[PATCH v3 12/22] vfs: define kernel_read_file_from_path

[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_path(), a wrapper for the VFS
> common kernel_read_file().
>
> Changelog:
> - Separated from the IMA patch
>
> Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>

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

-Kees

> ---
>  fs/exec.c          | 22 ++++++++++++++++++++++
>  include/linux/fs.h |  2 ++
>  2 files changed, 24 insertions(+)
>
> diff --git a/fs/exec.c b/fs/exec.c
> index cd2b5b2..5629958 100644
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -884,6 +884,28 @@ out:
>  }
>  EXPORT_SYMBOL_GPL(kernel_read_file);
>
> +int kernel_read_file_from_path(char *path, void **buf, loff_t *size,
> +                              loff_t max_size, enum kernel_read_file_id id)
> +{
> +       struct file *file;
> +       int ret;
> +
> +       if (!path || !*path)
> +               return -EINVAL;
> +
> +       file = filp_open(path, O_RDONLY, 0);
> +       if (IS_ERR(file)) {
> +               ret = PTR_ERR(file);
> +               pr_err("Unable to open file: %s (%d)", path, ret);
> +               return ret;
> +       }
> +
> +       ret = kernel_read_file(file, buf, size, max_size, id);
> +       fput(file);
> +       return ret;
> +}
> +EXPORT_SYMBOL_GPL(kernel_read_file_from_path);
> +
>  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 1458ca5..962c491 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2533,6 +2533,8 @@ enum kernel_read_file_id {
>  extern int kernel_read(struct file *, loff_t, char *, unsigned long);
>  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 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