readpassphrase.c revision 295367 
1/*	$OpenBSD: readpassphrase.c,v 1.22 2010/01/13 10:20:54 dtucker Exp $	*/
2
3/*
4 * Copyright (c) 2000-2002, 2007 Todd C. Miller <Todd.Miller@courtesan.com>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 *
18 * Sponsored in part by the Defense Advanced Research Projects
19 * Agency (DARPA) and Air Force Research Laboratory, Air Force
20 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
21 */
22
23/* OPENBSD ORIGINAL: lib/libc/gen/readpassphrase.c */
24
25#include "includes.h"
26
27#ifndef HAVE_READPASSPHRASE
28
29#include <termios.h>
30#include <signal.h>
31#include <ctype.h>
32#include <fcntl.h>
33#include <readpassphrase.h>
34#include <errno.h>
35#include <string.h>
36#include <unistd.h>
37
38#ifdef TCSASOFT
39# define _T_FLUSH	(TCSAFLUSH|TCSASOFT)
40#else
41# define _T_FLUSH	(TCSAFLUSH)
42#endif
43
44/* SunOS 4.x which lacks _POSIX_VDISABLE, but has VDISABLE */
45#if !defined(_POSIX_VDISABLE) && defined(VDISABLE)
46#  define _POSIX_VDISABLE       VDISABLE
47#endif
48
49#ifndef _NSIG
50# ifdef NSIG
51#  define _NSIG NSIG
52# else
53#  define _NSIG 128
54# endif
55#endif
56
57static volatile sig_atomic_t signo[_NSIG];
58
59static void handler(int);
60
61char *
62readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
63{
64	ssize_t nr;
65	int input, output, save_errno, i, need_restart;
66	char ch, *p, *end;
67	struct termios term, oterm;
68	struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
69	struct sigaction savetstp, savettin, savettou, savepipe;
70
71	/* I suppose we could alloc on demand in this case (XXX). */
72	if (bufsiz == 0) {
73		errno = EINVAL;
74		return(NULL);
75	}
76
77restart:
78	for (i = 0; i < _NSIG; i++)
79		signo[i] = 0;
80	nr = -1;
81	save_errno = 0;
82	need_restart = 0;
83	/*
84	 * Read and write to /dev/tty if available.  If not, read from
85	 * stdin and write to stderr unless a tty is required.
86	 */
87	if ((flags & RPP_STDIN) ||
88	    (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
89		if (flags & RPP_REQUIRE_TTY) {
90			errno = ENOTTY;
91			return(NULL);
92		}
93		input = STDIN_FILENO;
94		output = STDERR_FILENO;
95	}
96
97	/*
98	 * Catch signals that would otherwise cause the user to end
99	 * up with echo turned off in the shell.  Don't worry about
100	 * things like SIGXCPU and SIGVTALRM for now.
101	 */
102	sigemptyset(&sa.sa_mask);
103	sa.sa_flags = 0;		/* don't restart system calls */
104	sa.sa_handler = handler;
105	(void)sigaction(SIGALRM, &sa, &savealrm);
106	(void)sigaction(SIGHUP, &sa, &savehup);
107	(void)sigaction(SIGINT, &sa, &saveint);
108	(void)sigaction(SIGPIPE, &sa, &savepipe);
109	(void)sigaction(SIGQUIT, &sa, &savequit);
110	(void)sigaction(SIGTERM, &sa, &saveterm);
111	(void)sigaction(SIGTSTP, &sa, &savetstp);
112	(void)sigaction(SIGTTIN, &sa, &savettin);
113	(void)sigaction(SIGTTOU, &sa, &savettou);
114
115	/* Turn off echo if possible. */
116	if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
117		memcpy(&term, &oterm, sizeof(term));
118		if (!(flags & RPP_ECHO_ON))
119			term.c_lflag &= ~(ECHO | ECHONL);
120#ifdef VSTATUS
121		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
122			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
123#endif
124		(void)tcsetattr(input, _T_FLUSH, &term);
125	} else {
126		memset(&term, 0, sizeof(term));
127		term.c_lflag |= ECHO;
128		memset(&oterm, 0, sizeof(oterm));
129		oterm.c_lflag |= ECHO;
130	}
131
132	/* No I/O if we are already backgrounded. */
133	if (signo[SIGTTOU] != 1 && signo[SIGTTIN] != 1) {
134		if (!(flags & RPP_STDIN))
135			(void)write(output, prompt, strlen(prompt));
136		end = buf + bufsiz - 1;
137		p = buf;
138		while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
139			if (p < end) {
140				if ((flags & RPP_SEVENBIT))
141					ch &= 0x7f;
142				if (isalpha(ch)) {
143					if ((flags & RPP_FORCELOWER))
144						ch = (char)tolower(ch);
145					if ((flags & RPP_FORCEUPPER))
146						ch = (char)toupper(ch);
147				}
148				*p++ = ch;
149			}
150		}
151		*p = '\0';
152		save_errno = errno;
153		if (!(term.c_lflag & ECHO))
154			(void)write(output, "\n", 1);
155	}
156
157	/* Restore old terminal settings and signals. */
158	if (memcmp(&term, &oterm, sizeof(term)) != 0) {
159		while (tcsetattr(input, _T_FLUSH, &oterm) == -1 &&
160		    errno == EINTR)
161			continue;
162	}
163	(void)sigaction(SIGALRM, &savealrm, NULL);
164	(void)sigaction(SIGHUP, &savehup, NULL);
165	(void)sigaction(SIGINT, &saveint, NULL);
166	(void)sigaction(SIGQUIT, &savequit, NULL);
167	(void)sigaction(SIGPIPE, &savepipe, NULL);
168	(void)sigaction(SIGTERM, &saveterm, NULL);
169	(void)sigaction(SIGTSTP, &savetstp, NULL);
170	(void)sigaction(SIGTTIN, &savettin, NULL);
171	(void)sigaction(SIGTTOU, &savettou, NULL);
172	if (input != STDIN_FILENO)
173		(void)close(input);
174
175	/*
176	 * If we were interrupted by a signal, resend it to ourselves
177	 * now that we have restored the signal handlers.
178	 */
179	for (i = 0; i < _NSIG; i++) {
180		if (signo[i]) {
181			kill(getpid(), i);
182			switch (i) {
183			case SIGTSTP:
184			case SIGTTIN:
185			case SIGTTOU:
186				need_restart = 1;
187			}
188		}
189	}
190	if (need_restart)
191		goto restart;
192
193	if (save_errno)
194		errno = save_errno;
195	return(nr == -1 ? NULL : buf);
196}
197
198#if 0
199char *
200getpass(const char *prompt)
201{
202	static char buf[_PASSWORD_LEN + 1];
203
204	return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
205}
206#endif
207
208static void handler(int s)
209{
210
211	signo[s] = 1;
212}
213#endif /* HAVE_READPASSPHRASE */
214