns:     Zero on success, @-1@ on error.
 592  *
 593  * Use:         Formats a string and emits it to the output file.
 594  */
 595
 596 static int PRINTF_LIKE(2, 3) pixserv_write(pixserv *px, const char *p, ...)
 597 {
 598   dstr d = DSTR_INIT;
 599   va_list ap;
 600   int rc;
 601
 602   va_start(ap, p);
 603   dstr_vputf(&d, p, &ap);
 604   rc = write(px->fd, d.buf, d.len);
 605   va_end(ap);
 606   dstr_destroy(&d);
 607   if (rc < 0) {
 608     pxlog("failed to write to client: %s (closing)", strerror(errno));
 609     return (-1);
 610   }
 611   return (0);
 612 }
 613
 614 /* --- @pixserv_timeout@ --- *
 615  *
 616  * Arguments:   @const char *p@ = pointer to timeout string
 617  *
 618  * Returns:     Timeout in seconds.
 619  *
 620  * Use:         Translates a string to a timeout value in seconds.
 621  */
 622
 623 static unsigned long pixserv_timeout(const char *p)
 624 {
 625   unsigned long t;
 626   char *q;
 627
 628   if (!p)
 629     return (timeout);
 630
 631   t = strtoul(p, &q, 0);
 632   switch (*q) {
 633     case 'd': t *= 24;
 634     case 'h': t *= 60;
 635     case 'm': t *= 60;
 636     case 's': if (q[1] != 0)
 637       default:    t = 0;
 638     case 0:   break;
 639   }
 640   return (t);
 641 }
 642
 643 /* --- @pixserv_line@ --- *
 644  *
 645  * Arguments:   @char *s@ = pointer to the line read
 646  *              @size_t len@ = length of the line
 647  *              @void *p@ = pointer to server block
 648  *
 649  * Returns:     ---
 650  *
 651  * Use:         Handles a line read from the client.
 652  */
 653
 654 static void pixserv_line(char *s, size_t len, void *p)
 655 {
 656   pixserv *px = p;
 657   char *q, *qq;
 658   unsigned mode;
 659
 660   /* --- Handle an end-of-file --- */
 661
 662   if (!(px->f & px_stdin))
 663     sel_rmtimer(&px->timer);
 664   if (!s) goto close;
 665
 666   /* --- Fiddle the timeout --- */
 667
 668   if (!(px->f & px_stdin)) {
 669     struct timeval tv;
 670     gettimeofday(&tv, 0);
 671     tv.tv_sec += PIXSERV_TIMEOUT;
 672     sel_addtimer(&sel, &px->timer, &tv, pixserv_expire, px);
 673   }
 674
 675   /* --- Scan out the first word --- */
 676
 677   if ((q = str_getword(&s)) == 0)
 678     return;
 679   for (qq = q; *qq; qq++)
 680     *qq = tolower((unsigned char)*qq);
 681
 682   /* --- Handle a help request --- */
 683
 684   if (strcmp(q, "help") == 0) {
 685     if (pixserv_write(px, "\
 686 INFO Commands supported:\n\
 687 INFO HELP\n\
 688 INFO LIST\n\
 689 INFO PASS tag [expire]\n\
 690 INFO VERIFY tag [expire]\n\
 691 INFO FLUSH [tag]\n\
 692 INFO SET tag [expire] -- phrase\n\
 693 INFO QUIT\n\
 694 OK\n\
 695 "))
 696       goto close;
 697   }
 698
 699   /* --- List the passphrases --- */
 700
 701   else if (strcmp(q, "list") == 0) {
 702     phrase *p;
 703
 704     for (p = p_head; p; p = p->next) {
 705       if (!p->t) {
 706         if (pixserv_write(px, "ITEM %s no-expire\n", p->tag)) goto close;
 707       } else {
 708         struct timeval tv;
 709         gettimeofday(&tv, 0);
 710         TV_SUB(&tv, &p->timer.tv, &tv);
 711         if (pixserv_write(px, "ITEM %s %lu\n",
 712                           p->tag, (unsigned long)tv.tv_sec))
