xref: /netbsd-src/crypto/external/bsd/openssh/dist/readpassphrase.c (revision 6a493d6bc668897c91594964a732d38505b70cbb)
1 /*	$NetBSD: readpassphrase.c,v 1.3 2012/04/14 01:34:37 christos Exp $	*/
2 /*
3  * Copyright (c) 2000 Todd C. Miller <Todd.Miller@courtesan.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. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
18  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
19  * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL
20  * THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
21  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
25  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
26  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include "includes.h"
30 #if defined(LIBC_SCCS) && !defined(lint)
31 static const char rcsid[] = "$OpenBSD: readpassphrase.c,v 1.7 2001/08/07 19:34:11 millert Exp $";
32 #endif /* LIBC_SCCS and not lint */
33 
34 #include <ctype.h>
35 #include <errno.h>
36 #include <fcntl.h>
37 #include <paths.h>
38 #include <pwd.h>
39 #include <signal.h>
40 #include <string.h>
41 #include <termios.h>
42 #include <unistd.h>
43 #include <readpassphrase.h>
44 
45 char *
46 readpassphrase(prompt, buf, bufsiz, flags)
47 	const char *prompt;
48 	char *buf;
49 	size_t bufsiz;
50 	int flags;
51 {
52 #ifdef GETPASS_ECHO
53 	int gflags = GETPASS_ECHO_NL;
54 
55 	if (flags & RPP_ECHO_ON)
56 		gflags |= GETPASS_ECHO;
57 	if (flags & RPP_REQUIRE_TTY)
58 		gflags |= GETPASS_NEED_TTY;
59 	if (flags & RPP_FORCELOWER)
60 		gflags |= GETPASS_FORCE_LOWER;
61 	if (flags & RPP_FORCEUPPER)
62 		gflags |= GETPASS_FORCE_UPPER;
63 	if (flags & RPP_SEVENBIT)
64 		gflags |= GETPASS_7BIT;
65 
66 	return getpassfd(prompt, buf, bufsiz, NULL, gflags, 0);
67 #else
68 	struct termios term, oterm;
69 	char ch, *p, *end;
70 	int input, output;
71 	sigset_t oset, nset;
72 
73 	/* I suppose we could alloc on demand in this case (XXX). */
74 	if (bufsiz == 0) {
75 		errno = EINVAL;
76 		return(NULL);
77 	}
78 
79 	/*
80 	 * Read and write to /dev/tty if available.  If not, read from
81 	 * stdin and write to stderr unless a tty is required.
82 	 */
83 	if ((input = output = open(_PATH_TTY, O_RDWR)) == -1) {
84 		if (flags & RPP_REQUIRE_TTY) {
85 			errno = ENOTTY;
86 			return(NULL);
87 		}
88 		input = STDIN_FILENO;
89 		output = STDERR_FILENO;
90 	}
91 
92 	/*
93 	 * We block SIGINT and SIGTSTP so the terminal is not left
94 	 * in an inconsistent state (ie: no echo).  It would probably
95 	 * be better to simply catch these though.
96 	 */
97 	sigemptyset(&nset);
98 	sigaddset(&nset, SIGINT);
99 	sigaddset(&nset, SIGTSTP);
100 	(void)sigprocmask(SIG_BLOCK, &nset, &oset);
101 
102 	/* Turn off echo if possible. */
103 	if (tcgetattr(input, &oterm) == 0) {
104 		memcpy(&term, &oterm, sizeof(term));
105 		if (!(flags & RPP_ECHO_ON) && (term.c_lflag & ECHO))
106 			term.c_lflag &= ~ECHO;
107 		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
108 			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
109 		(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
110 	} else {
111 		memset(&term, 0, sizeof(term));
112 		memset(&oterm, 0, sizeof(oterm));
113 	}
114 
115 	(void)write(output, prompt, strlen(prompt));
116 	end = buf + bufsiz - 1;
117 	for (p = buf; read(input, &ch, 1) == 1 && ch != '\n' && ch != '\r';) {
118 		if (p < end) {
119 			if ((flags & RPP_SEVENBIT))
120 				ch &= 0x7f;
121 			if (isalpha((unsigned char)ch)) {
122 				if ((flags & RPP_FORCELOWER))
123 					ch = tolower((unsigned char)ch);
124 				if ((flags & RPP_FORCEUPPER))
125 					ch = toupper((unsigned char)ch);
126 			}
127 			*p++ = ch;
128 		}
129 	}
130 	*p = '\0';
131 	if (!(term.c_lflag & ECHO))
132 		(void)write(output, "\n", 1);
133 
134 	/* Restore old terminal settings and signal mask. */
135 	if (memcmp(&term, &oterm, sizeof(term)) != 0)
136 		(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm);
137 	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
138 	if (input != STDIN_FILENO)
139 		(void)close(input);
140 	return(buf);
141 #endif
142 }
143 
144 char *
145 getpass(prompt)
146         const char *prompt;
147 {
148 	static char buf[_PASSWORD_LEN + 1];
149 
150 	return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
151 }
152