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shadow/src/chfn.c

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/*
* Copyright (c) 1989 - 1994, Julianne Frances Haugh
* Copyright (c) 1996 - 2000, Marek Michałkiewicz
* Copyright (c) 2001 - 2006, Tomasz Kłoczko
* Copyright (c) 2007 - 2011, Nicolas François
* 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. The name of the copyright holders or contributors may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 THE COPYRIGHT
* HOLDERS 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>
#include <getopt.h>
#ifdef WITH_SELINUX
#include <selinux/selinux.h>
#include <selinux/av_permissions.h>
#endif
#include "defines.h"
#include "getdef.h"
#include "nscd.h"
#ifdef USE_PAM
#include "pam_defs.h"
#endif
#include "prototypes.h"
#include "pwauth.h"
#include "pwio.h"
/*@-exitarg@*/
#include "exitcodes.h"
/*
* Global variables.
*/
const char *Prog;
static char fullnm[BUFSIZ];
static char roomno[BUFSIZ];
static char workph[BUFSIZ];
static char homeph[BUFSIZ];
static char slop[BUFSIZ];
static bool amroot;
/* Flags */
static bool fflg = false; /* -f - set full name */
static bool rflg = false; /* -r - set room number */
static bool wflg = false; /* -w - set work phone number */
static bool hflg = false; /* -h - set home phone number */
static bool oflg = false; /* -o - set other information */
static bool pw_locked = false;
/*
* External identifiers
*/
/* local function prototypes */
static void fail_exit (int code);
static /*@noreturn@*/void usage (int status);
static bool 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);
/*
* fail_exit - exit with an error and do some cleanup
*/
static void fail_exit (int code)
{
if (pw_locked) {
if (pw_unlock () == 0) {
fprintf (stderr, _("%s: failed to unlock %s\n"), Prog, pw_dbname ());
SYSLOG ((LOG_ERR, "failed to unlock %s", pw_dbname ()));
/* continue */
}
}
pw_locked = false;
closelog ();
exit (code);
}
/*
* usage - print command line syntax and exit
*/
static /*@noreturn@*/void usage (int status)
{
FILE *usageout = (E_SUCCESS != status) ? stderr : stdout;
(void) fprintf (usageout,
_("Usage: %s [options] [LOGIN]\n"
"\n"
"Options:\n"),
Prog);
(void) fputs (_(" -f, --full-name FULL_NAME change user's full name\n"), usageout);
(void) fputs (_(" -h, --home-phone HOME_PHONE change user's home phone number\n"), usageout);
(void) fputs (_(" -o, --other OTHER_INFO change user's other GECOS information\n"), usageout);
(void) fputs (_(" -r, --room ROOM_NUMBER change user's room number\n"), usageout);
(void) fputs (_(" -R, --root CHROOT_DIR directory to chroot into\n"), usageout);
(void) fputs (_(" -u, --help display this help message and exit\n"), usageout);
(void) fputs (_(" -w, --work-phone WORK_PHONE change user's office phone number\n"), usageout);
(void) fputs ("\n", usageout);
exit (status);
}
/*
* may_change_field - indicate if the user is allowed to change a given field
* of her gecos information
*
* root can change any field.
*
* field should be one of 'f', 'r', 'w', 'h'
*
* Return true if the user can change the field and false otherwise.