 713           goto close;
 714       }
 715     }
 716     if (pixserv_write(px, "OK\n")) goto close;
 717   }
 718
 719   /* --- Request a passphrase --- */
 720
 721   else if ((mode = PMODE_READ, strcmp(q, "pass") == 0) ||
 722            (mode = PMODE_VERIFY, strcmp(q, "verify") == 0)) {
 723     unsigned long t;
 724     const char *p;
 725     int rc;
 726
 727     if ((q = str_getword(&s)) == 0)
 728       pixserv_write(px, "FAIL missing tag\n");
 729     else if ((t = pixserv_timeout(s)) == 0)
 730       pixserv_write(px, "FAIL bad timeout\n");
 731     else {
 732       rc = p_get(&p, q, mode, t > timeout ? timeout : t);
 733       switch (rc) {
 734         case 0:
 735           if (pixserv_write(px, "OK %s\n", p)) goto close;
 736           break;
 737         case -1:
 738           if (pixserv_write(px, "FAIL error reading passphrase\n"))
 739             goto close;
 740           break;
 741         case +1:
 742           if (pixserv_write(px, "MISSING\n")) goto close;
 743           break;
 744       }
 745     }
 746   }
 747
 748   /* --- Flush existing passphrases --- */
 749
 750   else if (strcmp(q, "flush") == 0) {
 751     q = str_getword(&s);
 752     p_flush(q);
 753     if (pixserv_write(px, "OK\n")) goto close;
 754   }
 755
 756   /* --- Set a passphrase --- */
 757
 758   else if (strcmp(q, "set") == 0) {
 759     char *tag;
 760     unsigned long t;
 761     if ((tag = str_getword(&s)) == 0) {
 762       if (pixserv_write(px, "FAIL missing tag\n")) goto close;
 763     } else if ((q = str_getword(&s)) == 0) {
 764       if (pixserv_write(px, "FAIL no passphrase\n")) goto close;
 765     } else {
 766       if (strcmp(q, "--") != 0) {
 767         t = pixserv_timeout(q);
 768         q = str_getword(&s);
 769       } else
 770         t = pixserv_timeout(0);
 771       if (!q) {
 772         if (pixserv_write(px, "FAIL no passphrase\n")) goto close;
 773       } else if (strcmp(q, "--") != 0) {
 774         if (pixserv_write(px, "FAIL rubbish found before passphrase\n"))
 775           goto close;
 776       } else {
 777         p_flush(tag);
 778         p_add(tag, s, t);
 779         if (pixserv_write(px, "OK\n")) goto close;
 780       }
 781     }
 782   }
 783
 784   /* --- Shut the server down --- */
 785
 786   else if (strcmp(q, "quit") == 0) {
 787     if (verbose) {
 788       pxlog("%s client requested shutdown",
 789             px->f & px_stdin ? "local" : "remote");
 790     }
 791     if (pixserv_write(px, "OK\n")) goto close;
 792     exit(0);
 793   }
 794
 795   /* --- Report an error for other commands --- */
 796
 797   else {
 798     if (pixserv_write(px, "FAIL unknown command `%s'\n", q)) goto close;
 799   }
 800   return;
 801
 802 close:
 803   if (px->fd != px->b.reader.fd)
 804     close(px->fd);
 805   selbuf_destroy(&px->b);
 806   close(px->b.reader.fd);
 807 }
 808
 809 /* --- @pixserv_create@ --- *
 810  *
 811  * Arguments:   @int fd@ = file descriptor to read from
 812  *              @int ofd@ = file descriptor to write to
 813  *
 814  * Returns:     Pointer to the new connection.
 815  *
 816  * Use:         Creates a new Pixie server instance for a new connection.
