LXR busybox/libbb/correct

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * Copyright 1989 - 1991, Julianne Frances Haugh <jockgrrl@austin.rr.com>
   4 * All rights reserved.
   5 *
   6 * Redistribution and use in source and binary forms, with or without
   7 * modification, are permitted provided that the following conditions
   8 * are met:
   9 * 1. Redistributions of source code must retain the above copyright
  10 *    notice, this list of conditions and the following disclaimer.
  11 * 2. Redistributions in binary form must reproduce the above copyright
  12 *    notice, this list of conditions and the following disclaimer in the
  13 *    documentation and/or other materials provided with the distribution.
  14 * 3. Neither the name of Julianne F. Haugh nor the names of its contributors
  15 *    may be used to endorse or promote products derived from this software
  16 *    without specific prior written permission.
  17 *
  18 * THIS SOFTWARE IS PROVIDED BY JULIE HAUGH AND CONTRIBUTORS ``AS IS'' AND
  19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  21 * ARE DISCLAIMED.  IN NO EVENT SHALL JULIE HAUGH OR CONTRIBUTORS BE LIABLE
  22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  28 * SUCH DAMAGE.
  29 */
  30
  31#include "libbb.h"
  32
  33#define SHADOW_BUFSIZE 256
  34
  35/* Retrieve encrypted password string for pw.
  36 * If pw == NULL, return a string which fails password check against any
  37 * password.
  38 */
  39#if !ENABLE_FEATURE_SHADOWPASSWDS
  40#define get_passwd(pw, buffer) get_passwd(pw)
  41#endif
  42static const char *get_passwd(const struct passwd *pw, char buffer[SHADOW_BUFSIZE])
  43{
  44        const char *pass;
  45
  46        if (!pw)
  47                return "aa"; /* "aa" will never match */
  48
  49        pass = pw->pw_passwd;
  50#if ENABLE_FEATURE_SHADOWPASSWDS
  51        /* Using _r function to avoid pulling in static buffers */
  52        if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) {
  53                struct spwd spw;
  54                int r;
  55                /* getspnam_r may return 0 yet set result to NULL.
  56                 * At least glibc 2.4 does this. Be extra paranoid here. */
  57                struct spwd *result = NULL;
  58                r = getspnam_r(pw->pw_name, &spw, buffer, SHADOW_BUFSIZE, &result);
  59                pass = (r || !result) ? "aa" : result->sp_pwdp;
  60        }
  61#endif
  62        return pass;
  63}
  64
  65/*
  66 * Return 1 if PW has an empty password.
  67 * Return 1 if the user gives the correct password for entry PW,
  68 * 0 if not.
  69 * NULL pw means "just fake it for login with bad username"
  70 */
  71int FAST_FUNC check_password(const struct passwd *pw, const char *plaintext)
  72{
  73        IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
  74        char *encrypted;
  75        const char *pw_pass;
  76        int r;
  77
  78        pw_pass = get_passwd(pw, buffer);
  79        if (!pw_pass[0]) { /* empty password field? */
  80                return 1;
  81        }
  82
  83        encrypted = pw_encrypt(plaintext, /*salt:*/ pw_pass, 1);
  84        r = (strcmp(encrypted, pw_pass) == 0);
  85        free(encrypted);
  86        return r;
  87}
  88
  89
  90/* Ask the user for a password.
  91 * Return 1 without asking if PW has an empty password.
  92 * Return -1 on EOF, error while reading input, or timeout.
  93 * Return 1 if the user gives the correct password for entry PW,
  94 * 0 if not.
  95 *
  96 * NULL pw means "just fake it for login with bad username"
  97 */
  98int FAST_FUNC ask_and_check_password_extended(const struct passwd *pw,
  99                int timeout, const char *prompt)
 100{
 101        IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
 102        char *plaintext;
 103        const char *pw_pass;
 104        int r;
 105
 106        pw_pass = get_passwd(pw, buffer);
 107        if (!pw_pass[0]) /* empty password field? */
 108                return 1;
 109
 110        plaintext = bb_ask(STDIN_FILENO, timeout, prompt);
 111        if (!plaintext) {
 112                /* EOF (such as ^D) or error (such as ^C) or timeout */
 113                return -1;
 114        }
 115
 116        r = check_password(pw, plaintext);
 117        nuke_str(plaintext);
 118        return r;
 119}
 120
 121int FAST_FUNC ask_and_check_password(const struct passwd *pw)
 122{
 123        return ask_and_check_password_extended(pw, 0, "Password: ");
 124}
 125