shadow/src/chfn.c

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/*
* Copyright 1989 - 1994, Julianne Frances Haugh
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Julianne F. Haugh nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#ident "$Id$"
#include <fcntl.h>
#include <pwd.h>
#include <signal.h>
#include <stdio.h>
#include <sys/types.h>
#ifdef HAVE_SHADOW_H
#include <shadow.h>
#endif
#ifdef WITH_SELINUX
#include <selinux/selinux.h>
#include <selinux/av_permissions.h>
#endif
#include "defines.h"
#include "exitcodes.h"
#include "getdef.h"
#include "nscd.h"
#ifdef USE_PAM
#include "pam_defs.h"
#endif
#include "prototypes.h"
#include "pwauth.h"
#include "pwio.h"
/*
* Global variables.
*/
static char *Prog;
static char fullnm[BUFSIZ];
static char roomno[BUFSIZ];
static char workph[BUFSIZ];
static char homeph[BUFSIZ];
static char slop[BUFSIZ];
static int amroot;
/* Flags */
static int fflg = 0; /* -f - set full name */
static int rflg = 0; /* -r - set room number */
static int wflg = 0; /* -w - set work phone number */
static int hflg = 0; /* -h - set home phone number */
static int oflg = 0; /* -o - set other information */
#ifdef USE_PAM
static pam_handle_t *pamh = NULL;
#endif
/*
* External identifiers
*/
/* local function prototypes */
static void usage (void);
static int may_change_field (int);
static void new_fields (void);
static char *copy_field (char *, char *, char *);
static void process_flags (int argc, char **argv);
static void check_perms (const struct passwd *pw);
static void update_gecos (const char *user, char *gecos);
static void get_old_fields (const char *gecos);
/*
* usage - print command line syntax and exit
*/
static void usage (void)
{
if (amroot)
fprintf (stderr,
_("Usage: %s [-f full_name] [-r room_no] "
"[-w work_ph]\n"
"\t[-h home_ph] [-o other] [user]\n"), Prog);
else
fprintf (stderr,
_("Usage: %s [-f full_name] [-r room_no] "
"[-w work_ph] [-h home_ph]\n"), Prog);
exit (E_USAGE);
}
static int may_change_field (int field)
{
const char *cp;
/*
* CHFN_RESTRICT can now specify exactly which fields may be changed
* by regular users, by using any combination of the following
* letters:
* f - full name
* r - room number
* w - work phone
* h - home phone
*
* This makes it possible to disallow changing the room number
* information, for example - this feature was suggested by Maciej
* 'Tycoon' Majchrowski.
*
* For backward compatibility, "yes" is equivalent to "rwh",
* "no" is equivalent to "frwh". Only root can change anything
* if the string is empty or not defined at all.
*/
if (amroot)
return 1;
cp = getdef_str ("CHFN_RESTRICT");
if (!cp)
cp = "";
else if (strcmp (cp, "yes") == 0)
cp = "rwh";
else if (strcmp (cp, "no") == 0)
cp = "frwh";
if (strchr (cp, field))
return 1;
return 0;
}
/*
* new_fields - change the user's GECOS information interactively
*
* prompt the user for each of the four fields and fill in the fields from
* the user's response, or leave alone if nothing was entered.
*/
static void new_fields (void)
{
printf (_("Enter the new value, or press ENTER for the default\n"));
if (may_change_field ('f'))
change_field (fullnm, sizeof fullnm, _("Full Name"));
else
printf (_("\tFull Name: %s\n"), fullnm);
if (may_change_field ('r'))
change_field (roomno, sizeof roomno, _("Room Number"));
else
printf (_("\tRoom Number: %s\n"), roomno);
if (may_change_field ('w'))
change_field (workph, sizeof workph, _("Work Phone"));
else
printf (_("\tWork Phone: %s\n"), workph);
if (may_change_field ('h'))
change_field (homeph, sizeof homeph, _("Home Phone"));
else
printf (_("\tHome Phone: %s\n"), homeph);
if (amroot)
change_field (slop, sizeof slop, _("Other"));
}
/*
* copy_field - get the next field from the gecos field
*
* copy_field copies the next field from the gecos field, returning a
* pointer to the field which follows, or NULL if there are no more fields.