 817  */
 818
 819 static pixserv *pixserv_create(int fd, int ofd)
 820 {
 821   pixserv *px = CREATE(pixserv);
 822   struct timeval tv;
 823   fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 824   if (ofd != fd)
 825     fdflags(ofd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
 826   px->fd = ofd;
 827   selbuf_init(&px->b, &sel, fd, pixserv_line, px);
 828   px->b.b.a = arena_secure;
 829   selbuf_setsize(&px->b, 1024);
 830   gettimeofday(&tv, 0);
 831   tv.tv_sec += PIXSERV_TIMEOUT;
 832   sel_addtimer(&sel, &px->timer, &tv, pixserv_expire, px);
 833   px->f = 0;
 834   return (px);
 835 }
 836
 837 /* --- @pixserv_accept@ --- *
 838  *
 839  * Arguments:   @int fd@ = file descriptor
 840  *              @unsigned mode@ = what's happened
 841  *              @void *p@ = an uninteresting argument
 842  *
 843  * Returns:     ---
 844  *
 845  * Use:         Accepts a new connection.
 846  */
 847
 848 static void pixserv_accept(int fd, unsigned mode, void *p)
 849 {
 850   int nfd;
 851   struct sockaddr_un sun;
 852   socklen_t sunsz = sizeof(sun);
 853
 854   if (mode != SEL_READ)
 855     return;
 856   if ((nfd = accept(fd, (struct sockaddr *)&sun, &sunsz)) < 0) {
 857     if (verbose && errno != EAGAIN && errno != EWOULDBLOCK &&
 858         errno != ECONNABORTED && errno != EPROTO && errno != EINTR)
 859       pxlog("new connection failed: %s", strerror(errno));
 860     return;
 861   }
 862   pixserv_create(nfd, nfd);
 863 }
 864
 865 /*----- Setting up the server ---------------------------------------------*/
 866
 867 /* --- @unlinksocket@ --- *
 868  *
 869  * Arguments:   ---
 870  *
 871  * Returns:     ---
 872  *
 873  * Use:         Tidies up the socket when it's finished with.
 874  */
 875
 876 static char *sockpath;
 877
 878 static void unlinksocket(void)
 879 {
 880   unlink(sockpath);
 881   l_purge(&lm);
 882 }
 883
 884 /* --- @pix_sigdie@ --- *
 885  *
 886  * Arguments:   @int sig@ = signal number
 887  *              @void *p@ = uninteresting argument
 888  *
 889  * Returns:     ---
 890  *
 891  * Use:         Shuts down the program after a fatal signal.
 892  */
 893
 894 static void pix_sigdie(int sig, void *p)
 895 {
 896   if (verbose) {
 897     char *p;
 898     char buf[20];
 899
 900     switch (sig) {
 901       case SIGTERM:     p = "SIGTERM"; break;
 902       case SIGINT:      p = "SIGINT"; break;
 903       default:
 904         sprintf(buf, "signal %i", sig);
 905         p = buf;
 906         break;
 907     }
 908     pxlog("shutting down on %s", p);
 909   }
 910   exit(0);
 911 }
 912
 913 /* --- @pix_sigflush@ --- *
 914  *
 915  * Arguments:   @int sig@ = signal number
 916  *              @void *p@ = uninteresting argument
 917  *
 918  * Returns:     ---
 919  *
 920  * Use:         Flushes the passphrase cache on receipt of a signal.
