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 int     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, j;
 202
 203                 for (i = 1; i < 20; i++) {
 204                     pid = fork();
 205                     if (pid < 0) {
 206                                 sleep(i);
 207                                 /*
 208                                  * flush out to most recently sent request.
 209                                  *
 210                                  * This may drop some requests, but those
 211                                  * will be resent by the clients when
 212                                  * they timeout.  The positive effect of
 213                                  * this flush is to (try to) prevent more
 214                                  * than one kdumpd being started up to service
 215                                  * a single request from a single client.
 216                                  */
 217                                 j = sizeof from;
 218                                 i = recvfrom(0, buf, sizeof (buf), 0,
 219                                     (struct sockaddr *)&from, &j);
 220                                 if (i > 0) {
 221                                         n = i;
 222                                         fromlen = j;
 223                                 }
 224                     } else {
 225                                 break;
 226                     }
 227                 }
 228                 if (pid < 0) {
 229                         syslog(LOG_ERR, "fork: %m");
 230                         exit(1);
 231                 } else if (pid != 0) {
 232                         exit(0);
 233                 }
 234         }
 235
 236         /*
 237          * Since we exit here, we should do that only after the above
 238          * recvfrom to keep inetd from constantly forking should there
 239          * be a problem.  See the above comment about system clogging.
 240          */
 241         if (chroot_dir) {
 242                 if (ipchroot) {
 243                         char tempchroot[MAXPATHLEN];
 244                         char *tempaddr;
 245                         struct stat sb;
 246                         int statret;
 247
 248                         tempaddr = inet_ntoa(from.sin_addr);
 249                         snprintf(tempchroot, sizeof(tempchroot), "%s/%s", chroot_dir, tempaddr);
 250                         statret = stat(tempchroot, &sb);
 251                         if ((sb.st_mode & S_IFDIR) &&
 252                             (statret == 0 || (statret == -1 && ipchroot == 1)))
 253                                 chroot_dir = tempchroot;
 254                 }
 255                 /* Must get this before chroot because /etc might go away */
 256                 if ((nobody = getpwnam(chuser)) == NULL) {
 257                         syslog(LOG_ERR, "%s: no such user", chuser);
 258                         exit(1);
 259                 }
 260                 if (chroot(chroot_dir)) {
 261                         syslog(LOG_ERR, "chroot: %s: %m", chroot_dir);
 262                         exit(1);
 263                 }
 264                 chdir( "/" );
 265                 setuid(nobody->pw_uid);
 266         }
 267         else
 268           if (0 !=  chdir(dirs->name))
 269             syslog(LOG_ERR, "chdir%s: %m", dirs->name);
 270
 271         from.sin_family = AF_INET;
 272         alarm(0);
 273         close(0);
 274         close(1);
 275         peer = socket(AF_INET, SOCK_DGRAM, 0);
 276         if (peer < 0) {
 277                 syslog(LOG_ERR, "socket: %m");
 278                 exit(1);
 279         }
 280         memset(&sin, 0, sizeof(sin));
 281         sin.sin_family = AF_INET;
 282         if (bind(peer, (struct sockaddr *)&sin, sizeof (sin)) < 0) {
 283                 syslog(LOG_ERR, "bind: %m");
 284                 exit(1);
 285         }
 286         if (connect(peer, (struct sockaddr *)&from, sizeof(from)) < 0) {
 287                 syslog(LOG_ERR, "connect: %m");
 288                 exit(1);
 289         }
 290         tp = (struct kdumphdr *)buf;
 291         tp->th_opcode = ntohs(tp->th_opcode);
 292         if (tp->th_opcode == WRQ)
 293                 kdump(tp, n);
 294         exit(1);
 295 }
 296
 297 struct formats;
 298 int     validate_access __P((char **, int));
 299
 300 void    recvfile __P((struct formats *));
 301
 302 struct formats {
 303         char    *f_mode;
 304         int     (*f_validate) __P((char **, int));
 305
 306         void    (*f_recv) __P((struct formats *));
 307         int     f_convert;
 308 } formats[] = {
 309   { "netascii", validate_access, recvfile, 1 },
 310   { "octet",    validate_access, recvfile, 0 },
 311   { 0 }
 312 };
 313
 314 /*
 315  * Handle initial connection protocol.
