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 *ip_addr_str,
 119                         const char *id_str, int id_num)
 120 {}
 121
 122 void sys_utmp_yield(const char *username, const char *hostname,
 123                         const char *ip_addr_str,
 124                         const char *id_str, int id_num)
 125 {}
 126
 127 #else /* WITH_UTMP */
 128
 129 #ifdef HAVE_UTMP_H
 130 #include <utmp.h>
 131 #endif
 132
 133 #ifdef HAVE_UTMPX_H
 134 #include <utmpx.h>
 135 #endif
 136
 137 /* BSD systems: some may need lastlog.h (SunOS 4), some may not (FreeBSD) */
 138 /* Some System-V systems (e.g. Solaris 2) declare this too. */
 139 #ifdef HAVE_LASTLOG_H
 140 #include <lastlog.h>
 141 #endif
 142
 143 /****************************************************************************
 144  Default paths to various {u,w}tmp{,x} files.
 145 ****************************************************************************/
 146
 147 #ifdef  HAVE_UTMPX_H
 148
 149 static const char * const ux_pathname =
 150 # if defined (UTMPX_FILE)
 151         UTMPX_FILE ;
 152 # elif defined (_UTMPX_FILE)
 153         _UTMPX_FILE ;
 154 # elif defined (_PATH_UTMPX)
 155         _PATH_UTMPX ;
 156 # else
 157         "" ;
 158 # endif
 159
 160 static const char * const wx_pathname =
 161 # if defined (WTMPX_FILE)
 162         WTMPX_FILE ;
 163 # elif defined (_WTMPX_FILE)
 164         _WTMPX_FILE ;
 165 # elif defined (_PATH_WTMPX)
 166         _PATH_WTMPX ;
 167 # else
 168         "" ;
 169 # endif
 170
 171 #endif  /* HAVE_UTMPX_H */
 172
 173 static const char * const ut_pathname =
 174 # if defined (UTMP_FILE)
 175         UTMP_FILE ;
 176 # elif defined (_UTMP_FILE)
 177         _UTMP_FILE ;
 178 # elif defined (_PATH_UTMP)
 179         _PATH_UTMP ;
 180 # else
 181         "" ;
 182 # endif
 183
 184 static const char * const wt_pathname =
 185 # if defined (WTMP_FILE)
 186         WTMP_FILE ;
 187 # elif defined (_WTMP_FILE)
 188         _WTMP_FILE ;
 189 # elif defined (_PATH_WTMP)
 190         _PATH_WTMP ;
 191 # else
 192         "" ;
 193 # endif
 194
 195 /* BSD-like systems might want "lastlog" support. */
 196 #if 0 /* *** Not yet implemented */
 197 #ifndef HAVE_PUTUTLINE          /* see "pututline_my()" */
 198 static const char *ll_pathname =
 199 # if defined (_PATH_LASTLOG)    /* what other names (if any?) */
 200         _PATH_LASTLOG ;
 201 # else
 202         "" ;
 203 # endif /* _PATH_LASTLOG */
 204 #endif  /* HAVE_PUTUTLINE */
 205 #endif
 206
 207 /*
 208  * Get name of {u,w}tmp{,x} file.
 209  *      return: fname contains filename
 210  *              Possibly empty if this code not yet ported to this system.
 211  *
 212  * utmp{,x}:  try "utmp dir", then default (a define)
 213  * wtmp{,x}:  try "wtmp dir", then "utmp dir", then default (a define)
 214  */
 215 static char *uw_pathname(TALLOC_CTX *ctx,
 216                 const char *uw_name,
 217                 const char *uw_default)
 218 {
 219         char *dirname = NULL;
 220
 221         /* For w-files, first look for explicit "wtmp dir" */
 222         if (uw_name[0] == 'w') {
 223                 dirname = talloc_strdup(ctx, lp_wtmpdir());
 224                 if (!dirname) {
 225                         return NULL;
 226                 }
 227                 trim_char(dirname,'\0','/');
 228         }
 229
 230         /* For u-files and non-explicit w-dir, look for "utmp dir" */
 231         if ((dirname == NULL) || (strlen(dirname) == 0)) {
 232                 dirname = talloc_strdup(ctx, lp_utmpdir());
 233                 if (!dirname) {
 234                         return NULL;
 235                 }
 236                 trim_char(dirname,'\0','/');
 237         }
 238
 239         /* If explicit directory above, use it */
 240         if (dirname && strlen(dirname) != 0) {
 241                 return talloc_asprintf(ctx,
 242                                 "%s/%s",
 243                                 dirname,
 244                                 uw_name);
 245         }
 246
 247         /* No explicit directory: attempt to use default paths */
 248         if (strlen(uw_default) == 0) {
 249                 /* No explicit setting, no known default.