*/
static bool 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 true;
}
cp = getdef_str ("CHFN_RESTRICT");
if (NULL == cp) {
cp = "";
} else if (strcmp (cp, "yes") == 0) {
cp = "rwh";
} else if (strcmp (cp, "no") == 0) {
cp = "frwh";
}
if (strchr (cp, field) != NULL) {
return true;
}
return false;
}
/*
* 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)
{
puts (_("Enter the new value, or press ENTER for the default"));
if (may_change_field ('f')) {
change_field (fullnm, sizeof fullnm, _("Full Name"));
} else {
printf (_("\t%s: %s\n"), _("Full Name"), fullnm);
}
if (may_change_field ('r')) {
change_field (roomno, sizeof roomno, _("Room Number"));
} else {
printf (_("\t%s: %s\n"), _("Room Number"), fullnm);
}
if (may_change_field ('w')) {
change_field (workph, sizeof workph, _("Work Phone"));
} else {
printf (_("\t%s: %s\n"), _("Work Phone"), fullnm);
}
if (may_change_field ('h')) {
change_field (homeph, sizeof homeph, _("Home Phone"));
} else {
printf (_("\t%s: %s\n"), _("Home Phone"), fullnm);
}
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 (NULL != in) {
cp = strchr (in, ',');
if (NULL != cp) {
*cp++ = '\0';
}
if (strchr (in, '=') == NULL) {
break;
}
if (NULL != extra) {
if ('\0' != extra[0]) {
strcat (extra, ",");
}
strcat (extra, in);
}
in = cp;
}
if ((NULL != in) && (NULL != 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 c; /* flag currently being processed */
static struct option long_options[] = {
{"full-name", required_argument, NULL, 'f'},
{"home-phone", required_argument, NULL, 'h'},
{"other", required_argument, NULL, 'o'},
{"room", required_argument, NULL, 'r'},
{"root", required_argument, NULL, 'R'},
{"help", no_argument, NULL, 'u'},
{"work-phone", required_argument, NULL, 'w'},
{NULL, 0, NULL, '\0'}
};
/*
* 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 ((c = getopt_long (argc, argv, "f:h:o:r:R:uw:",
long_options, NULL)) != -1) {
switch (c) {
case 'f':
if (!may_change_field ('f')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
fflg = true;
STRFCPY (fullnm, optarg);
break;
case 'h':
if (!may_change_field ('h')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
hflg = true;
STRFCPY (homeph, optarg);
break;
case 'o':
if (!amroot) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
oflg = true;
STRFCPY (slop, optarg);
break;
case 'r':
if (!may_change_field ('r')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
rflg = true;
STRFCPY (roomno, optarg);
break;
case 'R': /* no-op, handled in process_root_flag () */
break;
case 'u':
usage (E_SUCCESS);
/*@notreached@*/break;
case 'w':
if (!may_change_field ('w')) {
fprintf (stderr,
_("%s: Permission denied.\n"), Prog);
exit (E_NOPERM);
}
wflg = true;
STRFCPY (workph, optarg);
break;
default:
usage (E_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
pam_handle_t *pamh = NULL;
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 */
pampw = getpwuid (getuid ()); /* local, no need for xgetpwuid */
if (NULL == pampw) {
fprintf (stderr,
_("%s: Cannot determine your user name.\n"),
Prog);
exit (E_NOPERM);
}
retval = pam_start ("chfn", pampw->pw_name, &conv, &pamh);
if (PAM_SUCCESS == retval) {
retval = pam_authenticate (pamh, 0);
}
if (PAM_SUCCESS == retval) {
retval = pam_acct_mgmt (pamh, 0);
}
if (NULL != pamh) {
(void) pam_end (pamh, retval);
}
if (PAM_SUCCESS != retval) {
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) != 0) {
fputs (_("Cannot change ID to root.\n"), stderr);
SYSLOG ((LOG_ERR, "can't setuid(0)"));
fail_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 () == 0) {
fprintf (stderr,
_("%s: cannot lock %s; try again later.\n"),
Prog, pw_dbname ());
fail_exit (E_NOPERM);
}
pw_locked = true;
if (pw_open (O_RDWR) == 0) {
fprintf (stderr,
_("%s: cannot open %s\n"), Prog, pw_dbname ());
fail_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 (NULL == pw) {
fprintf (stderr,
_("%s: user '%s' does not exist in %s\n"),
Prog, user, pw_dbname ());
fail_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) == 0) {
fprintf (stderr,
_("%s: failed to prepare the new %s entry '%s'\n"),
Prog, pw_dbname (), pwent.pw_name);
fail_exit (E_NOPERM);
}
/*
* Changes have all been made, so commit them and unlock the file.
*/
if (pw_close () == 0) {
fprintf (stderr, _("%s: failure while writing changes to %s\n"), Prog, pw_dbname ());
SYSLOG ((LOG_ERR, "failure while writing changes to %s", pw_dbname ()));
fail_exit (E_NOPERM);
}
if (pw_unlock () == 0) {
fprintf (stderr, _("%s: failed to unlock %s\n"), Prog, pw_dbname ());
SYSLOG ((LOG_ERR, "failed to unlock %s", pw_dbname ()));
/* continue */
}
pw_locked = false;
}
/*
* 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 (NULL != cp) {
cp = copy_field (cp, rflg ? (char *) 0 : roomno, slop);
}
/*
* Now get the work phone number. It is the third field.
*/
if (NULL != cp) {
cp = copy_field (cp, wflg ? (char *) 0 : workph, slop);
}
/*
* Now get the home phone number. It is the fourth field.
*/
if (NULL != cp) {
cp = copy_field (cp, hflg ? (char *) 0 : homeph, slop);
}
/*
* Anything left over is "slop".
*/
if ((NULL != cp) && !oflg) {
if ('\0' != 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)
{
int err;
err = valid_field (fullnm, ":,=\n");
if (err > 0) {
fprintf (stderr, _("%s: name with non-ASCII characters: '%s'\n"), Prog, fullnm);
} else if (err < 0) {
fprintf (stderr, _("%s: invalid name: '%s'\n"), Prog, fullnm);
fail_exit (E_NOPERM);
}
err = valid_field (roomno, ":,=\n");
if (err > 0) {
fprintf (stderr, _("%s: room number with non-ASCII characters: '%s'\n"), Prog, roomno);
} else if (err < 0) {
fprintf (stderr, _("%s: invalid room number: '%s'\n"),
Prog, roomno);
fail_exit (E_NOPERM);
}
if (valid_field (workph, ":,=\n") != 0) {
fprintf (stderr, _("%s: invalid work phone: '%s'\n"),
Prog, workph);
fail_exit (E_NOPERM);
}
if (valid_field (homeph, ":,=\n") != 0) {
fprintf (stderr, _("%s: invalid home phone: '%s'\n"),
Prog, homeph);
fail_exit (E_NOPERM);
}
err = valid_field (slop, ":\n");
if (err > 0) {
fprintf (stderr, _("%s: '%s' contains non-ASCII characters\n"), Prog, slop);
} else if (err < 0) {
fprintf (stderr,
_("%s: '%s' contains illegal characters\n"),
Prog, slop);
fail_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;
/*
* Get the program name. The program name is used as a
* prefix to most error messages.
*/
Prog = Basename (argv[0]);
sanitize_env ();
(void) setlocale (LC_ALL, "");
(void) bindtextdomain (PACKAGE, LOCALEDIR);
(void) textdomain (PACKAGE);
process_root_flag ("-R", argc, argv);
/*
* This command behaves different for root and non-root
* users.
*/
amroot = (getuid () == 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 (NULL == pw) {
fprintf (stderr, _("%s: user '%s' does not exist\n"), Prog,
user);
fail_exit (E_NOPERM);
}
} else {
pw = get_my_pwent ();
if (NULL == pw) {
fprintf (stderr,
_("%s: Cannot determine your user name.\n"),
Prog);
SYSLOG ((LOG_WARN, "Cannot determine the user name of the caller (UID %lu)",
(unsigned long) getuid ()));
fail_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);
}
fail_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);
fail_exit (E_NOPERM);
}
snprintf (new_gecos, sizeof new_gecos, "%s,%s,%s,%s%s%s",
fullnm, roomno, workph, homeph,
('\0' != 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");
closelog ();
exit (E_SUCCESS);
}
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