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5188ba17 | 1 | /* $OpenBSD: readpass.c,v 1.43 2006/07/17 01:31:09 stevesk Exp $ */ |
8efc0c15 | 2 | /* |
b984f12e | 3 | * Copyright (c) 2001 Markus Friedl. All rights reserved. |
2d86a6cc | 4 | * |
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. | |
2d86a6cc | 13 | * |
b984f12e | 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. | |
5260325f | 24 | */ |
8efc0c15 | 25 | |
26 | #include "includes.h" | |
aa2eae64 | 27 | |
28 | #include <sys/types.h> | |
29 | #include <sys/wait.h> | |
a75f5360 | 30 | |
028094f4 | 31 | #include <errno.h> |
d3221cca | 32 | #include <fcntl.h> |
a75f5360 | 33 | #ifdef HAVE_PATHS_H |
6f61e0ec | 34 | # include <paths.h> |
a75f5360 | 35 | #endif |
4c72fcfd | 36 | #include <stdarg.h> |
5188ba17 | 37 | #include <unistd.h> |
1843a425 | 38 | |
8efc0c15 | 39 | #include "xmalloc.h" |
58ae9cb8 | 40 | #include "misc.h" |
561e5254 | 41 | #include "pathnames.h" |
42 | #include "log.h" | |
561e5254 | 43 | #include "ssh.h" |
82aeee5d | 44 | #include "uidswap.h" |
561e5254 | 45 | |
396c147e | 46 | static char * |
742ee8f2 | 47 | ssh_askpass(char *askpass, const char *msg) |
561e5254 | 48 | { |
49 | pid_t pid; | |
50 | size_t len; | |
56b551e2 | 51 | char *pass; |
f9654cd7 | 52 | int p[2], status, ret; |
561e5254 | 53 | char buf[1024]; |
54 | ||
55 | if (fflush(stdout) != 0) | |
56 | error("ssh_askpass: fflush: %s", strerror(errno)); | |
57 | if (askpass == NULL) | |
58 | fatal("internal error: askpass undefined"); | |
333b5ba7 | 59 | if (pipe(p) < 0) { |
60 | error("ssh_askpass: pipe: %s", strerror(errno)); | |
c4087616 | 61 | return NULL; |
333b5ba7 | 62 | } |
63 | if ((pid = fork()) < 0) { | |
64 | error("ssh_askpass: fork: %s", strerror(errno)); | |
c4087616 | 65 | return NULL; |
333b5ba7 | 66 | } |
561e5254 | 67 | if (pid == 0) { |
3c33c1b6 | 68 | permanently_drop_suid(getuid()); |
561e5254 | 69 | close(p[0]); |
70 | if (dup2(p[1], STDOUT_FILENO) < 0) | |
71 | fatal("ssh_askpass: dup2: %s", strerror(errno)); | |
72 | execlp(askpass, askpass, msg, (char *) 0); | |
73 | fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); | |
74 | } | |
75 | close(p[1]); | |
f9654cd7 | 76 | |
77 | len = ret = 0; | |
78 | do { | |
79 | ret = read(p[0], buf + len, sizeof(buf) - 1 - len); | |
80 | if (ret == -1 && errno == EINTR) | |
81 | continue; | |
82 | if (ret <= 0) | |
83 | break; | |
84 | len += ret; | |
85 | } while (sizeof(buf) - 1 - len > 0); | |
86 | buf[len] = '\0'; | |
87 | ||
561e5254 | 88 | close(p[0]); |
89 | while (waitpid(pid, &status, 0) < 0) | |
90 | if (errno != EINTR) | |
91 | break; | |
f9654cd7 | 92 | |
c4087616 | 93 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
94 | memset(buf, 0, sizeof(buf)); | |
95 | return NULL; | |
96 | } | |
97 | ||
56b551e2 | 98 | buf[strcspn(buf, "\r\n")] = '\0'; |
561e5254 | 99 | pass = xstrdup(buf); |
100 | memset(buf, 0, sizeof(buf)); | |
