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 *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 *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 *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 *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 /* *** 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
 202 /*
 203  * Get name of {u,w}tmp{,x} file.
 204  *      return: fname contains filename
 205  *              Possibly empty if this code not yet ported to this system.
 206  *
 207  * utmp{,x}:  try "utmp dir", then default (a define)
 208  * wtmp{,x}:  try "wtmp dir", then "utmp dir", then default (a define)
 209  */
 210 static char *uw_pathname(TALLOC_CTX *ctx,
 211                 const char *uw_name,
 212                 const char *uw_default)
 213 {
 214         char *dirname = NULL;
 215
 216         /* For w-files, first look for explicit "wtmp dir" */
 217         if (uw_name[0] == 'w') {
 218                 dirname = talloc_strdup(ctx, lp_wtmpdir());
 219                 if (!dirname) {
 220                         return NULL;
 221                 }
 222                 trim_char(dirname,'\0','/');
 223         }
 224
 225         /* For u-files and non-explicit w-dir, look for "utmp dir" */
 226         if ((dirname == NULL) || (strlen(dirname) == 0)) {
 227                 dirname = talloc_strdup(ctx, lp_utmpdir());
 228                 if (!dirname) {
 229                         return NULL;
 230                 }
 231                 trim_char(dirname,'\0','/');
 232         }
 233
 234         /* If explicit directory above, use it */
 235         if (dirname && strlen(dirname) != 0) {
 236                 return talloc_asprintf(ctx,
 237                                 "%s/%s",
 238                                 dirname,
 239                                 uw_name);
 240         }
 241
 242         /* No explicit directory: attempt to use default paths */
 243         if (strlen(uw_default) == 0) {
 244                 /* No explicit setting, no known default.
 245                  * Has it yet been ported to this OS?
 246                  */
 247                 DEBUG(2,("uw_pathname: unable to determine pathname\n"));
 248         }
 249         return talloc_strdup(ctx, uw_default);
 250 }
 251
 252 #ifndef HAVE_PUTUTLINE
 253 /****************************************************************************
 254  Update utmp file directly.  No subroutine interface: probably a BSD system.
 255 ****************************************************************************/
 256
 257 static void pututline_my(const char *uname, struct utmp *u, bool claim)
 258 {
 259         DEBUG(1,("pututline_my: not yet implemented\n"));
 260         /* BSD implementor: may want to consider (or not) adjusting "lastlog" */
 261 }
 262 #endif /* HAVE_PUTUTLINE */
 263
 264 #ifndef HAVE_UPDWTMP
 265
 266 /****************************************************************************
 267  Update wtmp file directly.  No subroutine interface: probably a BSD system.
 268  Credit: Michail Vidiassov <master@iaas.msu.ru>
 269 ****************************************************************************/
 270
 271 static void updwtmp_my(const char *wname, struct utmp *u, bool claim)
 272 {
 273         int fd;
 274         struct stat buf;
 275
 276         if (! claim) {
 277                 /*
 278                  * BSD-like systems:
 279                  *      may use empty ut_name to distinguish a logout record.
 280                  *
 281                  * May need "if defined(SUNOS4)" etc. around some of these,
 282                  * but try to avoid if possible.
 283                  *
 284                  * SunOS 4:
 285                  *      man page indicates ut_name and ut_host both NULL
 286                  * FreeBSD 4.0:
 287                  *      man page appears not to specify (hints non-NULL)
 288                  *      A correspondent suggest at least ut_name should be NULL
 289                  */
 290 #if defined(HAVE_UT_UT_NAME)
 291                 memset((char *)&u->ut_name, '\0', sizeof(u->ut_name));
 292 #endif
 293 #if defined(HAVE_UT_UT_HOST)
 294                 memset((char *)&u->ut_host, '\0', sizeof(u->ut_host));
 295 #endif
 296         }
 297         /* Stolen from logwtmp function in libutil.
 298          * May be more locking/blocking is needed?
