[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 1.19 2001/06/24 05:35:33 markus Exp $");

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

static char *
ssh_askpass(char *askpass, const char *msg)
{
	pid_t pid;
	size_t len;
	char *nl, *pass;
	int p[2], status;
	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)
		fatal("ssh_askpass: pipe: %s", strerror(errno));
	if ((pid = fork()) < 0)
		fatal("ssh_askpass: fork: %s", strerror(errno));
	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 = read(p[0], buf, sizeof buf);
	close(p[0]);
	while (waitpid(pid, &status, 0) < 0)
		if (errno != EINTR)
			break;
	if (len <= 1)
		return xstrdup("");
	nl = strchr(buf, '\n');
	if (nl)
		*nl = '\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 NULL;

	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"
1843a425	35	RCSID("$OpenBSD: readpass.c,v 1.19 2001/06/24 05:35:33 markus Exp $");
1843a425	36
8efc0c15	37	#include "xmalloc.h"
5ca51e19	38	#include "readpass.h"
561e5254	39	#include "pathnames.h"
	40	#include "log.h"
	41	#include "atomicio.h"
	42	#include "ssh.h"
	43
396c147e	44	static char *
742ee8f2	45	ssh_askpass(char askpass, const char msg)
561e5254	46	{
	47	pid_t pid;
	48	size_t len;
	49	char nl, pass;
	50	int p[2], status;
	51	char buf[1024];
	52
	53	if (fflush(stdout) != 0)
	54	error("ssh_askpass: fflush: %s", strerror(errno));
	55	if (askpass == NULL)
	56	fatal("internal error: askpass undefined");
	57	if (pipe(p) < 0)
	58	fatal("ssh_askpass: pipe: %s", strerror(errno));
	59	if ((pid = fork()) < 0)
	60	fatal("ssh_askpass: fork: %s", strerror(errno));
	61	if (pid == 0) {
	62	seteuid(getuid());
	63	setuid(getuid());
	64	close(p[0]);
	65	if (dup2(p[1], STDOUT_FILENO) < 0)
	66	fatal("ssh_askpass: dup2: %s", strerror(errno));
	67	execlp(askpass, askpass, msg, (char *) 0);
	68	fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
	69	}
	70	close(p[1]);
	71	len = read(p[0], buf, sizeof buf);
	72	close(p[0]);
	73	while (waitpid(pid, &status, 0) < 0)
	74	if (errno != EINTR)
	75	break;
	76	if (len <= 1)
	77	return xstrdup("");
	78	nl = strchr(buf, '\n');
	79	if (nl)
	80	*nl = '\0';
	81	pass = xstrdup(buf);
	82	memset(buf, 0, sizeof(buf));
	83	return pass;
	84	}
	85
aa3378df	86	/*
1843a425	87	* Reads a passphrase from /dev/tty with echo turned off/on. Returns the
	88	* passphrase (allocated with xmalloc). Exits if EOF is encountered. If
	89	* RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
	90	* tty is available
94ec8c6b	91	*/
5260325f	92	char *
1843a425	93	read_passphrase(const char *prompt, int flags)
8efc0c15	94	{
1843a425	95	char askpass = NULL, ret, buf[1024];
1843a425	96	int rppflags, use_askpass = 0, ttyfd;
561e5254	97
1843a425	98	rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
1843a425	99	if (flags & RP_ALLOW_STDIN) {
561e5254	100	if (!isatty(STDIN_FILENO))
	101	use_askpass = 1;
	102	} else {
1843a425	103	rppflags \|= RPP_REQUIRE_TTY;
561e5254	104	ttyfd = open("/dev/tty", O_RDWR);
	105	if (ttyfd >= 0)
	106	close(ttyfd);
	107	else
	108	use_askpass = 1;
	109	}
	110
	111	if (use_askpass && getenv("DISPLAY")) {
	112	if (getenv(SSH_ASKPASS_ENV))
	113	askpass = getenv(SSH_ASKPASS_ENV);
	114	else
	115	askpass = _PATH_SSH_ASKPASS_DEFAULT;
	116	return ssh_askpass(askpass, prompt);
	117	}
	118
1843a425	119	if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL)
	120	return NULL;
	121
	122	ret = xstrdup(buf);
	123	memset(buf, 'x', sizeof buf);
	124	return ret;
8efc0c15	125	}