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 * 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, input_is_tty; 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 input_is_tty = 0; 72 if (!(flags & RPP_STDIN)) { 73 input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC); 74 if (input == -1) { 75 if (flags & RPP_REQUIRE_TTY) { 76 errno = ENOTTY; 77 return(NULL); 78 } 79 input = STDIN_FILENO; 80 output = STDERR_FILENO; 81 } else { 82 input_is_tty = 1; 83 } 84 } else { 85 input = STDIN_FILENO; 86 output = STDERR_FILENO; 87 } 88 89 /* 90 * Turn off echo if possible. 91 * If we are using a tty but are not the foreground pgrp this will 92 * generate SIGTTOU, so do it *before* installing the signal handlers. 93 */ 94 if (input_is_tty && tcgetattr(input, &oterm) == 0) { 95 memcpy(&term, &oterm, sizeof(term)); 96 if (!(flags & RPP_ECHO_ON)) 97 term.c_lflag &= ~(ECHO | ECHONL); 98 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE) 99 term.c_cc[VSTATUS] = _POSIX_VDISABLE; 100 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term); 101 } else { 102 memset(&term, 0, sizeof(term)); 103 term.c_lflag |= ECHO; 104 memset(&oterm, 0, sizeof(oterm)); 105 oterm.c_lflag |= ECHO; 106 } 107 108 /* 109 * Catch signals that would otherwise cause the user to end 110 * up with echo turned off in the shell. Don't worry about 111 * things like SIGXCPU and SIGVTALRM for now. 112 */ 113 sigemptyset(&sa.sa_mask); 114 sa.sa_flags = 0; /* don't restart system calls */ 115 sa.sa_handler = handler; 116 (void)__libc_sigaction(SIGALRM, &sa, &savealrm); 117 (void)__libc_sigaction(SIGHUP, &sa, &savehup); 118 (void)__libc_sigaction(SIGINT, &sa, &saveint); 119 (void)__libc_sigaction(SIGPIPE, &sa, &savepipe); 120 (void)__libc_sigaction(SIGQUIT, &sa, &savequit); 121 (void)__libc_sigaction(SIGTERM, &sa, &saveterm); 122 (void)__libc_sigaction(SIGTSTP, &sa, &savetstp); 123 (void)__libc_sigaction(SIGTTIN, &sa, &savettin); 124 (void)__libc_sigaction(SIGTTOU, &sa, &savettou); 125 126 if (!(flags & RPP_STDIN)) 127 (void)_write(output, prompt, strlen(prompt)); 128 end = buf + bufsiz - 1; 129 p = buf; 130 while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') { 131 if (p < end) { 132 if ((flags & RPP_SEVENBIT)) 133 ch &= 0x7f; 134 if (isalpha((unsigned char)ch)) { 135 if ((flags & RPP_FORCELOWER)) 136 ch = (char)tolower((unsigned char)ch); 137 if ((flags & RPP_FORCEUPPER)) 138 ch = (char)toupper((unsigned char)ch); 139 } 140 *p++ = ch; 141 } 142 } 143 *p = '\0'; 144 save_errno = errno; 145 if (!(term.c_lflag & ECHO)) 146 (void)_write(output, "\n", 1); 147 148 /* Restore old terminal settings and signals. */ 149 if (memcmp(&term, &oterm, sizeof(term)) != 0) { 150 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 && 151 errno == EINTR && !signo[SIGTTOU]) 152 continue; 153 } 154 (void)__libc_sigaction(SIGALRM, &savealrm, NULL); 155 (void)__libc_sigaction(SIGHUP, &savehup, NULL); 156 (void)__libc_sigaction(SIGINT, &saveint, NULL); 157 (void)__libc_sigaction(SIGQUIT, &savequit, NULL); 158 (void)__libc_sigaction(SIGPIPE, &savepipe, NULL); 159 (void)__libc_sigaction(SIGTERM, &saveterm, NULL); 160 (void)__libc_sigaction(SIGTSTP, &savetstp, NULL); 161 (void)__libc_sigaction(SIGTTIN, &savettin, NULL); 162 (void)__libc_sigaction(SIGTTOU, &savettou, NULL); 163 if (input_is_tty) 164 (void)_close(input); 165 166 /* 167 * If we were interrupted by a signal, resend it to ourselves 168 * now that we have restored the signal handlers. 169 */ 170 for (i = 0; i < NSIG; i++) { 171 if (signo[i]) { 172 kill(getpid(), i); 173 switch (i) { 174 case SIGTSTP: 175 case SIGTTIN: 176 case SIGTTOU: 177 need_restart = 1; 178 } 179 } 180 } 181 if (need_restart) 182 goto restart; 183 184 if (save_errno) 185 errno = save_errno; 186 return(nr == -1 ? NULL : buf); 187 } 188 189 char * 190 getpass(const char *prompt) 191 { 192 static char buf[_PASSWORD_LEN + 1]; 193 194 if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL) 195 buf[0] = '\0'; 196 return(buf); 197 } 198 199 static void handler(int s) 200 { 201 202 signo[s] = 1; 203 } 204