Import OpenSSH 4.6p1.
[dragonfly.git] / crypto / openssh-4 / readpass.c
blobbd144c2e39177a15f8fd21535782b9e141de6d8e
1 /* $OpenBSD: readpass.c,v 1.47 2006/08/03 03:34:42 deraadt Exp $ */
2 /*
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
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.
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.
26 #include "includes.h"
28 #include <sys/types.h>
29 #include <sys/wait.h>
31 #include <errno.h>
32 #include <fcntl.h>
33 #ifdef HAVE_PATHS_H
34 # include <paths.h>
35 #endif
36 #include <stdarg.h>
37 #include <stdio.h>
38 #include <stdlib.h>
39 #include <string.h>
40 #include <unistd.h>
42 #include "xmalloc.h"
43 #include "misc.h"
44 #include "pathnames.h"
45 #include "log.h"
46 #include "ssh.h"
47 #include "uidswap.h"
49 static char *
50 ssh_askpass(char *askpass, const char *msg)
52 pid_t pid;
53 size_t len;
54 char *pass;
55 int p[2], status, ret;
56 char buf[1024];
58 if (fflush(stdout) != 0)
59 error("ssh_askpass: fflush: %s", strerror(errno));
60 if (askpass == NULL)
61 fatal("internal error: askpass undefined");
62 if (pipe(p) < 0) {
63 error("ssh_askpass: pipe: %s", strerror(errno));
64 return NULL;
66 if ((pid = fork()) < 0) {
67 error("ssh_askpass: fork: %s", strerror(errno));
68 return NULL;
70 if (pid == 0) {
71 permanently_drop_suid(getuid());
72 close(p[0]);
73 if (dup2(p[1], STDOUT_FILENO) < 0)
74 fatal("ssh_askpass: dup2: %s", strerror(errno));
75 execlp(askpass, askpass, msg, (char *) 0);
76 fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno));
78 close(p[1]);
80 len = ret = 0;
81 do {
82 ret = read(p[0], buf + len, sizeof(buf) - 1 - len);
83 if (ret == -1 && errno == EINTR)
84 continue;
85 if (ret <= 0)
86 break;
87 len += ret;
88 } while (sizeof(buf) - 1 - len > 0);
89 buf[len] = '\0';
91 close(p[0]);
92 while (waitpid(pid, &status, 0) < 0)
93 if (errno != EINTR)
94 break;
96 if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) {
97 memset(buf, 0, sizeof(buf));
98 return NULL;
101 buf[strcspn(buf, "\r\n")] = '\0';
102 pass = xstrdup(buf);
103 memset(buf, 0, sizeof(buf));
104 return pass;
108 * Reads a passphrase from /dev/tty with echo turned off/on. Returns the
109 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
110 * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no
111 * tty is available
113 char *
114 read_passphrase(const char *prompt, int flags)
116 char *askpass = NULL, *ret, buf[1024];
117 int rppflags, use_askpass = 0, ttyfd;
119 rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
120 if (flags & RP_USE_ASKPASS)
121 use_askpass = 1;
122 else if (flags & RP_ALLOW_STDIN) {
123 if (!isatty(STDIN_FILENO)) {
124 debug("read_passphrase: stdin is not a tty");
125 use_askpass = 1;
127 } else {
128 rppflags |= RPP_REQUIRE_TTY;
129 ttyfd = open(_PATH_TTY, O_RDWR);
130 if (ttyfd >= 0)
131 close(ttyfd);
132 else {
133 debug("read_passphrase: can't open %s: %s", _PATH_TTY,
134 strerror(errno));
135 use_askpass = 1;
139 if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL)
140 return (flags & RP_ALLOW_EOF) ? NULL : xstrdup("");
142 if (use_askpass && getenv("DISPLAY")) {
143 if (getenv(SSH_ASKPASS_ENV))
144 askpass = getenv(SSH_ASKPASS_ENV);
145 else
146 askpass = _PATH_SSH_ASKPASS_DEFAULT;
147 if ((ret = ssh_askpass(askpass, prompt)) == NULL)
148 if (!(flags & RP_ALLOW_EOF))
149 return xstrdup("");
150 return ret;
153 if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) {
154 if (flags & RP_ALLOW_EOF)
155 return NULL;
156 return xstrdup("");
159 ret = xstrdup(buf);
160 memset(buf, 'x', sizeof buf);
161 return ret;
165 ask_permission(const char *fmt, ...)
167 va_list args;
168 char *p, prompt[1024];
169 int allowed = 0;
171 va_start(args, fmt);
172 vsnprintf(prompt, sizeof(prompt), fmt, args);
173 va_end(args);
175 p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
176 if (p != NULL) {
178 * Accept empty responses and responses consisting
179 * of the word "yes" as affirmative.
181 if (*p == '\0' || *p == '\n' ||
182 strcasecmp(p, "yes") == 0)
183 allowed = 1;
184 xfree(p);
187 return (allowed);