 299          */
 300         if ((fd = open(wname, O_WRONLY|O_APPEND, 0)) < 0)
 301                 return;
 302         if (fstat(fd, &buf) == 0) {
 303                 if (write(fd, (char *)u, sizeof(struct utmp)) != sizeof(struct utmp))
 304                 (void) ftruncate(fd, buf.st_size);
 305         }
 306         (void) close(fd);
 307 }
 308 #endif /* HAVE_UPDWTMP */
 309
 310 /****************************************************************************
 311  Update via utmp/wtmp (not utmpx/wtmpx).
 312 ****************************************************************************/
 313
 314 static void utmp_nox_update(struct utmp *u, bool claim)
 315 {
 316         char *uname = NULL;
 317         char *wname = NULL;
 318 #if defined(PUTUTLINE_RETURNS_UTMP)
 319         struct utmp *urc;
 320 #endif /* PUTUTLINE_RETURNS_UTMP */
 321
 322         uname = uw_pathname(talloc_tos(), "utmp", ut_pathname);
 323         if (!uname) {
 324                 return;
 325         }
 326         DEBUG(2,("utmp_nox_update: uname:%s\n", uname));
 327
 328 #ifdef HAVE_PUTUTLINE
 329         if (strlen(uname) != 0) {
 330                 utmpname(uname);
 331         }
 332
 333 # if defined(PUTUTLINE_RETURNS_UTMP)
 334         setutent();
 335         urc = pututline(u);
 336         endutent();
 337         if (urc == NULL) {
 338                 DEBUG(2,("utmp_nox_update: pututline() failed\n"));
 339                 return;
 340         }
 341 # else  /* PUTUTLINE_RETURNS_UTMP */
 342         setutent();
 343         pututline(u);
 344         endutent();
 345 # endif /* PUTUTLINE_RETURNS_UTMP */
 346
 347 #else   /* HAVE_PUTUTLINE */
 348         if (strlen(uname) != 0) {
 349                 pututline_my(uname, u, claim);
 350         }
 351 #endif /* HAVE_PUTUTLINE */
 352
 353         wname = uw_pathname(talloc_tos(), "wtmp", wt_pathname);
 354         if (!wname) {
 355                 return;
 356         }
 357         DEBUG(2,("utmp_nox_update: wname:%s\n", wname));
 358         if (strlen(wname) != 0) {
 359 #ifdef HAVE_UPDWTMP
 360                 updwtmp(wname, u);
 361                 /*
 362                  * updwtmp() and the newer updwtmpx() may be unsymmetrical.
 363                  * At least one OS, Solaris 2.x declares the former in the
 364                  * "utmpx" (latter) file and context.
 365                  * In the Solaris case this is irrelevant: it has both and
 366                  * we always prefer the "x" case, so doesn't come here.
 367                  * But are there other systems, with no "x", which lack
 368                  * updwtmp() perhaps?
 369                  */
 370 #else
 371                 updwtmp_my(wname, u, claim);
 372 #endif /* HAVE_UPDWTMP */
 373         }
 374 }
 375
 376 /****************************************************************************
 377  Copy a string in the utmp structure.
 378 ****************************************************************************/
 379
 380 static void utmp_strcpy(char *dest, const char *src, size_t n)
 381 {
 382         size_t len = 0;
 383
 384         memset(dest, '\0', n);
 385         if (src)
 386                 len = strlen(src);
 387         if (len >= n) {
 388                 memcpy(dest, src, n);
 389         } else {
 390                 if (len)
 391                         memcpy(dest, src, len);
 392         }
 393 }
 394
 395 /****************************************************************************
