lib/pam_module/pam_lastlog/pam_lastlog.c

   1 /*-
   2  * Copyright (c) 1980, 1987, 1988, 1991, 1993, 1994
   3  *      The Regents of the University of California.  All rights reserved.
   4  * Copyright (c) 2001 Mark R V Murray
   5  * All rights reserved.
   6  * Copyright (c) 2001 Networks Associates Technology, Inc.
   7  * All rights reserved.
   8  * Copyright (c) 2004 Joe R. Doupnik
   9  * All rights reserved.
  10  *
  11  * Portions of this software were developed for the FreeBSD Project by
  12  * ThinkSec AS and NAI Labs, the Security Research Division of Network
  13  * Associates, Inc.  under DARPA/SPAWAR contract N66001-01-C-8035
  14  * ("CBOSS"), as part of the DARPA CHATS research program.
  15  *
  16  * Redistribution and use in source and binary forms, with or without
  17  * modification, are permitted provided that the following conditions
  18  * are met:
  19  * 1. Redistributions of source code must retain the above copyright
  20  *    notice, this list of conditions and the following disclaimer.
  21  * 2. Redistributions in binary form must reproduce the above copyright
  22  *    notice, this list of conditions and the following disclaimer in the
  23  *    documentation and/or other materials provided with the distribution.
  24  * 3. The name of the author may not be used to endorse or promote
  25  *    products derived from this software without specific prior written
  26  *    permission.
  27  * 4. Neither the name of the University nor the names of its contributors
  28  *    may be used to endorse or promote products derived from this software
  29  *    without specific prior written permission.
  30  *
  31  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  32  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  33  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  34  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  35  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  39  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  40  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  41  * SUCH DAMAGE.
  42  *
  43  * $FreeBSD: src/lib/libpam/modules/pam_lastlog/pam_lastlog.c,v 1.23 2007/07/22 15:17:29 des Exp $
  44  */
  45
  46 #define _BSD_SOURCE
  47
  48 #include <sys/param.h>
  49
  50 #include <fcntl.h>
  51 #include <libutil.h>
  52 #include <paths.h>
  53 #include <pwd.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <syslog.h>
  58 #include <time.h>
  59 #include <unistd.h>
  60 #include <utmp.h>
  61
  62 #define PAM_SM_SESSION
  63
  64 #include <security/pam_appl.h>
  65 #include <security/pam_modules.h>
  66 #include <security/pam_mod_misc.h>
  67
  68 PAM_EXTERN int
  69 pam_sm_open_session(pam_handle_t *pamh, int flags,
  70                     int argc __unused, const char *argv[] __unused)
  71 {
  72         struct passwd *pwd;
  73         struct utmp utmp;
  74         struct lastlog ll;
  75         time_t t;
  76         const char *user;
  77         const void *rhost, *tty;
  78         off_t llpos;
  79         int fd, pam_err;
  80
  81         pam_err = pam_get_user(pamh, &user, NULL);
  82         if (pam_err != PAM_SUCCESS)
  83                 return (pam_err);
  84         if (user == NULL || (pwd = getpwnam(user)) == NULL)
  85                 return (PAM_SERVICE_ERR);
  86         PAM_LOG("Got user: %s", user);
  87
  88         pam_err = pam_get_item(pamh, PAM_RHOST, &rhost);
  89         if (pam_err != PAM_SUCCESS) {
  90                 PAM_LOG("No PAM_RHOST");
  91                 goto err;
  92         }
  93         pam_err = pam_get_item(pamh, PAM_TTY, &tty);
  94         if (pam_err != PAM_SUCCESS) {
  95                 PAM_LOG("No PAM_TTY");
  96                 goto err;
  97         }
  98         if (tty == NULL) {
  99                 PAM_LOG("No PAM_TTY");
 100                 pam_err = PAM_SERVICE_ERR;
 101                 goto err;
 102         }
 103         if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0)
 104                 tty = (const char *)tty + strlen(_PATH_DEV);
 105         if (*(const char *)tty == '\0')
 106                 return (PAM_SERVICE_ERR);
 107
 108         fd = open(_PATH_LASTLOG, O_RDWR|O_CREAT, 0644);
 109         if (fd == -1) {
 110                 PAM_LOG("Failed to open %s", _PATH_LASTLOG);
 111                 goto file_err;
 112         }
 113
 114         /*
 115          * Record session in lastlog(5).