*
* in - the current GECOS field
* out - where to copy the field to
* extra - fields with '=' get copied here
*/
static char *copy_field (char *in, char *out, char *extra)
{
char *cp = NULL;
while (in) {
if ((cp = strchr (in, ',')))
*cp++ = '\0';
if (!strchr (in, '='))
break;
if (extra) {
if (extra[0])
strcat (extra, ",");
strcat (extra, in);
}
in = cp;
}
if (in && out)
strcpy (out, in);
return cp;
}
/*
* process_flags - parse the command line options
*
* It will not return if an error is encountered.
*/
static void process_flags (int argc, char **argv)
{
int flag; /* flag currently being processed */
/*
* The remaining arguments will be processed one by one and executed
* by this command. The name is the last argument if it does not
* begin with a "-", otherwise the name is determined from the
* environment and must agree with the real UID. Also, the UID will
* be checked for any commands which are restricted to root only.
*/
while ((flag = getopt (argc, argv, "f:r:w:h:o:")) != EOF) {
switch (flag) {
case 'f':
if (!may_change_field ('f')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
fflg++;
STRFCPY (fullnm, optarg);
break;
case 'h':
if (!may_change_field ('h')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
hflg++;
STRFCPY (homeph, optarg);
break;
case 'r':
if (!may_change_field ('r')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
rflg++;
STRFCPY (roomno, optarg);
break;
case 'o':
if (!amroot) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
oflg++;
STRFCPY (slop, optarg);
break;
case 'w':
if (!may_change_field ('w')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
wflg++;
STRFCPY (workph, optarg);
break;
default:
usage ();
}
}
}
/*
* check_perms - check if the caller is allowed to add a group
*
* Non-root users are only allowed to change their gecos field.
* (see also may_change_field())
*
* Non-root users must be authenticated.
*
* It will not return if the user is not allowed.
*/
static void check_perms (const struct passwd *pw)
{
#ifdef USE_PAM
int retval;
struct passwd *pampw;
#endif
/*
* Non-privileged users are only allowed to change the gecos field
* if the UID of the user matches the current real UID.
*/
if (!amroot && pw->pw_uid != getuid ()) {
fprintf (stderr, _("%s: Permission denied.\n"), Prog);
closelog ();
exit (E_NOPERM);
}
#ifdef WITH_SELINUX
/*
* If the UID of the user does not match the current real UID,
* check if the change is allowed by SELinux policy.
*/
if ((pw->pw_uid != getuid ())
&& (is_selinux_enabled () > 0)
&& (selinux_check_passwd_access (PASSWD__CHFN) != 0)) {
fprintf (stderr, _("%s: Permission denied.\n"), Prog);
closelog ();
exit (E_NOPERM);
}
#endif
#ifndef USE_PAM
/*
* Non-privileged users are optionally authenticated (must enter the
* password of the user whose information is being changed) before
* any changes can be made. Idea from util-linux chfn/chsh.
* --marekm
*/
if (!amroot && getdef_bool ("CHFN_AUTH"))
passwd_check (pw->pw_name, pw->pw_passwd, "chfn");
#else /* !USE_PAM */
retval = PAM_SUCCESS;
pampw = getpwuid (getuid ()); /* local, no need for xgetpwuid */
if (pampw == NULL) {
retval = PAM_USER_UNKNOWN;
}
if (retval == PAM_SUCCESS) {
retval = pam_start ("chfn", pampw->pw_name, &conv, &pamh);
}
if (retval == PAM_SUCCESS) {
retval = pam_authenticate (pamh, 0);
if (retval != PAM_SUCCESS) {
pam_end (pamh, retval);
}
}
if (retval == PAM_SUCCESS) {
retval = pam_acct_mgmt (pamh, 0);
if (retval != PAM_SUCCESS) {
pam_end (pamh, retval);
}
}
if (retval != PAM_SUCCESS) {
fprintf (stderr, _("%s: PAM authentication failed\n"), Prog);
exit (E_NOPERM);
}
#endif /* USE_PAM */
}
/*
* update_gecos - update the gecos fields in the password database
*
* Commit the user's entry after changing her gecos field.
