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 "namespace.h"
25 #include <ctype.h>
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <paths.h>
29 #include <pwd.h>
30 #include <signal.h>
31 #include <string.h>
32 #include <termios.h>
33 #include <unistd.h>
34 #include <readpassphrase.h>
35 #include "un-namespace.h"
36 #include "libc_private.h"
37
38 static volatile sig_atomic_t signo[NSIG];
39
40 static void handler(int);
41
42 char *
readpassphrase(const char * prompt,char * buf,size_t bufsiz,int flags)43 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
44 {
45 ssize_t nr;
46 int input, output, save_errno, i, need_restart, input_is_tty;
47 char ch, *p, *end;
48 struct termios term, oterm;
49 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
50 struct sigaction savetstp, savettin, savettou, savepipe;
51
52 /* I suppose we could alloc on demand in this case (XXX). */
53 if (bufsiz == 0) {
54 errno = EINVAL;
55 return(NULL);
56 }
57
58 restart:
59 for (i = 0; i < NSIG; i++)
60 signo[i] = 0;
61 nr = -1;
62 save_errno = 0;
63 need_restart = 0;
64 /*
65 * Read and write to /dev/tty if available. If not, read from
66 * stdin and write to stderr unless a tty is required.
67 */
68 input_is_tty = 0;
69 if (!(flags & RPP_STDIN)) {
70 input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC);
71 if (input == -1) {
72 if (flags & RPP_REQUIRE_TTY) {
73 errno = ENOTTY;
74 return(NULL);
75 }
76 input = STDIN_FILENO;
77 output = STDERR_FILENO;
78 } else {
79 input_is_tty = 1;
80 }
81 } else {
82 input = STDIN_FILENO;
83 output = STDERR_FILENO;
84 }
85
86 /*
87 * Turn off echo if possible.
88 * If we are using a tty but are not the foreground pgrp this will
89 * generate SIGTTOU, so do it *before* installing the signal handlers.
90 */
91 if (input_is_tty && tcgetattr(input, &oterm) == 0) {
92 memcpy(&term, &oterm, sizeof(term));
93 if (!(flags & RPP_ECHO_ON))
94 term.c_lflag &= ~(ECHO | ECHONL);
95 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
96 term.c_cc[VSTATUS] = _POSIX_VDISABLE;
97 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
98 } else {
99 memset(&term, 0, sizeof(term));
100 term.c_lflag |= ECHO;
101 memset(&oterm, 0, sizeof(oterm));
102 oterm.c_lflag |= ECHO;
103 }
104
105 /*
106 * Catch signals that would otherwise cause the user to end
107 * up with echo turned off in the shell. Don't worry about
108 * things like SIGXCPU and SIGVTALRM for now.
109 */
110 sigemptyset(&sa.sa_mask);
111 sa.sa_flags = 0; /* don't restart system calls */
112 sa.sa_handler = handler;
113 (void)__libc_sigaction(SIGALRM, &sa, &savealrm);
114 (void)__libc_sigaction(SIGHUP, &sa, &savehup);
115 (void)__libc_sigaction(SIGINT, &sa, &saveint);
116 (void)__libc_sigaction(SIGPIPE, &sa, &savepipe);
117 (void)__libc_sigaction(SIGQUIT, &sa, &savequit);
118 (void)__libc_sigaction(SIGTERM, &sa, &saveterm);
119 (void)__libc_sigaction(SIGTSTP, &sa, &savetstp);
120 (void)__libc_sigaction(SIGTTIN, &sa, &savettin);
121 (void)__libc_sigaction(SIGTTOU, &sa, &savettou);
122
123 if (!(flags & RPP_STDIN))
124 (void)_write(output, prompt, strlen(prompt));
125 end = buf + bufsiz - 1;
126 p = buf;
127 while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
128 if (p < end) {
129 if ((flags & RPP_SEVENBIT))
130 ch &= 0x7f;
131 if (isalpha((unsigned char)ch)) {
132 if ((flags & RPP_FORCELOWER))
133 ch = (char)tolower((unsigned char)ch);
134 if ((flags & RPP_FORCEUPPER))
135 ch = (char)toupper((unsigned char)ch);
136 }
137 *p++ = ch;
138 }
139 }
140 *p = '\0';
141 save_errno = errno;
142 if (!(term.c_lflag & ECHO))
143 (void)_write(output, "\n", 1);
144
145 /* Restore old terminal settings and signals. */
146 if (memcmp(&term, &oterm, sizeof(term)) != 0) {
147 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
148 errno == EINTR && !signo[SIGTTOU])
149 continue;
150 }
151 (void)__libc_sigaction(SIGALRM, &savealrm, NULL);
152 (void)__libc_sigaction(SIGHUP, &savehup, NULL);
153 (void)__libc_sigaction(SIGINT, &saveint, NULL);
154 (void)__libc_sigaction(SIGQUIT, &savequit, NULL);
155 (void)__libc_sigaction(SIGPIPE, &savepipe, NULL);
156 (void)__libc_sigaction(SIGTERM, &saveterm, NULL);
157 (void)__libc_sigaction(SIGTSTP, &savetstp, NULL);
158 (void)__libc_sigaction(SIGTTIN, &savettin, NULL);
159 (void)__libc_sigaction(SIGTTOU, &savettou, NULL);
160 if (input_is_tty)
161 (void)_close(input);
162
163 /*
164 * If we were interrupted by a signal, resend it to ourselves
165 * now that we have restored the signal handlers.
166 */
167 for (i = 0; i < NSIG; i++) {
168 if (signo[i]) {
169 kill(getpid(), i);
170 switch (i) {
171 case SIGTSTP:
172 case SIGTTIN:
173 case SIGTTOU:
174 need_restart = 1;
175 }
176 }
177 }
178 if (need_restart)
179 goto restart;
180
181 if (save_errno)
182 errno = save_errno;
183 return(nr == -1 ? NULL : buf);
184 }
185
186 char *
getpass(const char * prompt)187 getpass(const char *prompt)
188 {
189 static char buf[_PASSWORD_LEN + 1];
190
191 if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL)
192 buf[0] = '\0';
193 return(buf);
194 }
195
handler(int s)196 static void handler(int s)
197 {
198
199 signo[s] = 1;
200 }
201