1 /* $OpenBSD: readpass.c,v 1.50 2014/02/02 03:44:31 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 explicit_bzero(buf
, sizeof(buf
));
106 buf
[strcspn(buf
, "\r\n")] = '\0';
108 explicit_bzero(buf
, 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 explicit_bzero(buf
, 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)