source3/smbd/utmp.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    utmp routines
   4    Copyright (C) T.D.Lee@durham.ac.uk 1999
   5    Heavily modified by Andrew Bartlett and Tridge, April 2001
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22
  23 /****************************************************************************
  24 Reflect connection status in utmp/wtmp files.
  25         T.D.Lee@durham.ac.uk  September 1999
  26
  27         With grateful thanks since then to many who have helped port it to
  28         different operating systems.  The variety of OS quirks thereby
  29         uncovered is amazing...
  30
  31 Hints for porting:
  32         o  Always attempt to use programmatic interface (pututline() etc.)
  33            Indeed, at present only programmatic use is supported.
  34         o  The only currently supported programmatic interface to "wtmp{,x}"
  35            is through "updwtmp*()" routines.
  36         o  The "x" (utmpx/wtmpx; HAVE_UTMPX_H) seems preferable.
  37         o  The HAVE_* items should identify supported features.
  38         o  If at all possible, avoid "if defined(MY-OS)" constructions.
  39
  40 OS observations and status:
  41         Almost every OS seems to have its own quirks.
  42
  43         Solaris 2.x:
  44                 Tested on 2.6 and 2.7; should be OK on other flavours.
  45         AIX:
  46                 Apparently has utmpx.h but doesn't implement.
  47         OSF:
  48                 Has utmpx.h, but (e.g.) no "getutmpx()".  (Is this like AIX ?)
  49         Redhat 6:
  50                 utmpx.h seems not to set default filenames.  non-x better.
  51         IRIX 6.5:
  52                 Not tested.  Appears to have "x".
  53         HP-UX 9.x:
  54                 Not tested.  Appears to lack "x".
  55         HP-UX 10.x:
  56                 Not tested.
  57                 "updwtmp*()" routines seem absent, so no current wtmp* support.
  58                 Has "ut_addr": probably trivial to implement (although remember
  59                 that IPv6 is coming...).
  60
  61         FreeBSD:
  62                 No "putut*()" type of interface.
  63                 No "ut_type" and associated defines.
  64                 Write files directly.  Alternatively use its login(3)/logout(3).
  65         SunOS 4:
  66                 Not tested.  Resembles FreeBSD, but no login()/logout().
  67
  68 lastlog:
  69         Should "lastlog" files, if any, be updated?
  70         BSD systems (SunOS 4, FreeBSD):
  71                 o  Prominent mention on man pages.
  72         System-V (e.g. Solaris 2):
  73                 o  No mention on man pages, even under "man -k".
  74                 o  Has a "/var/adm/lastlog" file, but pututxline() etc. seem
  75                    not to touch it.
  76                 o  Despite downplaying (above), nevertheless has <lastlog.h>.
  77         So perhaps UN*X "lastlog" facility is intended for tty/terminal only?
  78
  79 Notes:
  80         Each connection requires a small number (starting at 0, working up)
  81         to represent the line.  This must be unique within and across all
  82         smbd processes.  It is the 'id_num' from Samba's session.c code.
  83
  84         The 4 byte 'ut_id' component is vital to distinguish connections,
  85         of which there could be several hundred or even thousand.
  86         Entries seem to be printable characters, with optional NULL pads.
  87
  88         We need to be distinct from other entries in utmp/wtmp.
  89
  90         Observed things: therefore avoid them.  Add to this list please.
  91         From Solaris 2.x (because that's what I have):
  92                 'sN'    : run-levels; N: [0-9]
  93                 'co'    : console
  94                 'CC'    : arbitrary things;  C: [a-z]
  95                 'rXNN'  : rlogin;  N: [0-9]; X: [0-9a-z]
  96                 'tXNN'  : rlogin;  N: [0-9]; X: [0-9a-z]
  97                 '/NNN'  : Solaris CDE
  98                 'ftpZ'  : ftp (Z is the number 255, aka 0377, aka 0xff)
  99         Mostly a record uses the same 'ut_id' in both "utmp" and "wtmp",
 100         but differences have been seen.
 101
 102         Arbitrarily I have chosen to use a distinctive 'SM' for the
 103         first two bytes.
