[openssh.git] / readpass.c

/*
 * Copyright (c) 1988, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "includes.h"
RCSID("$OpenBSD: readpass.c,v 1.24 2001/12/21 08:53:45 djm Exp $");

#include "xmalloc.h"
#include "readpass.h"
#include "pathnames.h"
#include "log.h"
#include "ssh.h"

static char *
ssh_askpass(char *askpass, const char *msg)
{
	pid_t pid;
	size_t len;
	char *pass;
	int p[2], status, ret;
	char buf[1024];

	if (fflush(stdout) != 0)
		error("ssh_askpass: fflush: %s", strerror(errno));
	if (askpass == NULL)
		fatal("internal error: askpass undefined");
	if (pipe(p) < 0) {
		error("ssh_askpass: pipe: %s", strerror(errno));
		return xstrdup("");
	}
	if ((pid = fork()) < 0) {
		error("ssh_askpass: fork: %s", strerror(errno));
		return xstrdup("");
	}
	if (pid == 0) {
		seteuid(getuid());
		setuid(getuid());
		close(p[0]);
		if (dup2(p[1], STDOUT_FILENO) < 0)
			fatal("ssh_askpass: dup2: %s", strerror(errno));
		execlp(askpass, askpass, msg, (char *) 0);
		fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
	}
	close(p[1]);

	len = ret = 0;
	do {
		ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
		if (ret == -1 && errno == EINTR)
			continue;
		if (ret <= 0)
			break;
		len += ret;
	} while (sizeof(buf) - 1 - len > 0);
	buf[len] = '\0';

	close(p[0]);
	while (waitpid(pid, &status, 0) < 0)
		if (errno != EINTR)
			break;

	buf[strcspn(buf, "\r\n")] = '\0';
	pass = xstrdup(buf);
	memset(buf, 0, sizeof(buf));
	return pass;
}

/*
 * Reads a passphrase from /dev/tty with echo turned off/on.  Returns the
 * passphrase (allocated with xmalloc).  Exits if EOF is encountered. If
 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
 * tty is available
 */
char *
read_passphrase(const char *prompt, int flags)
{
	char *askpass = NULL, *ret, buf[1024];
	int rppflags, use_askpass = 0, ttyfd;

	rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
	if (flags & RP_ALLOW_STDIN) {
		if (!isatty(STDIN_FILENO))
			use_askpass = 1;
	} else {
		rppflags |= RPP_REQUIRE_TTY;
		ttyfd = open("/dev/tty", O_RDWR);
		if (ttyfd >= 0)
			close(ttyfd);
		else
			use_askpass = 1;
	}

	if (use_askpass && getenv("DISPLAY")) {
		if (getenv(SSH_ASKPASS_ENV))
			askpass = getenv(SSH_ASKPASS_ENV);
		else
			askpass = _PATH_SSH_ASKPASS_DEFAULT;
		return ssh_askpass(askpass, prompt);
	}

	if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL)
		return xstrdup("");

