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|
/* pam_lastlog module */
/*
* $Id: pam_lastlog.c,v 1.3 1997/04/05 06:18:21 morgan Exp morgan $
*
* Written by Andrew Morgan <morgan@parc.power.net> 1996/3/11
*
* This module does the necessary work to display the last login
* time+date for this user, it then updates this entry for the
* present (login) service.
*
* $Log: pam_lastlog.c,v $
* Revision 1.3 1997/04/05 06:18:21 morgan
* removed xstrdup - unused
*
* Revision 1.2 1997/02/15 17:18:21 morgan
* removed fixed buffer in logging
*
* Revision 1.1 1997/01/04 20:29:28 morgan
* Initial revision
*
*/
#include <fcntl.h>
#include <time.h>
#ifdef HAVE_UTMP_H
# include <utmp.h>
#else
# include <lastlog.h>
#endif
#include <pwd.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <syslog.h>
#include <unistd.h>
#ifdef WANT_PWDB
#include <pwdb/pwdb_public.h> /* use POSIX front end */
#endif
#if defined(hpux) || defined(sunos) || defined(solaris)
# ifndef _PATH_LASTLOG
# define _PATH_LASTLOG "/usr/adm/lastlog"
# endif /* _PATH_LASTLOG */
# ifndef UT_HOSTSIZE
# define UT_HOSTSIZE 16
# endif /* UT_HOSTSIZE */
# ifndef UT_LINESIZE
# define UT_LINESIZE 12
# endif /* UT_LINESIZE */
#endif
#if defined(hpux)
struct lastlog {
time_t ll_time;
char ll_line[UT_LINESIZE];
char ll_host[UT_HOSTSIZE]; /* same as in utmp */
};
#endif /* hpux */
/* XXX - time before ignoring lock. Is 1 sec enough? */
#define LASTLOG_IGNORE_LOCK_TIME 1
#define DEFAULT_HOST "" /* "[no.where]" */
#define DEFAULT_TERM "" /* "tt???" */
#define LASTLOG_NEVER_WELCOME "Welcome to your new account!"
#define LASTLOG_INTRO "Last login:"
#define LASTLOG_TIME " %s"
#define _LASTLOG_HOST_FORMAT " from %%.%ds"
#define _LASTLOG_LINE_FORMAT " on %%.%ds"
#define LASTLOG_TAIL ""
#define LASTLOG_MAXSIZE (sizeof(LASTLOG_INTRO)+0 \
+sizeof(LASTLOG_TIME)+strlen(the_time) \
+sizeof(_LASTLOG_HOST_FORMAT)+UT_HOSTSIZE \
+sizeof(_LASTLOG_LINE_FORMAT)+UT_LINESIZE \
+sizeof(LASTLOG_TAIL))
/*
* here, we make a definition for the externally accessible function
* in this file (this definition is required for static a module
* but strongly encouraged generally) it is used to instruct the
* modules include file to define the function prototypes.
*/
#define PAM_SM_SESSION
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
/* some syslogging */
static void _log_err(int err, const char *format, ...)
{
va_list args;
va_start(args, format);
openlog("PAM-lastlog", LOG_CONS|LOG_PID, LOG_AUTH);
vsyslog(err, format, args);
va_end(args);
closelog();
}
/* argument parsing */
#define LASTLOG_DATE 01 /* display the date of the last login */
#define LASTLOG_HOST 02 /* display the last host used (if set) */
#define LASTLOG_LINE 04 /* display the last terminal used */
#define LASTLOG_NEVER 010 /* display a welcome message for first login */
#define LASTLOG_DEBUG 020 /* send info to syslog(3) */
#define LASTLOG_QUIET 040 /* keep quiet about things */
static int _pam_parse(int flags, int argc, const char **argv)
{
int ctrl=(LASTLOG_DATE|LASTLOG_HOST|LASTLOG_LINE);
/* does the appliction require quiet? */
if (flags & PAM_SILENT) {
ctrl |= LASTLOG_QUIET;
}
/* step through arguments */
for (; argc-- > 0; ++argv) {
/* generic options */
if (!strcmp(*argv,"debug")) {
ctrl |= LASTLOG_DEBUG;
} else if (!strcmp(*argv,"nodate")) {
ctrl |= ~LASTLOG_DATE;
} else if (!strcmp(*argv,"noterm")) {
ctrl |= ~LASTLOG_LINE;
} else if (!strcmp(*argv,"nohost")) {
ctrl |= ~LASTLOG_HOST;
} else if (!strcmp(*argv,"silent")) {
ctrl |= LASTLOG_QUIET;
} else if (!strcmp(*argv,"never")) {
ctrl |= LASTLOG_NEVER;
} else {
_log_err(LOG_ERR,"unknown option; %s",*argv);
}
}
D(("ctrl = %o", ctrl));
return ctrl;
}
/* a front end for conversations */
