pass

simple password manager
git clone git://git.2f30.org/pass.git
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readpassphrase.c (5310B)


      1 /*	$OpenBSD: readpassphrase.c,v 1.25 2015/09/14 10:45:27 guenther 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 <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 
     34 #include "readpassphrase.h"
     35 
     36 #ifdef TCSASOFT
     37 #define _T_FLUSH	(TCSAFLUSH|TCSASOFT)
     38 #else
     39 #define _T_FLUSH	(TCSAFLUSH)
     40 #endif
     41 
     42 static volatile sig_atomic_t signo[_NSIG];
     43 
     44 static void handler(int);
     45 
     46 char *
     47 readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
     48 {
     49 	ssize_t nr;
     50 	int input, output, save_errno, i, need_restart;
     51 	char ch, *p, *end;
     52 	struct termios term, oterm;
     53 	struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
     54 	struct sigaction savetstp, savettin, savettou, savepipe;
     55 
     56 	/* I suppose we could alloc on demand in this case (XXX). */
     57 	if (bufsiz == 0) {
     58 		errno = EINVAL;
     59 		return(NULL);
     60 	}
     61 
     62 restart:
     63 	for (i = 0; i < _NSIG; i++)
     64 		signo[i] = 0;
     65 	nr = -1;
     66 	save_errno = 0;
     67 	need_restart = 0;
     68 	/*
     69 	 * Read and write to /dev/tty if available.  If not, read from
     70 	 * stdin and write to stderr unless a tty is required.
     71 	 */
     72 	if ((flags & RPP_STDIN) ||
     73 	    (input = output = open(_PATH_TTY, O_RDWR)) == -1) {
     74 		if (flags & RPP_REQUIRE_TTY) {
     75 			errno = ENOTTY;
     76 			return(NULL);
     77 		}
     78 		input = STDIN_FILENO;
     79 		output = STDERR_FILENO;
     80 	}
     81 
     82 	/*
     83 	 * Turn off echo if possible.
     84 	 * If we are using a tty but are not the foreground pgrp this will
     85 	 * generate SIGTTOU, so do it *before* installing the signal handlers.
     86 	 */
     87 	if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
     88 		memcpy(&term, &oterm, sizeof(term));
     89 		if (!(flags & RPP_ECHO_ON))
     90 			term.c_lflag &= ~(ECHO | ECHONL);
     91 #ifdef VSTATUS
     92 		if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
     93 			term.c_cc[VSTATUS] = _POSIX_VDISABLE;
     94 #endif
     95 		(void)tcsetattr(input, _T_FLUSH, &term);
     96 	} else {
     97 		memset(&term, 0, sizeof(term));
     98 		term.c_lflag |= ECHO;
     99 		memset(&oterm, 0, sizeof(oterm));
    100 		oterm.c_lflag |= ECHO;
    101 	}
    102 
    103 	/*
    104 	 * Catch signals that would otherwise cause the user to end
    105 	 * up with echo turned off in the shell.  Don't worry about
    106 	 * things like SIGXCPU and SIGVTALRM for now.
    107 	 */
    108 	sigemptyset(&sa.sa_mask);
    109 	sa.sa_flags = 0;		/* don't restart system calls */
    110 	sa.sa_handler = handler;
    111 	(void)sigaction(SIGALRM, &sa, &savealrm);
    112 	(void)sigaction(SIGHUP, &sa, &savehup);
    113 	(void)sigaction(SIGINT, &sa, &saveint);
    114 	(void)sigaction(SIGPIPE, &sa, &savepipe);
    115 	(void)sigaction(SIGQUIT, &sa, &savequit);
    116 	(void)sigaction(SIGTERM, &sa, &saveterm);
    117 	(void)sigaction(SIGTSTP, &sa, &savetstp);
    118 	(void)sigaction(SIGTTIN, &sa, &savettin);
    119 	(void)sigaction(SIGTTOU, &sa, &savettou);
    120 
    121 	if (!(flags & RPP_STDIN))
    122 		(void)write(output, prompt, strlen(prompt));
    123 	end = buf + bufsiz - 1;
    124 	p = buf;
    125 	while ((nr = read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
    126 		if (p < end) {
    127 			if ((flags & RPP_SEVENBIT))
    128 				ch &= 0x7f;
    129 			if (isalpha((unsigned char)ch)) {
    130 				if ((flags & RPP_FORCELOWER))
    131 					ch = (char)tolower((unsigned char)ch);
    132 				if ((flags & RPP_FORCEUPPER))
    133 					ch = (char)toupper((unsigned char)ch);
    134 			}
    135 			*p++ = ch;
    136 		}
    137 	}
    138 	*p = '\0';
    139 	save_errno = errno;
    140 	if (!(term.c_lflag & ECHO))
    141 		(void)write(output, "\n", 1);
    142 
    143 	/* Restore old terminal settings and signals. */
    144 	if (memcmp(&term, &oterm, sizeof(term)) != 0) {
    145 		while (tcsetattr(input, _T_FLUSH, &oterm) == -1 &&
    146 		    errno == EINTR && !signo[SIGTTOU])
    147 			continue;
    148 	}
    149 	(void)sigaction(SIGALRM, &savealrm, NULL);
    150 	(void)sigaction(SIGHUP, &savehup, NULL);
    151 	(void)sigaction(SIGINT, &saveint, NULL);
    152 	(void)sigaction(SIGQUIT, &savequit, NULL);
    153 	(void)sigaction(SIGPIPE, &savepipe, NULL);
    154 	(void)sigaction(SIGTERM, &saveterm, NULL);
    155 	(void)sigaction(SIGTSTP, &savetstp, NULL);
    156 	(void)sigaction(SIGTTIN, &savettin, NULL);
    157 	(void)sigaction(SIGTTOU, &savettou, NULL);
    158 	if (input != STDIN_FILENO)
    159 		(void)close(input);
    160 
    161 	/*
    162 	 * If we were interrupted by a signal, resend it to ourselves
    163 	 * now that we have restored the signal handlers.
    164 	 */
    165 	for (i = 0; i < _NSIG; i++) {
    166 		if (signo[i]) {
    167 			kill(getpid(), i);
    168 			switch (i) {
    169 			case SIGTSTP:
    170 			case SIGTTIN:
    171 			case SIGTTOU:
    172 				need_restart = 1;
    173 			}
    174 		}
    175 	}
    176 	if (need_restart)
    177 		goto restart;
    178 
    179 	if (save_errno)
    180 		errno = save_errno;
    181 	return(nr == -1 ? NULL : buf);
    182 }
    183 
    184 static void handler(int s)
    185 {
    186 	signo[s] = 1;
    187 }