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Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller3606ee22002-02-13 14:05:23 +11002 * Copyright (c) 2001 Markus Friedl. All rights reserved.
Damien Miller50945fa1999-12-09 10:31:37 +11003 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
Damien Miller50945fa1999-12-09 10:31:37 +110012 *
Damien Miller3606ee22002-02-13 14:05:23 +110013 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110023 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100024
25#include "includes.h"
Darren Tuckerce327b62004-11-05 20:38:03 +110026RCSID("$OpenBSD: readpass.c,v 1.31 2004/10/29 22:53:56 djm Exp $");
Ben Lindstrom949974b2001-06-25 05:20:31 +000027
Damien Millerd4a8b7e1999-10-27 13:42:43 +100028#include "xmalloc.h"
Darren Tuckere608ca22004-05-13 16:15:47 +100029#include "misc.h"
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000030#include "pathnames.h"
31#include "log.h"
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000032#include "ssh.h"
33
Ben Lindstrombba81212001-06-25 05:01:22 +000034static char *
Ben Lindstrom6d849312001-05-02 01:30:32 +000035ssh_askpass(char *askpass, const char *msg)
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000036{
37 pid_t pid;
38 size_t len;
Damien Miller637b8ae2001-11-12 11:05:20 +110039 char *pass;
Damien Millerf451e222002-01-22 23:05:31 +110040 int p[2], status, ret;
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000041 char buf[1024];
42
43 if (fflush(stdout) != 0)
44 error("ssh_askpass: fflush: %s", strerror(errno));
45 if (askpass == NULL)
46 fatal("internal error: askpass undefined");
Damien Miller07ab49e2001-07-14 12:19:56 +100047 if (pipe(p) < 0) {
48 error("ssh_askpass: pipe: %s", strerror(errno));
Damien Miller6c711792003-01-24 11:36:23 +110049 return NULL;
Damien Miller07ab49e2001-07-14 12:19:56 +100050 }
51 if ((pid = fork()) < 0) {
52 error("ssh_askpass: fork: %s", strerror(errno));
Damien Miller6c711792003-01-24 11:36:23 +110053 return NULL;
Damien Miller07ab49e2001-07-14 12:19:56 +100054 }
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000055 if (pid == 0) {
56 seteuid(getuid());
57 setuid(getuid());
58 close(p[0]);
59 if (dup2(p[1], STDOUT_FILENO) < 0)
60 fatal("ssh_askpass: dup2: %s", strerror(errno));
61 execlp(askpass, askpass, msg, (char *) 0);
62 fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
63 }
64 close(p[1]);
Damien Millerf451e222002-01-22 23:05:31 +110065
66 len = ret = 0;
67 do {
68 ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
69 if (ret == -1 && errno == EINTR)
70 continue;
71 if (ret <= 0)
72 break;
73 len += ret;
74 } while (sizeof(buf) - 1 - len > 0);
75 buf[len] = '\0';
76
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000077 close(p[0]);
78 while (waitpid(pid, &status, 0) < 0)
79 if (errno != EINTR)
80 break;
Damien Millerf451e222002-01-22 23:05:31 +110081
Damien Miller6c711792003-01-24 11:36:23 +110082 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
83 memset(buf, 0, sizeof(buf));
84 return NULL;
85 }
86
Damien Miller637b8ae2001-11-12 11:05:20 +110087 buf[strcspn(buf, "\r\n")] = '\0';
Ben Lindstrom5eb97b62001-04-19 20:33:07 +000088 pass = xstrdup(buf);
89 memset(buf, 0, sizeof(buf));
90 return pass;
91}
92
Damien Miller5428f641999-11-25 11:54:57 +110093/*
Ben Lindstrom949974b2001-06-25 05:20:31 +000094 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
95 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
96 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
97 * tty is available
Damien Miller874d77b2000-10-14 16:23:11 +110098 */
Damien Miller95def091999-11-25 00:26:21 +110099char *
Ben Lindstrom949974b2001-06-25 05:20:31 +0000100read_passphrase(const char *prompt, int flags)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000101{
Ben Lindstrom949974b2001-06-25 05:20:31 +0000102 char *askpass = NULL, *ret, buf[1024];
103 int rppflags, use_askpass = 0, ttyfd;
Ben Lindstrom5eb97b62001-04-19 20:33:07 +0000104
Ben Lindstrom949974b2001-06-25 05:20:31 +0000105 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
Damien Miller23f07702004-06-18 01:19:03 +1000106 if (flags & RP_USE_ASKPASS)
107 use_askpass = 1;
108 else if (flags & RP_ALLOW_STDIN) {
Ben Lindstrom5eb97b62001-04-19 20:33:07 +0000109 if (!isatty(STDIN_FILENO))
110 use_askpass = 1;
111 } else {
Ben Lindstrom949974b2001-06-25 05:20:31 +0000112 rppflags |= RPP_REQUIRE_TTY;
Damien Miller85830d12002-01-22 23:24:51 +1100113 ttyfd = open(_PATH_TTY, O_RDWR);
Ben Lindstrom5eb97b62001-04-19 20:33:07 +0000114 if (ttyfd >= 0)
115 close(ttyfd);
116 else
117 use_askpass = 1;
118 }
119
Damien Miller23f07702004-06-18 01:19:03 +1000120 if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
121 return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
122
Ben Lindstrom5eb97b62001-04-19 20:33:07 +0000123 if (use_askpass && getenv("DISPLAY")) {
124 if (getenv(SSH_ASKPASS_ENV))
125 askpass = getenv(SSH_ASKPASS_ENV);
126 else
127 askpass = _PATH_SSH_ASKPASS_DEFAULT;
Damien Miller6c711792003-01-24 11:36:23 +1100128 if ((ret = ssh_askpass(askpass, prompt)) == NULL)
129 if (!(flags & RP_ALLOW_EOF))
130 return xstrdup("");
131 return ret;
Ben Lindstrom5eb97b62001-04-19 20:33:07 +0000132 }
133
Ben Lindstrom38a69e62002-03-27 17:28:46 +0000134 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
135 if (flags & RP_ALLOW_EOF)
136 return NULL;
Ben Lindstrom4f42d8c2001-07-04 05:19:27 +0000137 return xstrdup("");
Ben Lindstrom38a69e62002-03-27 17:28:46 +0000138 }
Ben Lindstrom949974b2001-06-25 05:20:31 +0000139
140 ret = xstrdup(buf);
141 memset(buf, 'x', sizeof buf);
142 return ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000143}
Darren Tuckerce327b62004-11-05 20:38:03 +1100144
145int
146ask_permission(const char *fmt, ...)
147{
148 va_list args;
149 char *p, prompt[1024];
150 int allowed = 0;
151
152 va_start(args, fmt);
153 vsnprintf(prompt, sizeof(prompt), fmt, args);
154 va_end(args);
155
156 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
157 if (p != NULL) {
158 /*
159 * Accept empty responses and responses consisting
160 * of the word "yes" as affirmative.
161 */
162 if (*p == '\0' || *p == '\n' ||
163 strcasecmp(p, "yes") == 0)
164 allowed = 1;
165 xfree(p);
166 }
167
168 return (allowed);
169}