scheduler/process.c

   1 /*
   2  * "$Id: process.c 7256 2008-01-25 00:48:54Z mike $"
   3  *
   4  *   Process management routines for the CUPS scheduler.
   5  *
   6  *   Copyright 2007-2011 by Apple Inc.
   7  *   Copyright 1997-2007 by Easy Software Products, all rights reserved.
   8  *
   9  *   These coded instructions, statements, and computer programs are the
  10  *   property of Apple Inc. and are protected by Federal copyright
  11  *   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
  12  *   which should have been included with this file.  If this file is
  13  *   file is missing or damaged, see the license at "http://www.cups.org/".
  14  *
  15  * Contents:
  16  *
  17  *   cupsdCreateProfile()  - Create an execution profile for a subprocess.
  18  *   cupsdDestroyProfile() - Delete an execution profile.
  19  *   cupsdEndProcess()     - End a process.
  20  *   cupsdFinishProcess()  - Finish a process and get its name.
  21  *   cupsdStartProcess()   - Start a process.
  22  *   compare_procs()       - Compare two processes.
  23  *   cupsd_requote()       - Make a regular-expression version of a string.
  24  */
  25
  26 /*
  27  * Include necessary headers...
  28  */
  29
  30 #include "cupsd.h"
  31 #include <grp.h>
  32 #ifdef __APPLE__
  33 #  include <libgen.h>
  34 #endif /* __APPLE__ */
  35
  36
  37 /*
  38  * Process structure...
  39  */
  40
  41 typedef struct
  42 {
  43   int   pid,                            /* Process ID */
  44         job_id;                         /* Job associated with process */
  45   char  name[1];                        /* Name of process */
  46 } cupsd_proc_t;
  47
  48
  49 /*
  50  * Local globals...
  51  */
  52
  53 static cups_array_t     *process_array = NULL;
  54
  55
  56 /*
  57  * Local functions...
  58  */
  59
  60 static int      compare_procs(cupsd_proc_t *a, cupsd_proc_t *b);
  61 #ifdef HAVE_SANDBOX_H
  62 static char     *cupsd_requote(char *dst, const char *src, size_t dstsize);
  63 #endif /* HAVE_SANDBOX_H */
  64
  65
  66 /*
  67  * 'cupsdCreateProfile()' - Create an execution profile for a subprocess.
  68  */
  69
  70 void *                                  /* O - Profile or NULL on error */
  71 cupsdCreateProfile(int job_id)          /* I - Job ID or 0 for none */
  72 {
  73 #ifdef HAVE_SANDBOX_H
  74   cups_file_t   *fp;                    /* File pointer */
  75   char          profile[1024],          /* File containing the profile */
  76                 cache[1024],            /* Quoted CacheDir */
  77                 request[1024],          /* Quoted RequestRoot */
  78                 root[1024],             /* Quoted ServerRoot */
  79                 temp[1024];             /* Quoted TempDir */
  80
  81
  82   if (!UseProfiles)
  83   {
  84    /*
  85     * Only use sandbox profiles as root...
