readpassphrase.c revision 287292
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 <sys/cdefs.h> 25__FBSDID("$FreeBSD: head/lib/libc/gen/readpassphrase.c 287292 2015-08-29 14:25:01Z kib $"); 26 27#include "namespace.h" 28#include <ctype.h> 29#include <errno.h> 30#include <fcntl.h> 31#include <paths.h> 32#include <pwd.h> 33#include <signal.h> 34#include <string.h> 35#include <termios.h> 36#include <unistd.h> 37#include <readpassphrase.h> 38#include "un-namespace.h" 39#include "libc_private.h" 40 41static volatile sig_atomic_t signo[NSIG]; 42 43static void handler(int); 44 45char * 46readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags) 47{ 48 ssize_t nr; 49 int input, output, save_errno, i, need_restart; 50 char ch, *p, *end; 51 struct termios term, oterm; 52 struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm; 53 struct sigaction savetstp, savettin, savettou, savepipe; 54 55 /* I suppose we could alloc on demand in this case (XXX). */ 56 if (bufsiz == 0) { 57 errno = EINVAL; 58 return(NULL); 59 } 60 61restart: 62 for (i = 0; i < NSIG; i++) 63 signo[i] = 0; 64 nr = -1; 65 save_errno = 0; 66 need_restart = 0; 67 /* 68 * Read and write to /dev/tty if available. If not, read from 69 * stdin and write to stderr unless a tty is required. 70 */ 71 if ((flags & RPP_STDIN) || 72 (input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC)) == -1) { 73 if (flags & RPP_REQUIRE_TTY) { 74 errno = ENOTTY; 75 return(NULL); 76 } 77 input = STDIN_FILENO; 78 output = STDERR_FILENO; 79 } 80 81 /* 82 * Turn off echo if possible. 83 * If we are using a tty but are not the foreground pgrp this will 84 * generate SIGTTOU, so do it *before* installing the signal handlers. 85 */ 86 if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) { 87 memcpy(&term, &oterm, sizeof(term)); 88 if (!(flags & RPP_ECHO_ON)) 89 term.c_lflag &= ~(ECHO | ECHONL); 90 if (term.c_cc[VSTATUS] != _POSIX_VDISABLE) 91 term.c_cc[VSTATUS] = _POSIX_VDISABLE; 92 (void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term); 93 } else { 94 memset(&term, 0, sizeof(term)); 95 term.c_lflag |= ECHO; 96 memset(&oterm, 0, sizeof(oterm)); 97 oterm.c_lflag |= ECHO; 98 } 99 100 /* 101 * Catch signals that would otherwise cause the user to end 102 * up with echo turned off in the shell. Don't worry about 103 * things like SIGXCPU and SIGVTALRM for now. 104 */ 105 sigemptyset(&sa.sa_mask); 106 sa.sa_flags = 0; /* don't restart system calls */ 107 sa.sa_handler = handler; 108 (void)__libc_sigaction(SIGALRM, &sa, &savealrm); 109 (void)__libc_sigaction(SIGHUP, &sa, &savehup); 110 (void)__libc_sigaction(SIGINT, &sa, &saveint); 111 (void)__libc_sigaction(SIGPIPE, &sa, &savepipe); 112 (void)__libc_sigaction(SIGQUIT, &sa, &savequit); 113 (void)__libc_sigaction(SIGTERM, &sa, &saveterm); 114 (void)__libc_sigaction(SIGTSTP, &sa, &savetstp); 115 (void)__libc_sigaction(SIGTTIN, &sa, &savettin); 116 (void)__libc_sigaction(SIGTTOU, &sa, &savettou); 117 118 if (!(flags & RPP_STDIN)) 119 (void)_write(output, prompt, strlen(prompt)); 120 end = buf + bufsiz - 1; 121 p = buf; 122 while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') { 123 if (p < end) { 124 if ((flags & RPP_SEVENBIT)) 125 ch &= 0x7f; 126 if (isalpha((unsigned char)ch)) { 127 if ((flags & RPP_FORCELOWER)) 128 ch = (char)tolower((unsigned char)ch); 129 if ((flags & RPP_FORCEUPPER)) 130 ch = (char)toupper((unsigned char)ch); 131 } 132 *p++ = ch; 133 } 134 } 135 *p = '\0'; 136 save_errno = errno; 137 if (!(term.c_lflag & ECHO)) 138 (void)_write(output, "\n", 1); 139 140 /* Restore old terminal settings and signals. */ 141 if (memcmp(&term, &oterm, sizeof(term)) != 0) { 142 while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 && 143 errno == EINTR && !signo[SIGTTOU]) 144 continue; 145 } 146 (void)__libc_sigaction(SIGALRM, &savealrm, NULL); 147 (void)__libc_sigaction(SIGHUP, &savehup, NULL); 148 (void)__libc_sigaction(SIGINT, &saveint, NULL); 149 (void)__libc_sigaction(SIGQUIT, &savequit, NULL); 150 (void)__libc_sigaction(SIGPIPE, &savepipe, NULL); 151 (void)__libc_sigaction(SIGTERM, &saveterm, NULL); 152 (void)__libc_sigaction(SIGTSTP, &savetstp, NULL); 153 (void)__libc_sigaction(SIGTTIN, &savettin, NULL); 154 (void)__libc_sigaction(SIGTTOU, &savettou, NULL); 155 if (input != STDIN_FILENO) 156 (void)_close(input); 157 158 /* 159 * If we were interrupted by a signal, resend it to ourselves 160 * now that we have restored the signal handlers. 161 */ 162 for (i = 0; i < NSIG; i++) { 163 if (signo[i]) { 164 kill(getpid(), i); 165 switch (i) { 166 case SIGTSTP: 167 case SIGTTIN: 168 case SIGTTOU: 169 need_restart = 1; 170 } 171 } 172 } 173 if (need_restart) 174 goto restart; 175 176 if (save_errno) 177 errno = save_errno; 178 return(nr == -1 ? NULL : buf); 179} 180 181char * 182getpass(const char *prompt) 183{ 184 static char buf[_PASSWORD_LEN + 1]; 185 186 if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL) 187 buf[0] = '\0'; 188 return(buf); 189} 190 191static void handler(int s) 192{ 193 194 signo[s] = 1; 195} 196