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 * 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 182 183 static void handler(int s) 184 { 185 186 signo = s; 187 } 188