static int converse(pam_handle_t *pamh, int ctrl, int nargs
, struct pam_message **message
, struct pam_response **response)
{
int retval;
struct pam_conv *conv;
D(("begin to converse"));
retval = pam_get_item( pamh, PAM_CONV, (const void **) &conv ) ;
if ( retval == PAM_SUCCESS ) {
retval = conv->conv(nargs, ( const struct pam_message ** ) message
, response, conv->appdata_ptr);
D(("returned from application's conversation function"));
if (retval != PAM_SUCCESS && (ctrl & LASTLOG_DEBUG) ) {
_log_err(LOG_DEBUG, "conversation failure [%s]"
, pam_strerror(pamh, retval));
}
} else {
_log_err(LOG_ERR, "couldn't obtain coversation function [%s]"
, pam_strerror(pamh, retval));
}
D(("ready to return from module conversation"));
return retval; /* propagate error status */
}
static int make_remark(pam_handle_t *pamh, int ctrl, const char *remark)
{
int retval;
if (!(ctrl & LASTLOG_QUIET)) {
struct pam_message msg[1], *mesg[1];
struct pam_response *resp=NULL;
mesg[0] = &msg[0];
msg[0].msg_style = PAM_TEXT_INFO;
msg[0].msg = remark;
retval = converse(pamh, ctrl, 1, mesg, &resp);
msg[0].msg = NULL;
if (resp) {
_pam_drop_reply(resp, 1);
}
} else {
D(("keeping quiet"));
retval = PAM_SUCCESS;
}
D(("returning %s", pam_strerror(pamh, retval)));
return retval;
}
/*
* Values for the announce flags..
*/
static int last_login_date(pam_handle_t *pamh, int announce, uid_t uid)
{
struct flock last_lock;
struct lastlog last_login;
int retval = PAM_SESSION_ERR;
int last_fd;
/* obtain the last login date and all the relevant info */
last_fd = open(_PATH_LASTLOG, O_RDWR);
if (last_fd < 0) {
D(("unable to open the %s file", _PATH_LASTLOG));
if (announce & LASTLOG_DEBUG) {
_log_err(LOG_DEBUG, "unable to open %s file", _PATH_LASTLOG);
}
retval = PAM_PERM_DENIED;
} else {
int win;
/* read the lastlogin file - for this uid */
(void) lseek(last_fd, sizeof(last_login) * (off_t) uid, SEEK_SET);
memset(&last_lock, 0, sizeof(last_lock));
last_lock.l_type = F_RDLCK;
last_lock.l_whence = SEEK_SET;
last_lock.l_start = sizeof(last_login) * (off_t) uid;
last_lock.l_len = sizeof(last_login);
if ( fcntl(last_fd, F_SETLK, &last_lock) < 0 ) {
D(("locking %s failed..(waiting a little)", _PATH_LASTLOG));
_log_err(LOG_ALERT, "%s file is locked/read", _PATH_LASTLOG);
sleep(LASTLOG_IGNORE_LOCK_TIME);
}
win = ( read(last_fd, &last_login, sizeof(last_login))
== sizeof(last_login) );
last_lock.l_type = F_UNLCK;
(void) fcntl(last_fd, F_SETLK, &last_lock); /* unlock */
if (!win) {
D(("First login for user uid=%d", _PATH_LASTLOG, uid));
if (announce & LASTLOG_DEBUG) {
_log_err(LOG_DEBUG, "creating lastlog for uid %d", uid);
}
memset(&last_login, 0, sizeof(last_login));
}
/* rewind */
(void) lseek(last_fd, sizeof(last_login) * (off_t) uid, SEEK_SET);
if (!(announce & LASTLOG_QUIET)) {
if (last_login.ll_time) {
char *the_time;
char *remark;
the_time = ctime(&last_login.ll_time);
the_time[-1+strlen(the_time)] = '\0'; /* delete '\n' */
remark = malloc(LASTLOG_MAXSIZE);
if (remark == NULL) {
D(("no memory for last login remark"));
retval = PAM_BUF_ERR;
} else {
int at;
/* printing prefix */
at = sprintf(remark, "%s", LASTLOG_INTRO);
/* we want the date? */
if (announce & LASTLOG_DATE) {
at += sprintf(remark+at, LASTLOG_TIME, the_time);
}
/* we want & have the host? */
if ((announce & LASTLOG_HOST)
&& (last_login.ll_host[0] != '\0')) {
char format[2*sizeof(_LASTLOG_HOST_FORMAT)];
(void) sprintf(format, _LASTLOG_HOST_FORMAT
, UT_HOSTSIZE);
D(("format: %s", format));
at += sprintf(remark+at, format, last_login.ll_host);
_pam_overwrite(format);
}
/* we want and have the terminal? */
if ((announce & LASTLOG_LINE)
&& (last_login.ll_line[0] != '\0')) {
char format[2*sizeof(_LASTLOG_LINE_FORMAT)];