 396  Update via utmpx/wtmpx (preferred) or via utmp/wtmp.
 397 ****************************************************************************/
 398
 399 static void sys_utmp_update(struct utmp *u, const char *hostname, bool claim)
 400 {
 401 #if !defined(HAVE_UTMPX_H)
 402         /* No utmpx stuff.  Drop to non-x stuff */
 403         utmp_nox_update(u, claim);
 404 #elif !defined(HAVE_PUTUTXLINE)
 405         /* Odd.  Have utmpx.h but no "pututxline()".  Drop to non-x stuff */
 406         DEBUG(1,("utmp_update: have utmpx.h but no pututxline() function\n"));
 407         utmp_nox_update(u, claim);
 408 #elif !defined(HAVE_GETUTMPX)
 409         /* Odd.  Have utmpx.h but no "getutmpx()".  Drop to non-x stuff */
 410         DEBUG(1,("utmp_update: have utmpx.h but no getutmpx() function\n"));
 411         utmp_nox_update(u, claim);
 412 #else
 413         char *uname = NULL;
 414         char *wname = NULL;
 415         struct utmpx ux, *uxrc;
 416
 417         getutmpx(u, &ux);
 418
 419 #if defined(HAVE_UX_UT_SYSLEN)
 420         if (hostname)
 421                 ux.ut_syslen = strlen(hostname) + 1;    /* include end NULL */
 422         else
 423                 ux.ut_syslen = 0;
 424 #endif
 425 #if defined(HAVE_UT_UT_HOST)
 426         utmp_strcpy(ux.ut_host, hostname, sizeof(ux.ut_host));
 427 #endif
 428
 429         uname = uw_pathname(talloc_tos(), "utmpx", ux_pathname);
 430         wname = uw_pathname(talloc_tos(), "wtmpx", wx_pathname);
 431         if (uname && wname) {
 432                 DEBUG(2,("utmp_update: uname:%s wname:%s\n", uname, wname));
 433         }
 434
 435         /*
 436          * Check for either uname or wname being empty.
 437          * Some systems, such as Redhat 6, have a "utmpx.h" which doesn't
 438          * define default filenames.
 439          * Also, our local installation has not provided an override.
 440          * Drop to non-x method.  (E.g. RH6 has good defaults in "utmp.h".)
 441          */
 442         if (!uname || !wname || (strlen(uname) == 0) || (strlen(wname) == 0)) {
 443                 utmp_nox_update(u, claim);
 444         } else {
 445                 utmpxname(uname);
 446                 setutxent();
 447                 uxrc = pututxline(&ux);
 448                 endutxent();
 449                 if (uxrc == NULL) {
 450                         DEBUG(2,("utmp_update: pututxline() failed\n"));
 451                         return;
 452                 }
 453                 updwtmpx(wname, &ux);
 454         }
 455 #endif /* HAVE_UTMPX_H */
 456 }
 457
 458 #if defined(HAVE_UT_UT_ID)
 459 /****************************************************************************
 460  Encode the unique connection number into "ut_id".
 461 ****************************************************************************/
 462
 463 static int ut_id_encode(int i, char *fourbyte)
 464 {
 465         int nbase;
 466         const char *ut_id_encstr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 467
 468         fourbyte[0] = 'S';
 469         fourbyte[1] = 'M';
 470
 471 /*
 472  * Encode remaining 2 bytes from 'i'.
 473  * 'ut_id_encstr' is the character set on which modulo arithmetic is done.
 474  * Example: digits would produce the base-10 numbers from '001'.
 475  */
 476         nbase = strlen(ut_id_encstr);
 477
 478         fourbyte[3] = ut_id_encstr[i % nbase];
 479         i /= nbase;
 480         fourbyte[2] = ut_id_encstr[i % nbase];
 481         i /= nbase;
 482
 483         return(i);      /* 0: good; else overflow */
 484 }
 485 #endif /* defined(HAVE_UT_UT_ID) */
 486
 487
 488 /*
 489   fill a system utmp structure given all the info we can gather
 490 */
 491 static bool sys_utmp_fill(struct utmp *u,
 492                         const char *username, const char *hostname,
 493                         const char *ip_addr_str,
 494                         const char *id_str, int id_num)
 495 {
 496         struct timeval timeval;
 497
 498         /*
 499          * ut_name, ut_user:
 500          *      Several (all?) systems seems to define one as the other.
 501          *      It is easier and clearer simply to let the following take its course,
 502          *      rather than to try to detect and optimise.
 503          */
 504 #if defined(HAVE_UT_UT_USER)
 505         utmp_strcpy(u->ut_user, username, sizeof(u->ut_user));
 506 #elif defined(HAVE_UT_UT_NAME)
 507         utmp_strcpy(u->ut_name, username, sizeof(u->ut_name));
 508 #endif
 509
 510         /*
 511          * ut_line:
 512          *      If size limit proves troublesome, then perhaps use "ut_id_encode()".
