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
get_passwd(const struct passwd * pw,char buffer[SHADOW_BUFSIZE])41 static 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 */
check_password(const struct passwd * pw,const char * plaintext)70 int 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 */
ask_and_check_password_extended(const struct passwd * pw,int timeout,const char * prompt)97 int 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
ask_and_check_password(const struct passwd * pw)120 int FAST_FUNC ask_and_check_password(const struct passwd *pw)
121 {
122 return ask_and_check_password_extended(pw, 0, "Password: ");
123 }
124