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#include "libbb.h"
  31
  32#define SHADOW_BUFSIZE 256
  33
  34/* Retrieve encrypted password string for pw.
  35 * If pw == NULL, return a string which fails password check against any
  36 * password.
  37 */
  38#if !ENABLE_FEATURE_SHADOWPASSWDS
  39#define get_passwd(pw, buffer) get_passwd(pw)
  40#endif
  41static const char *get_passwd(const struct passwd *pw, char buffer[SHADOW_BUFSIZE])
  42{
  43        const char *pass;
  44
  45        if (!pw)
  46                return "aa"; /* "aa" will never match */
  47
  48        pass = pw->pw_passwd;
  49#if ENABLE_FEATURE_SHADOWPASSWDS
  50        /* Using _r function to avoid pulling in static buffers */
  51        if ((pass[0] == 'x' || pass[0] == '*') && !pass[1]) {
  52                struct spwd spw;
  53                int r;
  54                /* getspnam_r may return 0 yet set result to NULL.
  55                 * At least glibc 2.4 does this. Be extra paranoid here. */
  56                struct spwd *result = NULL;
  57                r = getspnam_r(pw->pw_name, &spw, buffer, SHADOW_BUFSIZE, &result);
  58                pass = (r || !result) ? "aa" : result->sp_pwdp;
  59        }
  60#endif
  61        return pass;
  62}
  63
  64/*
  65 * Return CHECKPASS_PW_HAS_EMPTY_PASSWORD if PW has an empty password.
  66 * Return 1 if the user gives the correct password for entry PW,
  67 * 0 if not.
  68 * NULL pw means "just fake it for login with bad username"
  69 */
  70int FAST_FUNC check_password(const struct passwd *pw, const char *plaintext)
  71{
  72        IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
  73        char *encrypted;
  74        const char *pw_pass;
  75        int r;
  76
  77        pw_pass = get_passwd(pw, buffer);
  78        if (!pw_pass[0]) { /* empty password field? */
  79                return CHECKPASS_PW_HAS_EMPTY_PASSWORD;
  80        }
  81
  82        encrypted = pw_encrypt(plaintext, /*salt:*/ pw_pass, 1);
  83        r = (strcmp(encrypted, pw_pass) == 0);
  84        free(encrypted);
  85        return r;
  86}
  87
  88
  89/* Ask the user for a password.
  90 * Return CHECKPASS_PW_HAS_EMPTY_PASSWORD without asking if PW has an empty password.
  91 * Return -1 on EOF, error while reading input, or timeout.
  92 * Return 1 if the user gives the correct password for entry PW,
  93 * 0 if not.
  94 *
  95 * NULL pw means "just fake it for login with bad username"
  96 */
  97int FAST_FUNC ask_and_check_password_extended(const struct passwd *pw,
  98                int timeout, const char *prompt)
  99{
 100        IF_FEATURE_SHADOWPASSWDS(char buffer[SHADOW_BUFSIZE];)
 101        char *plaintext;
 102        const char *pw_pass;
 103        int r;
 104
 105        pw_pass = get_passwd(pw, buffer);
 106        if (!pw_pass[0]) /* empty password field? */
 107                return CHECKPASS_PW_HAS_EMPTY_PASSWORD;
 108
 109        plaintext = bb_ask_noecho(STDIN_FILENO, timeout, prompt);
 110        if (!plaintext) {
 111                /* EOF (such as ^D) or error (such as ^C) or timeout */
 112                return -1;
 113        }
 114
 115        r = check_password(pw, plaintext);
 116        nuke_str(plaintext);
 117        return r;
 118}
 119
 120int FAST_FUNC ask_and_check_password(const struct passwd *pw)
 121{
 122        return ask_and_check_password_extended(pw, 0, "Password: ");
 123}
 124