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