 250                  * Has it yet been ported to this OS?
 251                  */
 252                 DEBUG(2,("uw_pathname: unable to determine pathname\n"));
 253         }
 254         return talloc_strdup(ctx, uw_default);
 255 }
 256
 257 #ifndef HAVE_PUTUTLINE
 258 /****************************************************************************
 259  Update utmp file directly.  No subroutine interface: probably a BSD system.
 260 ****************************************************************************/
 261
 262 static void pututline_my(const char *uname, struct utmp *u, bool claim)
 263 {
 264         DEBUG(1,("pututline_my: not yet implemented\n"));
 265         /* BSD implementor: may want to consider (or not) adjusting "lastlog" */
 266 }
 267 #endif /* HAVE_PUTUTLINE */
 268
 269 #ifndef HAVE_UPDWTMP
 270
 271 /****************************************************************************
 272  Update wtmp file directly.  No subroutine interface: probably a BSD system.
 273  Credit: Michail Vidiassov <master@iaas.msu.ru>
 274 ****************************************************************************/
 275
 276 static void updwtmp_my(const char *wname, struct utmp *u, bool claim)
 277 {
 278         int fd;
 279         struct stat buf;
 280
 281         if (! claim) {
 282                 /*
 283                  * BSD-like systems:
 284                  *      may use empty ut_name to distinguish a logout record.
 285                  *
 286                  * May need "if defined(SUNOS4)" etc. around some of these,
 287                  * but try to avoid if possible.
 288                  *
 289                  * SunOS 4:
 290                  *      man page indicates ut_name and ut_host both NULL
 291                  * FreeBSD 4.0:
 292                  *      man page appears not to specify (hints non-NULL)
 293                  *      A correspondent suggest at least ut_name should be NULL
 294                  */
 295 #if defined(HAVE_UT_UT_NAME)
 296                 memset((char *)&u->ut_name, '\0', sizeof(u->ut_name));
 297 #endif
 298 #if defined(HAVE_UT_UT_HOST)
 299                 memset((char *)&u->ut_host, '\0', sizeof(u->ut_host));
 300 #endif
 301         }
 302         /* Stolen from logwtmp function in libutil.
 303          * May be more locking/blocking is needed?
 304          */
 305         if ((fd = open(wname, O_WRONLY|O_APPEND, 0)) < 0)
 306                 return;
 307         if (fstat(fd, &buf) == 0) {
 308                 if (write(fd, (char *)u, sizeof(struct utmp)) != sizeof(struct utmp))
 309                 (void) ftruncate(fd, buf.st_size);
 310         }
 311         (void) close(fd);
 312 }
 313 #endif /* HAVE_UPDWTMP */
 314
 315 /****************************************************************************
