kdumpd.tproj/kdumpd.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #ifndef lint
  35 static const char copyright[] =
  36 "@(#) Copyright (c) 1983, 1993\n\
  37         The Regents of the University of California.  All rights reserved.\n";
  38 #endif /* not lint */
  39
  40 /* Mac OS X kernel core dump server, based on the BSD trivial file
  41  * transfer protocol server (FreeBSD distribution), with several
  42  * modifications. This server is *not* compatible with tftp, as the
  43  * protocol has changed considerably.
  44  */
  45
  46 /*
  47  * Based on the trivial file transfer protocol server.
  48  *
  49  * The original version included many modifications by Jim Guyton
  50  * <guyton@rand-unix>.
  51  */
  52
  53 #include <sys/param.h>
  54 #include <sys/ioctl.h>
  55 #include <sys/stat.h>
  56 #include <sys/socket.h>
  57 #include <sys/types.h>
  58
  59 #include <netinet/in.h>
  60 #include "kdump.h"
  61 #include <arpa/inet.h>
  62
  63 #include <ctype.h>
  64 #include <errno.h>
  65 #include <fcntl.h>
  66 #include <netdb.h>
  67 #include <pwd.h>
  68 #include <setjmp.h>
  69 #include <signal.h>
  70 #include <stdio.h>
  71 #include <stdlib.h>
  72 #include <string.h>
  73 #include <syslog.h>
  74 #include <unistd.h>
  75
  76 #include "kdumpsubs.h"
  77
  78 #define TIMEOUT         5
  79
  80 int     peer;
  81 int     rexmtval = TIMEOUT;
  82 int     maxtimeout = 10*TIMEOUT;
  83
  84 #define PKTSIZE SEGSIZE+6
  85 char    buf[PKTSIZE];
  86 char    ackbuf[PKTSIZE];
  87 struct  sockaddr_in from;
  88 socklen_t fromlen;
  89
  90 void    kdump __P((struct kdumphdr *, int));
  91
  92 /*
  93  * Null-terminated directory prefix list for absolute pathname requests and
  94  * search list for relative pathname requests.
  95  *
  96  * MAXDIRS should be at least as large as the number of arguments that
  97  * inetd allows (currently 20).
  98  */
  99 #define MAXDIRS 20
 100 static struct dirlist {
 101         char    *name;
 102         int     len;
 103 } dirs[MAXDIRS+1];
 104 static int      suppress_naks;
 105 static int      logging = 1;
 106 static int      ipchroot;
 107
 108 static char *errtomsg __P((int));
 109 static void  nak __P((int));
 110 static char * __P(verifyhost(struct sockaddr_in *));
 111
 112 int
 113 main(argc, argv)
 114         int argc;
 115         char *argv[];
 116 {
 117         register struct kdumphdr *tp;
 118         register int n;
 119         int ch, on;
 120         struct sockaddr_in sin;
 121         char *chroot_dir = NULL;
 122         struct passwd *nobody;
 123         char *chuser = "nobody";
 124
 125         openlog("kdumpd", LOG_PID | LOG_NDELAY, LOG_FTP);
 126         while ((ch = getopt(argc, argv, "cClns:u:")) != -1) {
 127                 switch (ch) {
 128                 case 'c':
 129                         ipchroot = 1;
 130                         break;
 131                 case 'C':
 132                         ipchroot = 2;
 133                         break;
 134                 case 'l':
 135                         logging = 1;
 136                         break;
 137                 case 'n':
 138                         suppress_naks = 1;
 139                         break;
 140                 case 's':
 141                         chroot_dir = optarg;
 142                         break;
 143                 case 'u':
 144                         chuser = optarg;
 145                         break;
 146                 default:
 147                         syslog(LOG_WARNING, "ignoring unknown option -%c", ch);
 148                 }
 149         }
 150
 151         if (optind < argc) {
 152                 struct dirlist *dirp;
 153
 154                 /* Get list of directory prefixes. Skip relative pathnames. */
 155                 for (dirp = dirs; optind < argc && dirp < &dirs[MAXDIRS];
 156                      optind++) {
 157                         if (argv[optind][0] == '/') {
 158                                 dirp->name = argv[optind];
 159                                 dirp->len  = strlen(dirp->name);
 160                                 dirp++;
 161                         }
 162                 }
 163         }
 164         else if (chroot_dir) {
 165                 dirs->name = "/";
 166                 dirs->len = 1;
 167         }
 168         if (ipchroot && chroot_dir == NULL) {
 169                 syslog(LOG_ERR, "-c requires -s");
 170                 exit(1);
 171         }
 172
 173         on = 1;
 174         if (ioctl(0, FIONBIO, &on) < 0) {
 175                 syslog(LOG_ERR, "ioctl(FIONBIO): %m");
 176                 exit(1);
 177         }
 178         fromlen = sizeof (from);
 179         n = recvfrom(0, buf, sizeof (buf), 0,
 180             (struct sockaddr *)&from, &fromlen);
 181         if (n < 0) {
 182                 syslog(LOG_ERR, "recvfrom: %m");
 183                 exit(1);
 184         }
 185         /*
 186          * Now that we have read the message out of the UDP
 187          * socket, we fork and exit.  Thus, inetd will go back
 188          * to listening to the kdump port, and the next request
 189          * to come in will start up a new instance of kdumpd.
