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00146caa | 1 | /* $OpenBSD: readpass.c,v 1.44 2006/07/22 20:48:23 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> |
00146caa | 37 | #include <string.h> |
5188ba17 | 38 | #include <unistd.h> |
1843a425 | 39 | |
8efc0c15 | 40 | #include "xmalloc.h" |
58ae9cb8 | 41 | #include "misc.h" |
561e5254 | 42 | #include "pathnames.h" |
43 | #include "log.h" | |
561e5254 | 44 | #include "ssh.h" |
82aeee5d | 45 | #include "uidswap.h" |
561e5254 | 46 | |
396c147e | 47 | static char * |
742ee8f2 | 48 | ssh_askpass(char *askpass, const char *msg) |
561e5254 | 49 | { |
50 | pid_t pid; | |
51 | size_t len; | |
56b551e2 | 52 | char *pass; |
f9654cd7 | 53 | int p[2], status, ret; |
561e5254 | 54 | char buf[1024]; |
55 | ||
56 | if (fflush(stdout) != 0) | |
57 | error("ssh_askpass: fflush: %s", strerror(errno)); | |
58 | if (askpass == NULL) | |
59 | fatal("internal error: askpass undefined"); | |
333b5ba7 | 60 | if (pipe(p) < 0) { |
61 | error("ssh_askpass: pipe: %s", strerror(errno)); | |
c4087616 | 62 | return NULL; |
333b5ba7 | 63 | } |
64 | if ((pid = fork()) < 0) { | |
65 | error("ssh_askpass: fork: %s", strerror(errno)); | |
c4087616 | 66 | return NULL; |
333b5ba7 | 67 | } |
561e5254 | 68 | if (pid == 0) { |
3c33c1b6 | 69 | permanently_drop_suid(getuid()); |
561e5254 | 70 | close(p[0]); |
71 | if (dup2(p[1], STDOUT_FILENO) < 0) | |
72 | fatal("ssh_askpass: dup2: %s", strerror(errno)); | |
73 | execlp(askpass, askpass, msg, (char *) 0); | |
74 | fatal("ssh_askpass: exec(%s): %s", askpass, strerror(errno)); | |
75 | } | |
76 | close(p[1]); | |
f9654cd7 | 77 | |
78 | len = ret = 0; | |
79 | do { | |
80 | ret = read(p[0], buf + len, sizeof(buf) - 1 - len); | |
81 | if (ret == -1 && errno == EINTR) | |
82 | continue; | |
83 | if (ret <= 0) | |
84 | break; | |
85 | len += ret; | |
86 | } while (sizeof(buf) - 1 - len > 0); | |
87 | buf[len] = '\0'; | |
88 | ||
561e5254 | 89 | close(p[0]); |
90 | while (waitpid(pid, &status, 0) < 0) | |
91 | if (errno != EINTR) | |
92 | break; | |
f9654cd7 | 93 | |
c4087616 | 94 | if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
95 | memset(buf, 0, sizeof(buf)); | |
96 | return NULL; | |
97 | } | |
98 | ||
56b551e2 | 99 | buf[strcspn(buf, "\r\n")] = '\0'; |
561e5254 | 100 | pass = xstrdup(buf); |
101 | memset(buf, 0, sizeof(buf)); | |
102 | return pass; | |
103 | } | |
104 | ||
aa3378df | 105 | /* |
1843a425 | 106 | * Reads a passphrase from /dev/tty with echo turned off/on. Returns the |
107 | * passphrase (allocated with xmalloc). Exits if EOF is encountered. If | |
108 | * RP_ALLOW_STDIN is set, the passphrase will be read from stdin if no | |
109 | * tty is available | |
94ec8c6b | 110 | */ |
5260325f | 111 | char * |
1843a425 | 112 | read_passphrase(const char *prompt, int flags) |
8efc0c15 | 113 | { |
1843a425 | 114 | char *askpass = NULL, *ret, buf[1024]; |
115 | int rppflags, use_askpass = 0, ttyfd; | |
561e5254 | 116 | |
1843a425 | 117 | rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF; |
0d34d6ce | 118 | if (flags & RP_USE_ASKPASS) |
119 | use_askpass = 1; | |
120 | else if (flags & RP_ALLOW_STDIN) { | |
c6eb32a1 | 121 | if (!isatty(STDIN_FILENO)) { |
d49d70a8 | 122 | debug("read_passphrase: stdin is not a tty"); |
561e5254 | 123 | use_askpass = 1; |
c6eb32a1 | 124 | } |
561e5254 | 125 | } else { |
1843a425 | 126 | rppflags |= RPP_REQUIRE_TTY; |
a62ebe1f | 127 | ttyfd = open(_PATH_TTY, O_RDWR); |
561e5254 | 128 | if (ttyfd >= 0) |
129 | close(ttyfd); | |
d49d70a8 | 130 | else { |
131 | debug("read_passphrase: can't open %s: %s", _PATH_TTY, | |
132 | strerror(errno)); | |
561e5254 | 133 | use_askpass = 1; |
d49d70a8 | 134 | } |
561e5254 | 135 | } |
136 | ||
0d34d6ce | 137 | if ((flags & RP_USE_ASKPASS) && getenv("DISPLAY") == NULL) |
138 | return (flags & RP_ALLOW_EOF) ? NULL : xstrdup(""); | |
139 | ||
561e5254 | 140 | if (use_askpass && getenv("DISPLAY")) { |
141 | if (getenv(SSH_ASKPASS_ENV)) | |
142 | askpass = getenv(SSH_ASKPASS_ENV); | |
143 | else | |
144 | askpass = _PATH_SSH_ASKPASS_DEFAULT; | |
c4087616 | 145 | if ((ret = ssh_askpass(askpass, prompt)) == NULL) |
146 | if (!(flags & RP_ALLOW_EOF)) | |
147 | return xstrdup(""); | |
148 | return ret; | |
561e5254 | 149 | } |
150 | ||
67ec167d | 151 | if (readpassphrase(prompt, buf, sizeof buf, rppflags) == NULL) { |
152 | if (flags & RP_ALLOW_EOF) | |
153 | return NULL; | |
613021ac | 154 | return xstrdup(""); |
67ec167d | 155 | } |
1843a425 | 156 | |
157 | ret = xstrdup(buf); | |
158 | memset(buf, 'x', sizeof buf); | |
159 | return ret; | |
8efc0c15 | 160 | } |
7a9c7a0b | 161 | |
162 | int | |
163 | ask_permission(const char *fmt, ...) | |
164 | { | |
165 | va_list args; | |
166 | char *p, prompt[1024]; | |
167 | int allowed = 0; | |
168 | ||
169 | va_start(args, fmt); | |
170 | vsnprintf(prompt, sizeof(prompt), fmt, args); | |
171 | va_end(args); | |
172 | ||
173 | p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF); | |
174 | if (p != NULL) { | |
175 | /* | |
176 | * Accept empty responses and responses consisting | |
177 | * of the word "yes" as affirmative. | |
178 | */ | |
179 | if (*p == '\0' || *p == '\n' || | |
180 | strcasecmp(p, "yes") == 0) | |
181 | allowed = 1; | |
182 | xfree(p); | |
183 | } | |
184 | ||
185 | return (allowed); | |
186 | } |