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/* Ask the user for a password.
  34 * Return 1 if the user gives the correct password for entry PW,
  35 * 0 if not.  Return 1 without asking if PW has an empty password.
  36 *
  37 * NULL pw means "just fake it for login with bad username" */
  38
  39int FAST_FUNC correct_password(const struct passwd *pw)
  40{
  41        char *unencrypted, *encrypted;
  42        const char *correct;
  43        int r;
  44#if ENABLE_FEATURE_SHADOWPASSWDS
  45        /* Using _r function to avoid pulling in static buffers */
  46        struct spwd spw;
  47        char buffer[256];
  48#endif
  49
  50        /* fake salt. crypt() can choke otherwise. */
  51        correct = "aa";
  52        if (!pw) {
  53                /* "aa" will never match */
  54                goto fake_it;
  55        }
  56        correct = pw->pw_passwd;
  57#if ENABLE_FEATURE_SHADOWPASSWDS
  58        if ((correct[0] == 'x' || correct[0] == '*') && !correct[1]) {
  59                /* getspnam_r may return 0 yet set result to NULL.
  60                 * At least glibc 2.4 does this. Be extra paranoid here. */
  61                struct spwd *result = NULL;
  62                r = getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result);
  63                correct = (r || !result) ? "aa" : result->sp_pwdp;
  64        }
  65#endif
  66
  67        if (!correct[0]) /* empty password field? */
  68                return 1;
  69
  70 fake_it:
  71        unencrypted = bb_ask_stdin("Password: ");
  72        if (!unencrypted) {
  73                return 0;
  74        }
  75        encrypted = pw_encrypt(unencrypted, correct, 1);
  76        r = (strcmp(encrypted, correct) == 0);
  77        free(encrypted);
  78        memset(unencrypted, 0, strlen(unencrypted));
  79        return r;
  80}
  81