 190          *
 191          * We do this so that inetd can run kdumpd in "wait" mode.
 192          * The problem with kdumpd running in "nowait" mode is that
 193          * inetd may get one or more successful "selects" on the
 194          * kdump port before we do our receive, so more than one
 195          * instance of kdumpd may be started up.  Worse, if kdumpd
 196          * breaks before doing the above "recvfrom", inetd would
 197          * spawn endless instances, clogging the system.
 198          */
 199         {
 200                 int pid;
 201                 int i;
 202                 socklen_t j;
 203
 204                 for (i = 1; i < 20; i++) {
 205                     pid = fork();
 206                     if (pid < 0) {
 207                                 sleep(i);
 208                                 /*
 209                                  * flush out to most recently sent request.
 210                                  *
 211                                  * This may drop some requests, but those
 212                                  * will be resent by the clients when
 213                                  * they timeout.  The positive effect of
 214                                  * this flush is to (try to) prevent more
 215                                  * than one kdumpd being started up to service
 216                                  * a single request from a single client.
 217                                  */
 218                                 j = sizeof from;
 219                                 i = recvfrom(0, buf, sizeof (buf), 0,
 220                                     (struct sockaddr *)&from, &j);
 221                                 if (i > 0) {
 222                                         n = i;
 223                                         fromlen = j;
 224                                 }
 225                     } else {
 226                                 break;
 227                     }
 228                 }
 229                 if (pid < 0) {
 230                         syslog(LOG_ERR, "fork: %m");
 231                         exit(1);
 232                 } else if (pid != 0) {
 233                         exit(0);
 234                 }
 235         }
 236
 237         /*
 238          * Since we exit here, we should do that only after the above
 239          * recvfrom to keep inetd from constantly forking should there
 240          * be a problem.  See the above comment about system clogging.
 241          */
 242         if (chroot_dir) {
 243                 if (ipchroot) {
 244                         char tempchroot[MAXPATHLEN];
 245                         char *tempaddr;
 246                         struct stat sb;
 247                         int statret;
 248
 249                         tempaddr = inet_ntoa(from.sin_addr);
 250                         snprintf(tempchroot, sizeof(tempchroot), "%s/%s", chroot_dir, tempaddr);
 251                         statret = stat(tempchroot, &sb);
 252                         if ((sb.st_mode & S_IFDIR) &&
 253                             (statret == 0 || (statret == -1 && ipchroot == 1)))
 254                                 chroot_dir = tempchroot;
 255                 }
 256                 /* Must get this before chroot because /etc might go away */
 257                 if ((nobody = getpwnam(chuser)) == NULL) {
 258                         syslog(LOG_ERR, "%s: no such user", chuser);
 259                         exit(1);
 260                 }
 261                 if (chroot(chroot_dir)) {
 262                         syslog(LOG_ERR, "chroot: %s: %m", chroot_dir);
 263                         exit(1);
 264                 }
 265                 chdir( "/" );
 266                 setuid(nobody->pw_uid);
 267         }
 268         else
 269           if (0 !=  chdir(dirs->name))
 270             syslog(LOG_ERR, "chdir%s: %m", dirs->name);
 271
 272         from.sin_family = AF_INET;
 273         alarm(0);
 274         close(0);
 275         close(1);