 104
 105         The remaining two bytes encode the session 'id_num' (see above).
 106         Our caller (session.c) should note our 16-bit limitation.
 107
 108 ****************************************************************************/
 109
 110 #ifndef WITH_UTMP
 111 /*
 112  * Not WITH_UTMP?  Simply supply dummy routines.
 113  */
 114
 115 void sys_utmp_claim(const char *username, const char *hostname,
 116                         const char *ip_addr_str,
 117                         const char *id_str, int id_num)
 118 {}
 119
 120 void sys_utmp_yield(const char *username, const char *hostname,
 121                         const char *ip_addr_str,
 122                         const char *id_str, int id_num)
 123 {}
 124
 125 #else /* WITH_UTMP */
 126
 127 #include <utmp.h>
 128
 129 #ifdef HAVE_UTMPX_H
 130 #include <utmpx.h>
 131 #endif
 132
 133 /* BSD systems: some may need lastlog.h (SunOS 4), some may not (FreeBSD) */
 134 /* Some System-V systems (e.g. Solaris 2) declare this too. */
 135 #ifdef HAVE_LASTLOG_H
 136 #include <lastlog.h>
 137 #endif
 138
 139 /****************************************************************************
 140  Default paths to various {u,w}tmp{,x} files.
 141 ****************************************************************************/
 142
 143 #ifdef  HAVE_UTMPX_H
 144
 145 static const char * const ux_pathname =
 146 # if defined (UTMPX_FILE)
 147         UTMPX_FILE ;
 148 # elif defined (_UTMPX_FILE)
 149         _UTMPX_FILE ;
 150 # elif defined (_PATH_UTMPX)
 151         _PATH_UTMPX ;
 152 # else
 153         "" ;
 154 # endif
 155
 156 static const char * const wx_pathname =
 157 # if defined (WTMPX_FILE)
 158         WTMPX_FILE ;
 159 # elif defined (_WTMPX_FILE)
 160         _WTMPX_FILE ;
 161 # elif defined (_PATH_WTMPX)
 162         _PATH_WTMPX ;
 163 # else
 164         "" ;
 165 # endif
 166
 167 #endif  /* HAVE_UTMPX_H */
 168
 169 static const char * const ut_pathname =
 170 # if defined (UTMP_FILE)
 171         UTMP_FILE ;
 172 # elif defined (_UTMP_FILE)
 173         _UTMP_FILE ;
 174 # elif defined (_PATH_UTMP)
 175         _PATH_UTMP ;
 176 # else
 177         "" ;
 178 # endif
 179
 180 static const char * const wt_pathname =
 181 # if defined (WTMP_FILE)
 182         WTMP_FILE ;
 183 # elif defined (_WTMP_FILE)
 184         _WTMP_FILE ;
 185 # elif defined (_PATH_WTMP)
 186         _PATH_WTMP ;
 187 # else
 188         "" ;
 189 # endif
 190
 191 /* BSD-like systems might want "lastlog" support. */
 192 #if 0 /* *** Not yet implemented */
 193 #ifndef HAVE_PUTUTLINE          /* see "pututline_my()" */
 194 static const char *ll_pathname =
 195 # if defined (_PATH_LASTLOG)    /* what other names (if any?) */
 196         _PATH_LASTLOG ;
 197 # else
 198         "" ;
 199 # endif /* _PATH_LASTLOG */
 200 #endif  /* HAVE_PUTUTLINE */
 201 #endif
 202
 203 /*
 204  * Get name of {u,w}tmp{,x} file.
 205  *      return: fname contains filename
 206  *              Possibly empty if this code not yet ported to this system.