	ret = xstrdup(buf);
	memset(buf, 'x', sizeof buf);
	return ret;
}
Commit	Line	Data
8efc0c15	1	/*
2d86a6cc	2	* Copyright (c) 1988, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	* 3. All advertising materials mentioning features or use of this software
	14	* must display the following acknowledgement:
	15	* This product includes software developed by the University of
	16	* California, Berkeley and its contributors.
	17	* 4. Neither the name of the University nor the names of its contributors
	18	* may be used to endorse or promote products derived from this software
	19	* without specific prior written permission.
	20	*
	21	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	22	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	23	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	24	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	25	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	26	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	27	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	28	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	29	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	30	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	31	* SUCH DAMAGE.
5260325f	32	*/
8efc0c15	33
8efc0c15	34	#include "includes.h"
f9654cd7	35	RCSID("$OpenBSD: readpass.c,v 1.24 2001/12/21 08:53:45 djm Exp $");
1843a425	36
8efc0c15	37	#include "xmalloc.h"
5ca51e19	38	#include "readpass.h"
561e5254	39	#include "pathnames.h"
561e5254	40	#include "log.h"
561e5254	41	#include "ssh.h"
561e5254	42
396c147e	43	static char *
742ee8f2	44	ssh_askpass(char askpass, const char msg)
561e5254	45	{
	46	pid_t pid;
	47	size_t len;
56b551e2	48	char *pass;
f9654cd7	49	int p[2], status, ret;
561e5254	50	char buf[1024];
	51
	52	if (fflush(stdout) != 0)
	53	error("ssh_askpass: fflush: %s", strerror(errno));
	54	if (askpass == NULL)
	55	fatal("internal error: askpass undefined");
333b5ba7	56	if (pipe(p) < 0) {
	57	error("ssh_askpass: pipe: %s", strerror(errno));
	58	return xstrdup("");
	59	}
	60	if ((pid = fork()) < 0) {
	61	error("ssh_askpass: fork: %s", strerror(errno));
	62	return xstrdup("");
	63	}
561e5254	64	if (pid == 0) {
	65	seteuid(getuid());
	66	setuid(getuid());
	67	close(p[0]);
	68	if (dup2(p[1], STDOUT_FILENO) < 0)
	69	fatal("ssh_askpass: dup2: %s", strerror(errno));
	70	execlp(askpass, askpass, msg, (char *) 0);
	71	fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
	72	}
	73	close(p[1]);
f9654cd7	74
	75	len = ret = 0;
	76	do {
	77	ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
	78	if (ret == -1 && errno == EINTR)
	79	continue;
	80	if (ret <= 0)
	81	break;
	82	len += ret;
	83	} while (sizeof(buf) - 1 - len > 0);
	84	buf[len] = '\0';
	85
561e5254	86	close(p[0]);
	87	while (waitpid(pid, &status, 0) < 0)
	88	if (errno != EINTR)
	89	break;
f9654cd7	90
56b551e2	91	buf[strcspn(buf, "\r\n")] = '\0';
561e5254	92	pass = xstrdup(buf);
	93	memset(buf, 0, sizeof(buf));
	94	return pass;
	95	}
	96
aa3378df	97	/*
1843a425	98	* Reads a passphrase from /dev/tty with echo turned off/on. Returns the
	99	* passphrase (allocated with xmalloc). Exits if EOF is encountered. If
	100	* RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
	101	* tty is available
94ec8c6b	102	*/
5260325f	103	char *
1843a425	104	read_passphrase(const char *prompt, int flags)
8efc0c15	105	{
1843a425	106	char askpass = NULL, ret, buf[1024];
1843a425	107	int rppflags, use_askpass = 0, ttyfd;
561e5254	108
1843a425	109	rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1843a425	110	if (flags & RP_ALLOW_STDIN) {
561e5254	111	if (!isatty(STDIN_FILENO))
	112	use_askpass = 1;
	113	} else {
1843a425	114	rppflags \|= RPP_REQUIRE_TTY;
561e5254	115	ttyfd = open("/dev/tty", O_RDWR);
	116	if (ttyfd >= 0)
	117	close(ttyfd);
	118	else
	119	use_askpass = 1;
	120	}
	121
	122	if (use_askpass && getenv("DISPLAY")) {
	123	if (getenv(SSH_ASKPASS_ENV))
	124	askpass = getenv(SSH_ASKPASS_ENV);
	125	else
	126	askpass = _PATH_SSH_ASKPASS_DEFAULT;
	127	return ssh_askpass(askpass, prompt);
	128	}
	129
1843a425	130	if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL)
613021ac	131	return xstrdup("");
1843a425	132
	133	ret = xstrdup(buf);
	134	memset(buf, 'x', sizeof buf);
	135	return ret;
8efc0c15	136	}