 316  */
 317 void
 318 kdump(tp, size)
 319         struct kdumphdr *tp;
 320         int size;
 321 {
 322         register char *cp;
 323         int first = 1, ecode;
 324         register struct formats *pf;
 325         char *filename, *mode = NULL;
 326
 327         filename = cp = tp->th_stuff;
 328 again:
 329         while (cp < buf + size) {
 330                 if (*cp == '\0')
 331                         break;
 332                 cp++;
 333         }
 334         if (*cp != '\0') {
 335                 nak(EBADOP);
 336                 exit(1);
 337         }
 338         if (first) {
 339                 mode = ++cp;
 340                 first = 0;
 341                 goto again;
 342         }
 343         for (cp = mode; *cp; cp++)
 344                 if (isupper(*cp))
 345                         *cp = tolower(*cp);
 346         for (pf = formats; pf->f_mode; pf++)
 347                 if (strcmp(pf->f_mode, mode) == 0)
 348                         break;
 349         if (pf->f_mode == 0) {
 350                 nak(EBADOP);
 351                 exit(1);
 352         }
 353         ecode = (*pf->f_validate)(&filename, tp->th_opcode);
 354         if (logging) {
 355                 syslog(LOG_INFO, "%s: %s request for %s: %s", verifyhost(&from),
 356                         tp->th_opcode == WRQ ? "write" : "read",
 357                         filename, errtomsg(ecode));
 358         }
 359         if (ecode) {
 360                 /*
 361                  * Avoid storms of naks to a RRQ broadcast for a relative
 362                  * bootfile pathname from a diskless Sun.
 363                  */
 364                 if (suppress_naks && *filename != '/' && ecode == ENOTFOUND)
 365                         exit(0);
 366                 nak(ecode);
 367                 exit(1);
 368         }
 369         if (tp->th_opcode == WRQ)
 370                 (*pf->f_recv)(pf);
 371
 372         exit(0);
 373 }
 374
 375
 376 FILE *file;
 377
 378 /*
 379  * Validate file access. We only allow storage of files that do not already
 380  * exist, and that do not include directory specifiers in their pathnames.
 381  * This is because kernel coredump filenames should always be of the form
 382  * "core-version-IP as dotted quad-random string" as in :
 383  * core-custom-17.202.40.204-a75b4eec
 384  * The file is written to the directory supplied as the first argument
 385  * in inetd.conf
 386  */
 387
 388 int
 389 validate_access(char **filep, int mode)
 390 {
 391   struct stat stbuf;
 392   int   fd;
 393   char *filename = *filep;
 394   static char pathname[MAXPATHLEN];
 395
 396   if (strstr(filename, "/") || strstr(filename, ".."))
 397     return (EACCESS);
 398
 399   snprintf(pathname, sizeof(pathname), "./%s", filename);
 400
 401   if (0 == stat(pathname, &stbuf))
 402     return (EEXIST);
 403
 404   if (errno != ENOENT)
 405     return (errno);
 406
 407
 408   fd = open(filename, O_WRONLY|O_CREAT|O_TRUNC);
 409
 410   if (fd < 0)
 411     return (errno + 100);
 412
 413   file = fdopen(fd, (mode == RRQ)? "r":"w");
 414   if (file == NULL) {
 415     return errno+100;
 416   }
 417   if (fchmod(fd, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP) < 0)
 418     return errno+100;
 419
 420   return (0);
 421 }
 422
 423 int     timeout;
 424 jmp_buf timeoutbuf;
 425
 426 void
 427 timer()
 428 {
 429
 430         timeout += rexmtval;
 431         if (timeout >= maxtimeout)
 432           {
 433             longjmp(timeoutbuf, 2);
 434           }
 435         longjmp(timeoutbuf, 1);
 436 }
 437
 438 void
 439 justquit()
 440 {
 441         exit(0);
 442 }
 443
 444
 445 /*
 446  * Receive a file.