 921  */
 922
 923 static void pix_sigflush(int sig, void *p)
 924 {
 925   if (verbose) {
 926     char *p;
 927     char buf[20];
 928
 929     switch (sig) {
 930       case SIGHUP:      p = "SIGHUP"; break;
 931       case SIGQUIT:     p = "SIGQUIT"; break;
 932       default:
 933         sprintf(buf, "signal %i", sig);
 934         p = buf;
 935         break;
 936     }
 937     pxlog("received %s; flushing passphrases", p);
 938   }
 939   p_flush(0);
 940 }
 941
 942 /* --- @pix_setup@ --- *
 943  *
 944  * Arguments:   @struct sockaddr_un *sun@ = pointer to address to use
 945  *              @size_t sz@ = size of socket address
 946  *
 947  * Returns:     ---
 948  *
 949  * Use:         Sets up the pixie's Unix-domain socket.
 950  */
 951
 952 static void pix_setup(struct sockaddr_un *sun, size_t sz)
 953 {
 954   int fd;
 955
 956   /* --- Set up the parent directory --- */
 957
 958   {
 959     char *p = sun->sun_path;
 960     char *q = strrchr(p, '/');
 961
 962     if (q) {
 963       dstr d = DSTR_INIT;
 964       struct stat st;
 965
 966       DPUTM(&d, p, q - p);
 967       DPUTZ(&d);
 968
 969       mkdir(d.buf, 0700);
 970       if (stat(d.buf, &st))
 971         die(1, "couldn't stat `%s': %s", d.buf, strerror(errno));
 972       if (!S_ISDIR(st.st_mode))
 973         die(1, "object `%s' isn't a directory", d.buf);
 974       if (st.st_mode & 0077)
 975         die(1, "parent directory `%s' has group or world access", d.buf);
 976       dstr_destroy(&d);
 977     }
 978   }
 979
 980   /* --- Initialize the socket --- */
 981
 982   {
 983     int n = 5;
 984     int e;
 985
 986     umask(0077);
 987   again:
 988     if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
 989       die(1, "couldn't create socket: %s", strerror(errno));
 990     if (bind(fd, (struct sockaddr *)sun, sz) < 0) {
 991       e = errno;
 992       if (errno != EADDRINUSE)
 993         die(1, "couldn't bind to address: %s", strerror(e));
 994       if (!n)
 995         die(1, "too many retries; giving up");
 996       n--;
 997       if (connect(fd, (struct sockaddr *)sun, sz)) {
 998         struct stat st;
 999         if (errno != ECONNREFUSED)
1000           die(1, "couldn't bind to address: %s", strerror(e));
1001         if (stat(sun->sun_path, &st))
1002           die(1, "couldn't stat `%s': %s", sun->sun_path, strerror(errno));
1003         if (!S_ISSOCK(st.st_mode))
1004           die(1, "object `%s' isn't a socket", sun->sun_path);
1005         if (verbose)
1006           pxlog("stale socket found; removing it");
1007         unlink(sun->sun_path);
1008         close(fd);
1009       } else if (flags & F_REPLACE) {
1010         if (verbose)
1011           pxlog("server already running; shutting it down");
1012         if (write(fd, "QUIT\n", 5) < 0) {
1013           die(EXIT_FAILURE, "failed to shut down old server: %s",
1014               strerror(errno));
1015         }
1016         sleep(1);
1017         close(fd);
1018       } else
1019         die(EXIT_FAILURE, "pixie already running; not starting");
1020       goto again;
1021     }
1022     chmod(sun->sun_path, 0600);
1023     fdflags(fd, O_NONBLOCK, O_NONBLOCK, FD_CLOEXEC, FD_CLOEXEC);
1024     if (listen(fd, 5))
1025       die(1, "couldn't listen on socket: %s", strerror(errno));
1026   }
1027
1028   /* --- Set up the rest of the server --- */
1029
1030   {
1031     static sel_file serv;
1032     sockpath = sun->sun_path;
1033     atexit(unlinksocket);
