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4c72fcfd | 1 | /* $OpenBSD: readpass.c,v 1.41 2006/07/10 16:37:36 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 | |
d3221cca | 31 | #include <fcntl.h> |
a75f5360 | 32 | #ifdef HAVE_PATHS_H |
6f61e0ec | 33 | # include <paths.h> |
a75f5360 | 34 | #endif |
4c72fcfd | 35 | #include <stdarg.h> |
1843a425 | 36 | |
8efc0c15 | 37 | #include "xmalloc.h" |
58ae9cb8 | 38 | #include "misc.h" |
561e5254 | 39 | #include "pathnames.h" |
40 | #include "log.h" | |
561e5254 | 41 | #include "ssh.h" |
82aeee5d | 42 | #include "uidswap.h" |
561e5254 | 43 | |
396c147e | 44 | static char * |
742ee8f2 | 45 | ssh_askpass(char *askpass, const char *msg) |
561e5254 | 46 | { |
47 | pid_t pid; | |
48 | size_t len; | |
56b551e2 | 49 | char *pass; |
f9654cd7 | 50 | int p[2], status, ret; |
561e5254 | 51 | char buf[1024]; |
52 | ||
53 | if (fflush(stdout) != 0) | |
54 | error("ssh_askpass: fflush: %s", strerror(errno)); | |
55 | if (askpass == NULL) | |
56 | fatal("internal error: askpass undefined"); | |
333b5ba7 | 57 | if (pipe(p) < 0) { |
58 | error("ssh_askpass: pipe: %s", strerror(errno)); | |
c4087616 | 59 | return NULL; |
333b5ba7 | 60 | } |
61 | if ((pid = fork()) < 0) { | |
62 | error("ssh_askpass: fork: %s", strerror(errno)); | |
c4087616 | 63 | return NULL; |
333b5ba7 | 64 | } |
561e5254 | 65 | if (pid == 0) { |
3c33c1b6 | 66 | permanently_drop_suid(getuid()); |
561e5254 | 67 | close(p[0]); |
68 | if (dup2(p[1], STDOUT_FILENO) < 0) | |
69 | fatal("ssh_askpass: dup2: %s", strerror(errno)); | |
70 | execlp(askpass, askpass, msg, (char *) 0); | |
71 | fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); | |
72 | } | |
73 | close(p[1]); | |
f9654cd7 | 74 | |
75 | len = ret = 0; | |
76 | do { | |
77 | ret = read(p[0], buf + len, sizeof(buf) - 1 - len); | |
78 | if (ret == -1 && errno == EINTR) | |
79 | continue; | |
80 | if (ret <= 0) | |
81 | break; | |
82 | len += ret; | |
83 | } while (sizeof(buf) - 1 - len > 0); | |
84 | buf[len] = '\0'; | |
85 | ||
561e5254 | 86 | close(p[0]); |
87 | while (waitpid(pid, &status, 0) < 0) | |
88 | if (errno != EINTR) | |
89 | break; | |
f9654cd7 | 90 | |
c4087616 | 91 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
92 | memset(buf, 0, sizeof(buf)); | |
93 | return NULL; | |
94 | } | |
95 | ||
56b551e2 | 96 | buf[strcspn(buf, "\r\n")] = '\0'; |
561e5254 | 97 | pass = xstrdup(buf); |
98 | memset(buf, 0, sizeof(buf)); | |
99 | return pass; | |
100 | } | |
101 | ||
aa3378df | 102 | /* |
1843a425 | 103 | * Reads a passphrase from /dev/tty with echo turned off/on. Returns the |
104 | * passphrase (allocated with xmalloc). Exits if EOF is encountered. If | |
105 | * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no | |
106 | * tty is available | |
94ec8c6b | 107 | */ |
5260325f | 108 | char * |
1843a425 | 109 | read_passphrase(const char *prompt, int flags) |
8efc0c15 | 110 | { |
1843a425 | 111 | char *askpass = NULL, *ret, buf[1024]; |
112 | int rppflags, use_askpass = 0, ttyfd; | |
561e5254 | 113 | |
1843a425 | 114 | rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; |
0d34d6ce | 115 | if (flags & RP_USE_ASKPASS) |
116 | use_askpass = 1; | |
117 | else if (flags & RP_ALLOW_STDIN) { | |
c6eb32a1 | 118 | if (!isatty(STDIN_FILENO)) { |
d49d70a8 | 119 | debug("read_passphrase: stdin is not a tty"); |
561e5254 | 120 | use_askpass = 1; |
c6eb32a1 | 121 | } |
561e5254 | 122 | } else { |
1843a425 | 123 | rppflags |= RPP_REQUIRE_TTY; |
a62ebe1f | 124 | ttyfd = open(_PATH_TTY, O_RDWR); |
561e5254 | 125 | if (ttyfd >= 0) |
126 | close(ttyfd); | |
d49d70a8 | 127 | else { |
128 | debug("read_passphrase: can't open %s: %s", _PATH_TTY, | |
129 | strerror(errno)); | |
561e5254 | 130 | use_askpass = 1; |
d49d70a8 | 131 | } |
561e5254 | 132 | } |
133 | ||
0d34d6ce | 134 | if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL) |
135 | return (flags & RP_ALLOW_EOF) ? NULL : xstrdup(""); | |
136 | ||
561e5254 | 137 | if (use_askpass && getenv("DISPLAY")) { |
138 | if (getenv(SSH_ASKPASS_ENV)) | |
139 | askpass = getenv(SSH_ASKPASS_ENV); | |
140 | else | |
141 | askpass = _PATH_SSH_ASKPASS_DEFAULT; | |
c4087616 | 142 | if ((ret = ssh_askpass(askpass, prompt)) == NULL) |
143 | if (!(flags & RP_ALLOW_EOF)) | |
144 | return xstrdup(""); | |
145 | return ret; | |
561e5254 | 146 | } |
147 | ||
67ec167d | 148 | if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) { |
149 | if (flags & RP_ALLOW_EOF) | |
150 | return NULL; | |
613021ac | 151 | return xstrdup(""); |
67ec167d | 152 | } |
1843a425 | 153 | |
154 | ret = xstrdup(buf); | |
155 | memset(buf, 'x', sizeof buf); | |
156 | return ret; | |
8efc0c15 | 157 | } |
7a9c7a0b | 158 | |
159 | int | |
160 | ask_permission(const char *fmt, ...) | |
161 | { | |
162 | va_list args; | |
163 | char *p, prompt[1024]; | |
164 | int allowed = 0; | |
165 | ||
166 | va_start(args, fmt); | |
167 | vsnprintf(prompt, sizeof(prompt), fmt, args); | |
168 | va_end(args); | |
169 | ||
170 | p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); | |
171 | if (p != NULL) { | |
172 | /* | |
173 | * Accept empty responses and responses consisting | |
174 | * of the word "yes" as affirmative. | |
175 | */ | |
176 | if (*p == '\0' || *p == '\n' || | |
177 | strcasecmp(p, "yes") == 0) | |
178 | allowed = 1; | |
179 | xfree(p); | |
180 | } | |
181 | ||
182 | return (allowed); | |
183 | } |