 447  */
 448 void
 449 recvfile(pf)
 450         struct formats *pf;
 451 {
 452         struct kdumphdr *dp, *w_init();
 453         register struct kdumphdr *ap;    /* ack buffer */
 454         register int n, size;
 455         volatile unsigned int block;
 456         volatile unsigned int jmpval = 0;
 457
 458         signal(SIGALRM, timer);
 459         dp = w_init();
 460         ap = (struct kdumphdr *)ackbuf;
 461         block = 0;
 462         do {
 463 send_seek_ack:  timeout = 0;
 464                 ap->th_opcode = htons((u_short)ACK);
 465                 ap->th_block = htonl((unsigned int)block);
 466                 block++;
 467                 jmpval = setjmp(timeoutbuf);
 468                 if (2 == jmpval)
 469                   {
 470                     syslog (LOG_ERR, "Timing out and flushing file to disk");
 471                     goto flushfile;
 472                   }
 473 send_ack:
 474                 if (send(peer, ackbuf, 6 , 0) != 6) {
 475                         syslog(LOG_ERR, "write: %m");
 476                         goto abort;
 477                 }
 478                 write_behind(file, pf->f_convert);
 479                 for ( ; ; ) {
 480                         alarm(rexmtval);
 481                         n = recv(peer, dp, PKTSIZE, 0);
 482                         alarm(0);
 483                         if (n < 0) {            /* really? */
 484                                 syslog(LOG_ERR, "read: %m");
 485                                 goto abort;
 486                         }
 487                         dp->th_opcode = ntohs((u_short)dp->th_opcode);
 488                         dp->th_block = ntohl((unsigned int)dp->th_block);
 489                         if (dp->th_opcode == ERROR)
 490                                 goto abort;
 491                         if (dp->th_opcode == KDP_EOF)
 492                           {
 493                             syslog (LOG_ERR, "Received last panic dump packet");
 494                             goto final_ack;
 495                           }
 496                         if (dp->th_opcode == KDP_SEEK)
 497                           {
 498                             if (dp->th_block == block)
 499                               {
 500                                 unsigned int tempoff = 0;
 501                                 bcopy (dp->th_data, &tempoff, sizeof(unsigned int));
 502                                 lseek (fileno (file), ntohl(tempoff), SEEK_SET);
 503                                 if (errno)
 504                                   syslog (LOG_ERR, "lseek: %m");
 505
 506                                 goto send_seek_ack;
 507                               }
 508                             (void) synchnet(peer);
 509                             if (dp->th_block == (block-1))
 510                               {
 511                                 syslog (LOG_DAEMON|LOG_ERR, "Retransmitting seek ack - current block %hu, received block %hu", block, dp->th_block);
 512                                 goto send_ack;          /* rexmit */
 513                               }
 514                           }
 515
 516                         if (dp->th_opcode == DATA) {
 517                                 if (dp->th_block == block) {
 518                                         break;   /* normal */
 519                                 }
 520                                 /* Re-synchronize with the other side */
 521                                 (void) synchnet(peer);
 522                                 if (dp->th_block == (block-1))
 523                                   {
 524                                     syslog (LOG_DAEMON|LOG_ERR, "Retransmitting ack - current block %hu, received block %hu", block, dp->th_block);
 525                                     goto send_ack;          /* rexmit */
 526                                   }
 527                                 else
