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input: mt: Annotate struct input_mt with __counted_by

PATCH Applied Kees Cook 3 participants 3 messages Sep 22, 2023 – Sep 30, 2023

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HID Input drivers
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Kees Cook

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#0 lore raw

PATCH 1/1 input: mt: Annotate struct input_mt 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 input_mt.

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

Cc Dmitry Torokhov <[email protected]>
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>
---
 include/linux/input/mt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
include/linux/input/mt.h +1 -1
index 3b8580bd33c1..2cf89a538b18 100644
@@ -47,7 +47,7 @@ struct input_mt {
 	unsigned int flags;
 	unsigned int frame;
 	int *red;
-	struct input_mt_slot slots[];
+	struct input_mt_slot slots[] __counted_by(num_slots);
 };
 
 static inline void input_mt_set_value(struct input_mt_slot *slot,
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 7 lines

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

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

Cc Dmitry Torokhov <[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
---
  include/linux/input/mt.h | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
include/linux/input/mt.h +1 -1
index 3b8580bd33c1..2cf89a538b18 100644
@@ -47,7 +47,7 @@ struct input_mt {
  	unsigned int flags;
  	unsigned int frame;
  	int *red;
-	struct input_mt_slot slots[];
+	struct input_mt_slot slots[] __counted_by(num_slots);
  };
 
  static inline void input_mt_set_value(struct input_mt_slot *slot,
maintainer Applied
#2 lore raw
In reply to Kees Cook
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 7 lines

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

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

Cc Dmitry Torokhov <[email protected]>
Cc [email protected]
Signed-off-by Kees Cook <[email protected]>

Applied, thank you.

Signature · 1 line
Dmitry