Re: [PATCH v13 03/13] file: Export receive_fd() to modules

Michael S. Tsirkin
2021-09-05T15:57:40Z

On Tue, Aug 31, 2021 at 06:36:24PM +0800, Xie Yongji wrote:
> Export receive_fd() so that some modules can use
> it to pass file descriptor between processes without
> missing any security stuffs.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> Acked-by: Jason Wang <jasowang@redhat.com>

This needs some acks from fs devels.
Viro?

> ---
> fs/file.c | 6 ++++++
> include/linux/file.h | 7 +++----
> 2 files changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/fs/file.c b/fs/file.c
> index 86dc9956af32..210e540672aa 100644
> --- a/fs/file.c
> +++ b/fs/file.c
> @@ -1134,6 +1134,12 @@ int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags)
> return new_fd;
> }
>
> +int receive_fd(struct file *file, unsigned int o_flags)
> +{
> + return __receive_fd(file, NULL, o_flags);
> +}
> +EXPORT_SYMBOL_GPL(receive_fd);
> +
> static int ksys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
> {
> int err = -EBADF;
> diff --git a/include/linux/file.h b/include/linux/file.h
> index 2de2e4613d7b..51e830b4fe3a 100644
> --- a/include/linux/file.h
> +++ b/include/linux/file.h
> @@ -94,6 +94,9 @@ extern void fd_install(unsigned int fd, struct file *file);
>
> extern int __receive_fd(struct file *file, int __user *ufd,
> unsigned int o_flags);
> +
> +extern int receive_fd(struct file *file, unsigned int o_flags);
> +
> static inline int receive_fd_user(struct file *file, int __user *ufd,
> unsigned int o_flags)
> {
> @@ -101,10 +104,6 @@ static inline int receive_fd_user(struct file *file, int __user *ufd,
> return -EFAULT;
> return __receive_fd(file, ufd, o_flags);
> }
> -static inline int receive_fd(struct file *file, unsigned int o_flags)
> -{
> - return __receive_fd(file, NULL, o_flags);
> -}
> int receive_fd_replace(int new_fd, struct file *file, unsigned int o_flags);
>
> extern void flush_delayed_fput(void);
> --
> 2.11.0