summaryrefslogtreecommitdiff
path: root/src/readpassphrase.c
blob: 1f4fe0eb0f54c3d3654fb5e250a26dae4cc65552 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
/*	$OpenBSD: readpassphrase.c,v 1.20 2007/10/30 12:03:48 millert Exp $	*/

/*
 * Copyright (c) 2000-2002, 2007 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * Sponsored in part by the Defense Advanced Research Projects
 * Agency (DARPA) and Air Force Research Laboratory, Air Force
 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
 */

#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <readpassphrase.h>

#ifndef TCSASOFT
#define TCSASOFT 0
#endif

static volatile sig_atomic_t signo;

static void handler(int);

char *
readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
{
	ssize_t nr;
	int input, output, save_errno;
	char ch, *p, *end;
	struct termios term, oterm;
	struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
	struct sigaction savetstp, savettin, savettou, savepipe;

	/* I suppose we could alloc on demand in this case (XXX). */
	if (bufsiz == 0) {
		errno = EINVAL;
		return(NULL);
	}

restart:
	signo = 0;
	nr = -1;
	save_errno = 0;
	/*
	 * Read and write to /dev/tty if available.  If not, read from
	 * stdin and write to stderr unless a tty is required.
	 */
	if ((flags & RPP_STDIN) ||
	    (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
		if (flags & RPP_REQUIRE_TTY) {
			errno = ENOTTY;
			return(NULL);
		}
		input = STDIN_FILENO;
		output = STDERR_FILENO;
	}

	/*
	 * Catch signals that would otherwise cause the user to end
	 * up with echo turned off in the shell.  Don't worry about
	 * things like SIGXCPU and SIGVTALRM for now.
	 */
	sigemptyset(&sa.sa_mask);
	sa.sa_flags = 0;		/* don't restart system calls */
	sa.sa_handler = handler;
	(void)sigaction(SIGALRM, &sa, &savealrm);
	(void)sigaction(SIGHUP, &sa, &savehup);
	(void)sigaction(SIGINT, &sa, &saveint);
	(void)sigaction(SIGPIPE, &sa, &savepipe);
	(void)sigaction(SIGQUIT, &sa, &savequit);
	(void)sigaction(SIGTERM, &sa, &saveterm);
	(void)sigaction(SIGTSTP, &sa, &savetstp);
	(void)sigaction(SIGTTIN, &sa, &savettin);
	(void)sigaction(SIGTTOU, &sa, &savettou);

	/* Turn off echo if possible. */
	if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
		memcpy(&term, &oterm, sizeof(term));
		if (!(flags & RPP_ECHO_ON))
			term.c_lflag &= ~(ECHO | ECHONL);
#ifdef VSTATUS
		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
#endif
		(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
	} else {
		memset(&term, 0, sizeof(term));
		term.c_lflag |= ECHO;
		memset(&oterm, 0, sizeof(oterm));
		oterm.c_lflag |= ECHO;
	}

	/* No I/O if we are already backgrounded. */
	if (signo != SIGTTOU && signo != SIGTTIN) {
		if (!(flags & RPP_STDIN))
			(void)write(output, prompt, strlen(prompt));
		end = buf + bufsiz - 1;
		p = buf;
		while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
			if (p < end) {
				if ((flags & RPP_SEVENBIT))
					ch &= 0x7f;
				if (isalpha(ch)) {
					if ((flags & RPP_FORCELOWER))
						ch = (char)tolower(ch);
					if ((flags & RPP_FORCEUPPER))
						ch = (char)toupper(ch);
				}
				*p++ = ch;
			}
		}
		*p = '\0';
		save_errno = errno;
		if (!(term.c_lflag & ECHO))
			(void)write(output, "\n", 1);
	}

	/* Restore old terminal settings and signals. */
	if (memcmp(&term, &oterm, sizeof(term)) != 0) {
		while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
		    errno == EINTR)
			continue;
	}
	(void)sigaction(SIGALRM, &savealrm, NULL);
	(void)sigaction(SIGHUP, &savehup, NULL);
	(void)sigaction(SIGINT, &saveint, NULL);
	(void)sigaction(SIGQUIT, &savequit, NULL);
	(void)sigaction(SIGPIPE, &savepipe, NULL);
	(void)sigaction(SIGTERM, &saveterm, NULL);
	(void)sigaction(SIGTSTP, &savetstp, NULL);
	(void)sigaction(SIGTTIN, &savettin, NULL);
	(void)sigaction(SIGTTOU, &savettou, NULL);
	if (input != STDIN_FILENO)
		(void)close(input);

	/*
	 * If we were interrupted by a signal, resend it to ourselves
	 * now that we have restored the signal handlers.
	 */
	if (signo) {
		kill(getpid(), signo);
		switch (signo) {
		case SIGTSTP:
		case SIGTTIN:
		case SIGTTOU:
			goto restart;
		}
	}

	if (save_errno)
		errno = save_errno;
	return(nr == -1 ? NULL : buf);
}

#if 0
char *
getpass(const char *prompt)
{
	static char buf[_PASSWORD_LEN + 1];

	return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
}
#endif

static void handler(int s)
{

	signo = s;
}