1/* $OpenBSD: readpassphrase.c,v 1.24 2013/11/24 23:51:29 deraadt 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 "namespace.h" 25#include <ctype.h> 26#include <errno.h> 27#include <fcntl.h> 28#include <paths.h> 29#include <pwd.h> 30#include <signal.h> 31#include <string.h> 32#include <termios.h> 33#include <unistd.h> 34#include <readpassphrase.h> 35#include "un-namespace.h" 36#include "libc_private.h" 37 38static volatile sig_atomic_t signo[NSIG]; 39 40static void handler(int); 41 42char * 43readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags) 44{ 45 ssize_t nr; 46 int input, output, save_errno, i, need_restart, input_is_tty; 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 58restart: 59 for (i = 0; i < NSIG; i++) 60 signo[i] = 0; 61 nr = -1; 62 save_errno = 0; 63 need_restart = 0; 64 /* 65 * Read and write to /dev/tty if available. If not, read from 66 * stdin and write to stderr unless a tty is required. 67 */ 68 input_is_tty = 0; 69 if (!(flags & RPP_STDIN)) { 70 input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC); 71 if (input == -1) { 72 if (flags & RPP_REQUIRE_TTY) { 73 errno = ENOTTY; 74 return(NULL); 75 } 76 input = STDIN_FILENO; 77 output = STDERR_FILENO; 78 } else { 79 input_is_tty = 1; 80 } 81 } else { 82 input = STDIN_FILENO; 83 output = STDERR_FILENO; 84 } 85 86 /* 87 * Turn off echo if possible. 88 * If we are using a tty but are not the foreground pgrp this will 89 * generate SIGTTOU, so do it *before* installing the signal handlers. 90 */ 91 if (input_is_tty && 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 /* 106 * Catch signals that would otherwise cause the user to end 107 * up with echo turned off in the shell. Don't worry about 108 * things like SIGXCPU and SIGVTALRM for now. 109 */ 110 sigemptyset(&sa.sa_mask); 111 sa.sa_flags = 0; /* don't restart system calls */ 112 sa.sa_handler = handler; 113 (void)__libc_sigaction(SIGALRM, &sa, &savealrm); 114 (void)__libc_sigaction(SIGHUP, &sa, &savehup); 115 (void)__libc_sigaction(SIGINT, &sa, &saveint); 116 (void)__libc_sigaction(SIGPIPE, &sa, &savepipe); 117 (void)__libc_sigaction(SIGQUIT, &sa, &savequit); 118 (void)__libc_sigaction(SIGTERM, &sa, &saveterm); 119 (void)__libc_sigaction(SIGTSTP, &sa, &savetstp); 120 (void)__libc_sigaction(SIGTTIN, &sa, &savettin); 121 (void)__libc_sigaction(SIGTTOU, &sa, &savettou); 122 123 if (!(flags & RPP_STDIN)) 124 (void)_write(output, prompt, strlen(prompt)); 125 end = buf + bufsiz - 1; 126 p = buf; 127 while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') { 128 if (p < end) { 129 if ((flags & RPP_SEVENBIT)) 130 ch &= 0x7f; 131 if (isalpha((unsigned char)ch)) { 132 if ((flags & RPP_FORCELOWER)) 133 ch = (char)tolower((unsigned char)ch); 134 if ((flags & RPP_FORCEUPPER)) 135 ch = (char)toupper((unsigned char)ch); 136 } 137 *p++ = ch; 138 } 139 } 140 *p = '\0'; 141 save_errno = errno; 142 if (!(term.c_lflag & ECHO)) 143 (void)_write(output, "\n", 1); 144 145 /* Restore old terminal settings and signals. */ 146 if (memcmp(&term, &oterm, sizeof(term)) != 0) { 147 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 && 148 errno == EINTR && !signo[SIGTTOU]) 149 continue; 150 } 151 (void)__libc_sigaction(SIGALRM, &savealrm, NULL); 152 (void)__libc_sigaction(SIGHUP, &savehup, NULL); 153 (void)__libc_sigaction(SIGINT, &saveint, NULL); 154 (void)__libc_sigaction(SIGQUIT, &savequit, NULL); 155 (void)__libc_sigaction(SIGPIPE, &savepipe, NULL); 156 (void)__libc_sigaction(SIGTERM, &saveterm, NULL); 157 (void)__libc_sigaction(SIGTSTP, &savetstp, NULL); 158 (void)__libc_sigaction(SIGTTIN, &savettin, NULL); 159 (void)__libc_sigaction(SIGTTOU, &savettou, NULL); 160 if (input_is_tty) 161 (void)_close(input); 162 163 /* 164 * If we were interrupted by a signal, resend it to ourselves 165 * now that we have restored the signal handlers. 166 */ 167 for (i = 0; i < NSIG; i++) { 168 if (signo[i]) { 169 kill(getpid(), i); 170 switch (i) { 171 case SIGTSTP: 172 case SIGTTIN: 173 case SIGTTOU: 174 need_restart = 1; 175 } 176 } 177 } 178 if (need_restart) 179 goto restart; 180 181 if (save_errno) 182 errno = save_errno; 183 return(nr == -1 ? NULL : buf); 184} 185 186char * 187getpass(const char *prompt) 188{ 189 static char buf[_PASSWORD_LEN + 1]; 190 191 if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL) 192 buf[0] = '\0'; 193 return(buf); 194} 195 196static void handler(int s) 197{ 198 199 signo[s] = 1; 200} 201