 276         peer = socket(AF_INET, SOCK_DGRAM, 0);
 277         if (peer < 0) {
 278                 syslog(LOG_ERR, "socket: %m");
 279                 exit(1);
 280         }
 281         memset(&sin, 0, sizeof(sin));
 282         sin.sin_family = AF_INET;
 283         if (bind(peer, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
 284                 syslog(LOG_ERR, "bind: %m");
 285                 exit(1);
 286         }
 287         if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
 288                 syslog(LOG_ERR, "connect: %m");
 289                 exit(1);
 290         }
 291         tp = (struct kdumphdr *)buf;
 292         tp->th_opcode = ntohs(tp->th_opcode);
 293         if (tp->th_opcode == WRQ)
 294                 kdump(tp, n);
 295         exit(1);
 296 }
 297
 298 struct formats;
 299 int     validate_access __P((char **, int));
 300
 301 void    recvfile __P((struct formats *));
 302
 303 struct formats {
 304         char    *f_mode;
 305         int     (*f_validate) __P((char **, int));
 306
 307         void    (*f_recv) __P((struct formats *));
 308         int     f_convert;
 309 } formats[] = {
 310   { "netascii", validate_access, recvfile, 1 },
 311   { "octet",    validate_access, recvfile, 0 },
 312   { 0 }
 313 };
 314
 315 /*
 316  * Handle initial connection protocol.
 317  */
 318 void
 319 kdump(tp, size)
 320         struct kdumphdr *tp;
 321         int size;
 322 {
 323         register char *cp;
 324         int first = 1, ecode;
 325         register struct formats *pf;
 326         char *filename, *mode = NULL;
 327
 328         filename = cp = tp->th_stuff;
 329 again:
 330         while (cp < buf + size) {
 331                 if (*cp == '\0')
 332                         break;
 333                 cp++;
 334         }
 335         if (*cp != '\0') {
 336                 nak(EBADOP);
 337                 exit(1);
 338         }
 339         if (first) {
 340                 mode = ++cp;
 341                 first = 0;
 342                 goto again;
 343         }
 344         for (cp = mode; *cp; cp++)
 345                 if (isupper(*cp))
 346                         *cp = tolower(*cp);
 347         for (pf = formats; pf->f_mode; pf++)
 348                 if (strcmp(pf->f_mode, mode) == 0)
 349                         break;
 350         if (pf->f_mode == 0) {
 351                 nak(EBADOP);
 352                 exit(1);
 353         }
 354         ecode = (*pf->f_validate)(&filename, tp->th_opcode);
 355         if (logging) {
 356                 syslog(LOG_INFO, "%s: %s request for %s: %s", verifyhost(&from),
 357                         tp->th_opcode == WRQ ? "write" : "read",
 358                         filename, errtomsg(ecode));
 359         }
 360         if (ecode) {
 361                 /*
 362                  * Avoid storms of naks to a RRQ broadcast for a relative
 363                  * bootfile pathname from a diskless Sun.
 364                  */
 365                 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
 366                         exit(0);
 367                 nak(ecode);
 368                 exit(1);
 369         }
 370         if (tp->th_opcode == WRQ)
 371                 (*pf->f_recv)(pf);
 372
 373         exit(0);
 374 }
 375
 376
 377 FILE *file;
 378
 379 /*
 380  * Validate file access. We only allow storage of files that do not already
 381  * exist, and that do not include directory specifiers in their pathnames.
 382  * This is because kernel coredump filenames should always be of the form
 383  * "core-version-IP as dotted quad-random string" as in :
 384  * core-custom-17.202.40.204-a75b4eec
 385  * The file is written to the directory supplied as the first argument
 386  * in inetd.conf
 387  */
 388
 389 int
 390 validate_access(char **filep, int mode)
 391 {
 392   struct stat stbuf;
 393   int   fd;
 394   char *filename = *filep;
 395   static char pathname[MAXPATHLEN];
 396
 397   if (strstr(filename, "/") || strstr(filename, ".."))
