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