1 /* $OpenBSD: readpassphrase.c,v 1.27 2019/01/25 00:19:25 millert Exp $ */ 2 3 /* 4 * Copyright (c) 2000-2002, 2007, 2010 5 * Todd C. Miller <millert@openbsd.org> 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 <ctype.h> 25 #include <errno.h> 26 #include <fcntl.h> 27 #include <paths.h> 28 #include <pwd.h> 29 #include <signal.h> 30 #include <string.h> 31 #include <termios.h> 32 #include <unistd.h> 33 #include <readpassphrase.h> 34 35 static volatile sig_atomic_t signo[_NSIG]; 36 37 static void handler(int); 38 39 char * 40 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags) 41 { 42 ssize_t nr; 43 int input, output, save_errno, i, need_restart; 44 char ch, *p, *end; 45 struct termios term, oterm; 46 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm; 47 struct sigaction savetstp, savettin, savettou, savepipe; 48 49 /* I suppose we could alloc on demand in this case (XXX). */ 50 if (bufsiz == 0) { 51 errno = EINVAL; 52 return(NULL); 53 } 54 55 restart: 56 for (i = 0; i < _NSIG; i++) 57 signo[i] = 0; 58 nr = -1; 59 save_errno = 0; 60 need_restart = 0; 61 /* 62 * Read and write to /dev/tty if available. If not, read from 63 * stdin and write to stderr unless a tty is required. 64 */ 65 if ((flags & RPP_STDIN) || 66 (input = output = open(_PATH_TTY, O_RDWR)) == -1) { 67 if (flags & RPP_REQUIRE_TTY) { 68 errno = ENOTTY; 69 return(NULL); 70 } 71 input = STDIN_FILENO; 72 output = STDERR_FILENO; 73 } 74 75 /* 76 * Turn off echo if possible. 77 * If we are using a tty but are not the foreground pgrp this will 78 * generate SIGTTOU, so do it *before* installing the signal handlers. 79 */ 80 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) { 81 memcpy(&term, &oterm, sizeof(term)); 82 if (!(flags & RPP_ECHO_ON)) 83 term.c_lflag &= ~(ECHO | ECHONL); 84 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE) 85 term.c_cc[VSTATUS] = _POSIX_VDISABLE; 86 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term); 87 } else { 88 memset(&term, 0, sizeof(term)); 89 term.c_lflag |= ECHO; 90 memset(&oterm, 0, sizeof(oterm)); 91 oterm.c_lflag |= ECHO; 92 } 93 94 /* 95 * Catch signals that would otherwise cause the user to end 96 * up with echo turned off in the shell. Don't worry about 97 * things like SIGXCPU and SIGVTALRM for now. 98 */ 99 sigemptyset(&sa.sa_mask); 100 sa.sa_flags = 0; /* don't restart system calls */ 101 sa.sa_handler = handler; 102 (void)sigaction(SIGALRM, &sa, &savealrm); 103 (void)sigaction(SIGHUP, &sa, &savehup); 104 (void)sigaction(SIGINT, &sa, &saveint); 105 (void)sigaction(SIGPIPE, &sa, &savepipe); 106 (void)sigaction(SIGQUIT, &sa, &savequit); 107 (void)sigaction(SIGTERM, &sa, &saveterm); 108 (void)sigaction(SIGTSTP, &sa, &savetstp); 109 (void)sigaction(SIGTTIN, &sa, &savettin); 110 (void)sigaction(SIGTTOU, &sa, &savettou); 111 112 if (!(flags & RPP_STDIN)) 113 (void)write(output, prompt, strlen(prompt)); 114 end = buf + bufsiz - 1; 115 p = buf; 116 while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') { 117 if (p < end) { 118 if ((flags & RPP_SEVENBIT)) 119 ch &= 0x7f; 120 if (isalpha((unsigned char)ch)) { 121 if ((flags & RPP_FORCELOWER)) 122 ch = (char)tolower((unsigned char)ch); 123 if ((flags & RPP_FORCEUPPER)) 124 ch = (char)toupper((unsigned char)ch); 125 } 126 *p++ = ch; 127 } 128 } 129 *p = '\0'; 130 save_errno = errno; 131 if (!(term.c_lflag & ECHO)) 132 (void)write(output, "\n", 1); 133 134 /* Restore old terminal settings and signals. */ 135 if (memcmp(&term, &oterm, sizeof(term)) != 0) { 136 const int sigttou = signo[SIGTTOU]; 137 138 /* Ignore SIGTTOU generated when we are not the fg pgrp. */ 139 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 && 140 errno == EINTR && !signo[SIGTTOU]) 141 continue; 142 signo[SIGTTOU] = sigttou; 143 } 144 (void)sigaction(SIGALRM, &savealrm, NULL); 145 (void)sigaction(SIGHUP, &savehup, NULL); 146 (void)sigaction(SIGINT, &saveint, NULL); 147 (void)sigaction(SIGQUIT, &savequit, NULL); 148 (void)sigaction(SIGPIPE, &savepipe, NULL); 149 (void)sigaction(SIGTERM, &saveterm, NULL); 150 (void)sigaction(SIGTSTP, &savetstp, NULL); 151 (void)sigaction(SIGTTIN, &savettin, NULL); 152 (void)sigaction(SIGTTOU, &savettou, NULL); 153 if (input != STDIN_FILENO) 154 (void)close(input); 155 156 /* 157 * If we were interrupted by a signal, resend it to ourselves 158 * now that we have restored the signal handlers. 159 */ 160 for (i = 0; i < _NSIG; i++) { 161 if (signo[i]) { 162 kill(getpid(), i); 163 switch (i) { 164 case SIGTSTP: 165 case SIGTTIN: 166 case SIGTTOU: 167 need_restart = 1; 168 } 169 } 170 } 171 if (need_restart) 172 goto restart; 173 174 if (save_errno) 175 errno = save_errno; 176 return(nr == -1 ? NULL : buf); 177 } 178 DEF_WEAK(readpassphrase); 179 180 char * 181 getpass(const char *prompt) 182 { 183 static char buf[_PASSWORD_LEN + 1]; 184 185 return(readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF)); 186 } 187 188 static void handler(int s) 189 { 190 191 signo[s] = 1; 192 } 193