1034     sel_initfile(&sel, &serv, fd, SEL_READ, pixserv_accept, 0);
1035     sel_addfile(&serv);
1036   }
1037 }
1038
1039 /*----- Client support code -----------------------------------------------*/
1040
1041 /* --- Variables --- */
1042
1043 static selbuf c_server, c_client;
1044 static unsigned c_flags = 0;
1045
1046 #define cf_uclose 1u
1047 #define cf_sclose 2u
1048 #define cf_cooked 4u
1049
1050 /* --- Line handler functions --- */
1051
1052 static void c_uline(char *s, size_t len, void *p)
1053 {
1054   if (!s) {
1055     selbuf_destroy(&c_client);
1056     shutdown(c_server.reader.fd, 1);
1057     c_flags |= cf_uclose;
1058   } else {
1059     s[len++] = '\n';
1060     if (write(c_server.reader.fd, s, len) < 0)
1061       die(EXIT_FAILURE, "failed to read from stdin: %s", strerror(errno));
1062   }
1063 }
1064
1065 static void c_sline(char *s, size_t len, void *p)
1066 {
1067   if (!s) {
1068     selbuf_destroy(&c_server);
1069     if (!(c_flags & cf_uclose)) {
1070       moan("server closed the connection");
1071       selbuf_destroy(&c_client);
1072     }
1073     exit(0);
1074   }
1075   if (!(c_flags & cf_cooked))
1076     puts(s);
1077   else {
1078     char *q = str_getword(&s);
1079     if (strcmp(q, "FAIL") == 0)
1080       die(1, "%s", s);
1081     else if (strcmp(q, "INFO") == 0 ||
1082              strcmp(q, "ITEM") == 0)
1083       puts(s);
1084     else if (strcmp(q, "OK") == 0) {
1085       if (s && *s) puts(s);
1086     } else if (strcmp(q, "MISSING") == 0)
1087       ;
1088     else
1089       moan("unexpected output: %s %s", q, s);
1090   }
1091 }
1092
1093 /* --- @pix_client@ --- *
1094  *
1095  * Arguments:   @struct sockaddr_un *sun@ = pointer to socket address
1096  *              @size_t sz@ = size of socket address
1097  *              @char *argv[]@ = pointer to arguments to send
1098  *
1099  * Returns:     ---
1100  *
1101  * Use:         Performs client-side actions for the passphrase pixie.
1102  */
1103
1104 static void pix_client(struct sockaddr_un *sun, size_t sz, char *argv[])
1105 {
1106   int fd;
1107
1108   /* --- Dispose of locked memory --- */
1109
1110   l_destroy(&lm);
1111
1112   /* --- Open the socket --- */
1113
1114   if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0)
1115     die(1, "couldn't create socket: %s", strerror(errno));
1116   if (connect(fd, (struct sockaddr *)sun, sz))
1117     die(1, "couldn't connect to server: %s", strerror(errno));
1118   selbuf_init(&c_server, &sel, fd, c_sline, 0);
1119
1120   /* --- If there are any arguments, turn them into a string --- */
1121
1122   if (!*argv)
1123     selbuf_init(&c_client, &sel, STDIN_FILENO, c_uline, 0);
1124   else {
1125     dstr d = DSTR_INIT;
1126     DPUTS(&d, *argv++);
1127     while (*argv) {
1128       DPUTC(&d, ' ');
1129       DPUTS(&d, *argv++);
1130     }
1131     DPUTC(&d, '\n');
1132     if (write(fd, d.buf, d.len) < 0 || shutdown(fd, 1))
1133       die(EXIT_FAILURE, "failed to write command: %s", strerror(errno));
1134     c_flags |= cf_uclose | cf_cooked;
1135     dstr_destroy(&d);
1136   }
1137
1138   /* --- And repeat --- */
1139
1140   for (;;) {
1141     if (sel_select(&sel))
1142       die(EXIT_FAILURE, "select error: %s", strerror(errno));
1143   }
1144 }
1145
1146 /*----- Main code ---------------------------------------------------------*/
1147
1148 /* --- @help@, @version@, @usage@ --- *
1149  *
1150  * Arguments:   @FILE *fp@ = stream to write on
1151  *
1152  * Returns:     ---
1153  *
1154  * Use:         Emit helpful messages.