  86     */
  87
  88     cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = NULL",
  89                     job_id);
  90
  91     return (NULL);
  92   }
  93
  94   if ((fp = cupsTempFile2(profile, sizeof(profile))) == NULL)
  95   {
  96     cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = NULL",
  97                     job_id);
  98     cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to create security profile: %s",
  99                     strerror(errno));
 100     return (NULL);
 101   }
 102
 103   fchown(cupsFileNumber(fp), RunUser, Group);
 104   fchmod(cupsFileNumber(fp), 0640);
 105
 106   cupsd_requote(cache, CacheDir, sizeof(cache));
 107   cupsd_requote(request, RequestRoot, sizeof(request));
 108   cupsd_requote(root, ServerRoot, sizeof(root));
 109   cupsd_requote(temp, TempDir, sizeof(temp));
 110
 111   cupsFilePuts(fp, "(version 1)\n");
 112   if (LogLevel >= CUPSD_LOG_DEBUG)
 113     cupsFilePuts(fp, "(debug deny)\n");
 114   cupsFilePuts(fp, "(allow default)\n");
 115   cupsFilePrintf(fp,
 116                  "(deny file-write* file-read-data file-read-metadata\n"
 117                  "  (regex"
 118                  " #\"^%s$\""           /* RequestRoot */
 119                  " #\"^%s/\""           /* RequestRoot/... */
 120                  "))\n",
 121                  request, request);
 122   if (!RunUser)
 123     cupsFilePuts(fp,
 124                  "(deny file-write* file-read-data file-read-metadata\n"
 125                  "  (regex"
 126                  " #\"^/Users$\""
 127                  " #\"^/Users/\""
 128                  "))\n");
 129   cupsFilePrintf(fp,
 130                  "(deny file-write*\n"
 131                  "  (regex"
 132                  " #\"^%s$\""           /* ServerRoot */
 133                  " #\"^%s/\""           /* ServerRoot/... */
 134                  " #\"^/private/etc$\""
 135                  " #\"^/private/etc/\""
 136                  " #\"^/usr/local/etc$\""
 137                  " #\"^/usr/local/etc/\""
 138                  " #\"^/Library$\""
 139                  " #\"^/Library/\""
 140                  " #\"^/System$\""
 141                  " #\"^/System/\""
 142                  "))\n",
 143                  root, root);
 144   /* Specifically allow applications to stat RequestRoot */
 145   cupsFilePrintf(fp,
 146                  "(allow file-read-metadata\n"
 147                  "  (regex"
 148                  " #\"^%s$\""           /* RequestRoot */
 149                  "))\n",
 150                  request);
 151   cupsFilePrintf(fp,
 152                  "(allow file-write* file-read-data file-read-metadata\n"
 153                  "  (regex"
 154                  " #\"^%s$\""           /* TempDir */
 155                  " #\"^%s/\""           /* TempDir/... */
 156                  " #\"^%s$\""           /* CacheDir */
 157                  " #\"^%s/\""           /* CacheDir/... */
 158                  " #\"^%s/Library$\""   /* RequestRoot/Library */
 159                  " #\"^%s/Library/\""   /* RequestRoot/Library/... */
 160                  " #\"^/Library/Application Support/\""
 161                  " #\"^/Library/Caches/\""
 162                  " #\"^/Library/Preferences/\""
 163                  " #\"^/Library/Printers/.*/\""
 164                  " #\"^/Users/Shared/\""
 165                  "))\n",
 166                  temp, temp, cache, cache, request, request);
 167   cupsFilePuts(fp,
 168                "(deny file-write*\n"
 169                "  (regex"
 170                " #\"^/Library/Printers/PPDs$\""
 171                " #\"^/Library/Printers/PPDs/\""
 172                " #\"^/Library/Printers/PPD Plugins$\""
 173                " #\"^/Library/Printers/PPD Plugins/\""
 174                "))\n");
 175   if (job_id)
 176   {
 177    /*
 178     * Allow job filters to read the spool file(s)...
 179     */
 180
 181     cupsFilePrintf(fp,
 182                    "(allow file-read-data file-read-metadata\n"
 183                    "  (regex #\"^%s/([ac]%05d|d%05d-[0-9][0-9][0-9])$\"))\n",
 184                    request, job_id, job_id);
 185   }
 186   else
 187   {
 188    /*
 189     * Allow email notifications from notifiers...
 190     */
 191
 192     cupsFilePuts(fp,
 193                  "(allow process-exec\n"
 194                  "  (literal \"/usr/sbin/sendmail\")\n"
 195                  "  (with no-sandbox)\n"
 196                  ")\n");
 197   }
 198
 199   cupsFileClose(fp);
 200
 201   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = \"%s\"",
 202                   job_id, profile);
 203   return ((void *)strdup(profile));
 204
 205 #else
 206   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = NULL",
 207                   job_id);
 208
 209   return (NULL);
 210 #endif /* HAVE_SANDBOX_H */
 211 }
 212
 213
 214 /*
 215  * 'cupsdDestroyProfile()' - Delete an execution profile.
 216  */
 217
 218 void
 219 cupsdDestroyProfile(void *profile)      /* I - Profile */
 220 {
 221   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDeleteProfile(profile=\"%s\")",
 222                   profile ? (char *)profile : "(null)");
 223
 224 #ifdef HAVE_SANDBOX_H
 225   if (profile)
 226   {
 227     unlink((char *)profile);
 228     free(profile);
 229   }
 230 #endif /* HAVE_SANDBOX_H */
 231 }
 232
 233
 234 /*
 235  * 'cupsdEndProcess()' - End a process.