 513          */
 514         if (strlen(id_str) > sizeof(u->ut_line)) {
 515                 DEBUG(1,("id_str [%s] is too long for %lu char utmp field\n",
 516                          id_str, (unsigned long)sizeof(u->ut_line)));
 517                 return False;
 518         }
 519         utmp_strcpy(u->ut_line, id_str, sizeof(u->ut_line));
 520
 521 #if defined(HAVE_UT_UT_PID)
 522         u->ut_pid = sys_getpid();
 523 #endif
 524
 525 /*
 526  * ut_time, ut_tv:
 527  *      Some have one, some the other.  Many have both, but defined (aliased).
 528  *      It is easier and clearer simply to let the following take its course.
 529  *      But note that we do the more precise ut_tv as the final assignment.
 530  */
 531 #if defined(HAVE_UT_UT_TIME)
 532         GetTimeOfDay(&timeval);
 533         u->ut_time = timeval.tv_sec;
 534 #elif defined(HAVE_UT_UT_TV)
 535         GetTimeOfDay(&timeval);
 536         u->ut_tv = timeval;
 537 #else
 538 #error "with-utmp must have UT_TIME or UT_TV"
 539 #endif
 540
 541 #if defined(HAVE_UT_UT_HOST)
 542         utmp_strcpy(u->ut_host, hostname, sizeof(u->ut_host));
 543 #endif
 544 #if defined(HAVE_IPV6) && defined(HAVE_UT_UT_ADDR_V6)
 545         memset(&u->ut_addr_v6, '\0', sizeof(u->ut_addr_v6));
 546         if (ip_addr_str) {
 547                 struct in6_addr addr;
 548                 if (inet_pton(AF_INET6, ip_addr_str, &addr) > 0) {
 549                         memcpy(&u->ut_addr_v6, &addr, sizeof(addr));
 550                 }
 551         }
 552 #elif defined(HAVE_UT_UT_ADDR)
 553         memset(&u->ut_addr, '\0', sizeof(u->ut_addr));
 554         if (ip_addr_str) {
 555                 struct in_addr addr;
 556                 if (inet_pton(AF_INET, ip_addr_str, &addr) > 0) {
 557                         memcpy(&u->ut_addr, &addr, sizeof(addr));
 558                 }
 559         }
 560         /*
 561          * "(unsigned long) ut_addr" apparently exists on at least HP-UX 10.20.
 562          * Volunteer to implement, please ...
 563          */
 564 #endif
 565
 566 #if defined(HAVE_UT_UT_ID)
 567         if (ut_id_encode(id_num, u->ut_id) != 0) {
 568                 DEBUG(1,("utmp_fill: cannot encode id %d\n", id_num));
 569                 return False;
 570         }
 571 #endif
 572
 573         return True;
 574 }
 575
 576 /****************************************************************************
 577  Close a connection.
 578 ****************************************************************************/
 579
 580 void sys_utmp_yield(const char *username, const char *hostname,
 581                         const char *ip_addr_str,
 582                         const char *id_str, int id_num)
 583 {
 584         struct utmp u;
 585
 586         ZERO_STRUCT(u);
 587
 588 #if defined(HAVE_UT_UT_EXIT)
 589         u.ut_exit.e_termination = 0;
 590         u.ut_exit.e_exit = 0;
 591 #endif
 592
 593 #if defined(HAVE_UT_UT_TYPE)
 594         u.ut_type = DEAD_PROCESS;
 595 #endif
 596
 597         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 598                 return;
 599
 600         sys_utmp_update(&u, NULL, False);
 601 }
 602
 603 /****************************************************************************
 604  Claim a entry in whatever utmp system the OS uses.
 605 ****************************************************************************/
 606
 607 void sys_utmp_claim(const char *username, const char *hostname,
 608                         const char *ip_addr_str,
 609                         const char *id_str, int id_num)
 610 {
 611         struct utmp u;
 612
 613         ZERO_STRUCT(u);
 614
 615 #if defined(HAVE_UT_UT_TYPE)
 616         u.ut_type = USER_PROCESS;
 617 #endif
 618
 619         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 620                 return;
 621
 622         sys_utmp_update(&u, hostname, True);
 623 }
 624
 625 #endif /* WITH_UTMP */