 207  *
 208  * utmp{,x}:  try "utmp dir", then default (a define)
 209  * wtmp{,x}:  try "wtmp dir", then "utmp dir", then default (a define)
 210  */
 211 static char *uw_pathname(TALLOC_CTX *ctx,
 212                 const char *uw_name,
 213                 const char *uw_default)
 214 {
 215         char *dirname = NULL;
 216
 217         /* For w-files, first look for explicit "wtmp dir" */
 218         if (uw_name[0] == 'w') {
 219                 dirname = talloc_strdup(ctx, lp_wtmpdir());
 220                 if (!dirname) {
 221                         return NULL;
 222                 }
 223                 trim_char(dirname,'\0','/');
 224         }
 225
 226         /* For u-files and non-explicit w-dir, look for "utmp dir" */
 227         if ((dirname == NULL) || (strlen(dirname) == 0)) {
 228                 dirname = talloc_strdup(ctx, lp_utmpdir());
 229                 if (!dirname) {
 230                         return NULL;
 231                 }
 232                 trim_char(dirname,'\0','/');
 233         }
 234
 235         /* If explicit directory above, use it */
 236         if (dirname && strlen(dirname) != 0) {
 237                 return talloc_asprintf(ctx,
 238                                 "%s/%s",
 239                                 dirname,
 240                                 uw_name);
 241         }
 242
 243         /* No explicit directory: attempt to use default paths */
 244         if (strlen(uw_default) == 0) {
 245                 /* No explicit setting, no known default.
 246                  * Has it yet been ported to this OS?
 247                  */
 248                 DEBUG(2,("uw_pathname: unable to determine pathname\n"));
 249         }
 250         return talloc_strdup(ctx, uw_default);
 251 }
 252
 253 #ifndef HAVE_PUTUTLINE
 254 /****************************************************************************
 255  Update utmp file directly.  No subroutine interface: probably a BSD system.
 256 ****************************************************************************/
 257
 258 static void pututline_my(const char *uname, struct utmp *u, bool claim)
 259 {
 260         DEBUG(1,("pututline_my: not yet implemented\n"));
 261         /* BSD implementor: may want to consider (or not) adjusting "lastlog" */
 262 }
 263 #endif /* HAVE_PUTUTLINE */
 264
 265 #ifndef HAVE_UPDWTMP
 266
 267 /****************************************************************************
 268  Update wtmp file directly.  No subroutine interface: probably a BSD system.
 269  Credit: Michail Vidiassov <master@iaas.msu.ru>
 270 ****************************************************************************/
 271
 272 static void updwtmp_my(const char *wname, struct utmp *u, bool claim)
 273 {
 274         int fd;
 275         struct stat buf;
 276
 277         if (! claim) {
 278                 /*
 279                  * BSD-like systems:
 280                  *      may use empty ut_name to distinguish a logout record.
 281                  *
 282                  * May need "if defined(SUNOS4)" etc. around some of these,
 283                  * but try to avoid if possible.
 284                  *
 285                  * SunOS 4:
 286                  *      man page indicates ut_name and ut_host both NULL
 287                  * FreeBSD 4.0:
 288                  *      man page appears not to specify (hints non-NULL)
 289                  *      A correspondent suggest at least ut_name should be NULL
 290                  */
 291 #if defined(HAVE_UT_UT_NAME)
 292                 memset((char *)&u->ut_name, '\0', sizeof(u->ut_name));
 293 #endif
 294 #if defined(HAVE_UT_UT_HOST)
 295                 memset((char *)&u->ut_host, '\0', sizeof(u->ut_host));
 296 #endif
 297         }
 298         /* Stolen from logwtmp function in libutil.
 299          * May be more locking/blocking is needed?
 300          */
 301         if ((fd = open(wname, O_WRONLY|O_APPEND, 0)) < 0)
 302                 return;
 303         if (fstat(fd, &buf) == 0) {
 304                 if (write(fd, (char *)u, sizeof(struct utmp)) != sizeof(struct utmp))
 305                 (void) ftruncate(fd, buf.st_size);
 306         }
 307         (void) close(fd);
 308 }
 309 #endif /* HAVE_UPDWTMP */
 310
 311 /****************************************************************************
