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

[Andy Shevchenko]

On Thu, 2016-04-21 at 09:47 -0700, Kees Cook wrote:
> On Thu, Apr 21, 2016 at 6:26 AM, Andy Shevchenko
>  wrote:
> > 
> > On Wed, 2016-04-20 at 15:46 -0700, Kees Cook wrote:
> > > 
> > > From: Mimi Zohar 
> > > 
> > > 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.


> > 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)
> What gcc version are you using? Seems like I need to drop the added
> "const" on the return?


$ gcc --version
gcc (Debian 5.3.1-14) 5.3.1 20160409


Build was done with 
$ make W=1


-- 
Andy Shevchenko 
Intel Finland Oy

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

[Kees Cook]

On Thu, Apr 21, 2016 at 6:26 AM, Andy Shevchenko
 wrote:
> On Wed, 2016-04-20 at 15:46 -0700, Kees Cook wrote:
>> From: Mimi Zohar 
>>
>> 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 
>> [kees: removed removal of my old version, constified pointer values]
>> Signed-off-by: Kees Cook 
>
>
> 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)

What gcc version are you using? Seems like I need to drop the added
"const" on the return?

-Kees

>
>> ---
>>  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 
> Intel Finland Oy
>



-- 
Kees Cook
Chrome OS & Brillo Security
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Re: [PATCH 5/6] fs: define a string representation of the kernel_read_file_id enumeration

[Andy Shevchenko]

On Wed, 2016-04-20 at 15:46 -0700, Kees Cook wrote:
> From: Mimi Zohar 
> 
> 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 
> [kees: removed removal of my old version, constified pointer values]
> Signed-off-by: Kees Cook 


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 
Intel Finland Oy

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

[Kees Cook]

From: Mimi Zohar 

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 
[kees: removed removal of my old version, constified pointer values]
Signed-off-by: Kees Cook 
---
 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);
-- 
2.6.3

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