 236  */
 237
 238 int                                     /* O - 0 on success, -1 on failure */
 239 cupsdEndProcess(int pid,                /* I - Process ID */
 240                 int force)              /* I - Force child to die */
 241 {
 242   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdEndProcess(pid=%d, force=%d)", pid,
 243                   force);
 244
 245   if (!pid)
 246     return (0);
 247   else if (force)
 248     return (kill(pid, SIGKILL));
 249   else
 250     return (kill(pid, SIGTERM));
 251 }
 252
 253
 254 /*
 255  * 'cupsdFinishProcess()' - Finish a process and get its name.
 256  */
 257
 258 const char *                            /* O - Process name */
 259 cupsdFinishProcess(int  pid,            /* I - Process ID */
 260                    char *name,          /* I - Name buffer */
 261                    int  namelen,        /* I - Size of name buffer */
 262                    int  *job_id)        /* O - Job ID pointer or NULL */
 263 {
 264   cupsd_proc_t  key,                    /* Search key */
 265                 *proc;                  /* Matching process */
 266
 267
 268   key.pid = pid;
 269
 270   if ((proc = (cupsd_proc_t *)cupsArrayFind(process_array, &key)) != NULL)
 271   {
 272     if (job_id)
 273       *job_id = proc->job_id;
 274
 275     strlcpy(name, proc->name, namelen);
 276     cupsArrayRemove(process_array, proc);
 277     free(proc);
 278   }
 279   else
 280   {
 281     if (job_id)
 282       *job_id = 0;
 283
 284     strlcpy(name, "unknown", namelen);
 285   }
 286
 287   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 288                   "cupsdFinishProcess(pid=%d, name=%p, namelen=%d, "
 289                   "job_id=%p(%d)) = \"%s\"", pid, name, namelen, job_id,
 290                   job_id ? *job_id : 0, name);
 291
 292   return (name);
 293 }
 294
 295
 296 /*
 297  * 'cupsdStartProcess()' - Start a process.
 298  */
 299
 300 int                                     /* O - Process ID or 0 */
 301 cupsdStartProcess(
 302     const char  *command,               /* I - Full path to command */
 303     char        *argv[],                /* I - Command-line arguments */
 304     char        *envp[],                /* I - Environment */
 305     int         infd,                   /* I - Standard input file descriptor */
 306     int         outfd,                  /* I - Standard output file descriptor */
 307     int         errfd,                  /* I - Standard error file descriptor */
 308     int         backfd,                 /* I - Backchannel file descriptor */
 309     int         sidefd,                 /* I - Sidechannel file descriptor */
 310     int         root,                   /* I - Run as root? */
 311     void        *profile,               /* I - Security profile to use */
 312     cupsd_job_t *job,                   /* I - Job associated with process */
 313     int         *pid)                   /* O - Process ID */
 314 {
 315   int           i;                      /* Looping var */
 316   const char    *exec_path = command;   /* Command to be exec'd */
 317   char          *real_argv[103],        /* Real command-line arguments */
 318                 cups_exec[1024];        /* Path to "cups-exec" program */
 319   int           user;                   /* Command UID */
 320   cupsd_proc_t  *proc;                  /* New process record */
 321 #if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
 322   struct sigaction action;              /* POSIX signal handler */
 323 #endif /* HAVE_SIGACTION && !HAVE_SIGSET */
 324 #if defined(__APPLE__)
 325   char          processPath[1024],      /* CFProcessPath environment variable */
 326                 linkpath[1024];         /* Link path for symlinks... */
 327   int           linkbytes;              /* Bytes for link path */
 328 #endif /* __APPLE__ */
 329
 330
 331   *pid = 0;
 332
 333  /*
 334   * Figure out the UID for the child process...
 335   */
 336
 337   if (RunUser)
 338     user = RunUser;
 339   else if (root)
 340     user = 0;
 341   else
 342     user = User;
 343
 344  /*
 345   * Check the permissions of the command we are running...
 346   */
 347
 348   if (_cupsFileCheck(command, _CUPS_FILE_CHECK_PROGRAM, !RunUser,
 349                      cupsdLogFCMessage, job ? job->printer : NULL))
 350     return (0);
 351
 352 #if defined(__APPLE__)
 353   if (envp)
 354   {
 355    /*
 356     * Add special voodoo magic for Mac OS X - this allows Mac OS X
 357     * programs to access their bundle resources properly...
 358     */
 359
 360     if ((linkbytes = readlink(command, linkpath, sizeof(linkpath) - 1)) > 0)
 361     {
 362      /*
 363       * Yes, this is a symlink to the actual program, nul-terminate and
 364       * use it...
 365       */
 366
 367       linkpath[linkbytes] = '\0';
 368
 369       if (linkpath[0] == '/')
 370         snprintf(processPath, sizeof(processPath), "CFProcessPath=%s",
 371                  linkpath);
 372       else
 373         snprintf(processPath, sizeof(processPath), "CFProcessPath=%s/%s",
 374                  dirname((char *)command), linkpath);
 375     }
 376     else
 377       snprintf(processPath, sizeof(processPath), "CFProcessPath=%s", command);
 378
 379     envp[0] = processPath;              /* Replace <CFProcessPath> string */
 380   }
 381 #endif  /* __APPLE__ */
 382
 383  /*
 384   * Use helper program when we have a sandbox profile...
 385   */
 386
 387   if (profile)
 388   {
 389     snprintf(cups_exec, sizeof(cups_exec), "%s/daemon/cups-exec", ServerBin);
 390
 391     real_argv[0] = cups_exec;
 392     real_argv[1] = profile;
 393     real_argv[2] = (char *)command;
 394
 395     for (i = 0;
 396          i < (int)(sizeof(real_argv) / sizeof(real_argv[0]) - 4) && argv[i];
 397          i ++)
 398       real_argv[i + 3] = argv[i];
 399
 400     real_argv[i + 3] = NULL;
 401
 402     argv      = real_argv;
 403     exec_path = cups_exec;
 404   }
 405
 406  /*
 407   * Block signals before forking...
 408   */
 409
 410   cupsdHoldSignals();
 411
 412   if ((*pid = fork()) == 0)
 413   {
 414    /*
 415     * Child process goes here...
 416     *
 417     * Update stdin/stdout/stderr as needed...
 418     */
 419
 420     if (infd != 0)
 421     {
 422       if (infd < 0)
 423         infd = open("/dev/null", O_RDONLY);
 424
 425       if (infd != 0)
 426       {
 427         dup2(infd, 0);
 428         close(infd);
 429       }
 430     }
 431
 432     if (outfd != 1)
 433     {
 434       if (outfd < 0)
 435         outfd = open("/dev/null", O_WRONLY);
 436
 437       if (outfd != 1)
 438       {
 439         dup2(outfd, 1);
 440         close(outfd);
 441       }
 442     }
 443
 444     if (errfd != 2)
 445     {
 446       if (errfd < 0)
 447         errfd = open("/dev/null", O_WRONLY);
 448
 449       if (errfd != 2)
 450       {
 451         dup2(errfd, 2);
 452         close(errfd);
 453       }
 454     }
 455
 456     if (backfd != 3 && backfd >= 0)
 457     {
 458       dup2(backfd, 3);
 459       close(backfd);
 460       fcntl(3, F_SETFL, O_NDELAY);
 461     }
 462
 463     if (sidefd != 4 && sidefd >= 0)
 464     {
 465       dup2(sidefd, 4);
 466       close(sidefd);
 467       fcntl(4, F_SETFL, O_NDELAY);
 468     }
 469
 470    /*
 471     * Change the priority of the process based on the FilterNice setting.
 472     * (this is not done for root processes...)
 473     */
 474
 475     if (!root)
 476       nice(FilterNice);
 477
 478    /*
 479     * Change user to something "safe"...
 480     */
 481
 482     if (!root && !RunUser)
 483     {
 484      /*
 485       * Running as root, so change to non-priviledged user...
 486       */
 487
 488       if (setgid(Group))
 489         exit(errno);
 490
 491       if (setgroups(1, &Group))
 492         exit(errno);
 493
 494       if (setuid(User))
 495         exit(errno);
 496     }
 497     else
 498     {
 499      /*
 500       * Reset group membership to just the main one we belong to.
 501       */
 502
 503       if (setgid(Group) && !RunUser)
 504         exit(errno);
 505
 506       if (setgroups(1, &Group) && !RunUser)
 507         exit(errno);
 508     }
 509
 510    /*
 511     * Change umask to restrict permissions on created files...
 512     */
 513
 514     umask(077);
 515
 516    /*
 517     * Unblock signals before doing the exec...
 518     */
 519
 520 #ifdef HAVE_SIGSET
 521     sigset(SIGTERM, SIG_DFL);
 522     sigset(SIGCHLD, SIG_DFL);
 523     sigset(SIGPIPE, SIG_DFL);
 524 #elif defined(HAVE_SIGACTION)
 525     memset(&action, 0, sizeof(action));
 526
 527     sigemptyset(&action.sa_mask);
 528     action.sa_handler = SIG_DFL;
 529
 530     sigaction(SIGTERM, &action, NULL);
 531     sigaction(SIGCHLD, &action, NULL);
 532     sigaction(SIGPIPE, &action, NULL);
 533 #else
 534     signal(SIGTERM, SIG_DFL);
 535     signal(SIGCHLD, SIG_DFL);
 536     signal(SIGPIPE, SIG_DFL);
 537 #endif /* HAVE_SIGSET */
 538
 539     cupsdReleaseSignals();
 540
 541    /*
 542     * Execute the command; if for some reason this doesn't work, log an error
 543     * exit with a non-zero value...
 544     */
 545
 546     if (envp)
 547       execve(exec_path, argv, envp);
 548     else
 549       execv(exec_path, argv);
 550
 551     perror(command);
 552
 553     exit(1);
 554   }
 555   else if (*pid < 0)
 556   {
 557    /*
 558     * Error - couldn't fork a new process!
 559     */
 560
 561     cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to fork %s - %s.", command,
 562                     strerror(errno));
 563
 564     *pid = 0;
 565   }
 566   else
 567   {
 568     if (!process_array)
 569       process_array = cupsArrayNew((cups_array_func_t)compare_procs, NULL);
 570
 571     if (process_array)
 572     {
 573       if ((proc = calloc(1, sizeof(cupsd_proc_t) + strlen(command))) != NULL)
 574       {
 575         proc->pid    = *pid;
 576         proc->job_id = job ? job->id : 0;
 577         _cups_strcpy(proc->name, command);
 578
 579         cupsArrayAdd(process_array, proc);
 580       }
 581     }
 582   }
 583
 584   cupsdReleaseSignals();
 585
 586   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 587                   "cupsdStartProcess(command=\"%s\", argv=%p, envp=%p, "
 588                   "infd=%d, outfd=%d, errfd=%d, backfd=%d, sidefd=%d, root=%d, "
 589                   "profile=%p, job=%p(%d), pid=%p) = %d",
 590                   command, argv, envp, infd, outfd, errfd, backfd, sidefd,
 591                   root, profile, job, job ? job->id : 0, pid, *pid);
 592
 593   return (*pid);
 594 }
 595
 596
 597 /*
 598  * 'compare_procs()' - Compare two processes.
 599  */
 600
 601 static int                              /* O - Result of comparison */
 602 compare_procs(cupsd_proc_t *a,          /* I - First process */
 603               cupsd_proc_t *b)          /* I - Second process */
 604 {
 605   return (a->pid - b->pid);
 606 }
 607
 608
 609 #ifdef HAVE_SANDBOX_H
 610 /*
 611  * 'cupsd_requote()' - Make a regular-expression version of a string.
 612  */
 613
 614 static char *                           /* O - Quoted string */
 615 cupsd_requote(char       *dst,          /* I - Destination buffer */
 616               const char *src,          /* I - Source string */
 617               size_t     dstsize)       /* I - Size of destination buffer */
 618 {
 619   int   ch;                             /* Current character */
 620   char  *dstptr,                        /* Current position in buffer */
 621         *dstend;                        /* End of destination buffer */
 622
 623
 624   dstptr = dst;
 625   dstend = dst + dstsize - 2;
 626
 627   while (*src && dstptr < dstend)
 628   {
 629     ch = *src++;
 630
 631     if (strchr(".?*()[]^$\\", ch))
 632       *dstptr++ = '\\';
 633
 634     *dstptr++ = ch;
 635   }
 636
 637   *dstptr = '\0';
 638
 639   return (dst);
 640 }
 641 #endif /* HAVE_SANDBOX_H */
 642
 643
 644 /*
 645  * End of "$Id: process.c 7256 2008-01-25 00:48:54Z mike $".
 646  */