 312  Update via utmp/wtmp (not utmpx/wtmpx).
 313 ****************************************************************************/
 314
 315 static void utmp_nox_update(struct utmp *u, bool claim)
 316 {
 317         char *uname = NULL;
 318         char *wname = NULL;
 319 #if defined(PUTUTLINE_RETURNS_UTMP)
 320         struct utmp *urc;
 321 #endif /* PUTUTLINE_RETURNS_UTMP */
 322
 323         uname = uw_pathname(talloc_tos(), "utmp", ut_pathname);
 324         if (!uname) {
 325                 return;
 326         }
 327         DEBUG(2,("utmp_nox_update: uname:%s\n", uname));
 328
 329 #ifdef HAVE_PUTUTLINE
 330         if (strlen(uname) != 0) {
 331                 utmpname(uname);
 332         }
 333
 334 # if defined(PUTUTLINE_RETURNS_UTMP)
 335         setutent();
 336         urc = pututline(u);
 337         endutent();
 338         if (urc == NULL) {
 339                 DEBUG(2,("utmp_nox_update: pututline() failed\n"));
 340                 return;
 341         }
 342 # else  /* PUTUTLINE_RETURNS_UTMP */
 343         setutent();
 344         pututline(u);
 345         endutent();
 346 # endif /* PUTUTLINE_RETURNS_UTMP */
 347
 348 #else   /* HAVE_PUTUTLINE */
 349         if (strlen(uname) != 0) {
 350                 pututline_my(uname, u, claim);
 351         }
 352 #endif /* HAVE_PUTUTLINE */
 353
 354         wname = uw_pathname(talloc_tos(), "wtmp", wt_pathname);
 355         if (!wname) {
 356                 return;
 357         }
 358         DEBUG(2,("utmp_nox_update: wname:%s\n", wname));
 359         if (strlen(wname) != 0) {
 360 #ifdef HAVE_UPDWTMP
 361                 updwtmp(wname, u);
 362                 /*
 363                  * updwtmp() and the newer updwtmpx() may be unsymmetrical.
 364                  * At least one OS, Solaris 2.x declares the former in the
 365                  * "utmpx" (latter) file and context.
 366                  * In the Solaris case this is irrelevant: it has both and
 367                  * we always prefer the "x" case, so doesn't come here.
 368                  * But are there other systems, with no "x", which lack
 369                  * updwtmp() perhaps?
 370                  */
 371 #else
 372                 updwtmp_my(wname, u, claim);
 373 #endif /* HAVE_UPDWTMP */
 374         }
 375 }
 376
 377 /****************************************************************************
 378  Copy a string in the utmp structure.
 379 ****************************************************************************/
 380
 381 static void utmp_strcpy(char *dest, const char *src, size_t n)
 382 {
 383         size_t len = 0;
 384
 385         memset(dest, '\0', n);
 386         if (src)
 387                 len = strlen(src);
 388         if (len >= n) {
 389                 memcpy(dest, src, n);
 390         } else {
 391                 if (len)
 392                         memcpy(dest, src, len);
 393         }
 394 }
 395
 396 /****************************************************************************
 397  Update via utmpx/wtmpx (preferred) or via utmp/wtmp.
 398 ****************************************************************************/
 399
 400 static void sys_utmp_update(struct utmp *u, const char *hostname, bool claim)
 401 {
 402 #if !defined(HAVE_UTMPX_H)
 403         /* No utmpx stuff.  Drop to non-x stuff */
 404         utmp_nox_update(u, claim);
 405 #elif !defined(HAVE_PUTUTXLINE)
 406         /* Odd.  Have utmpx.h but no "pututxline()".  Drop to non-x stuff */
 407         DEBUG(1,("utmp_update: have utmpx.h but no pututxline() function\n"));
 408         utmp_nox_update(u, claim);
 409 #elif !defined(HAVE_GETUTMPX)
 410         /* Odd.  Have utmpx.h but no "getutmpx()".  Drop to non-x stuff */
 411         DEBUG(1,("utmp_update: have utmpx.h but no getutmpx() function\n"));
 412         utmp_nox_update(u, claim);
 413 #elif !defined(HAVE_UPDWTMPX)
 414         /* Have utmpx.h but no "updwtmpx()".  Drop to non-x stuff */
 415         DEBUG(1,("utmp_update: have utmpx.h but no updwtmpx() function\n"));
 416         utmp_nox_update(u, claim);
 417 #else
 418         char *uname = NULL;
 419         char *wname = NULL;
 420         struct utmpx ux, *uxrc;
 421
 422         getutmpx(u, &ux);
 423
 424 #if defined(HAVE_UX_UT_SYSLEN)
 425         if (hostname)
 426                 ux.ut_syslen = strlen(hostname) + 1;    /* include end NULL */
 427         else
 428                 ux.ut_syslen = 0;
 429 #endif
 430 #if defined(HAVE_UT_UT_HOST)
 431         utmp_strcpy(ux.ut_host, hostname, sizeof(ux.ut_host));
 432 #endif
 433
 434         uname = uw_pathname(talloc_tos(), "utmpx", ux_pathname);
 435         wname = uw_pathname(talloc_tos(), "wtmpx", wx_pathname);
 436         if (uname && wname) {
 437                 DEBUG(2,("utmp_update: uname:%s wname:%s\n", uname, wname));
 438         }
 439
 440         /*
 441          * Check for either uname or wname being empty.
