ladybird/Userland/Libraries/LibC/fcntl.cpp
Andreas Kling e87eac9273 Userland: Add LibSystem and funnel all syscalls through it
This achieves two things:

- Programs can now intentionally perform arbitrary syscalls by calling
  syscall(). This allows us to work on things like syscall fuzzing.

- It restricts the ability of userspace to make syscalls to a single
  4KB page of code. In order to call the kernel directly, an attacker
  must now locate this page and call through it.
2021-02-05 12:23:39 +01:00

96 lines
2.9 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <errno.h>
#include <fcntl.h>
#include <stdarg.h>
#include <string.h>
#include <syscall.h>
extern "C" {
int fcntl(int fd, int cmd, ...)
{
va_list ap;
va_start(ap, cmd);
u32 extra_arg = va_arg(ap, u32);
int rc = syscall(SC_fcntl, fd, cmd, extra_arg);
va_end(ap);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int watch_file(const char* path, size_t path_length)
{
int rc = syscall(SC_watch_file, path, path_length);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int creat(const char* path, mode_t mode)
{
return open(path, O_CREAT | O_WRONLY | O_TRUNC, mode);
}
int open(const char* path, int options, ...)
{
if (!path) {
errno = EFAULT;
return -1;
}
auto path_length = strlen(path);
if (path_length > INT32_MAX) {
errno = EINVAL;
return -1;
}
va_list ap;
va_start(ap, options);
auto mode = (mode_t)va_arg(ap, unsigned);
va_end(ap);
Syscall::SC_open_params params { AT_FDCWD, { path, path_length }, options, mode };
int rc = syscall(SC_open, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
int openat(int dirfd, const char* path, int options, ...)
{
if (!path) {
errno = EFAULT;
return -1;
}
auto path_length = strlen(path);
if (path_length > INT32_MAX) {
errno = EINVAL;
return -1;
}
va_list ap;
va_start(ap, options);
auto mode = (mode_t)va_arg(ap, unsigned);
va_end(ap);
Syscall::SC_open_params params { dirfd, { path, path_length }, options, mode };
int rc = syscall(SC_open, &params);
__RETURN_WITH_ERRNO(rc, rc, -1);
}
}