Skip to contentSkip to conversation

input: Annotate struct evdev_client with __counted_by

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

Subsystems (2)
HID Input drivers
lore
Share & tools
lore

Kees Cook

author
#0 lore raw

PATCH 1/1 input: Annotate struct evdev_client 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 evdev_client.

[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]>
---
 drivers/input/evdev.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
drivers/input/evdev.c +1 -1
index 95f90699d2b1..51e0c4954600 100644
@@ -50,7 +50,7 @@ struct evdev_client {
 	bool revoked;
 	unsigned long *evmasks[EV_CNT];
 	unsigned int bufsize;
-	struct input_event buffer[];
+	struct input_event buffer[] __counted_by(bufsize);
 };
 
 static size_t evdev_get_mask_cnt(unsigned int type)
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 evdev_client.

[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
---
  drivers/input/evdev.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)
drivers/input/evdev.c +1 -1
index 95f90699d2b1..51e0c4954600 100644
@@ -50,7 +50,7 @@ struct evdev_client {
  	bool revoked;
  	unsigned long *evmasks[EV_CNT];
  	unsigned int bufsize;
-	struct input_event buffer[];
+	struct input_event buffer[] __counted_by(bufsize);
  };
 
  static size_t evdev_get_mask_cnt(unsigned int type)
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 evdev_client.

[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