 316  Update via utmp/wtmp (not utmpx/wtmpx).
 317 ****************************************************************************/
 318
 319 static void utmp_nox_update(struct utmp *u, bool claim)
 320 {
 321         char *uname = NULL;
 322         char *wname = NULL;
 323 #if defined(PUTUTLINE_RETURNS_UTMP)
 324         struct utmp *urc;
 325 #endif /* PUTUTLINE_RETURNS_UTMP */
 326
 327         uname = uw_pathname(talloc_tos(), "utmp", ut_pathname);
 328         if (!uname) {
 329                 return;
 330         }
 331         DEBUG(2,("utmp_nox_update: uname:%s\n", uname));
 332
 333 #ifdef HAVE_PUTUTLINE
 334         if (strlen(uname) != 0) {
 335                 utmpname(uname);
 336         }
 337
 338 # if defined(PUTUTLINE_RETURNS_UTMP)
 339         setutent();
 340         urc = pututline(u);
 341         endutent();
 342         if (urc == NULL) {
 343                 DEBUG(2,("utmp_nox_update: pututline() failed\n"));
 344                 return;
 345         }
 346 # else  /* PUTUTLINE_RETURNS_UTMP */
 347         setutent();
 348         pututline(u);
 349         endutent();
 350 # endif /* PUTUTLINE_RETURNS_UTMP */
 351
 352 #else   /* HAVE_PUTUTLINE */
 353         if (strlen(uname) != 0) {
 354                 pututline_my(uname, u, claim);
 355         }
 356 #endif /* HAVE_PUTUTLINE */
 357
 358         wname = uw_pathname(talloc_tos(), "wtmp", wt_pathname);
 359         if (!wname) {
 360                 return;
 361         }
 362         DEBUG(2,("utmp_nox_update: wname:%s\n", wname));
 363         if (strlen(wname) != 0) {
 364 #ifdef HAVE_UPDWTMP
 365                 updwtmp(wname, u);
 366                 /*
 367                  * updwtmp() and the newer updwtmpx() may be unsymmetrical.
 368                  * At least one OS, Solaris 2.x declares the former in the
 369                  * "utmpx" (latter) file and context.
 370                  * In the Solaris case this is irrelevant: it has both and
 371                  * we always prefer the "x" case, so doesn't come here.
 372                  * But are there other systems, with no "x", which lack
 373                  * updwtmp() perhaps?
 374                  */
 375 #else
 376                 updwtmp_my(wname, u, claim);
 377 #endif /* HAVE_UPDWTMP */
 378         }
 379 }
 380
 381 /****************************************************************************
 382  Copy a string in the utmp structure.
 383 ****************************************************************************/
 384
 385 static void utmp_strcpy(char *dest, const char *src, size_t n)
 386 {
 387         size_t len = 0;
 388
 389         memset(dest, '\0', n);
 390         if (src)
 391                 len = strlen(src);
 392         if (len >= n) {
 393                 memcpy(dest, src, n);
 394         } else {
 395                 if (len)
 396                         memcpy(dest, src, len);
 397         }
 398 }
 399
 400 /****************************************************************************
 401  Update via utmpx/wtmpx (preferred) or via utmp/wtmp.
 402 ****************************************************************************/
 403
 404 static void sys_utmp_update(struct utmp *u, const char *hostname, bool claim)
 405 {
 406 #if !defined(HAVE_UTMPX_H)
 407         /* No utmpx stuff.  Drop to non-x stuff */
 408         utmp_nox_update(u, claim);
 409 #elif !defined(HAVE_PUTUTXLINE)
 410         /* Odd.  Have utmpx.h but no "pututxline()".  Drop to non-x stuff */
 411         DEBUG(1,("utmp_update: have utmpx.h but no pututxline() function\n"));
 412         utmp_nox_update(u, claim);
 413 #elif !defined(HAVE_GETUTMPX)
 414         /* Odd.  Have utmpx.h but no "getutmpx()".  Drop to non-x stuff */
 415         DEBUG(1,("utmp_update: have utmpx.h but no getutmpx() function\n"));
 416         utmp_nox_update(u, claim);
 417 #elif !defined(HAVE_UPDWTMPX)
 418         /* Have utmpx.h but no "updwtmpx()".  Drop to non-x stuff */
 419         DEBUG(1,("utmp_update: have utmpx.h but no updwtmpx() function\n"));
 420         utmp_nox_update(u, claim);
 421 #else
 422         char *uname = NULL;
 423         char *wname = NULL;
 424         struct utmpx ux, *uxrc;
 425
 426         getutmpx(u, &ux);
 427
 428 #if defined(HAVE_UX_UT_SYSLEN)
 429         if (hostname)
 430                 ux.ut_syslen = strlen(hostname) + 1;    /* include end NULL */
 431         else
 432                 ux.ut_syslen = 0;
 433 #endif
 434 #if defined(HAVE_UT_UT_HOST)
 435         utmp_strcpy(ux.ut_host, hostname, sizeof(ux.ut_host));
 436 #endif
 437
 438         uname = uw_pathname(talloc_tos(), "utmpx", ux_pathname);
 439         wname = uw_pathname(talloc_tos(), "wtmpx", wx_pathname);
 440         if (uname && wname) {
 441                 DEBUG(2,("utmp_update: uname:%s wname:%s\n", uname, wname));
 442         }
 443
 444         /*
 445          * Check for either uname or wname being empty.