 442          * Some systems, such as Redhat 6, have a "utmpx.h" which doesn't
 443          * define default filenames.
 444          * Also, our local installation has not provided an override.
 445          * Drop to non-x method.  (E.g. RH6 has good defaults in "utmp.h".)
 446          */
 447         if (!uname || !wname || (strlen(uname) == 0) || (strlen(wname) == 0)) {
 448                 utmp_nox_update(u, claim);
 449         } else {
 450                 utmpxname(uname);
 451                 setutxent();
 452                 uxrc = pututxline(&ux);
 453                 endutxent();
 454                 if (uxrc == NULL) {
 455                         DEBUG(2,("utmp_update: pututxline() failed\n"));
 456                         return;
 457                 }
 458                 updwtmpx(wname, &ux);
 459         }
 460 #endif /* HAVE_UTMPX_H */
 461 }
 462
 463 #if defined(HAVE_UT_UT_ID)
 464 /****************************************************************************
 465  Encode the unique connection number into "ut_id".
 466 ****************************************************************************/
 467
 468 static int ut_id_encode(int i, char *fourbyte)
 469 {
 470         int nbase;
 471         const char *ut_id_encstr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 472
 473         fourbyte[0] = 'S';
 474         fourbyte[1] = 'M';
 475
 476 /*
 477  * Encode remaining 2 bytes from 'i'.
 478  * 'ut_id_encstr' is the character set on which modulo arithmetic is done.
 479  * Example: digits would produce the base-10 numbers from '001'.
 480  */
 481         nbase = strlen(ut_id_encstr);
 482
 483         fourbyte[3] = ut_id_encstr[i % nbase];
 484         i /= nbase;
 485         fourbyte[2] = ut_id_encstr[i % nbase];
 486         i /= nbase;
 487
 488         return(i);      /* 0: good; else overflow */
 489 }
 490 #endif /* defined(HAVE_UT_UT_ID) */
 491
 492
 493 /*
 494   fill a system utmp structure given all the info we can gather
 495 */
 496 static bool sys_utmp_fill(struct utmp *u,
 497                         const char *username, const char *hostname,
 498                         const char *ip_addr_str,
 499                         const char *id_str, int id_num)
 500 {
 501         struct timeval timeval;
 502
 503         /*
 504          * ut_name, ut_user:
 505          *      Several (all?) systems seems to define one as the other.
 506          *      It is easier and clearer simply to let the following take its course,
 507          *      rather than to try to detect and optimise.
 508          */
 509 #if defined(HAVE_UT_UT_USER)
 510         utmp_strcpy(u->ut_user, username, sizeof(u->ut_user));
 511 #elif defined(HAVE_UT_UT_NAME)
 512         utmp_strcpy(u->ut_name, username, sizeof(u->ut_name));
 513 #endif
 514
 515         /*
 516          * ut_line:
 517          *      If size limit proves troublesome, then perhaps use "ut_id_encode()".
