1 /* $OpenBSD: readpass.c,v 1.52 2018/07/18 11:34:04 dtucker 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);
76 if (dup2(p[1], STDOUT_FILENO) < 0)
77 fatal("ssh_askpass: dup2: %s", strerror(errno));
78 execlp(askpass, askpass, msg, (char *)NULL);
79 fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
85 ssize_t r = read(p[0], buf + len, sizeof(buf) - 1 - len);
87 if (r == -1 && errno == EINTR)
92 } while (sizeof(buf) - 1 - len > 0);
96 while ((ret = waitpid(pid, &status, 0)) < 0)
99 signal(SIGCHLD, osigchld);
100 if (ret == -1 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) {
101 explicit_bzero(buf, sizeof(buf));
105 buf[strcspn(buf, "\r\n")] = '\0';
107 explicit_bzero(buf, sizeof(buf));
112 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
113 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
114 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
118 read_passphrase(const char *prompt, int flags)
120 char *askpass = NULL, *ret, buf[1024];
121 int rppflags, use_askpass = 0, ttyfd;
123 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
124 if (flags & RP_USE_ASKPASS)
126 else if (flags & RP_ALLOW_STDIN) {
127 if (!isatty(STDIN_FILENO)) {
128 debug("read_passphrase: stdin is not a tty");
132 rppflags |= RPP_REQUIRE_TTY;
133 ttyfd = open(_PATH_TTY, O_RDWR);
137 debug("read_passphrase: can't open %s: %s", _PATH_TTY,
143 if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
144 return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
146 if (use_askpass && getenv("DISPLAY")) {
147 if (getenv(SSH_ASKPASS_ENV))
148 askpass = getenv(SSH_ASKPASS_ENV);
150 askpass = _PATH_SSH_ASKPASS_DEFAULT;
151 if ((ret = ssh_askpass(askpass, prompt)) == NULL)
152 if (!(flags & RP_ALLOW_EOF))
157 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
158 if (flags & RP_ALLOW_EOF)
164 explicit_bzero(buf, sizeof(buf));
169 ask_permission(const char *fmt, ...)
172 char *p, prompt[1024];
176 vsnprintf(prompt, sizeof(prompt), fmt, args);
179 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
182 * Accept empty responses and responses consisting
183 * of the word "yes" as affirmative.
185 if (*p == '\0' || *p == '\n' ||
186 strcasecmp(p, "yes") == 0)