Re: [PATCH 5/6] fs: define a string representation of the kernel_read_file_id enumeration

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Wed, 2016-04-20 at 15:46 -0700, Kees Cook wrote:
> From: Mimi Zohar <zohar@linux.vnet.ibm.com>
> 
> A string representation of the kernel_read_file_id enumeration is
> needed for displaying messages (eg. pr_info, auditing) that can be
> used by multiple LSMs and the integrity subsystem.  To simplify
> keeping the list of strings up to date with the enumeration, this
> patch defines two new preprocessing macros named __fid_enumify and
> __fid_stringify to create the enumeration and an array of strings.
> kernel_read_file_id_str() returns a string based on the enumeration.
> 
> Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
> [kees: removed removal of my old version, constified pointer values]
> Signed-off-by: Kees Cook <keescook@chromium.org>


I got this

In file included from /home/andy/prj/linux-
topic/include/linux/seq_file.h:10:0,
                 from /home/andy/prj/linux-
topic/include/linux/pinctrl/consumer.h:17,
                 from /home/andy/prj/linux-
topic/include/linux/pinctrl/devinfo.h:21,
                 from /home/andy/prj/linux-
topic/include/linux/device.h:24,
                 from /home/andy/prj/linux-
topic/include/linux/dmaengine.h:20,
                 from /home/andy/prj/linux-
topic/drivers/dma/dw/core.c:15:
/home/andy/prj/linux-topic/include/linux/fs.h:2627:74: warning: type
qualifiers ignored on function return type [-Wignored-qualifiers]
 static inline const char * const kernel_read_file_id_str(enum
kernel_read_file_id id)

> ---
>  include/linux/fs.h | 31 +++++++++++++++++++++++++------
>  1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 70e61b58baaf..518716b4834e 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2590,15 +2590,34 @@ static inline void i_readcount_inc(struct
> inode *inode)
>  #endif
>  extern int do_pipe_flags(int *, int);
>  
> +#define __kernel_read_file_id(id) \
> +	id(UNKNOWN, unknown)		\
> +	id(FIRMWARE, firmware)		\
> +	id(MODULE, kernel-module)		\
> +	id(KEXEC_IMAGE, kexec-image)		\
> +	id(KEXEC_INITRAMFS, kexec-initramfs)	\
> +	id(POLICY, security-policy)		\
> +	id(MAX_ID, )
> +
> +#define __fid_enumify(ENUM, dummy) READING_ ## ENUM,
> +#define __fid_stringify(dummy, str) #str,
> +
>  enum kernel_read_file_id {
> -	READING_FIRMWARE = 1,
> -	READING_MODULE,
> -	READING_KEXEC_IMAGE,
> -	READING_KEXEC_INITRAMFS,
> -	READING_POLICY,
> -	READING_MAX_ID
> +	__kernel_read_file_id(__fid_enumify)
> +};
> +
> +static const char * const kernel_read_file_str[] = {
> +	__kernel_read_file_id(__fid_stringify)
>  };
>  
> +static inline const char * const kernel_read_file_id_str(enum
> kernel_read_file_id id)
> +{
> +	if (id < 0 || id >= READING_MAX_ID)
> +		return kernel_read_file_str[READING_UNKNOWN];
> +
> +	return kernel_read_file_str[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);

-- 
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy