scheduler/process.c

   1 /*
   2  * "$Id: process.c 10996 2013-05-29 11:51:34Z msweet $"
   3  *
   4  *   Process management routines for the CUPS scheduler.
   5  *
   6  *   Copyright 2007-2012 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   const char    *nodebug;               /* " (with no-log)" for no debug */
  81
  82
  83   if (!UseProfiles)
  84   {
  85    /*
  86     * Only use sandbox profiles as root...
  87     */
  88
  89     cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = NULL",
  90                     job_id);
  91
  92     return (NULL);
  93   }
  94
  95   if ((fp = cupsTempFile2(profile, sizeof(profile))) == NULL)
  96   {
  97     cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = NULL",
  98                     job_id);
  99     cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to create security profile: %s",
 100                     strerror(errno));
 101     return (NULL);
 102   }
 103
 104   fchown(cupsFileNumber(fp), RunUser, Group);
 105   fchmod(cupsFileNumber(fp), 0640);
 106
 107   cupsd_requote(cache, CacheDir, sizeof(cache));
 108   cupsd_requote(request, RequestRoot, sizeof(request));
 109   cupsd_requote(root, ServerRoot, sizeof(root));
 110   cupsd_requote(temp, TempDir, sizeof(temp));
 111
 112   nodebug = LogLevel < CUPSD_LOG_DEBUG ? " (with no-log)" : "";
 113
 114   cupsFilePuts(fp, "(version 1)\n");
 115   cupsFilePuts(fp, "(allow default)\n");
 116   cupsFilePrintf(fp,
 117                  "(deny file-write* file-read-data file-read-metadata\n"
 118                  "  (regex"
 119                  " #\"^%s$\""           /* RequestRoot */
 120                  " #\"^%s/\""           /* RequestRoot/... */
 121                  ")%s)\n",
 122                  request, request, nodebug);
 123   if (!RunUser)
 124     cupsFilePrintf(fp,
 125                    "(deny file-write* file-read-data file-read-metadata\n"
 126                    "  (regex"
 127                    " #\"^/Users$\""
 128                    " #\"^/Users/\""
 129                    ")%s)\n", nodebug);
 130   cupsFilePrintf(fp,
 131                  "(deny file-write*\n"
 132                  "  (regex"
 133                  " #\"^%s$\""           /* ServerRoot */
 134                  " #\"^%s/\""           /* ServerRoot/... */
 135                  " #\"^/private/etc$\""
 136                  " #\"^/private/etc/\""
 137                  " #\"^/usr/local/etc$\""
 138                  " #\"^/usr/local/etc/\""
 139                  " #\"^/Library$\""
 140                  " #\"^/Library/\""
 141                  " #\"^/System$\""
 142                  " #\"^/System/\""
 143                  ")%s)\n",
 144                  root, root, nodebug);
 145   /* Specifically allow applications to stat RequestRoot */
 146   cupsFilePrintf(fp,
 147                  "(allow file-read-metadata\n"
 148                  "  (regex"
 149                  " #\"^%s$\""           /* RequestRoot */
 150                  "))\n",
 151                  request);
 152   cupsFilePrintf(fp,
 153                  "(allow file-write* file-read-data file-read-metadata\n"
 154                  "  (regex"
 155                  " #\"^%s$\""           /* TempDir */
 156                  " #\"^%s/\""           /* TempDir/... */
 157                  " #\"^%s$\""           /* CacheDir */
 158                  " #\"^%s/\""           /* CacheDir/... */
 159                  " #\"^%s/Library$\""   /* RequestRoot/Library */
 160                  " #\"^%s/Library/\""   /* RequestRoot/Library/... */
 161                  " #\"^/Library/Application Support/\""
 162                  " #\"^/Library/Caches/\""
 163                  " #\"^/Library/Preferences/\""
 164                  " #\"^/Library/Printers/.*/\""
 165                  " #\"^/Users/Shared/\""
 166                  "))\n",
 167                  temp, temp, cache, cache, request, request);
 168   cupsFilePrintf(fp,
 169                  "(deny file-write*\n"
 170                  "  (regex"
 171                  " #\"^/Library/Printers/PPDs$\""
 172                  " #\"^/Library/Printers/PPDs/\""
 173                  " #\"^/Library/Printers/PPD Plugins$\""
 174                  " #\"^/Library/Printers/PPD Plugins/\""
 175                  ")%s)\n", nodebug);
 176   if (job_id)
 177   {
 178    /*
 179     * Allow job filters to read the spool file(s)...
 180     */
 181
 182     cupsFilePrintf(fp,
 183                    "(allow file-read-data file-read-metadata\n"
 184                    "  (regex #\"^%s/([ac]%05d|d%05d-[0-9][0-9][0-9])$\"))\n",
 185                    request, job_id, job_id);
 186   }
 187   else
 188   {
 189    /*
 190     * Allow email notifications from notifiers...
 191     */
 192
 193     cupsFilePuts(fp,
 194                  "(allow process-exec\n"
 195                  "  (literal \"/usr/sbin/sendmail\")\n"
 196                  "  (with no-sandbox)\n"
 197                  ")\n");
 198   }
 199
 200   cupsFileClose(fp);
 201
 202   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = \"%s\"",
 203                   job_id, profile);
 204   return ((void *)strdup(profile));
 205
 206 #else
 207   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdCreateProfile(job_id=%d) = NULL",
 208                   job_id);
 209
 210   return (NULL);
 211 #endif /* HAVE_SANDBOX_H */
 212 }
 213
 214
 215 /*
 216  * 'cupsdDestroyProfile()' - Delete an execution profile.
 217  */
 218
 219 void
 220 cupsdDestroyProfile(void *profile)      /* I - Profile */
 221 {
 222   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdDeleteProfile(profile=\"%s\")",
 223                   profile ? (char *)profile : "(null)");
 224
 225 #ifdef HAVE_SANDBOX_H
 226   if (profile)
 227   {
 228     unlink((char *)profile);
 229     free(profile);
 230   }
 231 #endif /* HAVE_SANDBOX_H */
 232 }
 233
 234
 235 /*
 236  * 'cupsdEndProcess()' - End a process.
 237  */
 238
 239 int                                     /* O - 0 on success, -1 on failure */
 240 cupsdEndProcess(int pid,                /* I - Process ID */
 241                 int force)              /* I - Force child to die */
 242 {
 243   cupsdLogMessage(CUPSD_LOG_DEBUG2, "cupsdEndProcess(pid=%d, force=%d)", pid,
 244                   force);
 245
 246   if (!pid)
 247     return (0);
 248
 249   if (!RunUser)
 250   {
 251    /*
 252     * When running as root, cupsd puts child processes in their own process
 253     * group.  Using "-pid" sends a signal to all processes in the group.
 254     */
 255
 256     pid = -pid;
 257   }
 258
 259   if (force)
 260     return (kill(pid, SIGKILL));
 261   else
 262     return (kill(pid, SIGTERM));
 263 }
 264
 265
 266 /*
 267  * 'cupsdFinishProcess()' - Finish a process and get its name.
 268  */
 269
 270 const char *                            /* O - Process name */
 271 cupsdFinishProcess(int  pid,            /* I - Process ID */
 272                    char *name,          /* I - Name buffer */
 273                    int  namelen,        /* I - Size of name buffer */
 274                    int  *job_id)        /* O - Job ID pointer or NULL */
 275 {
 276   cupsd_proc_t  key,                    /* Search key */
 277                 *proc;                  /* Matching process */
 278
 279
 280   key.pid = pid;
 281
 282   if ((proc = (cupsd_proc_t *)cupsArrayFind(process_array, &key)) != NULL)
 283   {
 284     if (job_id)
 285       *job_id = proc->job_id;
 286
 287     strlcpy(name, proc->name, namelen);
 288     cupsArrayRemove(process_array, proc);
 289     free(proc);
 290   }
 291   else
 292   {
 293     if (job_id)
 294       *job_id = 0;
 295
 296     strlcpy(name, "unknown", namelen);
 297   }
 298
 299   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 300                   "cupsdFinishProcess(pid=%d, name=%p, namelen=%d, "
 301                   "job_id=%p(%d)) = \"%s\"", pid, name, namelen, job_id,
 302                   job_id ? *job_id : 0, name);
 303
 304   return (name);
 305 }
 306
 307
 308 /*
 309  * 'cupsdStartProcess()' - Start a process.
 310  */
 311
 312 int                                     /* O - Process ID or 0 */
 313 cupsdStartProcess(
 314     const char  *command,               /* I - Full path to command */
 315     char        *argv[],                /* I - Command-line arguments */
 316     char        *envp[],                /* I - Environment */
 317     int         infd,                   /* I - Standard input file descriptor */
 318     int         outfd,                  /* I - Standard output file descriptor */
 319     int         errfd,                  /* I - Standard error file descriptor */
 320     int         backfd,                 /* I - Backchannel file descriptor */
 321     int         sidefd,                 /* I - Sidechannel file descriptor */
 322     int         root,                   /* I - Run as root? */
 323     void        *profile,               /* I - Security profile to use */
 324     cupsd_job_t *job,                   /* I - Job associated with process */
 325     int         *pid)                   /* O - Process ID */
 326 {
 327   int           i;                      /* Looping var */
 328   const char    *exec_path = command;   /* Command to be exec'd */
 329   char          *real_argv[103],        /* Real command-line arguments */
 330                 cups_exec[1024];        /* Path to "cups-exec" program */
 331   int           user;                   /* Command UID */
 332   cupsd_proc_t  *proc;                  /* New process record */
 333 #if defined(HAVE_SIGACTION) && !defined(HAVE_SIGSET)
 334   struct sigaction action;              /* POSIX signal handler */
 335 #endif /* HAVE_SIGACTION && !HAVE_SIGSET */
 336 #if defined(__APPLE__)
 337   char          processPath[1024],      /* CFProcessPath environment variable */
 338                 linkpath[1024];         /* Link path for symlinks... */
 339   int           linkbytes;              /* Bytes for link path */
 340 #endif /* __APPLE__ */
 341
 342
 343   *pid = 0;
 344
 345  /*
 346   * Figure out the UID for the child process...
 347   */
 348
 349   if (RunUser)
 350     user = RunUser;
 351   else if (root)
 352     user = 0;
 353   else
 354     user = User;
 355
 356  /*
 357   * Check the permissions of the command we are running...
 358   */
 359
 360   if (_cupsFileCheck(command, _CUPS_FILE_CHECK_PROGRAM, !RunUser,
 361                      cupsdLogFCMessage, job ? job->printer : NULL))
 362     return (0);
 363
 364 #if defined(__APPLE__)
 365   if (envp)
 366   {
 367    /*
 368     * Add special voodoo magic for OS X - this allows OS X programs to access
 369     * their bundle resources properly...
 370     */
 371
 372     if ((linkbytes = readlink(command, linkpath, sizeof(linkpath) - 1)) > 0)
 373     {
 374      /*
 375       * Yes, this is a symlink to the actual program, nul-terminate and
 376       * use it...
 377       */
 378
 379       linkpath[linkbytes] = '\0';
 380
 381       if (linkpath[0] == '/')
 382         snprintf(processPath, sizeof(processPath), "CFProcessPath=%s",
 383                  linkpath);
 384       else
 385         snprintf(processPath, sizeof(processPath), "CFProcessPath=%s/%s",
 386                  dirname((char *)command), linkpath);
 387     }
 388     else
 389       snprintf(processPath, sizeof(processPath), "CFProcessPath=%s", command);
 390
 391     envp[0] = processPath;              /* Replace <CFProcessPath> string */
 392   }
 393 #endif  /* __APPLE__ */
 394
 395  /*
 396   * Use helper program when we have a sandbox profile...
 397   */
 398
 399   if (profile)
 400   {
 401     snprintf(cups_exec, sizeof(cups_exec), "%s/daemon/cups-exec", ServerBin);
 402
 403     real_argv[0] = cups_exec;
 404     real_argv[1] = profile;
 405     real_argv[2] = (char *)command;
 406
 407     for (i = 0;
 408          i < (int)(sizeof(real_argv) / sizeof(real_argv[0]) - 4) && argv[i];
 409          i ++)
 410       real_argv[i + 3] = argv[i];
 411
 412     real_argv[i + 3] = NULL;
 413
 414     argv      = real_argv;
 415     exec_path = cups_exec;
 416   }
 417
 418  /*
 419   * Block signals before forking...
 420   */
 421
 422   cupsdHoldSignals();
 423
 424   if ((*pid = fork()) == 0)
 425   {
 426    /*
 427     * Child process goes here; update stderr as needed...
 428     */
 429
 430     if (errfd != 2)
 431     {
 432       if (errfd < 0)
 433         errfd = open("/dev/null", O_WRONLY);
 434
 435       if (errfd != 2)
 436       {
 437         dup2(errfd, 2);
 438         close(errfd);
 439       }
 440     }
 441
 442    /*
 443     * Put this process in its own process group so that we can kill any child
 444     * processes it creates.
 445     */
 446
 447 #ifdef HAVE_SETPGID
 448     if (!RunUser && setpgid(0, 0))
 449       exit(errno + 100);
 450 #else
 451     if (!RunUser && setpgrp())
 452       exit(errno + 100);
 453 #endif /* HAVE_SETPGID */
 454
 455    /*
 456     * Update the remaining file descriptors as needed...
 457     */
 458
 459     if (infd != 0)
 460     {
 461       if (infd < 0)
 462         infd = open("/dev/null", O_RDONLY);
 463
 464       if (infd != 0)
 465       {
 466         dup2(infd, 0);
 467         close(infd);
 468       }
 469     }
 470
 471     if (outfd != 1)
 472     {
 473       if (outfd < 0)
 474         outfd = open("/dev/null", O_WRONLY);
 475
 476       if (outfd != 1)
 477       {
 478         dup2(outfd, 1);
 479         close(outfd);
 480       }
 481     }
 482
 483     if (backfd != 3 && backfd >= 0)
 484     {
 485       dup2(backfd, 3);
 486       close(backfd);
 487       fcntl(3, F_SETFL, O_NDELAY);
 488     }
 489
 490     if (sidefd != 4 && sidefd >= 0)
 491     {
 492       dup2(sidefd, 4);
 493       close(sidefd);
 494       fcntl(4, F_SETFL, O_NDELAY);
 495     }
 496
 497    /*
 498     * Change the priority of the process based on the FilterNice setting.
 499     * (this is not done for root processes...)
 500     */
 501
 502     if (!root)
 503       nice(FilterNice);
 504
 505    /*
 506     * Reset group membership to just the main one we belong to.
 507     */
 508
 509     if (!RunUser && setgid(Group))
 510       exit(errno + 100);
 511
 512     if (!RunUser && setgroups(1, &Group))
 513       exit(errno + 100);
 514
 515    /*
 516     * Change user to something "safe"...
 517     */
 518
 519     if (!RunUser && user && setuid(user))
 520       exit(errno + 100);
 521
 522    /*
 523     * Change umask to restrict permissions on created files...
 524     */
 525
 526     umask(077);
 527
 528    /*
 529     * Unblock signals before doing the exec...
