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video: mmp: Annotate struct mmp_path with __counted_by

PATCH In review Kees Cook 2 participants 2 messages Sep 22, 2023 – Sep 23, 2023 Framebuffer layer

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Kees Cook

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PATCH 1/1 video: mmp: Annotate struct mmp_path 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 mmp_path.

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

---
 include/video/mmp_disp.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
include/video/mmp_disp.h +1 -1
index 77252cb46361..a722dcbf5073 100644
@@ -231,7 +231,7 @@ struct mmp_path {
 
 	/* layers */
 	int overlay_num;
-	struct mmp_overlay overlays[];
+	struct mmp_overlay overlays[] __counted_by(overlay_num);
 };
 
 extern struct mmp_path *mmp_get_path(const char *name);
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 mmp_path.

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

Thanks

Signature · 1 line
Gustavo
Quoted 17 lines
---
  include/video/mmp_disp.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
include/video/mmp_disp.h +1 -1
index 77252cb46361..a722dcbf5073 100644
@@ -231,7 +231,7 @@ struct mmp_path {
 
  	/* layers */
  	int overlay_num;
-	struct mmp_overlay overlays[];
+	struct mmp_overlay overlays[] __counted_by(overlay_num);
  };
 
  extern struct mmp_path *mmp_get_path(const char *name);