[PATCH v3 15/22] vfs: define kernel_copy_file_from_fd()

[Kees Cook]

On Wed, Feb 3, 2016 at 11:06 AM, Mimi Zohar <zohar at linux.vnet.ibm.com> wrote:
> This patch defines kernel_read_file_from_fd(), a wrapper for the VFS
> common kernel_read_file().
>
> Changelog:
> - Separated from the kernel modules patch
>
> Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>

Acked-by: Kees Cook <keescook at chromium.org>

-Kees

> ---
>  fs/exec.c          | 16 ++++++++++++++++
>  include/linux/fs.h |  2 ++
>  2 files changed, 18 insertions(+)
>
> diff --git a/fs/exec.c b/fs/exec.c
> index 1d39c4e..f3a0ce2 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -910,6 +910,22 @@ int kernel_read_file_from_path(char *path, void **buf, loff_t *size,
>  }
>  EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
>
> +int kernel_read_file_from_fd(int fd, void **buf, loff_t *size, loff_t max_size,
> +                            enum kernel_read_file_id id)
> +{
> +       struct fd f = fdget(fd);
> +       int ret = -EBADF;
> +
> +       if (!f.file)
> +               goto out;
> +
> +       ret = kernel_read_file(f.file, buf, size, max_size, id);
> +out:
> +       fdput(f);
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(kernel_read_file_from_fd);
> +
>  ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
>  {
>         ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 2a9670a..5ba806b 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2536,6 +2536,8 @@ extern int kernel_read_file(struct file *, void **, loff_t *, loff_t,
>                             enum kernel_read_file_id);
>  extern int kernel_read_file_from_path(char *, void **, loff_t *, loff_t,
>                                       enum kernel_read_file_id);
> +extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t,
> +                                   enum kernel_read_file_id);
>  extern ssize_t kernel_write(struct file *, const char *, size_t, loff_t);
>  extern ssize_t __kernel_write(struct file *, const char *, size_t, loff_t *);
>  extern struct file * open_exec(const char *);
> --
> 2.1.0
>



-- 
Kees Cook
Chrome OS & Brillo Security