1 /* $OpenBSD: readpassphrase.c,v 1.20 2007/10/30 12:03:48 millert Exp $ */
2
3 /*
4 * Copyright (c) 2000-2002, 2007 Todd C. Miller <Todd.Miller@courtesan.com>
5 *
6 * Permission to use, copy, modify, and distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 *
18 * Sponsored in part by the Defense Advanced Research Projects
19 * Agency (DARPA) and Air Force Research Laboratory, Air Force
20 * Materiel Command, USAF, under agreement number F39502-99-1-0512.
21 */
22
23 #include <ctype.h>
24 #include <errno.h>
25 #include <fcntl.h>
26 #include <paths.h>
27 #include <pwd.h>
28 #include <signal.h>
29 #include <string.h>
30 #include <termios.h>
31 #include <unistd.h>
32 #include <readpassphrase.h>
33
34 #ifndef TCSASOFT
35 #define TCSASOFT 0
36 #endif
37
38 static volatile sig_atomic_t signo;
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;
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 signo = 0;
60 nr = -1;
61 save_errno = 0;
62 /*
63 * Read and write to /dev/tty if available. If not, read from
64 * stdin and write to stderr unless a tty is required.
65 */
66 if ((flags & RPP_STDIN) ||
67 (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
68 if (flags & RPP_REQUIRE_TTY) {
69 errno = ENOTTY;
70 return(NULL);
71 }
72 input = STDIN_FILENO;
73 output = STDERR_FILENO;
74 }
75
76 /*
77 * Catch signals that would otherwise cause the user to end
78 * up with echo turned off in the shell. Don't worry about
79 * things like SIGXCPU and SIGVTALRM for now.
80 */
81 sigemptyset(&sa.sa_mask);
82 sa.sa_flags = 0; /* don't restart system calls */
83 sa.sa_handler = handler;
84 (void)sigaction(SIGALRM, &sa, &savealrm);
85 (void)sigaction(SIGHUP, &sa, &savehup);
86 (void)sigaction(SIGINT, &sa, &saveint);
87 (void)sigaction(SIGPIPE, &sa, &savepipe);
88 (void)sigaction(SIGQUIT, &sa, &savequit);
89 (void)sigaction(SIGTERM, &sa, &saveterm);
90 (void)sigaction(SIGTSTP, &sa, &savetstp);
91 (void)sigaction(SIGTTIN, &sa, &savettin);
92 (void)sigaction(SIGTTOU, &sa, &savettou);
93
94 /* Turn off echo if possible. */
95 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
96 memcpy(&term, &oterm, sizeof(term));
97 if (!(flags & RPP_ECHO_ON))
98 term.c_lflag &= ~(ECHO | ECHONL);
99 #ifdef VSTATUS
100 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
101 term.c_cc[VSTATUS] = _POSIX_VDISABLE;
102 #endif
103 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
104 } else {
105 memset(&term, 0, sizeof(term));
106 term.c_lflag |= ECHO;
107 memset(&oterm, 0, sizeof(oterm));
108 oterm.c_lflag |= ECHO;
109 }
110
111 /* No I/O if we are already backgrounded. */
112 if (signo != SIGTTOU && signo != SIGTTIN) {
113 if (!(flags & RPP_STDIN))
114 (void)write(output, prompt, strlen(prompt));
115 end = buf + bufsiz - 1;
116 p = buf;
117 while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
118 if (p < end) {
119 if ((flags & RPP_SEVENBIT))
120 ch &= 0x7f;
121 if (isalpha(ch)) {
122 if ((flags & RPP_FORCELOWER))
123 ch = (char)tolower(ch);
124 if ((flags & RPP_FORCEUPPER))
125 ch = (char)toupper(ch);
126 }
127 *p++ = ch;
128 }
129 }
130 *p = '\0';
131 save_errno = errno;
132 if (!(term.c_lflag & ECHO))
133 (void)write(output, "\n", 1);
134 }
135
136 /* Restore old terminal settings and signals. */
137 if (memcmp(&term, &oterm, sizeof(term)) != 0) {
138 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
139 errno == EINTR)
140 continue;
141 }
142 (void)sigaction(SIGALRM, &savealrm, NULL);
143 (void)sigaction(SIGHUP, &savehup, NULL);
144 (void)sigaction(SIGINT, &saveint, NULL);
145 (void)sigaction(SIGQUIT, &savequit, NULL);
146 (void)sigaction(SIGPIPE, &savepipe, NULL);
147 (void)sigaction(SIGTERM, &saveterm, NULL);
148 (void)sigaction(SIGTSTP, &savetstp, NULL);
149 (void)sigaction(SIGTTIN, &savettin, NULL);
150 (void)sigaction(SIGTTOU, &savettou, NULL);
151 if (input != STDIN_FILENO)
152 (void)close(input);
153
154 /*
155 * If we were interrupted by a signal, resend it to ourselves
156 * now that we have restored the signal handlers.
157 */
158 if (signo) {
159 kill(getpid(), signo);
160 switch (signo) {
161 case SIGTSTP:
162 case SIGTTIN:
163 case SIGTTOU:
164 goto restart;
165 }
166 }
167
168 if (save_errno)
169 errno = save_errno;
170 return(nr == -1 ? NULL : buf);
171 }
172
173 #if 0
174 char *
175 getpass(const char *prompt)
176 {
177 static char buf[_PASSWORD_LEN + 1];
178
179 return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF));
180 }
181 #endif
182
handler(int s)183 static void handler(int s)
184 {
185
186 signo = s;
187 }
188