| /* Copyright (C) 2000-2014 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 accidentally 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 |