 398     return (EACCESS);
 399
 400   snprintf(pathname, sizeof(pathname), "./%s", filename);
 401
 402   if (0 == stat(pathname, &stbuf))
 403     return (EEXIST);
 404
 405   if (errno != ENOENT)
 406     return (errno);
 407
 408
 409   fd = open(filename, O_WRONLY|O_CREAT|O_TRUNC);
 410
 411   if (fd < 0)
 412     return (errno + 100);
 413
 414   file = fdopen(fd, (mode == RRQ)? "r":"w");
 415   if (file == NULL) {
 416     return errno+100;
 417   }
 418   if (fchmod(fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) < 0)
 419     return errno+100;
 420
 421   return (0);
 422 }
 423
 424 int     timeout;
 425 jmp_buf timeoutbuf;
 426
 427 void
 428 timer()
 429 {
 430
 431         timeout += rexmtval;
 432         if (timeout >= maxtimeout)
 433           {
 434             longjmp(timeoutbuf, 2);
 435           }
 436         longjmp(timeoutbuf, 1);
 437 }
 438
 439 void
 440 justquit()
 441 {
 442         exit(0);
 443 }
 444
 445
 446 /*
 447  * Receive a file.
 448  */
 449 void
 450 recvfile(pf)
 451         struct formats *pf;
 452 {
 453         struct kdumphdr *dp, *w_init();
 454         register struct kdumphdr *ap;    /* ack buffer */
 455         register int n, size;
 456         volatile unsigned int block;
 457         volatile unsigned int jmpval = 0;
 458
 459         signal(SIGALRM, timer);
 460         dp = w_init();
 461         ap = (struct kdumphdr *)ackbuf;
 462         block = 0;
 463         do {
 464 send_seek_ack:  timeout = 0;
 465                 ap->th_opcode = htons((u_short)ACK);
 466                 ap->th_block = htonl((unsigned int)block);
 467                 block++;
 468                 jmpval = setjmp(timeoutbuf);
 469                 if (2 == jmpval)
 470                   {
 471                     syslog (LOG_ERR, "Timing out and flushing file to disk");
 472                     goto flushfile;
 473                   }
 474 send_ack:
 475                 if (send(peer, ackbuf, 6 , 0) != 6) {
 476                         syslog(LOG_ERR, "write: %m");
 477                         goto abort;
 478                 }
 479                 write_behind(file, pf->f_convert);
 480                 for ( ; ; ) {
 481                         alarm(rexmtval);
 482                         n = recv(peer, dp, PKTSIZE, 0);
 483                         alarm(0);
 484                         if (n < 0) {            /* really? */
 485                                 syslog(LOG_ERR, "read: %m");
 486                                 goto abort;
 487                         }
 488                         dp->th_opcode = ntohs((u_short)dp->th_opcode);
 489                         dp->th_block = ntohl((unsigned int)dp->th_block);
 490                         if (dp->th_opcode == ERROR)
 491                                 goto abort;
 492                         if (dp->th_opcode == KDP_EOF)
 493                           {
 494                             syslog (LOG_ERR, "Received last panic dump packet");
 495                             goto final_ack;
 496                           }
 497                         if (dp->th_opcode == KDP_SEEK)
 498                           {
 499                             if (dp->th_block == block)
 500                               {
 501                                 unsigned int tempoff = 0;
 502                                 bcopy (dp->th_data, &tempoff, sizeof(unsigned int));
 503                                 lseek (fileno (file), ntohl(tempoff), SEEK_SET);
 504                                 if (errno)
 505                                   syslog (LOG_ERR, "lseek: %m");
 506
 507                                 goto send_seek_ack;
 508                               }
 509                             (void) synchnet(peer);
 510                             if (dp->th_block == (block-1))
 511                               {
 512                                 syslog (LOG_DAEMON|LOG_ERR, "Retransmitting seek ack - current block %hu, received block %hu", block, dp->th_block);
 513                                 goto send_ack;          /* rexmit */
 514                               }
 515                           }
 516
 517                         if (dp->th_opcode == DATA) {
 518                                 if (dp->th_block == block) {
 519                                         break;   /* normal */
 520                                 }
 521                                 /* Re-synchronize with the other side */
