mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-23 13:30:06 +00:00
108 lines
3.0 KiB
C
108 lines
3.0 KiB
C
/* Copyright (C) 2000 Free Software Foundation, Inc.
|
||
This file is part of the GNU C Library.
|
||
|
||
The GNU C Library is free software; you can redistribute it and/or
|
||
modify it under the terms of the GNU Lesser General Public
|
||
License as published by the Free Software Foundation; either
|
||
version 2.1 of the License, or (at your option) any later version.
|
||
|
||
The GNU C Library is distributed in the hope that it will be useful,
|
||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
Lesser General Public License for more details.
|
||
|
||
You should have received a copy of the GNU Lesser General Public
|
||
License along with the GNU C Library; if not, see
|
||
<http://www.gnu.org/licenses/>. */
|
||
|
||
#include <fcntl.h>
|
||
#include <paths.h>
|
||
#include <unistd.h>
|
||
|
||
#include <hurd.h>
|
||
#include <hurd/fd.h>
|
||
|
||
#include <set-hooks.h>
|
||
|
||
/* Try to get a machine dependent instruction which will make the
|
||
program crash. This is used in case everything else fails. */
|
||
#include <abort-instr.h>
|
||
#ifndef ABORT_INSTRUCTION
|
||
/* No such instruction is available. */
|
||
# define ABORT_INSTRUCTION
|
||
#endif
|
||
|
||
static void
|
||
check_one_fd (int fd, int mode)
|
||
{
|
||
struct hurd_fd *d;
|
||
|
||
d = _hurd_fd_get (fd);
|
||
if (d == NULL)
|
||
{
|
||
/* This descriptor hasn't been opened. We try to allocate the
|
||
descriptor and open /dev/null on it so that the SUID program
|
||
we are about to start does not accidently use this
|
||
descriptor. */
|
||
d = _hurd_alloc_fd (NULL, fd);
|
||
if (d != NULL)
|
||
{
|
||
mach_port_t port;
|
||
|
||
port = __file_name_lookup (_PATH_DEVNULL, mode, 0);
|
||
if (port)
|
||
{
|
||
/* Since /dev/null isn't supposed to be a terminal, we
|
||
avoid any ctty magic. */
|
||
d->port.port = port;
|
||
d->flags = 0;
|
||
|
||
__spin_unlock (&d->port.lock);
|
||
return;
|
||
}
|
||
}
|
||
|
||
/* We cannot even give an error message here since it would run
|
||
into the same problems. */
|
||
while (1)
|
||
/* Try for ever and ever. */
|
||
ABORT_INSTRUCTION;
|
||
}
|
||
}
|
||
|
||
static void
|
||
check_standard_fds (void)
|
||
{
|
||
/* Check all three standard file descriptors. */
|
||
check_one_fd (STDIN_FILENO, O_RDONLY);
|
||
check_one_fd (STDOUT_FILENO, O_RDWR);
|
||
check_one_fd (STDERR_FILENO, O_RDWR);
|
||
}
|
||
|
||
static void
|
||
init_standard_fds (void)
|
||
{
|
||
/* Now that we have FDs, make sure that, if this is a SUID program,
|
||
FDs 0, 1 and 2 are allocated. If necessary we'll set them up
|
||
ourselves. If that's not possible we stop the program. */
|
||
if (__builtin_expect (__libc_enable_secure, 0))
|
||
check_standard_fds ();
|
||
|
||
(void) &init_standard_fds; /* Avoid "defined but not used" warning. */
|
||
}
|
||
text_set_element (_hurd_fd_subinit, init_standard_fds);
|
||
|
||
|
||
#ifndef SHARED
|
||
void
|
||
__libc_check_standard_fds (void)
|
||
{
|
||
/* We don't check the standard file descriptors here. They will be
|
||
checked when we initialize the file descriptor table, as part of
|
||
the _hurd_fd_subinit hook.
|
||
|
||
This function is only present to make sure that this module gets
|
||
linked in when part of the static libc. */
|
||
}
|
||
#endif
|