 530     */
 531
 532 #ifdef HAVE_SIGSET
 533     sigset(SIGTERM, SIG_DFL);
 534     sigset(SIGCHLD, SIG_DFL);
 535     sigset(SIGPIPE, SIG_DFL);
 536 #elif defined(HAVE_SIGACTION)
 537     memset(&action, 0, sizeof(action));
 538
 539     sigemptyset(&action.sa_mask);
 540     action.sa_handler = SIG_DFL;
 541
 542     sigaction(SIGTERM, &action, NULL);
 543     sigaction(SIGCHLD, &action, NULL);
 544     sigaction(SIGPIPE, &action, NULL);
 545 #else
 546     signal(SIGTERM, SIG_DFL);
 547     signal(SIGCHLD, SIG_DFL);
 548     signal(SIGPIPE, SIG_DFL);
 549 #endif /* HAVE_SIGSET */
 550
 551     cupsdReleaseSignals();
 552
 553    /*
 554     * Execute the command; if for some reason this doesn't work, log an error
 555     * exit with a non-zero value...
 556     */
 557
 558     if (envp)
 559       execve(exec_path, argv, envp);
 560     else
 561       execv(exec_path, argv);
 562
 563     exit(errno + 100);
 564   }
 565   else if (*pid < 0)
 566   {
 567    /*
 568     * Error - couldn't fork a new process!
 569     */
 570
 571     cupsdLogMessage(CUPSD_LOG_ERROR, "Unable to fork %s - %s.", command,
 572                     strerror(errno));
 573
 574     *pid = 0;
 575   }
 576   else
 577   {
 578     if (!process_array)
 579       process_array = cupsArrayNew((cups_array_func_t)compare_procs, NULL);
 580
 581     if (process_array)
 582     {
 583       if ((proc = calloc(1, sizeof(cupsd_proc_t) + strlen(command))) != NULL)
 584       {
 585         proc->pid    = *pid;
 586         proc->job_id = job ? job->id : 0;
 587         _cups_strcpy(proc->name, command);
 588
 589         cupsArrayAdd(process_array, proc);
 590       }
 591     }
 592   }
 593
 594   cupsdReleaseSignals();
 595
 596   cupsdLogMessage(CUPSD_LOG_DEBUG2,
 597                   "cupsdStartProcess(command=\"%s\", argv=%p, envp=%p, "
 598                   "infd=%d, outfd=%d, errfd=%d, backfd=%d, sidefd=%d, root=%d, "
 599                   "profile=%p, job=%p(%d), pid=%p) = %d",
 600                   command, argv, envp, infd, outfd, errfd, backfd, sidefd,
 601                   root, profile, job, job ? job->id : 0, pid, *pid);
 602
 603   return (*pid);
 604 }
 605
 606
 607 /*
 608  * 'compare_procs()' - Compare two processes.
 609  */
 610
 611 static int                              /* O - Result of comparison */
 612 compare_procs(cupsd_proc_t *a,          /* I - First process */
 613               cupsd_proc_t *b)          /* I - Second process */
 614 {
 615   return (a->pid - b->pid);
 616 }
 617
 618
 619 #ifdef HAVE_SANDBOX_H
 620 /*
 621  * 'cupsd_requote()' - Make a regular-expression version of a string.
 622  */
 623
 624 static char *                           /* O - Quoted string */
 625 cupsd_requote(char       *dst,          /* I - Destination buffer */
 626               const char *src,          /* I - Source string */
 627               size_t     dstsize)       /* I - Size of destination buffer */
 628 {
 629   int   ch;                             /* Current character */
 630   char  *dstptr,                        /* Current position in buffer */
 631         *dstend;                        /* End of destination buffer */
 632
 633
 634   dstptr = dst;
 635   dstend = dst + dstsize - 2;
 636
 637   while (*src && dstptr < dstend)
 638   {
 639     ch = *src++;
 640
 641     if (ch == '/' && !*src)
 642       break;                            /* Don't add trailing slash */
 643
 644     if (strchr(".?*()[]^$\\", ch))
 645       *dstptr++ = '\\';
 646
 647     *dstptr++ = ch;
 648   }
 649
 650   *dstptr = '\0';
 651
 652   return (dst);
 653 }
 654 #endif /* HAVE_SANDBOX_H */
 655
 656
 657 /*
 658  * End of "$Id: process.c 10996 2013-05-29 11:51:34Z msweet $".
 659  */