freebsd-dev/lib/libc/gen/readpassphrase.c
Jilles Tjoelker 05eb11cbc4 libc: Use O_CLOEXEC for various internal file descriptors.
This fixes a race condition where another thread may fork() before CLOEXEC
is set, unintentionally passing the descriptor to the child process.

This commit only adds O_CLOEXEC flags to open() or openat() calls where no
fcntl(fd, F_SETFD, FD_CLOEXEC) follows. The separate fcntl() call still
leaves a race window so it should be fixed later.
2012-09-29 11:54:34 +00:00

195 lines
5.3 KiB
C

/* $OpenBSD: readpassphrase.c,v 1.23 2010/05/14 13:30:34 millert Exp $ */
/*
* Copyright (c) 2000-2002, 2007, 2010
* Todd C. Miller <Todd.Miller@courtesan.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "namespace.h"
#include <ctype.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <pwd.h>
#include <signal.h>
#include <string.h>
#include <termios.h>
#include <unistd.h>
#include <readpassphrase.h>
#include "un-namespace.h"
static volatile sig_atomic_t signo[NSIG];
static void handler(int);
char *
readpassphrase(const char *prompt, char *buf, size_t bufsiz, int flags)
{
ssize_t nr;
int input, output, save_errno, i, need_restart;
char ch, *p, *end;
struct termios term, oterm;
struct sigaction sa, savealrm, saveint, savehup, savequit, saveterm;
struct sigaction savetstp, savettin, savettou, savepipe;
/* I suppose we could alloc on demand in this case (XXX). */
if (bufsiz == 0) {
errno = EINVAL;
return(NULL);
}
restart:
for (i = 0; i < NSIG; i++)
signo[i] = 0;
nr = -1;
save_errno = 0;
need_restart = 0;
/*
* Read and write to /dev/tty if available. If not, read from
* stdin and write to stderr unless a tty is required.
*/
if ((flags & RPP_STDIN) ||
(input = output = _open(_PATH_TTY, O_RDWR | O_CLOEXEC)) == -1) {
if (flags & RPP_REQUIRE_TTY) {
errno = ENOTTY;
return(NULL);
}
input = STDIN_FILENO;
output = STDERR_FILENO;
}
/*
* Turn off echo if possible.
* If we are using a tty but are not the foreground pgrp this will
* generate SIGTTOU, so do it *before* installing the signal handlers.
*/
if (input != STDIN_FILENO && tcgetattr(input, &oterm) == 0) {
memcpy(&term, &oterm, sizeof(term));
if (!(flags & RPP_ECHO_ON))
term.c_lflag &= ~(ECHO | ECHONL);
if (term.c_cc[VSTATUS] != _POSIX_VDISABLE)
term.c_cc[VSTATUS] = _POSIX_VDISABLE;
(void)tcsetattr(input, TCSAFLUSH|TCSASOFT, &term);
} else {
memset(&term, 0, sizeof(term));
term.c_lflag |= ECHO;
memset(&oterm, 0, sizeof(oterm));
oterm.c_lflag |= ECHO;
}
/*
* Catch signals that would otherwise cause the user to end
* up with echo turned off in the shell. Don't worry about
* things like SIGXCPU and SIGVTALRM for now.
*/
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0; /* don't restart system calls */
sa.sa_handler = handler;
(void)_sigaction(SIGALRM, &sa, &savealrm);
(void)_sigaction(SIGHUP, &sa, &savehup);
(void)_sigaction(SIGINT, &sa, &saveint);
(void)_sigaction(SIGPIPE, &sa, &savepipe);
(void)_sigaction(SIGQUIT, &sa, &savequit);
(void)_sigaction(SIGTERM, &sa, &saveterm);
(void)_sigaction(SIGTSTP, &sa, &savetstp);
(void)_sigaction(SIGTTIN, &sa, &savettin);
(void)_sigaction(SIGTTOU, &sa, &savettou);
if (!(flags & RPP_STDIN))
(void)_write(output, prompt, strlen(prompt));
end = buf + bufsiz - 1;
p = buf;
while ((nr = _read(input, &ch, 1)) == 1 && ch != '\n' && ch != '\r') {
if (p < end) {
if ((flags & RPP_SEVENBIT))
ch &= 0x7f;
if (isalpha(ch)) {
if ((flags & RPP_FORCELOWER))
ch = (char)tolower(ch);
if ((flags & RPP_FORCEUPPER))
ch = (char)toupper(ch);
}
*p++ = ch;
}
}
*p = '\0';
save_errno = errno;
if (!(term.c_lflag & ECHO))
(void)_write(output, "\n", 1);
/* Restore old terminal settings and signals. */
if (memcmp(&term, &oterm, sizeof(term)) != 0) {
while (tcsetattr(input, TCSAFLUSH|TCSASOFT, &oterm) == -1 &&
errno == EINTR && !signo[SIGTTOU])
continue;
}
(void)_sigaction(SIGALRM, &savealrm, NULL);
(void)_sigaction(SIGHUP, &savehup, NULL);
(void)_sigaction(SIGINT, &saveint, NULL);
(void)_sigaction(SIGQUIT, &savequit, NULL);
(void)_sigaction(SIGPIPE, &savepipe, NULL);
(void)_sigaction(SIGTERM, &saveterm, NULL);
(void)_sigaction(SIGTSTP, &savetstp, NULL);
(void)_sigaction(SIGTTIN, &savettin, NULL);
(void)_sigaction(SIGTTOU, &savettou, NULL);
if (input != STDIN_FILENO)
(void)_close(input);
/*
* If we were interrupted by a signal, resend it to ourselves
* now that we have restored the signal handlers.
*/
for (i = 0; i < NSIG; i++) {
if (signo[i]) {
kill(getpid(), i);
switch (i) {
case SIGTSTP:
case SIGTTIN:
case SIGTTOU:
need_restart = 1;
}
}
}
if (need_restart)
goto restart;
if (save_errno)
errno = save_errno;
return(nr == -1 ? NULL : buf);
}
char *
getpass(const char *prompt)
{
static char buf[_PASSWORD_LEN + 1];
if (readpassphrase(prompt, buf, sizeof(buf), RPP_ECHO_OFF) == NULL)
buf[0] = '\0';
return(buf);
}
static void handler(int s)
{
signo[s] = 1;
}