1 /* $OpenBSD: readpassphrase.c,v 1.16 2003/06/17 21:56:23 millert Exp $ */ 2 3 /* 4 * Copyright (c) 2000-2002 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 #if defined(LIBC_SCCS) && !defined(lint) 24 static const char rcsid[] = "$OpenBSD: readpassphrase.c,v 1.16 2003/06/17 21:56:23 millert Exp $"; 25 #endif /* LIBC_SCCS and not lint */ 26 27 #include <ctype.h> 28 #include <errno.h> 29 #include <fcntl.h> 30 #include <paths.h> 31 #include <pwd.h> 32 #include <signal.h> 33 #include <string.h> 34 #include <termios.h> 35 #include <unistd.h> 36 #include <readpassphrase.h> 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 /* 61 * Read and write to /dev/tty if available. If not, read from 62 * stdin and write to stderr unless a tty is required. 63 */ 64 if ((flags & RPP_STDIN) || 65 (input = output = open(_PATH_TTY, O_RDWR)) == -1) { 66 if (flags & RPP_REQUIRE_TTY) { 67 errno = ENOTTY; 68 return(NULL); 69 } 70 input = STDIN_FILENO; 71 output = STDERR_FILENO; 72 } 73 74 /* 75 * Catch signals that would otherwise cause the user to end 76 * up with echo turned off in the shell. Don't worry about 77 * things like SIGXCPU and SIGVTALRM for now. 78 */ 79 sigemptyset(&sa.sa_mask); 80 sa.sa_flags = 0; /* don't restart system calls */ 81 sa.sa_handler = handler; 82 (void)sigaction(SIGALRM, &sa, &savealrm); 83 (void)sigaction(SIGHUP, &sa, &savehup); 84 (void)sigaction(SIGINT, &sa, &saveint); 85 (void)sigaction(SIGPIPE, &sa, &savepipe); 86 (void)sigaction(SIGQUIT, &sa, &savequit); 87 (void)sigaction(SIGTERM, &sa, &saveterm); 88 (void)sigaction(SIGTSTP, &sa, &savetstp); 89 (void)sigaction(SIGTTIN, &sa, &savettin); 90 (void)sigaction(SIGTTOU, &sa, &savettou); 91 92 /* Turn off echo if possible. */ 93 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) { 94 memcpy(&term, &oterm, sizeof(term)); 95 if (!(flags & RPP_ECHO_ON)) 96 term.c_lflag &= ~(ECHO | ECHONL); 97 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE) 98 term.c_cc[VSTATUS] = _POSIX_VDISABLE; 99 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term); 100 } else { 101 memset(&term, 0, sizeof(term)); 102 term.c_lflag |= ECHO; 103 memset(&oterm, 0, sizeof(oterm)); 104 oterm.c_lflag |= ECHO; 105 } 106 107 if (!(flags & RPP_STDIN)) 108 (void)write(output, prompt, strlen(prompt)); 109 end = buf + bufsiz - 1; 110 for (p = buf; (nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r';) { 111 if (p < end) { 112 if ((flags & RPP_SEVENBIT)) 113 ch &= 0x7f; 114 if (isalpha(ch)) { 115 if ((flags & RPP_FORCELOWER)) 116 ch = tolower(ch); 117 if ((flags & RPP_FORCEUPPER)) 118 ch = toupper(ch); 119 } 120 *p++ = ch; 121 } 122 } 123 *p = '\0'; 124 save_errno = errno; 125 if (!(term.c_lflag & ECHO)) 126 (void)write(output, "\n", 1); 127 128 /* Restore old terminal settings and signals. */ 129 if (memcmp(&term, &oterm, sizeof(term)) != 0) 130 (void)tcsetattr(input, TCSANOW|TCSASOFT, &oterm); 131 (void)sigaction(SIGALRM, &savealrm, NULL); 132 (void)sigaction(SIGHUP, &savehup, NULL); 133 (void)sigaction(SIGINT, &saveint, NULL); 134 (void)sigaction(SIGQUIT, &savequit, NULL); 135 (void)sigaction(SIGPIPE, &savepipe, NULL); 136 (void)sigaction(SIGTERM, &saveterm, NULL); 137 (void)sigaction(SIGTSTP, &savetstp, NULL); 138 (void)sigaction(SIGTTIN, &savettin, NULL); 139 (void)sigaction(SIGTTOU, &savettou, NULL); 140 if (input != STDIN_FILENO) 141 (void)close(input); 142 143 /* 144 * If we were interrupted by a signal, resend it to ourselves 145 * now that we have restored the signal handlers. 146 */ 147 if (signo) { 148 kill(getpid(), signo); 149 switch (signo) { 150 case SIGTSTP: 151 case SIGTTIN: 152 case SIGTTOU: 153 goto restart; 154 } 155 } 156 157 errno = save_errno; 158 return(nr == -1 ? NULL : buf); 159 } 160 161 char * 162 getpass(const char *prompt) 163 { 164 static char buf[_PASSWORD_LEN + 1]; 165 166 return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF)); 167 } 168 169 static void handler(int s) 170 { 171 172 signo = s; 173 } 174