 522                                 (void) synchnet(peer);
 523                                 if (dp->th_block == (block-1))
 524                                   {
 525                                     syslog (LOG_DAEMON|LOG_ERR, "Retransmitting ack - current block %hu, received block %hu", block, dp->th_block);
 526                                     goto send_ack;          /* rexmit */
 527                                   }
 528                                 else
 529                                   syslog (LOG_DAEMON|LOG_ERR, "Not retransmitting ack - current block %hu, received block %hu", block, dp->th_block);
 530                         }
 531                 }
 532
 533                 size = writeit(file, &dp, n - 6, pf->f_convert);
 534                 if (size != (n-6)) {                    /* ahem */
 535                         if (size < 0) nak(errno + 100);
 536                         else nak(ENOSPACE);
 537                         goto abort;
 538                 }
 539         } while (dp->th_opcode != KDP_EOF);
 540
 541 final_ack:
 542         ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
 543         ap->th_block = htonl((unsigned int) (block));
 544         (void) send(peer, ackbuf, 6, 0);
 545 flushfile:
 546         write_behind(file, pf->f_convert);
 547         (void) fclose(file);            /* close data file */
 548         syslog (LOG_ERR, "file closed, sending final ACK\n");
 549
 550         signal(SIGALRM, justquit);      /* just quit on timeout */
 551         alarm(rexmtval);
 552         n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
 553         alarm(0);
 554         if (n >= 6 &&                   /* if read some data */
 555             dp->th_opcode == DATA &&    /* and got a data block */
 556             block == dp->th_block) {    /* then my last ack was lost */
 557                 (void) send(peer, ackbuf, 6, 0);     /* resend final ack */
 558         }
 559 abort:
 560         return;
 561 }
 562
 563 struct errmsg {
 564         int     e_code;
 565         char    *e_msg;
 566 } errmsgs[] = {
 567         { EUNDEF,       "Undefined error code" },
 568         { ENOTFOUND,    "File not found" },
 569         { EACCESS,      "Access violation" },
 570         { ENOSPACE,     "Disk full or allocation exceeded" },
 571         { EBADOP,       "Illegal KDUMP operation" },
 572         { EBADID,       "Unknown transfer ID" },
 573         { EEXISTS,      "File already exists" },
 574         { ENOUSER,      "No such user" },
 575         { -1,           0 }
 576 };
 577
 578 static char *
 579 errtomsg(error)
 580         int error;
 581 {
 582         static char buf[20];
 583         register struct errmsg *pe;
 584         if (error == 0)
 585                 return "success";
 586         for (pe = errmsgs; pe->e_code >= 0; pe++)
 587                 if (pe->e_code == error)
 588                         return pe->e_msg;
 589         snprintf(buf, sizeof(buf), "error %d", error);
 590         return buf;
 591 }
 592
 593 /*
 594  * Send a nak packet (error message).
 595  * Error code passed in is one of the
 596  * standard KDUMP codes, or a UNIX errno
 597  * offset by 100.
 598  */
 599 static void
 600 nak(error)
 601         int error;
 602 {
 603         register struct kdumphdr *tp;
 604         int length;
 605         register struct errmsg *pe;
 606
 607         tp = (struct kdumphdr *)buf;
 608         tp->th_opcode = htons((u_short)ERROR);
 609         tp->th_code = htons((unsigned int)error);
 610         for (pe = errmsgs; pe->e_code >= 0; pe++)
 611                 if (pe->e_code == error)
 612                         break;
 613         if (pe->e_code < 0) {
 614                 pe->e_msg = strerror(error - 100);
 615                 tp->th_code = EUNDEF;   /* set 'undef' errorcode */
 616         }
 617         strcpy(tp->th_msg, pe->e_msg);
 618         length = strlen(pe->e_msg);
 619         tp->th_msg[length] = '\0';
 620         length += 5;
 621         if (send(peer, buf, length, 0) != length)
 622                 syslog(LOG_ERR, "nak: %m");
 623 }
 624
 625 static char *
 626 verifyhost(fromp)
 627         struct sockaddr_in *fromp;
 628 {
 629         struct hostent *hp;
 630
 631         hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(fromp->sin_addr),
 632                 fromp->sin_family);
 633         if(hp)
 634                 return hp->h_name;
 635         else
 636                 return inet_ntoa(fromp->sin_addr);
 637 }