(void) sprintf(format, _LASTLOG_LINE_FORMAT
, UT_LINESIZE);
D(("format: %s", format));
at += sprintf(remark+at, format, last_login.ll_line);
_pam_overwrite(format);
}
/* display requested combo */
sprintf(remark+at, "%s", LASTLOG_TAIL);
retval = make_remark(pamh, announce, remark);
/* free all the stuff malloced */
_pam_overwrite(remark);
_pam_drop(remark);
}
} else if ((!last_login.ll_time) && (announce & LASTLOG_NEVER)) {
D(("this is the first time this user has logged in"));
retval = make_remark(pamh, announce, LASTLOG_NEVER_WELCOME);
}
} else {
D(("no text was requested"));
retval = PAM_SUCCESS;
}
/* write latest value */
{
const char *remote_host=NULL
, *terminal_line=DEFAULT_TERM;
/* set this login date */
D(("set the most recent login time"));
(void) time(&last_login.ll_time); /* set the time */
/* set the remote host */
(void) pam_get_item(pamh, PAM_RHOST, (const void **)&remote_host);
if (remote_host == NULL) {
remote_host = DEFAULT_HOST;
}
/* copy to last_login */
strncpy(last_login.ll_host, remote_host
, sizeof(last_login.ll_host));
remote_host = NULL;
/* set the terminal line */
(void) pam_get_item(pamh, PAM_TTY, (const void **)&terminal_line);
D(("terminal = %s", terminal_line));
if (terminal_line == NULL) {
terminal_line = DEFAULT_TERM;
} else if ( !strncmp("/dev/", terminal_line, 5) ) {
/* strip leading "/dev/" from tty.. */
terminal_line += 5;
}
D(("terminal = %s", terminal_line));
/* copy to last_login */
strncpy(last_login.ll_line, terminal_line
, sizeof(last_login.ll_line));
terminal_line = NULL;
D(("locking last_log file"));
/* now we try to lock this file-record exclusively; non-blocking */
memset(&last_lock, 0, sizeof(last_lock));
last_lock.l_type = F_WRLCK;
last_lock.l_whence = SEEK_SET;
last_lock.l_start = sizeof(last_login) * (off_t) uid;
last_lock.l_len = sizeof(last_login);
if ( fcntl(last_fd, F_SETLK, &last_lock) < 0 ) {
D(("locking %s failed..(waiting a little)", _PATH_LASTLOG));
_log_err(LOG_ALERT, "%s file is locked/write", _PATH_LASTLOG);
sleep(LASTLOG_IGNORE_LOCK_TIME);
}
D(("writing to the last_log file"));
(void) write(last_fd, &last_login, sizeof(last_login));
last_lock.l_type = F_UNLCK;
(void) fcntl(last_fd, F_SETLK, &last_lock); /* unlock */
D(("unlocked"));
close(last_fd); /* all done */
}
D(("all done with last login"));
}
/* reset the last login structure */
memset(&last_login, 0, sizeof(last_login));
return retval;
}
/* --- authentication management functions (only) --- */
PAM_EXTERN
int pam_sm_open_session(pam_handle_t *pamh, int flags, int argc
, const char **argv)
{
int retval, ctrl;
const char *user;
const struct passwd *pwd;
uid_t uid;
/*
* this module gets the uid of the PAM_USER. Uses it to display
* last login info and then updates the lastlog for that user.
*/
ctrl = _pam_parse(flags, argc, argv);
/* which user? */
retval = pam_get_item(pamh, PAM_USER, (const void **)&user);
if (retval != PAM_SUCCESS || user == NULL || *user == '\0') {
_log_err(LOG_NOTICE, "user unknown");
return PAM_USER_UNKNOWN;
}
/* what uid? */
pwd = getpwnam(user);
if (pwd == NULL) {
D(("couldn't identify user %s", user));
return PAM_CRED_INSUFFICIENT;
}
uid = pwd->pw_uid;
pwd = NULL; /* tidy up */
/* process the current login attempt (indicate last) */
retval = last_login_date(pamh, ctrl, uid);
/* indicate success or failure */
uid = -1; /* forget this */
return retval;
}
PAM_EXTERN
int pam_sm_close_session(pam_handle_t *pamh,int flags,int argc
,const char **argv)
{
return PAM_SUCCESS;
}
#ifdef PAM_STATIC
/* static module data */
struct pam_module _pam_lastlog_modstruct = {
"pam_lastlog",
NULL,
NULL,
NULL,
pam_sm_open_session,
pam_sm_close_session,
NULL,
};
#endif
/* end of module definition */
|