1 /* $OpenBSD: readpassphrase.c,v 1.26 2016/10/18 12:47:18 millert 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 /* OPENBSD ORIGINAL: lib/libc/gen/readpassphrase.c */
25
26 #include "openbsd-compat.h"
27
28 #ifndef HAVE_READPASSPHRASE
29
30 #include <termios.h>
31 #include <signal.h>
32 #include <ctype.h>
33 #include <fcntl.h>
34 #include <errno.h>
35 #include <string.h>
36 #ifdef HAVE_UNISTD_H
37 #include <unistd.h>
38 #endif
39 #include <paths.h>
40
41 #ifndef _PATH_TTY
42 # define _PATH_TTY "/dev/tty"
43 #endif
44
45 #ifndef TCSASOFT
46 /* If we don't have TCSASOFT define it so that ORing it it below is a no-op. */
47 # define TCSASOFT 0
48 #endif
49
50 /* SunOS 4.x which lacks _POSIX_VDISABLE, but has VDISABLE */
51 #if !defined(_POSIX_VDISABLE) && defined(VDISABLE)
52 # define _POSIX_VDISABLE VDISABLE
53 #endif
54
55 static volatile sig_atomic_t signo[NSIG];
56
57 static void handler(int);
58
59 char *
readpassphrase(const char * prompt,char * buf,size_t bufsiz,int flags)60 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
61 {
62 ssize_t nr;
63 int input, output, save_errno, i, need_restart;
64 char ch, *p, *end;
65 struct termios term, oterm;
66 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
67 struct sigaction savetstp, savettin, savettou, savepipe;
68
69 /* I suppose we could alloc on demand in this case (XXX). */
70 if (bufsiz == 0) {
71 errno = EINVAL;
72 return(NULL);
73 }
74
75 restart:
76 for (i = 0; i < NSIG; i++)
77 signo[i] = 0;
78 need_restart = 0;
79 /*
80 * Read and write to /dev/tty if available. If not, read from
81 * stdin and write to stderr unless a tty is required.
82 */
83 if ((flags & RPP_STDIN) ||
84 (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
85 if (flags & RPP_REQUIRE_TTY) {
86 errno = ENOTTY;
87 return(NULL);
88 }
89 input = STDIN_FILENO;
90 output = STDERR_FILENO;
91 }
92
93 /*
94 * Turn off echo if possible.
95 * If we are using a tty but are not the foreground pgrp this will
96 * generate SIGTTOU, so do it *before* installing the signal handlers.
97 */
98 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
99 memcpy(&term, &oterm, sizeof(term));
100 if (!(flags & RPP_ECHO_ON))
101 term.c_lflag &= ~(ECHO | ECHONL);
102 #ifdef VSTATUS
103 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
104 term.c_cc[VSTATUS] = _POSIX_VDISABLE;
105 #endif
106 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
107 } else {
108 memset(&term, 0, sizeof(term));
109 term.c_lflag |= ECHO;
110 memset(&oterm, 0, sizeof(oterm));
111 oterm.c_lflag |= ECHO;
112 }
113
114 /*
115 * Catch signals that would otherwise cause the user to end
116 * up with echo turned off in the shell. Don't worry about
117 * things like SIGXCPU and SIGVTALRM for now.
118 */
119 sigemptyset(&sa.sa_mask);
120 sa.sa_flags = 0; /* don't restart system calls */
121 sa.sa_handler = handler;
122 (void)sigaction(SIGALRM, &sa, &savealrm);
123 (void)sigaction(SIGHUP, &sa, &savehup);
124 (void)sigaction(SIGINT, &sa, &saveint);
125 (void)sigaction(SIGPIPE, &sa, &savepipe);
126 (void)sigaction(SIGQUIT, &sa, &savequit);
127 (void)sigaction(SIGTERM, &sa, &saveterm);
128 (void)sigaction(SIGTSTP, &sa, &savetstp);
129 (void)sigaction(SIGTTIN, &sa, &savettin);
130 (void)sigaction(SIGTTOU, &sa, &savettou);
131
132 if (!(flags & RPP_STDIN))
133 (void)write(output, prompt, strlen(prompt));
134 end = buf + bufsiz - 1;
135 p = buf;
136 while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
137 if (p < end) {
138 if ((flags & RPP_SEVENBIT))
139 ch &= 0x7f;
140 if (isalpha((unsigned char)ch)) {
141 if ((flags & RPP_FORCELOWER))
142 ch = (char)tolower((unsigned char)ch);
143 if ((flags & RPP_FORCEUPPER))
144 ch = (char)toupper((unsigned char)ch);
145 }
146 *p++ = ch;
147 }
148 }
149 *p = '\0';
150 save_errno = errno;
151 if (!(term.c_lflag & ECHO))
152 (void)write(output, "\n", 1);
153
154 /* Restore old terminal settings and signals. */
155 if (memcmp(&term, &oterm, sizeof(term)) != 0) {
156 const int sigttou = signo[SIGTTOU];
157
158 /* Ignore SIGTTOU generated when we are not the fg pgrp. */
159 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
160 errno == EINTR && !signo[SIGTTOU])
161 continue;
162 signo[SIGTTOU] = sigttou;
163 }
164 (void)sigaction(SIGALRM, &savealrm, NULL);
165 (void)sigaction(SIGHUP, &savehup, NULL);
166 (void)sigaction(SIGINT, &saveint, NULL);
167 (void)sigaction(SIGQUIT, &savequit, NULL);
168 (void)sigaction(SIGPIPE, &savepipe, NULL);
169 (void)sigaction(SIGTERM, &saveterm, NULL);
170 (void)sigaction(SIGTSTP, &savetstp, NULL);
171 (void)sigaction(SIGTTIN, &savettin, NULL);
172 (void)sigaction(SIGTTOU, &savettou, NULL);
173 if (input != STDIN_FILENO)
174 (void)close(input);
175
176 /*
177 * If we were interrupted by a signal, resend it to ourselves
178 * now that we have restored the signal handlers.
179 */
180 for (i = 0; i < NSIG; i++) {
181 if (signo[i]) {
182 kill(getpid(), i);
183 switch (i) {
184 case SIGTSTP:
185 case SIGTTIN:
186 case SIGTTOU:
187 need_restart = 1;
188 }
189 }
190 }
191 if (need_restart)
192 goto restart;
193
194 if (save_errno)
195 errno = save_errno;
196 return(nr == -1 ? NULL : buf);
197 }
198
199 #if 0
200 char *
201 getpass(const char *prompt)
202 {
203 static char buf[_PASSWORD_LEN + 1];
204
205 return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
206 }
207 #endif
208
handler(int s)209 static void handler(int s)
210 {
211
212 signo[s] = 1;
213 }
214 #endif /* HAVE_READPASSPHRASE */
215