1 /* $OpenBSD: readpassphrase.c,v 1.24 2013/11/24 23:51:29 deraadt Exp $ */
2
3 /*
4 * Copyright (c) 2000-2002, 2007, 2010
5 * Todd C. Miller <Todd.Miller@courtesan.com>
6 *
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
10 *
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 *
19 * Sponsored in part by the Defense Advanced Research Projects
20 * Agency (DARPA) and Air Force Research Laboratory, Air Force
21 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
22 */
23
24 #include <sys/cdefs.h>
25 __FBSDID("$FreeBSD$");
26
27 #include "namespace.h"
28 #include <ctype.h>
29 #include <errno.h>
30 #include <fcntl.h>
31 #include <paths.h>
32 #include <pwd.h>
33 #include <signal.h>
34 #include <string.h>
35 #include <termios.h>
36 #include <unistd.h>
37 #include <readpassphrase.h>
38 #include "un-namespace.h"
39 #include "libc_private.h"
40
41 static volatile sig_atomic_t signo[NSIG];
42
43 static void handler(int);
44
45 char *
readpassphrase(const char * prompt,char * buf,size_t bufsiz,int flags)46 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
47 {
48 ssize_t nr;
49 int input, output, save_errno, i, need_restart;
50 char ch, *p, *end;
51 struct termios term, oterm;
52 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
53 struct sigaction savetstp, savettin, savettou, savepipe;
54
55 /* I suppose we could alloc on demand in this case (XXX). */
56 if (bufsiz == 0) {
57 errno = EINVAL;
58 return(NULL);
59 }
60
61 restart:
62 for (i = 0; i < NSIG; i++)
63 signo[i] = 0;
64 nr = -1;
65 save_errno = 0;
66 need_restart = 0;
67 /*
68 * Read and write to /dev/tty if available. If not, read from
69 * stdin and write to stderr unless a tty is required.
70 */
71 if ((flags & RPP_STDIN) ||
72 (input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC)) == -1) {
73 if (flags & RPP_REQUIRE_TTY) {
74 errno = ENOTTY;
75 return(NULL);
76 }
77 input = STDIN_FILENO;
78 output = STDERR_FILENO;
79 }
80
81 /*
82 * Turn off echo if possible.
83 * If we are using a tty but are not the foreground pgrp this will
84 * generate SIGTTOU, so do it *before* installing the signal handlers.
85 */
86 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
87 memcpy(&term, &oterm, sizeof(term));
88 if (!(flags & RPP_ECHO_ON))
89 term.c_lflag &= ~(ECHO | ECHONL);
90 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
91 term.c_cc[VSTATUS] = _POSIX_VDISABLE;
92 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
93 } else {
94 memset(&term, 0, sizeof(term));
95 term.c_lflag |= ECHO;
96 memset(&oterm, 0, sizeof(oterm));
97 oterm.c_lflag |= ECHO;
98 }
99
100 /*
101 * Catch signals that would otherwise cause the user to end
102 * up with echo turned off in the shell. Don't worry about
103 * things like SIGXCPU and SIGVTALRM for now.
104 */
105 sigemptyset(&sa.sa_mask);
106 sa.sa_flags = 0; /* don't restart system calls */
107 sa.sa_handler = handler;
108 (void)__libc_sigaction(SIGALRM, &sa, &savealrm);
109 (void)__libc_sigaction(SIGHUP, &sa, &savehup);
110 (void)__libc_sigaction(SIGINT, &sa, &saveint);
111 (void)__libc_sigaction(SIGPIPE, &sa, &savepipe);
112 (void)__libc_sigaction(SIGQUIT, &sa, &savequit);
113 (void)__libc_sigaction(SIGTERM, &sa, &saveterm);
114 (void)__libc_sigaction(SIGTSTP, &sa, &savetstp);
115 (void)__libc_sigaction(SIGTTIN, &sa, &savettin);
116 (void)__libc_sigaction(SIGTTOU, &sa, &savettou);
117
118 if (!(flags & RPP_STDIN))
119 (void)_write(output, prompt, strlen(prompt));
120 end = buf + bufsiz - 1;
121 p = buf;
122 while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
123 if (p < end) {
124 if ((flags & RPP_SEVENBIT))
125 ch &= 0x7f;
126 if (isalpha((unsigned char)ch)) {
127 if ((flags & RPP_FORCELOWER))
128 ch = (char)tolower((unsigned char)ch);
129 if ((flags & RPP_FORCEUPPER))
130 ch = (char)toupper((unsigned char)ch);
131 }
132 *p++ = ch;
133 }
134 }
135 *p = '\0';
136 save_errno = errno;
137 if (!(term.c_lflag & ECHO))
138 (void)_write(output, "\n", 1);
139
140 /* Restore old terminal settings and signals. */
141 if (memcmp(&term, &oterm, sizeof(term)) != 0) {
142 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
143 errno == EINTR && !signo[SIGTTOU])
144 continue;
145 }
146 (void)__libc_sigaction(SIGALRM, &savealrm, NULL);
147 (void)__libc_sigaction(SIGHUP, &savehup, NULL);
148 (void)__libc_sigaction(SIGINT, &saveint, NULL);
149 (void)__libc_sigaction(SIGQUIT, &savequit, NULL);
150 (void)__libc_sigaction(SIGPIPE, &savepipe, NULL);
151 (void)__libc_sigaction(SIGTERM, &saveterm, NULL);
152 (void)__libc_sigaction(SIGTSTP, &savetstp, NULL);
153 (void)__libc_sigaction(SIGTTIN, &savettin, NULL);
154 (void)__libc_sigaction(SIGTTOU, &savettou, NULL);
155 if (input != STDIN_FILENO)
156 (void)_close(input);
157
158 /*
159 * If we were interrupted by a signal, resend it to ourselves
160 * now that we have restored the signal handlers.
161 */
162 for (i = 0; i < NSIG; i++) {
163 if (signo[i]) {
164 kill(getpid(), i);
165 switch (i) {
166 case SIGTSTP:
167 case SIGTTIN:
168 case SIGTTOU:
169 need_restart = 1;
170 }
171 }
172 }
173 if (need_restart)
174 goto restart;
175
176 if (save_errno)
177 errno = save_errno;
178 return(nr == -1 ? NULL : buf);
179 }
180
181 char *
getpass(const char * prompt)182 getpass(const char *prompt)
183 {
184 static char buf[_PASSWORD_LEN + 1];
185
186 if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL)
187 buf[0] = '\0';
188 return(buf);
189 }
190
handler(int s)191 static void handler(int s)
192 {
193
194 signo[s] = 1;
195 }
196