 116          */
 117         llpos = (off_t)(pwd->pw_uid * sizeof(ll));
 118         if (lseek(fd, llpos, L_SET) != llpos)
 119                 goto file_err;
 120         if ((flags & PAM_SILENT) == 0) {
 121                 if (read(fd, &ll, sizeof ll) == sizeof ll && ll.ll_time != 0) {
 122                         t = ll.ll_time;
 123                         if (*ll.ll_host != '\0')
 124                                 pam_info(pamh, "Last login: %.*s from %.*s",
 125                                     24 - 5, ctime(&t),
 126                                     (int)sizeof(ll.ll_host), ll.ll_host);
 127                         else
 128                                 pam_info(pamh, "Last login: %.*s on %.*s",
 129                                     24 - 5, ctime(&t),
 130                                     (int)sizeof(ll.ll_line), ll.ll_line);
 131                 }
 132                 if (lseek(fd, llpos, L_SET) != llpos)
 133                         goto file_err;
 134         }
 135
 136         bzero(&ll, sizeof(ll));
 137         ll.ll_time = time(NULL);
 138
 139         /* note: does not need to be NUL-terminated */
 140         strncpy(ll.ll_line, tty, sizeof(ll.ll_line));
 141         if (rhost != NULL && *(const char *)rhost != '\0')
 142                 /* note: does not need to be NUL-terminated */
 143                 strncpy(ll.ll_host, rhost, sizeof(ll.ll_host));
 144
 145         if (write(fd, (char *)&ll, sizeof(ll)) != sizeof(ll) || close(fd) != 0)
 146                 goto file_err;
 147
 148         PAM_LOG("Login recorded in %s", _PATH_LASTLOG);
 149
 150         /*
 151          * Record session in utmp(5) and wtmp(5).
 152          */
 153         bzero(&utmp, sizeof(utmp));
 154         utmp.ut_time = time(NULL);
 155         /* note: does not need to be NUL-terminated */
 156         strncpy(utmp.ut_name, user, sizeof(utmp.ut_name));
 157         if (rhost != NULL && *(const char *)rhost != '\0')
 158                 strncpy(utmp.ut_host, rhost, sizeof(utmp.ut_host));
 159         strncpy(utmp.ut_line, tty, sizeof(utmp.ut_line));
 160         login(&utmp);
 161
 162         return (PAM_SUCCESS);
 163
 164 file_err:
 165         syslog(LOG_ERR, "%s: %m", _PATH_LASTLOG);
 166         if (fd != -1)
 167                 close(fd);
 168         pam_err = PAM_SYSTEM_ERR;
 169 err:
 170         if (openpam_get_option(pamh, "no_fail"))
 171                 return (PAM_SUCCESS);
 172         return (pam_err);
 173 }
 174
 175 PAM_EXTERN int
 176 pam_sm_close_session(pam_handle_t *pamh __unused, int flags __unused,
 177                      int argc __unused, const char *argv[] __unused)
 178 {
 179         const void *tty;
 180         int pam_err;
 181
 182         pam_err = pam_get_item(pamh, PAM_TTY, (const void **)&tty);
 183         if (pam_err != PAM_SUCCESS)
 184                 goto err;
 185         if (strncmp(tty, _PATH_DEV, strlen(_PATH_DEV)) == 0)
 186                 tty = (const char *)tty + strlen(_PATH_DEV);
 187         if (*(const char *)tty == '\0')
 188                 return (PAM_SERVICE_ERR);
 189         if (logout(tty) != 1)
 190                 syslog(LOG_ERR, "%s(): no utmp record for %s",
 191                     __func__, (const char *)tty);
 192         logwtmp(tty, "", "");
 193         return (PAM_SUCCESS);
 194
 195  err:
 196         if (openpam_get_option(pamh, "no_fail"))
 197                 return (PAM_SUCCESS);
 198         return (pam_err);
 199 }
 200
 201 PAM_MODULE_ENTRY("pam_lastlog");