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
get_passwd(const struct passwd * pw,char buffer[SHADOW_BUFSIZE])42 static 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 */
check_password(const struct passwd * pw,const char * plaintext)71 int 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 */
ask_and_check_password_extended(const struct passwd * pw,int timeout,const char * prompt)98 int 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
ask_and_check_password(const struct passwd * pw)121 int FAST_FUNC ask_and_check_password(const struct passwd *pw)
122 {
123 return ask_and_check_password_extended(pw, 0, "Password: ");
124 }
125