1 /* $OpenBSD: readpassphrase.c,v 1.23 2010/05/14 13:30:34 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 #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 40 static volatile sig_atomic_t signo[NSIG]; 41 42 static void handler(int); 43 44 char * 45 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags) 46 { 47 ssize_t nr; 48 int input, output, save_errno, i, need_restart; 49 char ch, *p, *end; 50 struct termios term, oterm; 51 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm; 52 struct sigaction savetstp, savettin, savettou, savepipe; 53 54 /* I suppose we could alloc on demand in this case (XXX). */ 55 if (bufsiz == 0) { 56 errno = EINVAL; 57 return(NULL); 58 } 59 60 restart: 61 for (i = 0; i < NSIG; i++) 62 signo[i] = 0; 63 nr = -1; 64 save_errno = 0; 65 need_restart = 0; 66 /* 67 * Read and write to /dev/tty if available. If not, read from 68 * stdin and write to stderr unless a tty is required. 69 */ 70 if ((flags & RPP_STDIN) || 71 (input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC)) == -1) { 72 if (flags & RPP_REQUIRE_TTY) { 73 errno = ENOTTY; 74 return(NULL); 75 } 76 input = STDIN_FILENO; 77 output = STDERR_FILENO; 78 } 79 80 /* 81 * Turn off echo if possible. 82 * If we are using a tty but are not the foreground pgrp this will 83 * generate SIGTTOU, so do it *before* installing the signal handlers. 84 */ 85 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) { 86 memcpy(&term, &oterm, sizeof(term)); 87 if (!(flags & RPP_ECHO_ON)) 88 term.c_lflag &= ~(ECHO | ECHONL); 89 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE) 90 term.c_cc[VSTATUS] = _POSIX_VDISABLE; 91 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term); 92 } else { 93 memset(&term, 0, sizeof(term)); 94 term.c_lflag |= ECHO; 95 memset(&oterm, 0, sizeof(oterm)); 96 oterm.c_lflag |= ECHO; 97 } 98 99 /* 100 * Catch signals that would otherwise cause the user to end 101 * up with echo turned off in the shell. Don't worry about 102 * things like SIGXCPU and SIGVTALRM for now. 103 */ 104 sigemptyset(&sa.sa_mask); 105 sa.sa_flags = 0; /* don't restart system calls */ 106 sa.sa_handler = handler; 107 (void)_sigaction(SIGALRM, &sa, &savealrm); 108 (void)_sigaction(SIGHUP, &sa, &savehup); 109 (void)_sigaction(SIGINT, &sa, &saveint); 110 (void)_sigaction(SIGPIPE, &sa, &savepipe); 111 (void)_sigaction(SIGQUIT, &sa, &savequit); 112 (void)_sigaction(SIGTERM, &sa, &saveterm); 113 (void)_sigaction(SIGTSTP, &sa, &savetstp); 114 (void)_sigaction(SIGTTIN, &sa, &savettin); 115 (void)_sigaction(SIGTTOU, &sa, &savettou); 116 117 if (!(flags & RPP_STDIN)) 118 (void)_write(output, prompt, strlen(prompt)); 119 end = buf + bufsiz - 1; 120 p = buf; 121 while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') { 122 if (p < end) { 123 if ((flags & RPP_SEVENBIT)) 124 ch &= 0x7f; 125 if (isalpha(ch)) { 126 if ((flags & RPP_FORCELOWER)) 127 ch = (char)tolower(ch); 128 if ((flags & RPP_FORCEUPPER)) 129 ch = (char)toupper(ch); 130 } 131 *p++ = ch; 132 } 133 } 134 *p = '\0'; 135 save_errno = errno; 136 if (!(term.c_lflag & ECHO)) 137 (void)_write(output, "\n", 1); 138 139 /* Restore old terminal settings and signals. */ 140 if (memcmp(&term, &oterm, sizeof(term)) != 0) { 141 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 && 142 errno == EINTR && !signo[SIGTTOU]) 143 continue; 144 } 145 (void)_sigaction(SIGALRM, &savealrm, NULL); 146 (void)_sigaction(SIGHUP, &savehup, NULL); 147 (void)_sigaction(SIGINT, &saveint, NULL); 148 (void)_sigaction(SIGQUIT, &savequit, NULL); 149 (void)_sigaction(SIGPIPE, &savepipe, NULL); 150 (void)_sigaction(SIGTERM, &saveterm, NULL); 151 (void)_sigaction(SIGTSTP, &savetstp, NULL); 152 (void)_sigaction(SIGTTIN, &savettin, NULL); 153 (void)_sigaction(SIGTTOU, &savettou, NULL); 154 if (input != STDIN_FILENO) 155 (void)_close(input); 156 157 /* 158 * If we were interrupted by a signal, resend it to ourselves 159 * now that we have restored the signal handlers. 160 */ 161 for (i = 0; i < NSIG; i++) { 162 if (signo[i]) { 163 kill(getpid(), i); 164 switch (i) { 165 case SIGTSTP: 166 case SIGTTIN: 167 case SIGTTOU: 168 need_restart = 1; 169 } 170 } 171 } 172 if (need_restart) 173 goto restart; 174 175 if (save_errno) 176 errno = save_errno; 177 return(nr == -1 ? NULL : buf); 178 } 179 180 char * 181 getpass(const char *prompt) 182 { 183 static char buf[_PASSWORD_LEN + 1]; 184 185 if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL) 186 buf[0] = '\0'; 187 return(buf); 188 } 189 190 static void handler(int s) 191 { 192 193 signo[s] = 1; 194 } 195