101 | return pass; | |
102 | } | |
103 | ||
aa3378df | 104 | /* |
1843a425 | 105 | * Reads a passphrase from /dev/tty with echo turned off/on. Returns the |
106 | * passphrase (allocated with xmalloc). Exits if EOF is encountered. If | |
107 | * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no | |
108 | * tty is available | |
94ec8c6b | 109 | */ |
5260325f | 110 | char * |
1843a425 | 111 | read_passphrase(const char *prompt, int flags) |
8efc0c15 | 112 | { |
1843a425 | 113 | char *askpass = NULL, *ret, buf[1024]; |
114 | int rppflags, use_askpass = 0, ttyfd; | |
561e5254 | 115 | |
1843a425 | 116 | rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; |
0d34d6ce | 117 | if (flags & RP_USE_ASKPASS) |
118 | use_askpass = 1; | |
119 | else if (flags & RP_ALLOW_STDIN) { | |
c6eb32a1 | 120 | if (!isatty(STDIN_FILENO)) { |
d49d70a8 | 121 | debug("read_passphrase: stdin is not a tty"); |
561e5254 | 122 | use_askpass = 1; |
c6eb32a1 | 123 | } |
561e5254 | 124 | } else { |
1843a425 | 125 | rppflags |= RPP_REQUIRE_TTY; |
a62ebe1f | 126 | ttyfd = open(_PATH_TTY, O_RDWR); |
561e5254 | 127 | if (ttyfd >= 0) |
128 | close(ttyfd); | |
d49d70a8 | 129 | else { |
130 | debug("read_passphrase: can't open %s: %s", _PATH_TTY, | |
131 | strerror(errno)); | |
561e5254 | 132 | use_askpass = 1; |
d49d70a8 | 133 | } |
561e5254 | 134 | } |
135 | ||
0d34d6ce | 136 | if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL) |
137 | return (flags & RP_ALLOW_EOF) ? NULL : xstrdup(""); | |
138 | ||
561e5254 | 139 | if (use_askpass && getenv("DISPLAY")) { |
140 | if (getenv(SSH_ASKPASS_ENV)) | |
141 | askpass = getenv(SSH_ASKPASS_ENV); | |
142 | else | |
143 | askpass = _PATH_SSH_ASKPASS_DEFAULT; | |
c4087616 | 144 | if ((ret = ssh_askpass(askpass, prompt)) == NULL) |
145 | if (!(flags & RP_ALLOW_EOF)) | |
146 | return xstrdup(""); | |
147 | return ret; | |
561e5254 | 148 | } |
149 | ||
67ec167d | 150 | if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) { |
151 | if (flags & RP_ALLOW_EOF) | |
152 | return NULL; | |
613021ac | 153 | return xstrdup(""); |
67ec167d | 154 | } |
1843a425 | 155 | |
156 | ret = xstrdup(buf); | |
157 | memset(buf, 'x', sizeof buf); | |
158 | return ret; | |
8efc0c15 | 159 | } |
7a9c7a0b | 160 | |
161 | int | |
162 | ask_permission(const char *fmt, ...) | |
163 | { | |
164 | va_list args; | |
165 | char *p, prompt[1024]; | |
166 | int allowed = 0; | |
167 | ||
168 | va_start(args, fmt); | |
169 | vsnprintf(prompt, sizeof(prompt), fmt, args); | |
170 | va_end(args); | |
171 | ||
172 | p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); | |
173 | if (p != NULL) { | |
174 | /* | |
175 | * Accept empty responses and responses consisting | |
176 | * of the word "yes" as affirmative. | |
177 | */ | |
178 | if (*p == '\0' || *p == '\n' || | |
179 | strcasecmp(p, "yes") == 0) | |
180 | allowed = 1; | |
181 | xfree(p); | |
182 | } | |
183 | ||
184 | return (allowed); | |
185 | } |