usr/src/cmd/login/login_audit.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright 2010 Sun Microsystems, Inc.  All rights reserved.
  23  * Use is subject to license terms.
  24  */
  25
  26 #include <assert.h>
  27 #include <priv.h>
  28 #include <pwd.h>
  29 #include <signal.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <syslog.h>
  33 #include <unistd.h>
  34 #include <sys/wait.h>
  35
  36 #include <bsm/adt.h>
  37 #include <bsm/adt_event.h>
  38 #include "login_audit.h"
  39
  40 /*
  41  * Key assumption:  login is single threaded.
  42  */
  43 static void audit_logout(adt_session_data_t *);
  44
  45 /*
  46  * if audit is not enabled, the adt_*() functions simply return without
  47  * doing anything.  In the success case, the credential has already been
  48  * setup with audit data by PAM.
  49  */
  50
  51 /*
  52  * There is no information passed to login.c from telnet
  53  * about the terminal id.  They both set the tid before they
  54  * exec login; the value is picked up by adt_start_session() and is
  55  * carefully *not* overwritten by adt_load_hostname().
  56  */
  57
  58 void
  59 audit_success(uint_t event_id, struct passwd *pwd, char *optional_text)
  60 {
  61         adt_session_data_t      *ah;
  62         adt_event_data_t        *event;
  63         int                     rc;
  64
  65         assert(pwd != NULL);
  66
  67         if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA)) {
  68                 syslog(LOG_AUTH | LOG_ALERT, "login adt_start_session(): %m");
  69                 return;
  70         }
  71         if (adt_set_user(ah, pwd->pw_uid,  pwd->pw_gid,
  72             pwd->pw_uid,  pwd->pw_gid, NULL, ADT_USER)) {
  73                 syslog(LOG_AUTH | LOG_ALERT, "login adt_set_user(): %m");
  74                 (void) adt_end_session(ah);
  75                 return;
  76         }
  77         event = adt_alloc_event(ah, event_id);
  78
  79         if (event == NULL)
  80                 return;
  81
  82         switch (event_id) {
  83         case ADT_zlogin:
  84                 event->adt_zlogin.message = optional_text;
  85                 break;
  86         default:
  87                 break;
  88         }
  89         rc = adt_put_event(event, ADT_SUCCESS, ADT_SUCCESS);
  90
  91         (void) adt_free_event(event);
  92         if (rc) {
  93                 (void) adt_end_session(ah);
  94                 syslog(LOG_AUTH | LOG_ALERT, "login adt_put_event(): %m");
  95                 return;
  96         }
  97         /*
  98          * The code above executes whether or not audit is enabled.
  99          * However audit_logout must only execute if audit is
 100          * enabled so we don't fork unnecessarily.
 101          */
 102         if (adt_audit_enabled()) {
 103                 switch (event_id) {
 104                 case ADT_login:
 105                 case ADT_telnet:
 106                 case ADT_zlogin:
 107                         audit_logout(ah);       /* fork to catch logout */
 108                         break;
 109                 }
 110         }
 111         (void) adt_end_session(ah);
 112 }
 113
 114 /*
 115  * errors are ignored since there is no action to take on error
 116  */
 117 static void
 118 audit_logout(adt_session_data_t *ah)
 119 {
 120         adt_event_data_t        *logout;
 121         int                     status;         /* wait status */
 122         pid_t                   pid;
 123         priv_set_t              *priv;          /* waiting process privs */
 124
 125         if ((logout = adt_alloc_event(ah, ADT_logout)) == NULL) {
 126                 syslog(LOG_AUTH | LOG_ALERT,
 127                     "adt_alloc_event(ADT_logout): %m");
 128                 return;
 129         }
 130         if ((priv = priv_allocset())  == NULL) {
 131                 syslog(LOG_AUTH | LOG_ALERT,
 132                     "login audit_logout: could not alloc basic privs: %m");
 133                 adt_free_event(logout);
 134                 return;
 135         }
 136
 137         /*
 138          * The child returns and continues the login processing.
 139          * The parent's sole job is to wait for child exit, write the
 140          * logout audit record, and replay the child's exit code.