 518          */
 519         if (strlen(id_str) > sizeof(u->ut_line)) {
 520                 DEBUG(1,("id_str [%s] is too long for %lu char utmp field\n",
 521                          id_str, (unsigned long)sizeof(u->ut_line)));
 522                 return False;
 523         }
 524         utmp_strcpy(u->ut_line, id_str, sizeof(u->ut_line));
 525
 526 #if defined(HAVE_UT_UT_PID)
 527         u->ut_pid = sys_getpid();
 528 #endif
 529
 530 /*
 531  * ut_time, ut_tv:
 532  *      Some have one, some the other.  Many have both, but defined (aliased).
 533  *      It is easier and clearer simply to let the following take its course.
 534  *      But note that we do the more precise ut_tv as the final assignment.
 535  */
 536 #if defined(HAVE_UT_UT_TIME)
 537         GetTimeOfDay(&timeval);
 538         u->ut_time = timeval.tv_sec;
 539 #elif defined(HAVE_UT_UT_TV)
 540         GetTimeOfDay(&timeval);
 541         u->ut_tv = timeval;
 542 #else
 543 #error "with-utmp must have UT_TIME or UT_TV"
 544 #endif
 545
 546 #if defined(HAVE_UT_UT_HOST)
 547         utmp_strcpy(u->ut_host, hostname, sizeof(u->ut_host));
 548 #endif
 549 #if defined(HAVE_IPV6) && defined(HAVE_UT_UT_ADDR_V6)
 550         memset(&u->ut_addr_v6, '\0', sizeof(u->ut_addr_v6));
 551         if (ip_addr_str) {
 552                 struct in6_addr addr;
 553                 if (inet_pton(AF_INET6, ip_addr_str, &addr) > 0) {
 554                         memcpy(&u->ut_addr_v6, &addr, sizeof(addr));
 555                 }
 556         }
 557 #elif defined(HAVE_UT_UT_ADDR)
 558         memset(&u->ut_addr, '\0', sizeof(u->ut_addr));
 559         if (ip_addr_str) {
 560                 struct in_addr addr;
 561                 if (inet_pton(AF_INET, ip_addr_str, &addr) > 0) {
 562                         memcpy(&u->ut_addr, &addr, sizeof(addr));
 563                 }
 564         }
 565         /*
 566          * "(unsigned long) ut_addr" apparently exists on at least HP-UX 10.20.
 567          * Volunteer to implement, please ...
 568          */
 569 #endif
 570
 571 #if defined(HAVE_UT_UT_ID)
 572         if (ut_id_encode(id_num, u->ut_id) != 0) {
 573                 DEBUG(1,("utmp_fill: cannot encode id %d\n", id_num));
 574                 return False;
 575         }
 576 #endif
 577
 578         return True;
 579 }
 580
 581 /****************************************************************************
 582  Close a connection.
 583 ****************************************************************************/
 584
 585 void sys_utmp_yield(const char *username, const char *hostname,
 586                         const char *ip_addr_str,
 587                         const char *id_str, int id_num)
 588 {
 589         struct utmp u;
 590
 591         ZERO_STRUCT(u);
 592
 593 #if defined(HAVE_UT_UT_EXIT)
 594         u.ut_exit.e_termination = 0;
 595         u.ut_exit.e_exit = 0;
 596 #endif
 597
 598 #if defined(HAVE_UT_UT_TYPE)
 599         u.ut_type = DEAD_PROCESS;
 600 #endif
 601
 602         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 603                 return;
 604
 605         sys_utmp_update(&u, NULL, False);
 606 }
 607
 608 /****************************************************************************
 609  Claim a entry in whatever utmp system the OS uses.
 610 ****************************************************************************/
 611
 612 void sys_utmp_claim(const char *username, const char *hostname,
 613                         const char *ip_addr_str,
 614                         const char *id_str, int id_num)
 615 {
 616         struct utmp u;
 617
 618         ZERO_STRUCT(u);
 619
 620 #if defined(HAVE_UT_UT_TYPE)
 621         u.ut_type = USER_PROCESS;
 622 #endif
 623
 624         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 625                 return;
 626
 627         sys_utmp_update(&u, hostname, True);
 628 }
 629
 630 #endif /* WITH_UTMP */