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Add ability to clear or set lastlog record for user via lastlog command

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This functionality is useful because there is now a feature
of Linux-PAM's pam_lastlog module to block expired users (users
which did not login recently enough) from login. This commit
complements it so the sysadmin is able to unblock such expired user.

Signed-off-by: Tomáš Mráz <tmraz@fedoraproject.org>
This commit is contained in:
Tomas Mraz 2016-03-03 15:37:01 +01:00
parent af064545bf
commit 66897b6f6d
3 changed files with 135 additions and 3 deletions
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22
man/lastlog.8.xml
View File

@ -103,6 +103,17 @@
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-C</option>, <option>--clear</option>
</term>
<listitem>
<para>
Clear lastlog record of an user. This option can be used only together
with <option>-u</option> (<option>--user</option>)).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-h</option>, <option>--help</option>
@ -123,6 +134,17 @@
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-S</option>, <option>--set</option>
</term>
<listitem>
<para>
Set lastlog record of an user to the current time. This option can be
used only together with <option>-u</option> (<option>--user</option>)).
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>-t</option>, <option>--time</option>&nbsp;<replaceable>DAYS</replaceable>

1
src/Makefile.am
View File

@ -98,6 +98,7 @@ groupmod_LDADD = $(LDADD) $(LIBPAM_SUID) $(LIBAUDIT) $(LIBSELINUX)
grpck_LDADD = $(LDADD) $(LIBSELINUX)
grpconv_LDADD = $(LDADD) $(LIBSELINUX)
grpunconv_LDADD = $(LDADD) $(LIBSELINUX)
lastlog_LDADD = $(LDADD) $(LIBAUDIT)
login_SOURCES = \
login.c \
login_nopam.c

115
src/lastlog.c
View File

@ -71,6 +71,8 @@ static struct stat statbuf; /* fstat buffer for file size */
static bool uflg = false; /* print only an user of range of users */
static bool tflg = false; /* print is restricted to most recent days */
static bool bflg = false; /* print excludes most recent days */
static bool Cflg = false; /* clear record for user */
static bool Sflg = false; /* set record for user */
#define NOW (time ((time_t *) 0))
@ -83,8 +85,10 @@ static /*@noreturn@*/void usage (int status)
"Options:\n"),
Prog);
(void) fputs (_(" -b, --before DAYS print only lastlog records older than DAYS\n"), usageout);
(void) fputs (_(" -C, --clear clear lastlog record of an user (usable only with -u)\n"), usageout);
(void) fputs (_(" -h, --help display this help message and exit\n"), usageout);
(void) fputs (_(" -R, --root CHROOT_DIR directory to chroot into\n"), usageout);
(void) fputs (_(" -S, --set set lastlog record to current time (usable only with -u)\n"), usageout);
(void) fputs (_(" -t, --time DAYS print only lastlog records more recent than DAYS\n"), usageout);
(void) fputs (_(" -u, --user LOGIN print lastlog record of the specified LOGIN\n"), usageout);
(void) fputs ("\n", usageout);
@ -194,6 +198,80 @@ static void print (void)
}
}
static void update_one (/*@null@*/const struct passwd *pw)
{
off_t offset;
struct lastlog ll;
int err;
if (NULL == pw) {
return;
}
offset = (off_t) pw->pw_uid * sizeof (ll);
/* fseeko errors are not really relevant for us. */
err = fseeko (lastlogfile, offset, SEEK_SET);
assert (0 == err);
memzero (&ll, sizeof (ll));
if (Sflg) {
ll.ll_time = NOW;
#ifdef HAVE_LL_HOST
strcpy (ll.ll_host, "localhost");
#endif
strcpy (ll.ll_line, "lastlog");
#ifdef WITH_AUDIT
audit_logger (AUDIT_ACCT_UNLOCK, Prog,
"clearing-lastlog",
pw->pw_name, (unsigned int) pw->pw_uid, SHADOW_AUDIT_SUCCESS);
#endif
}
#ifdef WITH_AUDIT
else {
audit_logger (AUDIT_ACCT_UNLOCK, Prog,
"refreshing-lastlog",
pw->pw_name, (unsigned int) pw->pw_uid, SHADOW_AUDIT_SUCCESS);
}
#endif
if (fwrite (&ll, sizeof(ll), 1, lastlogfile) != 1) {
fprintf (stderr,
_("%s: Failed to update the entry for UID %lu\n"),
Prog, (unsigned long int)pw->pw_uid);
exit (EXIT_FAILURE);
}
}
static void update (void)
{
const struct passwd *pwent;
if (!uflg) /* safety measure */
return;
if (has_umin && has_umax && (umin == umax)) {
update_one (getpwuid ((uid_t)umin));
} else {
setpwent ();
while ( (pwent = getpwent ()) != NULL ) {
if ((has_umin && (pwent->pw_uid < (uid_t)umin))
|| (has_umax && (pwent->pw_uid > (uid_t)umax))) {
continue;
}
update_one (pwent);
}
endpwent ();
}
if (fflush (lastlogfile) != 0 || fsync (fileno (lastlogfile)) != 0) {
fprintf (stderr,
_("%s: Failed to update the lastlog file\n"),
Prog);
exit (EXIT_FAILURE);
}
}
int main (int argc, char **argv)
{
/*
@ -208,18 +286,24 @@ int main (int argc, char **argv)
process_root_flag ("-R", argc, argv);
#ifdef WITH_AUDIT
audit_help_open ();
#endif
{
int c;
static struct option const longopts[] = {
{"before", required_argument, NULL, 'b'},
{"clear", no_argument, NULL, 'C'},
{"help", no_argument, NULL, 'h'},
{"root", required_argument, NULL, 'R'},
{"set", no_argument, NULL, 'S'},
{"time", required_argument, NULL, 't'},
{"user", required_argument, NULL, 'u'},
{NULL, 0, NULL, '\0'}
};
while ((c = getopt_long (argc, argv, "b:hR:t:u:", longopts,
while ((c = getopt_long (argc, argv, "b:ChR:St:u:", longopts,
NULL)) != -1) {
switch (c) {
case 'b':
@ -235,11 +319,21 @@ int main (int argc, char **argv)
bflg = true;
break;
}
case 'C':
{
Cflg = true;
break;
}
case 'h':
usage (EXIT_SUCCESS);
/*@notreached@*/break;
case 'R': /* no-op, handled in process_root_flag () */
break;
case 'S':
{
Sflg = true;
break;
}
case 't':
{
unsigned long days;
@ -294,9 +388,21 @@ int main (int argc, char **argv)
Prog, argv[optind]);
usage (EXIT_FAILURE);
}
if (Cflg && Sflg) {
fprintf (stderr,
_("%s: Option -C cannot be used together with option -S\n"),
Prog);
usage (EXIT_FAILURE);
}
if ((Cflg || Sflg) && !uflg) {
fprintf (stderr,
_("%s: Options -C and -S require option -u to specify the user\n"),
Prog);
usage (EXIT_FAILURE);
}
}
lastlogfile = fopen (LASTLOG_FILE, "r");
lastlogfile = fopen (LASTLOG_FILE, (Cflg || Sflg)?"r+":"r");
if (NULL == lastlogfile) {
perror (LASTLOG_FILE);
exit (EXIT_FAILURE);
@ -310,7 +416,10 @@ int main (int argc, char **argv)
exit (EXIT_FAILURE);
}
print ();
if (Cflg || Sflg)
update ();
else
print ();
(void) fclose (lastlogfile);