linux-stable/include/linux/file.h
Kees Cook 173817151b fs: Expand __receive_fd() to accept existing fd
Expand __receive_fd() with support for replace_fd() for the coming seccomp
"addfd" ioctl(). Add new wrapper receive_fd_replace() for the new behavior
and update existing wrappers to retain old behavior.

Thanks to Colin Ian King <colin.king@canonical.com> for pointing out an
uninitialized variable exposure in an earlier version of this patch.

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dmitry Kadashev <dkadashev@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-fsdevel@vger.kernel.org
Reviewed-by: Sargun Dhillon <sargun@sargun.me>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-13 11:03:45 -07:00

118 lines
3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Wrapper functions for accessing the file_struct fd array.
*/
#ifndef __LINUX_FILE_H
#define __LINUX_FILE_H
#include <linux/compiler.h>
#include <linux/types.h>
#include <linux/posix_types.h>
#include <linux/errno.h>
struct file;
extern void fput(struct file *);
extern void fput_many(struct file *, unsigned int);
struct file_operations;
struct task_struct;
struct vfsmount;
struct dentry;
struct inode;
struct path;
extern struct file *alloc_file_pseudo(struct inode *, struct vfsmount *,
const char *, int flags, const struct file_operations *);
extern struct file *alloc_file_clone(struct file *, int flags,
const struct file_operations *);
static inline void fput_light(struct file *file, int fput_needed)
{
if (fput_needed)
fput(file);
}
struct fd {
struct file *file;
unsigned int flags;
};
#define FDPUT_FPUT 1
#define FDPUT_POS_UNLOCK 2
static inline void fdput(struct fd fd)
{
if (fd.flags & FDPUT_FPUT)
fput(fd.file);
}
extern struct file *fget(unsigned int fd);
extern struct file *fget_many(unsigned int fd, unsigned int refs);
extern struct file *fget_raw(unsigned int fd);
extern struct file *fget_task(struct task_struct *task, unsigned int fd);
extern unsigned long __fdget(unsigned int fd);
extern unsigned long __fdget_raw(unsigned int fd);
extern unsigned long __fdget_pos(unsigned int fd);
extern void __f_unlock_pos(struct file *);
static inline struct fd __to_fd(unsigned long v)
{
return (struct fd){(struct file *)(v & ~3),v & 3};
}
static inline struct fd fdget(unsigned int fd)
{
return __to_fd(__fdget(fd));
}
static inline struct fd fdget_raw(unsigned int fd)
{
return __to_fd(__fdget_raw(fd));
}
static inline struct fd fdget_pos(int fd)
{
return __to_fd(__fdget_pos(fd));
}
static inline void fdput_pos(struct fd f)
{
if (f.flags & FDPUT_POS_UNLOCK)
__f_unlock_pos(f.file);
fdput(f);
}
extern int f_dupfd(unsigned int from, struct file *file, unsigned flags);
extern int replace_fd(unsigned fd, struct file *file, unsigned flags);
extern void set_close_on_exec(unsigned int fd, int flag);
extern bool get_close_on_exec(unsigned int fd);
extern int __get_unused_fd_flags(unsigned flags, unsigned long nofile);
extern int get_unused_fd_flags(unsigned flags);
extern void put_unused_fd(unsigned int fd);
extern void fd_install(unsigned int fd, struct file *file);
extern int __receive_fd(int fd, struct file *file, int __user *ufd,
unsigned int o_flags);
static inline int receive_fd_user(struct file *file, int __user *ufd,
unsigned int o_flags)
{
if (ufd == NULL)
return -EFAULT;
return __receive_fd(-1, file, ufd, o_flags);
}
static inline int receive_fd(struct file *file, unsigned int o_flags)
{
return __receive_fd(-1, file, NULL, o_flags);
}
static inline int receive_fd_replace(int fd, struct file *file, unsigned int o_flags)
{
return __receive_fd(fd, file, NULL, o_flags);
}
extern void flush_delayed_fput(void);
extern void __fput_sync(struct file *);
extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
#endif /* __LINUX_FILE_H */