exportfs: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

[PATCH][next] exportfs: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

Posted by Gustavo A. R. Silva 3 years, 7 months ago

Zero-length arrays are deprecated and we are moving towards adopting
C99 flexible-array members instead. So, replace zero-length array
declaration in struct fid with the new DECLARE_FLEX_ARRAY()
helper macro.

This helper allows for a flexible-array member in a union.

Link: https://github.com/KSPP/linux/issues/21
Link: https://github.com/KSPP/linux/issues/193
Link: https://github.com/KSPP/linux/issues/197
Link: https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 include/linux/exportfs.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/exportfs.h b/include/linux/exportfs.h
index fe848901fcc3..1640d97e4c0d 100644
--- a/include/linux/exportfs.h
+++ b/include/linux/exportfs.h
@@ -131,7 +131,7 @@ struct fid {
  			u32 parent_block;
  			u32 parent_generation;
  		} udf;
-		__u32 raw[0];
+		DECLARE_FLEX_ARRAY(__u32, raw);
 	};
 };
 
-- 
2.34.1

Re: [PATCH][next] exportfs: Replace zero-length array with DECLARE_FLEX_ARRAY() helper

Posted by Kees Cook 3 years, 7 months ago

On Sat, Sep 03, 2022 at 12:08:51AM +0100, Gustavo A. R. Silva wrote:
> Zero-length arrays are deprecated and we are moving towards adopting
> C99 flexible-array members instead. So, replace zero-length array
> declaration in struct fid with the new DECLARE_FLEX_ARRAY()
> helper macro.
> 
> This helper allows for a flexible-array member in a union.
> 
> Link: https://github.com/KSPP/linux/issues/21
> Link: https://github.com/KSPP/linux/issues/193
> Link: https://github.com/KSPP/linux/issues/197
> Link: https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>

-- 
Kees Cook