1 /* $OpenBSD: readpass.c,v 1.48 2010/12/15 00:49:27 djm Exp $ */
3 * Copyright (c) 2001 Markus Friedl. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 #include <sys/types.h>
45 #include "pathnames.h"
51 ssh_askpass(char *askpass, const char *msg)
58 void (*osigchld)(int);
60 if (fflush(stdout) != 0)
61 error("ssh_askpass: fflush: %s", strerror(errno));
63 fatal("internal error: askpass undefined");
65 error("ssh_askpass: pipe: %s", strerror(errno));
68 osigchld = signal(SIGCHLD, SIG_DFL);
69 if ((pid = fork()) < 0) {
70 error("ssh_askpass: fork: %s", strerror(errno));
71 signal(SIGCHLD, osigchld);
75 permanently_drop_suid(getuid());
77 if (dup2(p[1], STDOUT_FILENO) < 0)
78 fatal("ssh_askpass: dup2: %s", strerror(errno));
79 execlp(askpass, askpass, msg, (char *) 0);
80 fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
86 ssize_t r = read(p[0], buf + len, sizeof(buf) - 1 - len);
88 if (r == -1 && errno == EINTR)
93 } while (sizeof(buf) - 1 - len > 0);
97 while ((ret = waitpid(pid, &status, 0)) < 0)
100 signal(SIGCHLD, osigchld);
101 if (ret == -1 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
102 memset(buf, 0, sizeof(buf));
106 buf[strcspn(buf, "\r\n")] = '\0';
108 memset(buf, 0, sizeof(buf));
113 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
114 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
115 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
119 read_passphrase(const char *prompt, int flags)
121 char *askpass = NULL, *ret, buf[1024];
122 int rppflags, use_askpass = 0, ttyfd;
124 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
125 if (flags & RP_USE_ASKPASS)
127 else if (flags & RP_ALLOW_STDIN) {
128 if (!isatty(STDIN_FILENO)) {
129 debug("read_passphrase: stdin is not a tty");
133 rppflags |= RPP_REQUIRE_TTY;
134 ttyfd = open(_PATH_TTY, O_RDWR);
138 debug("read_passphrase: can't open %s: %s", _PATH_TTY,
144 if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
145 return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
147 if (use_askpass && getenv("DISPLAY")) {
148 if (getenv(SSH_ASKPASS_ENV))
149 askpass = getenv(SSH_ASKPASS_ENV);
151 askpass = _PATH_SSH_ASKPASS_DEFAULT;
152 if ((ret = ssh_askpass(askpass, prompt)) == NULL)
153 if (!(flags & RP_ALLOW_EOF))
158 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
159 if (flags & RP_ALLOW_EOF)
165 memset(buf, 'x', sizeof buf);
170 ask_permission(const char *fmt, ...)
173 char *p, prompt[1024];
177 vsnprintf(prompt, sizeof(prompt), fmt, args);
180 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
183 * Accept empty responses and responses consisting
184 * of the word "yes" as affirmative.
186 if (*p == '\0' || *p == '\n' ||
187 strcasecmp(p, "yes") == 0)