 446          * Some systems, such as Redhat 6, have a "utmpx.h" which doesn't
 447          * define default filenames.
 448          * Also, our local installation has not provided an override.
 449          * Drop to non-x method.  (E.g. RH6 has good defaults in "utmp.h".)
 450          */
 451         if (!uname || !wname || (strlen(uname) == 0) || (strlen(wname) == 0)) {
 452                 utmp_nox_update(u, claim);
 453         } else {
 454                 utmpxname(uname);
 455                 setutxent();
 456                 uxrc = pututxline(&ux);
 457                 endutxent();
 458                 if (uxrc == NULL) {
 459                         DEBUG(2,("utmp_update: pututxline() failed\n"));
 460                         return;
 461                 }
 462                 updwtmpx(wname, &ux);
 463         }
 464 #endif /* HAVE_UTMPX_H */
 465 }
 466
 467 #if defined(HAVE_UT_UT_ID)
 468 /****************************************************************************
 469  Encode the unique connection number into "ut_id".
 470 ****************************************************************************/
 471
 472 static int ut_id_encode(int i, char *fourbyte)
 473 {
 474         int nbase;
 475         const char *ut_id_encstr = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 476
 477         fourbyte[0] = 'S';
 478         fourbyte[1] = 'M';
 479
 480 /*
 481  * Encode remaining 2 bytes from 'i'.
 482  * 'ut_id_encstr' is the character set on which modulo arithmetic is done.
 483  * Example: digits would produce the base-10 numbers from '001'.
 484  */
 485         nbase = strlen(ut_id_encstr);
 486
 487         fourbyte[3] = ut_id_encstr[i % nbase];
 488         i /= nbase;
 489         fourbyte[2] = ut_id_encstr[i % nbase];
 490         i /= nbase;
 491
 492         return(i);      /* 0: good; else overflow */
 493 }
 494 #endif /* defined(HAVE_UT_UT_ID) */
 495
 496
 497 /*
 498   fill a system utmp structure given all the info we can gather
 499 */
 500 static bool sys_utmp_fill(struct utmp *u,
 501                         const char *username, const char *hostname,
 502                         const char *ip_addr_str,
 503                         const char *id_str, int id_num)
 504 {
 505         struct timeval timeval;
 506
 507         /*
 508          * ut_name, ut_user:
 509          *      Several (all?) systems seems to define one as the other.
 510          *      It is easier and clearer simply to let the following take its course,
 511          *      rather than to try to detect and optimise.
 512          */
 513 #if defined(HAVE_UT_UT_USER)
 514         utmp_strcpy(u->ut_user, username, sizeof(u->ut_user));
 515 #elif defined(HAVE_UT_UT_NAME)
 516         utmp_strcpy(u->ut_name, username, sizeof(u->ut_name));
 517 #endif
 518
 519         /*
 520          * ut_line:
 521          *      If size limit proves troublesome, then perhaps use "ut_id_encode()".
