1 /* $OpenBSD: readpassphrase.c,v 1.21 2008/01/17 16:27:07 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 static volatile sig_atomic_t signo; 35 36 static void handler(int); 37 38 char * 39 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags) 40 { 41 ssize_t nr; 42 int input, output, save_errno; 43 char ch, *p, *end; 44 struct termios term, oterm; 45 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm; 46 struct sigaction savetstp, savettin, savettou, savepipe; 47 48 /* I suppose we could alloc on demand in this case (XXX). */ 49 if (bufsiz == 0) { 50 errno = EINVAL; 51 return(NULL); 52 } 53 54 restart: 55 signo = 0; 56 nr = -1; 57 save_errno = 0; 58 /* 59 * Read and write to /dev/tty if available. If not, read from 60 * stdin and write to stderr unless a tty is required. 61 */ 62 if ((flags & RPP_STDIN) || 63 (input = output = open(_PATH_TTY, O_RDWR)) == -1) { 64 if (flags & RPP_REQUIRE_TTY) { 65 errno = ENOTTY; 66 return(NULL); 67 } 68 input = STDIN_FILENO; 69 output = STDERR_FILENO; 70 } 71 72 /* 73 * Catch signals that would otherwise cause the user to end 74 * up with echo turned off in the shell. Don't worry about 75 * things like SIGXCPU and SIGVTALRM for now. 76 */ 77 sigemptyset(&sa.sa_mask); 78 sa.sa_flags = 0; /* don't restart system calls */ 79 sa.sa_handler = handler; 80 (void)sigaction(SIGALRM, &sa, &savealrm); 81 (void)sigaction(SIGHUP, &sa, &savehup); 82 (void)sigaction(SIGINT, &sa, &saveint); 83 (void)sigaction(SIGPIPE, &sa, &savepipe); 84 (void)sigaction(SIGQUIT, &sa, &savequit); 85 (void)sigaction(SIGTERM, &sa, &saveterm); 86 (void)sigaction(SIGTSTP, &sa, &savetstp); 87 (void)sigaction(SIGTTIN, &sa, &savettin); 88 (void)sigaction(SIGTTOU, &sa, &savettou); 89 90 /* Turn off echo if possible. */ 91 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) { 92 memcpy(&term, &oterm, sizeof(term)); 93 if (!(flags & RPP_ECHO_ON)) 94 term.c_lflag &= ~(ECHO | ECHONL); 95 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE) 96 term.c_cc[VSTATUS] = _POSIX_VDISABLE; 97 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term); 98 } else { 99 memset(&term, 0, sizeof(term)); 100 term.c_lflag |= ECHO; 101 memset(&oterm, 0, sizeof(oterm)); 102 oterm.c_lflag |= ECHO; 103 } 104 105 /* No I/O if we are already backgrounded. */ 106 if (signo != SIGTTOU && signo != SIGTTIN) { 107 if (!(flags & RPP_STDIN)) 108 (void)write(output, prompt, strlen(prompt)); 109 end = buf + bufsiz - 1; 110 p = buf; 111 while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') { 112 if (p < end) { 113 if ((flags & RPP_SEVENBIT)) 114 ch &= 0x7f; 115 if (isalpha(ch)) { 116 if ((flags & RPP_FORCELOWER)) 117 ch = (char)tolower(ch); 118 if ((flags & RPP_FORCEUPPER)) 119 ch = (char)toupper(ch); 120 } 121 *p++ = ch; 122 } 123 } 124 *p = '\0'; 125 save_errno = errno; 126 if (!(term.c_lflag & ECHO)) 127 (void)write(output, "\n", 1); 128 } 129 130 /* Restore old terminal settings and signals. */ 131 if (memcmp(&term, &oterm, sizeof(term)) != 0) { 132 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 && 133 errno == EINTR) 134 continue; 135 } 136 (void)sigaction(SIGALRM, &savealrm, NULL); 137 (void)sigaction(SIGHUP, &savehup, NULL); 138 (void)sigaction(SIGINT, &saveint, NULL); 139 (void)sigaction(SIGQUIT, &savequit, NULL); 140 (void)sigaction(SIGPIPE, &savepipe, NULL); 141 (void)sigaction(SIGTERM, &saveterm, NULL); 142 (void)sigaction(SIGTSTP, &savetstp, NULL); 143 (void)sigaction(SIGTTIN, &savettin, NULL); 144 (void)sigaction(SIGTTOU, &savettou, NULL); 145 if (input != STDIN_FILENO) 146 (void)close(input); 147 148 /* 149 * If we were interrupted by a signal, resend it to ourselves 150 * now that we have restored the signal handlers. 151 */ 152 if (signo) { 153 kill(getpid(), signo); 154 switch (signo) { 155 case SIGTSTP: 156 case SIGTTIN: 157 case SIGTTOU: 158 goto restart; 159 } 160 } 161 162 if (save_errno) 163 errno = save_errno; 164 return(nr == -1 ? NULL : buf); 165 } 166 167 char * 168 getpass(const char *prompt) 169 { 170 static char buf[_PASSWORD_LEN + 1]; 171 172 return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF)); 173 } 174 175 static void handler(int s) 176 { 177 178 signo = s; 179 } 180