 141          */
 142
 143         if ((pid = fork()) == 0) {
 144                 /* child */
 145
 146                 adt_free_event(logout);
 147                 priv_freeset(priv);
 148                 return;
 149         }
 150         if (pid == -1) {
 151                 /* failure */
 152
 153                 syslog(LOG_AUTH | LOG_ALERT,
 154                     "login audit_logout: could not fork: %m");
 155                 adt_free_event(logout);
 156                 priv_freeset(priv);
 157                 return;
 158         }
 159
 160         /* parent process */
 161
 162         /*
 163          * When this routine is called, the current working
 164          * directory is the user's home directory and there are
 165          * unknown open files. For the waiting process, change the
 166          * current directory to root and close files so that the
 167          * user's home directory and anything else can be unmounted
 168          * if necessary.
 169          */
 170         if (chdir("/") != 0) {
 171                 syslog(LOG_AUTH | LOG_ALERT,
 172                     "login audit_logut: could not chdir /: %m");
 173         }
 174         /*
 175          * Reduce privileges to just those needed.
 176          */
 177         priv_basicset(priv);
 178         (void) priv_delset(priv, PRIV_PROC_EXEC);
 179         (void) priv_delset(priv, PRIV_PROC_FORK);
 180         (void) priv_delset(priv, PRIV_PROC_INFO);
 181         (void) priv_delset(priv, PRIV_PROC_SESSION);
 182         (void) priv_delset(priv, PRIV_FILE_LINK_ANY);
 183         if ((priv_addset(priv, PRIV_PROC_AUDIT) != 0) ||
 184             (setppriv(PRIV_SET, PRIV_PERMITTED, priv) != 0)) {
 185                 syslog(LOG_AUTH | LOG_ALERT,
 186                     "login audit_logout: could not reduce privs: %m");
 187         }
 188         closefrom(0);
 189         priv_freeset(priv);
 190         while (pid != waitpid(pid, &status, 0))
 191                 continue;
 192
 193         (void) adt_put_event(logout, ADT_SUCCESS, ADT_SUCCESS);
 194         adt_free_event(logout);
 195         (void) adt_end_session(ah);
 196         exit(WEXITSTATUS(status));
 197 }
 198
 199 /*
 200  * errors are ignored since there is no action to take on error.
 201  *
 202  * If the user id is invalid, pwd is NULL.
 203  */
 204 void
 205 audit_failure(uint_t event_id, int failure_code, struct passwd *pwd,
 206     const char *hostname, const char *ttyname, char *optional_text)
 207 {
 208         adt_session_data_t      *ah;
 209         adt_event_data_t        *event;
 210         uid_t                   uid;
 211         gid_t                   gid;
 212         adt_termid_t            *p_tid;
 213
 214         if (adt_start_session(&ah, NULL, ADT_USE_PROC_DATA))
 215                 return;
 216
 217         uid = ADT_NO_ATTRIB;
 218         gid = ADT_NO_ATTRIB;
 219         if (pwd != NULL) {
 220                 uid = pwd->pw_uid;
 221                 gid = pwd->pw_gid;
 222         }
 223         /*
 224          * If this is a remote login, in.telnetd has
 225          * already set the terminal id, in which case
 226          * adt_load_hostname() will use the preset terminal id and
 227          * ignore hostname.  (If no remote host and ttyname is NULL,
 228          * let adt_load_ttyname() figure out what to do.)
 229          */
 230         if (*hostname == '\0')
 231                 (void) adt_load_ttyname(ttyname, &p_tid);
 232         else
 233                 (void) adt_load_hostname(hostname, &p_tid);
 234
 235         if (adt_set_user(ah, uid, gid, uid, gid, p_tid, ADT_NEW)) {
 236                 (void) adt_end_session(ah);
 237                 free(p_tid);
 238                 return;
 239         }
 240         free(p_tid);
 241
 242         event = adt_alloc_event(ah, event_id);
 243         if (event == NULL) {
 244                 return;
 245         }
 246         switch (event_id) {
 247         case ADT_zlogin:
 248                 event->adt_zlogin.message = optional_text;
 249                 break;
 250         }
 251         (void) adt_put_event(event, ADT_FAILURE, failure_code);
 252
 253         adt_free_event(event);
 254         (void) adt_end_session(ah);
 255 }