*/
static void update_gecos (const char *user, char *gecos)
{
const struct passwd *pw; /* The user's password file entry */
struct passwd pwent; /* modified password file entry */
/*
* Before going any further, raise the ulimit to prevent colliding
* into a lowered ulimit, and set the real UID to root to protect
* against unexpected signals. Any keyboard signals are set to be
* ignored.
*/
if (setuid (0)) {
fprintf (stderr, _("Cannot change ID to root.\n"));
SYSLOG ((LOG_ERR, "can't setuid(0)"));
closelog ();
exit (E_NOPERM);
}
pwd_init ();
/*
* The passwd entry is now ready to be committed back to the
* password file. Get a lock on the file and open it.
*/
if (!pw_lock ()) {
fprintf (stderr,
_
("Cannot lock the password file; try again later.\n"));
SYSLOG ((LOG_WARN, "can't lock /etc/passwd"));
closelog ();
exit (E_NOPERM);
}
if (!pw_open (O_RDWR)) {
fprintf (stderr, _("Cannot open the password file.\n"));
pw_unlock ();
SYSLOG ((LOG_ERR, "can't open /etc/passwd"));
closelog ();
exit (E_NOPERM);
}
/*
* Get the entry to update using pw_locate() - we want the real one
* from /etc/passwd, not the one from getpwnam() which could contain
* the shadow password if (despite the warnings) someone enables
* AUTOSHADOW (or SHADOW_COMPAT in libc). --marekm
*/
pw = pw_locate (user);
if (!pw) {
pw_unlock ();
fprintf (stderr,
_("%s: %s not found in /etc/passwd\n"), Prog, user);
exit (E_NOPERM);
}
/*
* Make a copy of the entry, then change the gecos field. The other
* fields remain unchanged.
*/
pwent = *pw;
pwent.pw_gecos = gecos;
/*
* Update the passwd file entry. If there is a DBM file, update that
* entry as well.
*/
if (!pw_update (&pwent)) {
fprintf (stderr, _("Error updating the password entry.\n"));
pw_unlock ();
SYSLOG ((LOG_ERR, "error updating passwd entry"));
closelog ();
exit (E_NOPERM);
}
/*
* Changes have all been made, so commit them and unlock the file.
*/
if (!pw_close ()) {
fprintf (stderr, _("Cannot commit password file changes.\n"));
pw_unlock ();
SYSLOG ((LOG_ERR, "can't rewrite /etc/passwd"));
closelog ();
exit (E_NOPERM);
}
if (!pw_unlock ()) {
fprintf (stderr, _("Cannot unlock the password file.\n"));
SYSLOG ((LOG_ERR, "can't unlock /etc/passwd"));
closelog ();
exit (E_NOPERM);
}
}
/*
* get_old_fields - parse the old gecos and use the old value for the fields
* which are not set on the command line
*/
static void get_old_fields (const char *gecos)
{
char *cp; /* temporary character pointer */
char old_gecos[BUFSIZ]; /* buffer for old GECOS fields */
STRFCPY (old_gecos, gecos);
/*
* Now get the full name. It is the first comma separated field in
* the GECOS field.
*/
cp = copy_field (old_gecos, fflg ? (char *) 0 : fullnm, slop);
/*
* Now get the room number. It is the next comma separated field,
* if there is indeed one.
*/
if (cp)
cp = copy_field (cp, rflg ? (char *) 0 : roomno, slop);
/*
* Now get the work phone number. It is the third field.
*/
if (cp)
cp = copy_field (cp, wflg ? (char *) 0 : workph, slop);
/*
* Now get the home phone number. It is the fourth field.
*/
if (cp)
cp = copy_field (cp, hflg ? (char *) 0 : homeph, slop);
/*
* Anything left over is "slop".
*/
if (cp && !oflg) {
if (slop[0])
strcat (slop, ",");
strcat (slop, cp);
}
}
/*
* check_fields - check all of the fields for valid information
*
* It will not return if a field is not valid.
