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video: fbdev: mmp: Annotate struct mmphw_ctrl with __counted_by

PATCH In review Kees Cook 3 participants 3 messages Sep 22, 2023 – Sep 23, 2023 Framebuffer layer

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Kees Cook

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#0 lore raw

PATCH 1/1 video: fbdev: mmp: Annotate struct mmphw_ctrl with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct mmphw_ctrl.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc Helge Deller <[email protected]>
Cc [email protected]
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
---
 drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/video/fbdev/mmp/hw/mmp_ctrl.h +1 -1
index 167585a889d3..719b99a9bc77 100644
@@ -1406,7 +1406,7 @@ struct mmphw_ctrl {
 
 	/*pathes*/
 	int path_num;
-	struct mmphw_path_plat path_plats[];
+	struct mmphw_path_plat path_plats[] __counted_by(path_num);
 };
 
 static inline int overlay_is_vid(struct mmp_overlay *overlay)
Signature · 1 line
2.34.1
Reviewed-by on v1 1/1
#1 lore raw
Quoted 6 lines · Kees Cook

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

Quoted 8 lines

As found with Coccinelle[1], add __counted_by for struct mmphw_ctrl.

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc Helge Deller <[email protected]>
Cc [email protected]
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
Reviewed-by Gustavo A. R. Silva <[email protected]>

Thanks

Signature · 1 line
Gustavo
Quoted 17 lines
---
  drivers/video/fbdev/mmp/hw/mmp_ctrl.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
drivers/video/fbdev/mmp/hw/mmp_ctrl.h +1 -1
index 167585a889d3..719b99a9bc77 100644
@@ -1406,7 +1406,7 @@ struct mmphw_ctrl {
 
  	/*pathes*/
  	int path_num;
-	struct mmphw_path_plat path_plats[];
+	struct mmphw_path_plat path_plats[] __counted_by(path_num);
  };
 
  static inline int overlay_is_vid(struct mmp_overlay *overlay)
maintainer
#2 lore raw
Quoted 9 lines · Gustavo A. R. Silva
Quoted 8 lines · Kees Cook

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions).

As found with Coccinelle[1], add __counted_by for struct mmphw_ctrl.

Quoted 8 lines
Quoted 6 lines

[1] https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci

Cc Helge Deller <[email protected]>
Cc [email protected]
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
Reviewed-by Gustavo A. R. Silva <[email protected]>

Both fbdev patches applied to fbdev git tree.

Thank you Kees!

Helge