1155  */
1156
1157 static void usage(FILE *fp)
1158 {
1159   pquis(fp, "\
1160 Usage:\n\
1161         $ [-qvfidl] [-c COMMAND] [-t TIMEOUT] [-s SOCKET]\n\
1162         $ [-s SOCKET] -C [COMMAND ARGS...]\n\
1163         $ [-s SOCKET] -P[P] TAG\n\
1164 ");
1165 }
1166
1167 static void version(FILE *fp)
1168 {
1169   pquis(fp, "$, Catacomb version " VERSION "\n");
1170 }
1171
1172 static void help(FILE *fp)
1173 {
1174   version(fp);
1175   fputc('\n', fp);
1176   usage(fp);
1177   pquis(fp, "\n\
1178 The Catacomb passphrase pixie collects and caches passphrases used to\n\
1179 protect important keys.  Options provided:\n\
1180 \n\
1181 -h, --help              Show this help text.\n\
1182 -V, --version           Show the program's version number.\n\
1183 -u, --usage             Show a (very) terse usage summary.\n\
1184 \n\
1185 -C, --client            Connect to a running pixie as a client.\n\
1186 -P, --passphrase        Request passphrase TAG and print to stdout.\n\
1187 -PP, --verify-passphrase\n\
1188                         Verify passphrase TAG and print to stdout.\n\
1189 \n\
1190 -q, --quiet             Emit fewer log messages.\n\
1191 -v, --version           Emit more log messages.\n\
1192 -s, --socket=FILE       Name the pixie's socket.\n\
1193 -r, --replace           Replace existing pixie, if one is running.\n\
1194 -c, --command=COMMAND   Shell command to read a passphrase.\n\
1195 -f, --fetch             Fetch passphrases from the terminal.\n\
1196 -t, --timeout=TIMEOUT   Length of time to retain a passphrase in memory.\n\
1197 -i, --interactive       Allow commands to be typed interactively.\n\
1198 -d, --daemon            Fork into the background after initialization.\n\
1199 -l, --syslog            Emit log messages to the system log.\n\
1200 \n\
1201 The COMMAND may contain `%m' and `%t' markers which are replaced by a\n\
1202 prompt message and the passphrase tag respectively.  The TIMEOUT is an\n\
1203 integer, optionally followed by `d', `h', `m' or `s' to specify units of\n\
1204 days, hours, minutes or seconds respectively.\n\
1205 \n\
1206 In client mode, if a command is specified on the command line, it is sent\n\
1207 to the running server; otherwise the program reads requests from stdin.\n\
1208 Responses from the pixie are written to stdout.  Send a HELP request for\n\
1209 a quick summary of the pixie communication protocol.\n\
1210 ");
1211 }
1212
1213 /* --- @main@ --- *
1214  *
1215  * Arguments:   @int argc@ = number of arguments
1216  *              @char *argv[]@ = vector of argument values
1217  *
1218  * Returns:     Zero if OK.
1219  *
1220  * Use:         Main program.  Listens on a socket and responds with a PGP
1221  *              passphrase when asked.