*/
static void check_fields (void)
{
if (valid_field (fullnm, ":,=")) {
fprintf (stderr, _("%s: invalid name: '%s'\n"), Prog, fullnm);
closelog ();
exit (E_NOPERM);
}
if (valid_field (roomno, ":,=")) {
fprintf (stderr, _("%s: invalid room number: '%s'\n"),
Prog, roomno);
closelog ();
exit (E_NOPERM);
}
if (valid_field (workph, ":,=")) {
fprintf (stderr, _("%s: invalid work phone: '%s'\n"),
Prog, workph);
closelog ();
exit (E_NOPERM);
}
if (valid_field (homeph, ":,=")) {
fprintf (stderr, _("%s: invalid home phone: '%s'\n"),
Prog, homeph);
closelog ();
exit (E_NOPERM);
}
if (valid_field (slop, ":")) {
fprintf (stderr,
_("%s: '%s' contains illegal characters\n"),
Prog, slop);
closelog ();
exit (E_NOPERM);
}
}
/*
* chfn - change a user's password file information
*
* This command controls the GECOS field information in the password
* file entry.
*
* The valid options are
*
* -f full name
* -r room number
* -w work phone number
* -h home phone number
* -o other information (*)
*
* (*) requires root permission to execute.
*/
int main (int argc, char **argv)
{
const struct passwd *pw; /* password file entry */
char new_gecos[BUFSIZ]; /* buffer for new GECOS fields */
char *user;
sanitize_env ();
setlocale (LC_ALL, "");
bindtextdomain (PACKAGE, LOCALEDIR);
textdomain (PACKAGE);
/*
* This command behaves different for root and non-root
* users.
*/
amroot = (getuid () == 0);
/*
* Get the program name. The program name is used as a
* prefix to most error messages.
*/
Prog = Basename (argv[0]);
OPENLOG ("chfn");
/* parse the command line options */
process_flags (argc, argv);
/*
* Get the name of the user to check. It is either the command line
* name, or the name getlogin() returns.
*/
if (optind < argc) {
user = argv[optind];
pw = xgetpwnam (user);
if (!pw) {
fprintf (stderr, _("%s: unknown user %s\n"), Prog,
user);
exit (E_NOPERM);
}
} else {
pw = get_my_pwent ();
if (!pw) {
fprintf (stderr,
_
("%s: Cannot determine your user name.\n"),
Prog);
exit (E_NOPERM);
}
user = xstrdup (pw->pw_name);
}
#ifdef USE_NIS
/*
* Now we make sure this is a LOCAL password entry for this user ...
*/
if (__ispwNIS ()) {
char *nis_domain;
char *nis_master;
fprintf (stderr,
_("%s: cannot change user '%s' on NIS client.\n"),
Prog, user);
if (!yp_get_default_domain (&nis_domain) &&
!yp_master (nis_domain, "passwd.byname", &nis_master)) {
fprintf (stderr,
_
("%s: '%s' is the NIS master for this client.\n"),
Prog, nis_master);
}
exit (E_NOPERM);
}
#endif
/* Check that the caller is allowed to change the gecos of the
* specified user */
check_perms (pw);
/* If some fields were not set on the command line, load the value from
* the old gecos fields. */
get_old_fields (pw->pw_gecos);
/*
* If none of the fields were changed from the command line, let the
* user interactively change them.
*/
if (!fflg && !rflg && !wflg && !hflg && !oflg) {
printf (_("Changing the user information for %s\n"), user);
new_fields ();
}
/*
* Check all of the fields for valid information
*/
check_fields ();
/*
* Build the new GECOS field by plastering all the pieces together,
* if they will fit ...
*/
if (strlen (fullnm) + strlen (roomno) + strlen (workph) +
strlen (homeph) + strlen (slop) > (unsigned int) 80) {
fprintf (stderr, _("%s: fields too long\n"), Prog);
closelog ();
exit (E_NOPERM);
}
snprintf (new_gecos, sizeof new_gecos, "%s,%s,%s,%s%s%s",
fullnm, roomno, workph, homeph, slop[0] ? "," : "", slop);
/* Rewrite the user's gecos in the passwd file */
update_gecos (user, new_gecos);
SYSLOG ((LOG_INFO, "changed user `%s' information", user));
nscd_flush_cache ("passwd");
#ifdef USE_PAM
pam_end (pamh, PAM_SUCCESS);
#endif /* USE_PAM */
closelog ();
exit (E_SUCCESS);
}