 522          */
 523         if (strlen(id_str) > sizeof(u->ut_line)) {
 524                 DEBUG(1,("id_str [%s] is too long for %lu char utmp field\n",
 525                          id_str, (unsigned long)sizeof(u->ut_line)));
 526                 return False;
 527         }
 528         utmp_strcpy(u->ut_line, id_str, sizeof(u->ut_line));
 529
 530 #if defined(HAVE_UT_UT_PID)
 531         u->ut_pid = getpid();
 532 #endif
 533
 534 /*
 535  * ut_time, ut_tv:
 536  *      Some have one, some the other.  Many have both, but defined (aliased).
 537  *      It is easier and clearer simply to let the following take its course.
 538  *      But note that we do the more precise ut_tv as the final assignment.
 539  */
 540 #if defined(HAVE_UT_UT_TIME)
 541         GetTimeOfDay(&timeval);
 542         u->ut_time = timeval.tv_sec;
 543 #elif defined(HAVE_UT_UT_TV)
 544         GetTimeOfDay(&timeval);
 545         u->ut_tv = timeval;
 546 #else
 547 #error "with-utmp must have UT_TIME or UT_TV"
 548 #endif
 549
 550 #if defined(HAVE_UT_UT_HOST)
 551         utmp_strcpy(u->ut_host, hostname, sizeof(u->ut_host));
 552 #endif
 553 #if defined(HAVE_IPV6) && defined(HAVE_UT_UT_ADDR_V6)
 554         memset(&u->ut_addr_v6, '\0', sizeof(u->ut_addr_v6));
 555         if (ip_addr_str) {
 556                 struct in6_addr addr;
 557                 if (inet_pton(AF_INET6, ip_addr_str, &addr) > 0) {
 558                         memcpy(&u->ut_addr_v6, &addr, sizeof(addr));
 559                 }
 560         }
 561 #elif defined(HAVE_UT_UT_ADDR)
 562         memset(&u->ut_addr, '\0', sizeof(u->ut_addr));
 563         if (ip_addr_str) {
 564                 struct in_addr addr;
 565                 if (inet_pton(AF_INET, ip_addr_str, &addr) > 0) {
 566                         memcpy(&u->ut_addr, &addr, sizeof(addr));
 567                 }
 568         }
 569         /*
 570          * "(unsigned long) ut_addr" apparently exists on at least HP-UX 10.20.
 571          * Volunteer to implement, please ...
 572          */
 573 #endif
 574
 575 #if defined(HAVE_UT_UT_ID)
 576         if (ut_id_encode(id_num, u->ut_id) != 0) {
 577                 DEBUG(1,("utmp_fill: cannot encode id %d\n", id_num));
 578                 return False;
 579         }
 580 #endif
 581
 582         return True;
 583 }
 584
 585 /****************************************************************************
 586  Close a connection.
 587 ****************************************************************************/
 588
 589 void sys_utmp_yield(const char *username, const char *hostname,
 590                         const char *ip_addr_str,
 591                         const char *id_str, int id_num)
 592 {
 593         struct utmp u;
 594
 595         ZERO_STRUCT(u);
 596
 597 #if defined(HAVE_UT_UT_EXIT)
 598         u.ut_exit.e_termination = 0;
 599         u.ut_exit.e_exit = 0;
 600 #endif
 601
 602 #if defined(HAVE_UT_UT_TYPE)
 603         u.ut_type = DEAD_PROCESS;
 604 #endif
 605
 606         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 607                 return;
 608
 609         sys_utmp_update(&u, NULL, False);
 610 }
 611
 612 /****************************************************************************
 613  Claim a entry in whatever utmp system the OS uses.
 614 ****************************************************************************/
 615
 616 void sys_utmp_claim(const char *username, const char *hostname,
 617                         const char *ip_addr_str,
 618                         const char *id_str, int id_num)
 619 {
 620         struct utmp u;
 621
 622         ZERO_STRUCT(u);
 623
 624 #if defined(HAVE_UT_UT_TYPE)
 625         u.ut_type = USER_PROCESS;
 626 #endif
 627
 628         if (!sys_utmp_fill(&u, username, hostname, ip_addr_str, id_str, id_num))
 629                 return;
 630
 631         sys_utmp_update(&u, hostname, True);
 632 }
 633
 634 #endif /* WITH_UTMP */