1222  */
1223
1224 int main(int argc, char *argv[])
1225 {
1226   char *path = 0;
1227   struct sockaddr_un *sun;
1228   size_t sz;
1229   unsigned f = 0;
1230
1231 #define f_bogus 1u
1232 #define f_client 2u
1233 #define f_stdin 4u
1234 #define f_daemon 8u
1235 #define f_syslog 16u
1236 #define f_fetch 32u
1237 #define f_verify 64u
1238
1239   /* --- Initialize libraries --- */
1240
1241   ego(argv[0]);
1242   sub_init();
1243
1244   /* --- Set up the locked memory area --- */
1245
1246   l_init(&lm, 16384);
1247   setuid(getuid());
1248
1249   /* --- Parse command line arguments --- */
1250
1251   for (;;) {
1252     static struct option opts[] = {
1253
1254       /* --- Standard GNUy help options --- */
1255
1256       { "help",         0,              0,      'h' },
1257       { "version",      0,              0,      'V' },
1258       { "usage",        0,              0,      'u' },
1259
1260       /* --- Other options --- */
1261
1262       { "quiet",        0,              0,      'q' },
1263       { "verbose",      0,              0,      'v' },
1264       { "client",       0,              0,      'C' },
1265       { "passphrase",   0,              0,      'P' },
1266       { "verify-passphrase",    0,      0,      '+' },
1267       { "socket",       OPTF_ARGREQ,    0,      's' },
1268       { "replace",      0,              0,      'r' },
1269       { "command",      OPTF_ARGREQ,    0,      'c' },
1270       { "fetch",        0,              0,      'f' },
1271       { "timeout",      OPTF_ARGREQ,    0,      't' },
1272       { "interactive",  0,              0,      'i' },
1273       { "stdin",        0,              0,      'i' },
1274       { "daemon",       0,              0,      'd' },
1275       { "log",          0,              0,      'l' },
1276       { "syslog",       0,              0,      'l' },
1277
1278       /* --- Magic terminator --- */
1279
1280       { 0,              0,              0,      0 }
1281     };
1282
1283     int i = mdwopt(argc, argv, "hVuqvCPs:rc:ft:idl", opts, 0, 0, 0);
1284     if (i < 0)
1285       break;
1286
1287     switch (i) {
1288
1289       /* --- GNUy help options --- */
1290
1291       case 'h':
1292         help(stdout);
1293         exit(0);
1294       case 'V':
1295         version(stdout);
1296         exit(0);
1297       case 'u':
1298         usage(stdout);
1299         exit(0);
1300
1301       /* --- Other interesting things --- */
1302
1303       case 'q':
1304         if (verbose)
1305           verbose--;
1306         break;
1307       case 'v':
1308         verbose++;
1309         break;
1310       case 'C':
1311         f |= f_client;
1312         f &= ~f_fetch;
1313         break;
1314       case 'P':
1315         if (!(f & f_fetch))
1316           f |= f_fetch;
1317         else
1318           f |= f_verify;
1319         break;
1320       case '+':
1321         f |= f_fetch | f_verify;
1322         f &= ~f_client;
1323         break;
1324       case 's':
1325         path = optarg;
1326         break;
1327       case 'r':
1328         flags |= F_REPLACE;
1329         break;
1330       case 't':
1331         if ((timeout = pixserv_timeout(optarg)) == 0)
1332           die(1, "bad timeout `%s'", optarg);
1333         break;
1334       case 'c':
1335         command = optarg;
1336         flags |= F_FETCH;
1337         break;
1338       case 'f':
1339         flags |= F_FETCH;
1340         break;
1341       case 'i':
1342         f |= f_stdin;
1343         break;
1344       case 'd':
1345         f |= f_daemon;
1346         break;
1347       case 'l':
1348         f |= f_syslog;
1349         break;
1350
1351       /* --- Something else --- */
1352
1353       default:
1354         f |= f_bogus;
1355         break;
1356     }
1357   }
1358
1359   if (f & f_bogus ||
1360       (optind < argc && !(f & (f_client|f_fetch))) ||
1361       ((f & f_fetch) && optind != argc - 1)) {
1362     usage(stderr);
1363     exit(1);
1364   }
1365
1366   /* --- Handle request for a passphrase --- */
1367
1368   if (f & f_fetch) {
1369     char *buf = l_alloc(&lm, 1024);
1370     passphrase_connect(path);
1371     if (passphrase_read(argv[optind],
1372                         (f & f_verify) ? PMODE_VERIFY : PMODE_READ,
1373                         buf, 1024))
1374       die(1, "failed to read passphrase: %s", strerror(errno));
1375     puts(buf);
1376     return (0);
1377   }
1378
1379   /* --- Set up the socket address --- */
1380
1381   sun = pixie_address(path, &sz);
1382
1383   /* --- Initialize selectory --- */
1384
1385   sel_init(&sel);
1386   signal(SIGPIPE, SIG_IGN);
1387
1388   /* --- Be a client if a client's wanted --- */
1389
1390   if (f & f_client)
1391     pix_client(sun, sz, argv + optind);
1392
1393   /* --- Open the syslog if requested --- */
1394
1395   if (f & f_syslog) {
1396     flags |= F_SYSLOG;
1397     openlog(QUIS, 0, LOG_DAEMON);
1398   }
1399
1400   /* --- Check on the locked memory area --- */
1401
1402   {
1403     dstr d = DSTR_INIT;
1404     int rc = l_report(&lm, &d);
1405     if (rc < 0)
1406       die(EXIT_FAILURE, "%s", d.buf);
1407     else if (rc && verbose) {
1408       pxlog("%s", d.buf);
1409       pxlog("couldn't lock passphrase buffer");
1410     }
1411     dstr_destroy(&d);
1412     arena_setsecure(&lm.a);
1413   }
1414
1415   /* --- Set signal behaviours --- */
1416
1417   {
1418     static sig sigint, sigterm, sigquit, sighup;
1419     struct sigaction sa;
1420     sig_init(&sel);
1421     sigaction(SIGINT, 0, &sa);
1422     if (sa.sa_handler != SIG_IGN)
1423       sig_add(&sigint, SIGINT, pix_sigdie, 0);
1424     sig_add(&sigterm, SIGTERM, pix_sigdie, 0);
1425     sig_add(&sigquit, SIGQUIT, pix_sigflush, 0);
1426     sig_add(&sighup, SIGHUP, pix_sigflush, 0);
1427   }
1428
1429   /* --- Set up the server --- */
1430
1431   pix_setup(sun, sz);
1432   if (f & f_stdin) {
1433     pixserv *px = pixserv_create(STDIN_FILENO, STDOUT_FILENO);
1434     sel_rmtimer(&px->timer);
1435     px->f |= px_stdin;
1436   }
1437
1438   /* --- Fork into the background if requested --- */
1439
1440   if (f & f_daemon) {
1441     pid_t kid;
1442
1443     if (((f & f_stdin) &&
1444          (isatty(STDIN_FILENO) || isatty(STDOUT_FILENO))) ||
1445         (!command && (flags & F_FETCH)))
1446       die(1, "can't become a daemon if terminal required");
1447
1448     if ((kid = fork()) < 0)
1449       die(1, "fork failed: %s", strerror(errno));
1450     if (kid)
1451       _exit(0);
1452 #ifdef TIOCNOTTY
1453     {
1454       int fd;
1455       if ((fd = open("/dev/tty", O_RDONLY)) >= 0) {
1456         ioctl(fd, TIOCNOTTY);
1457         close(fd);
1458       }
1459     }
1460 #endif
1461     DISCARD(chdir("/"));
1462     setsid();
1463
1464     if (fork() != 0)
1465       _exit(0);
1466   }
1467
1468   if (verbose)
1469     pxlog("initialized ok");
1470
1471   {
1472     int selerr = 0;
1473     for (;;) {
1474       if (!sel_select(&sel))
1475         selerr = 0;
1476       else if (errno != EINTR && errno != EAGAIN) {
1477         pxlog("error from select: %s", strerror(errno));
1478         selerr++;
1479         if (selerr > 8) {
1480           pxlog("too many consecutive select errors: bailing out");
1481           exit(EXIT_FAILURE);
1482         }
1483       }
1484     }
1485   }
1486   return (0);
1487 }
1488
1489 /*----- That's all, folks -------------------------------------------------*/