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 "includes.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 <readpassphrase.h>
35 #include <errno.h>
36 #include <string.h>
37 #include <unistd.h>
38
39 #ifndef TCSASOFT
40 /* If we don't have TCSASOFT define it so that ORing it it below is a no-op. */
41 # define TCSASOFT 0
42 #endif
43
44 /* SunOS 4.x which lacks _POSIX_VDISABLE, but has VDISABLE */
45 #if !defined(_POSIX_VDISABLE) && defined(VDISABLE)
46 # define _POSIX_VDISABLE VDISABLE
47 #endif
48
49 #ifndef _NSIG
50 # ifdef NSIG
51 # define _NSIG NSIG
52 # else
53 # define _NSIG 128
54 # endif
55 #endif
56
57 static volatile sig_atomic_t signo[_NSIG];
58
59 static void handler(int);
60
61 char *
readpassphrase(const char * prompt,char * buf,size_t bufsiz,int flags)62 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
63 {
64 ssize_t nr;
65 int input, output, save_errno, i, need_restart;
66 char ch, *p, *end;
67 struct termios term, oterm;
68 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
69 struct sigaction savetstp, savettin, savettou, savepipe;
70
71 /* I suppose we could alloc on demand in this case (XXX). */
72 if (bufsiz == 0) {
73 errno = EINVAL;
74 return(NULL);
75 }
76
77 restart:
78 for (i = 0; i < _NSIG; i++)
79 signo[i] = 0;
80 nr = -1;
81 save_errno = 0;
82 need_restart = 0;
83 /*
84 * Read and write to /dev/tty if available. If not, read from
85 * stdin and write to stderr unless a tty is required.
86 */
87 if ((flags & RPP_STDIN) ||
88 (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
89 if (flags & RPP_REQUIRE_TTY) {
90 errno = ENOTTY;
91 return(NULL);
92 }
93 input = STDIN_FILENO;
94 output = STDERR_FILENO;
95 }
96
97 /*
98 * Turn off echo if possible.
99 * If we are using a tty but are not the foreground pgrp this will
100 * generate SIGTTOU, so do it *before* installing the signal handlers.
101 */
102 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
103 memcpy(&term, &oterm, sizeof(term));
104 if (!(flags & RPP_ECHO_ON))
105 term.c_lflag &= ~(ECHO | ECHONL);
106 #ifdef VSTATUS
107 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
108 term.c_cc[VSTATUS] = _POSIX_VDISABLE;
109 #endif
110 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
111 } else {
112 memset(&term, 0, sizeof(term));
113 term.c_lflag |= ECHO;
114 memset(&oterm, 0, sizeof(oterm));
115 oterm.c_lflag |= ECHO;
116 }
117
118 /*
119 * Catch signals that would otherwise cause the user to end
120 * up with echo turned off in the shell. Don't worry about
121 * things like SIGXCPU and SIGVTALRM for now.
122 */
123 sigemptyset(&sa.sa_mask);
124 sa.sa_flags = 0; /* don't restart system calls */
125 sa.sa_handler = handler;
126 (void)sigaction(SIGALRM, &sa, &savealrm);
127 (void)sigaction(SIGHUP, &sa, &savehup);
128 (void)sigaction(SIGINT, &sa, &saveint);
129 (void)sigaction(SIGPIPE, &sa, &savepipe);
130 (void)sigaction(SIGQUIT, &sa, &savequit);
131 (void)sigaction(SIGTERM, &sa, &saveterm);
132 (void)sigaction(SIGTSTP, &sa, &savetstp);
133 (void)sigaction(SIGTTIN, &sa, &savettin);
134 (void)sigaction(SIGTTOU, &sa, &savettou);
135
136 if (!(flags & RPP_STDIN))
137 (void)write(output, prompt, strlen(prompt));
138 end = buf + bufsiz - 1;
139 p = buf;
140 while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
141 if (p < end) {
142 if ((flags & RPP_SEVENBIT))
143 ch &= 0x7f;
144 if (isalpha((unsigned char)ch)) {
145 if ((flags & RPP_FORCELOWER))
146 ch = (char)tolower((unsigned char)ch);
147 if ((flags & RPP_FORCEUPPER))
148 ch = (char)toupper((unsigned char)ch);
149 }
150 *p++ = ch;
151 }
152 }
153 *p = '\0';
154 save_errno = errno;
155 if (!(term.c_lflag & ECHO))
156 (void)write(output, "\n", 1);
157
158 /* Restore old terminal settings and signals. */
159 if (memcmp(&term, &oterm, sizeof(term)) != 0) {
160 const int sigttou = signo[SIGTTOU];
161
162 /* Ignore SIGTTOU generated when we are not the fg pgrp. */
163 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
164 errno == EINTR && !signo[SIGTTOU])
165 continue;
166 signo[SIGTTOU] = sigttou;
167 }
168 (void)sigaction(SIGALRM, &savealrm, NULL);
169 (void)sigaction(SIGHUP, &savehup, NULL);
170 (void)sigaction(SIGINT, &saveint, NULL);
171 (void)sigaction(SIGQUIT, &savequit, NULL);
172 (void)sigaction(SIGPIPE, &savepipe, NULL);
173 (void)sigaction(SIGTERM, &saveterm, NULL);
174 (void)sigaction(SIGTSTP, &savetstp, NULL);
175 (void)sigaction(SIGTTIN, &savettin, NULL);
176 (void)sigaction(SIGTTOU, &savettou, NULL);
177 if (input != STDIN_FILENO)
178 (void)close(input);
179
180 /*
181 * If we were interrupted by a signal, resend it to ourselves
182 * now that we have restored the signal handlers.
183 */
184 for (i = 0; i < _NSIG; i++) {
185 if (signo[i]) {
186 kill(getpid(), i);
187 switch (i) {
188 case SIGTSTP:
189 case SIGTTIN:
190 case SIGTTOU:
191 need_restart = 1;
192 }
193 }
194 }
195 if (need_restart)
196 goto restart;
197
198 if (save_errno)
199 errno = save_errno;
200 return(nr == -1 ? NULL : buf);
201 }
202 DEF_WEAK(readpassphrase);
203
204 #if 0
205 char *
206 getpass(const char *prompt)
207 {
208 static char buf[_PASSWORD_LEN + 1];
209
210 return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
211 }
212 #endif
213
handler(int s)214 static void handler(int s)
215 {
216
217 signo[s] = 1;
218 }
219 #endif /* HAVE_READPASSPHRASE */
220