 528                                   syslog (LOG_DAEMON|LOG_ERR, "Not retransmitting ack - current block %hu, received block %hu", block, dp->th_block);
 529                         }
 530                 }
 531
 532                 size = writeit(file, &dp, n - 6, pf->f_convert);
 533                 if (size != (n-6)) {                    /* ahem */
 534                         if (size < 0) nak(errno + 100);
 535                         else nak(ENOSPACE);
 536                         goto abort;
 537                 }
 538         } while (dp->th_opcode != KDP_EOF);
 539
 540 final_ack:
 541         ap->th_opcode = htons((u_short)ACK);    /* send the "final" ack */
 542         ap->th_block = htonl((unsigned int) (block));
 543         (void) send(peer, ackbuf, 6, 0);
 544 flushfile:
 545         write_behind(file, pf->f_convert);
 546         (void) fclose(file);            /* close data file */
 547         syslog (LOG_ERR, "file closed, sending final ACK\n");
 548
 549         signal(SIGALRM, justquit);      /* just quit on timeout */
 550         alarm(rexmtval);
 551         n = recv(peer, buf, sizeof (buf), 0); /* normally times out and quits */
 552         alarm(0);
 553         if (n >= 6 &&                   /* if read some data */
 554             dp->th_opcode == DATA &&    /* and got a data block */
 555             block == dp->th_block) {    /* then my last ack was lost */
 556                 (void) send(peer, ackbuf, 6, 0);     /* resend final ack */
 557         }
 558 abort:
 559         return;
 560 }
 561
 562 struct errmsg {
 563         int     e_code;
 564         char    *e_msg;
 565 } errmsgs[] = {
 566         { EUNDEF,       "Undefined error code" },
 567         { ENOTFOUND,    "File not found" },
 568         { EACCESS,      "Access violation" },
 569         { ENOSPACE,     "Disk full or allocation exceeded" },
 570         { EBADOP,       "Illegal KDUMP operation" },
 571         { EBADID,       "Unknown transfer ID" },
 572         { EEXISTS,      "File already exists" },
 573         { ENOUSER,      "No such user" },
 574         { -1,           0 }
 575 };
 576
 577 static char *
 578 errtomsg(error)
 579         int error;
 580 {
 581         static char buf[20];
 582         register struct errmsg *pe;
 583         if (error == 0)
 584                 return "success";
 585         for (pe = errmsgs; pe->e_code >= 0; pe++)
 586                 if (pe->e_code == error)
 587                         return pe->e_msg;
 588         snprintf(buf, sizeof(buf), "error %d", error);
 589         return buf;
 590 }
 591
 592 /*
 593  * Send a nak packet (error message).
 594  * Error code passed in is one of the
 595  * standard KDUMP codes, or a UNIX errno
 596  * offset by 100.
 597  */
 598 static void
 599 nak(error)
 600         int error;
 601 {
 602         register struct kdumphdr *tp;
 603         int length;
 604         register struct errmsg *pe;
 605
 606         tp = (struct kdumphdr *)buf;
 607         tp->th_opcode = htons((u_short)ERROR);
 608         tp->th_code = htons((unsigned int)error);
 609         for (pe = errmsgs; pe->e_code >= 0; pe++)
 610                 if (pe->e_code == error)
 611                         break;
 612         if (pe->e_code < 0) {
 613                 pe->e_msg = strerror(error - 100);
 614                 tp->th_code = EUNDEF;   /* set 'undef' errorcode */
 615         }
 616         strcpy(tp->th_msg, pe->e_msg);
 617         length = strlen(pe->e_msg);
 618         tp->th_msg[length] = '\0';
 619         length += 5;
 620         if (send(peer, buf, length, 0) != length)
 621                 syslog(LOG_ERR, "nak: %m");
 622 }
 623
 624 static char *
 625 verifyhost(fromp)
 626         struct sockaddr_in *fromp;
 627 {
 628         struct hostent *hp;
 629
 630         hp = gethostbyaddr((char *)&fromp->sin_addr, sizeof(fromp->sin_addr),
 631                 fromp->sin_family);
 632         if(hp)
 633                 return hp->h_name;
 634         else
 635                 return inet_ntoa(fromp->sin_addr);
 636 }