One-element arrays are deprecated, and we are replacing them with flexible
array members instead. So, replace one-element array with flexible-array
member in struct xen_page_directory.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

This results in no differences in binary output.

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/255
Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
---
 drivers/xen/xen-front-pgdir-shbuf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/xen-front-pgdir-shbuf.c b/drivers/xen/xen-front-pgdir-shbuf.c
index 5c0b5cb5b419..b52e0fa595a9 100644
--- a/drivers/xen/xen-front-pgdir-shbuf.c
+++ b/drivers/xen/xen-front-pgdir-shbuf.c
@@ -30,7 +30,7 @@
 struct xen_page_directory {
 	grant_ref_t gref_dir_next_page;
 #define XEN_GREF_LIST_END	0
-	grant_ref_t gref[1]; /* Variable length */
+	grant_ref_t gref[]; /* Variable length */
 };
 
 /**
-- 
2.34.1

On 03.02.23 02:28, Gustavo A. R. Silva wrote:
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct xen_page_directory.
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> This results in no differences in binary output.
> 
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/255
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Pushed-to: xen/tip.git for-linus-6.3


Juergen

On 03.02.23 02:28, Gustavo A. R. Silva wrote:
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct xen_page_directory.
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> This results in no differences in binary output.
> 
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/255
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Reviewed-by: Juergen Gross <jgross@suse.com>


Juergen

On Thu, Feb 02, 2023 at 07:28:23PM -0600, Gustavo A. R. Silva wrote:
> One-element arrays are deprecated, and we are replacing them with flexible
> array members instead. So, replace one-element array with flexible-array
> member in struct xen_page_directory.
> 
> This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
> routines on memcpy() and help us make progress towards globally
> enabling -fstrict-flex-arrays=3 [1].
> 
> This results in no differences in binary output.
> 
> Link: https://github.com/KSPP/linux/issues/79
> Link: https://github.com/KSPP/linux/issues/255
> Link: https://gcc.gnu.org/pipermail/gcc-patches/2022-October/602902.html [1]
> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

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

-- 
Kees Cook