freebsd-skq/usr.bin/chpass/field.c
Mike Pritchard d33c4953e7 Print some warnings if root invokes chpass and sets the
shell to one of the following:

- a non-existent file
- a non-regular file
- a file without any execute bits set

The shell is still set to whatever they entered even if the above
conditions exist (hey, it is the super user doing this after all :-),
but this might give the admin. some warning that they are about to screw
themselves and give them a chance to fix it before it is too late.

Inspired by: some new FreeBSD user on USENET who set his root shell
  to a shell that doesn't exist and now can't gain access to root (don't
  worry, I sent him some mail on how to recover from this).
1996-04-11 05:30:18 +00:00

288 lines
5.8 KiB
C

/*
* Copyright (c) 1988, 1993, 1994
* The Regents of the University of California. 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University 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 THE REGENTS 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 REGENTS 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.
*/
#ifndef lint
static char sccsid[] = "@(#)field.c 8.4 (Berkeley) 4/2/94";
#endif /* not lint */
#include <sys/param.h>
#include <sys/stat.h>
#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "chpass.h"
#include "pathnames.h"
/* ARGSUSED */
int
p_login(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!*p) {
warnx("empty login field");
return (1);
}
if (*p == '-') {
warnx("login names may not begin with a hyphen");
return (1);
}
if (!(pw->pw_name = strdup(p))) {
warnx("can't save entry");
return (1);
}
if (strchr(p, '.'))
warnx("\'.\' is dangerous in a login name");
for (; *p; ++p)
if (isupper(*p)) {
warnx("upper-case letters are dangerous in a login name");
break;
}
return (0);
}
/* ARGSUSED */
int
p_passwd(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!*p)
pw->pw_passwd = ""; /* "NOLOGIN"; */
else if (!(pw->pw_passwd = strdup(p))) {
warnx("can't save password entry");
return (1);
}
return (0);
}
/* ARGSUSED */
int
p_uid(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
uid_t id;
char *np;
if (!*p) {
warnx("empty uid field");
return (1);
}
if (!isdigit(*p)) {
warnx("illegal uid");
return (1);
}
errno = 0;
id = strtoul(p, &np, 10);
if (*np || (id == ULONG_MAX && errno == ERANGE)) {
warnx("illegal uid");
return (1);
}
pw->pw_uid = id;
return (0);
}
/* ARGSUSED */
int
p_gid(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
struct group *gr;
gid_t id;
char *np;
if (!*p) {
warnx("empty gid field");
return (1);
}
if (!isdigit(*p)) {
if (!(gr = getgrnam(p))) {
warnx("unknown group %s", p);
return (1);
}
pw->pw_gid = gr->gr_gid;
return (0);
}
errno = 0;
id = strtoul(p, &np, 10);
if (*np || (id == ULONG_MAX && errno == ERANGE)) {
warnx("illegal gid");
return (1);
}
pw->pw_gid = id;
return (0);
}
/* ARGSUSED */
int
p_class(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!*p)
pw->pw_class = "";
else if (!(pw->pw_class = strdup(p))) {
warnx("can't save entry");
return (1);
}
return (0);
}
/* ARGSUSED */
int
p_change(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!atot(p, &pw->pw_change))
return (0);
warnx("illegal date for change field");
return (1);
}
/* ARGSUSED */
int
p_expire(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!atot(p, &pw->pw_expire))
return (0);
warnx("illegal date for expire field");
return (1);
}
/* ARGSUSED */
int
p_gecos(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!*p)
ep->save = "";
else if (!(ep->save = strdup(p))) {
warnx("can't save entry");
return (1);
}
return (0);
}
/* ARGSUSED */
int
p_hdir(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
if (!*p) {
warnx("empty home directory field");
return (1);
}
if (!(pw->pw_dir = strdup(p))) {
warnx("can't save entry");
return (1);
}
return (0);
}
/* ARGSUSED */
int
p_shell(p, pw, ep)
char *p;
struct passwd *pw;
ENTRY *ep;
{
char *t, *ok_shell();
struct stat sbuf;
if (!*p) {
pw->pw_shell = _PATH_BSHELL;
return (0);
}
/* only admin can change from or to "restricted" shells */
if (uid && pw->pw_shell && !ok_shell(pw->pw_shell)) {
warnx("%s: current shell non-standard", pw->pw_shell);
return (1);
}
if (!(t = ok_shell(p))) {
if (uid) {
warnx("%s: non-standard shell", p);
return (1);
}
}
else
p = t;
if (!(pw->pw_shell = strdup(p))) {
warnx("can't save entry");
return (1);
}
if (stat(pw->pw_shell, &sbuf) < 0) {
if (errno == ENOENT)
warnx("WARNING: shell '%s' does not exist",
pw->pw_shell);
else
warn("WARNING: can't stat shell '%s'", pw->pw_shell);
return (0);
}
if (!S_ISREG(sbuf.st_mode)) {
warnx("WARNING: shell '%s' is not a regular file",
pw->pw_shell);
return (0);
}
if ((sbuf.st_mode & (S_IXOTH | S_IXGRP | S_IXUSR)) == 0) {
warnx("WARNING: shell '%s' is not executable", pw->pw_shell);
return (0);
}
return (0);
}