pinctrl: samsung: Annotate struct exynos_muxed_weint_data 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 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 exynos_muxed_weint_data. Additionally, since the element count member must be set before accessing the annotated flexible array member, move its initialization earlier.

Cc Tomasz Figa <[email protected]>

Cc Krzysztof Kozlowski <[email protected]>

Cc Sylwester Nawrocki <[email protected]>

Cc Alim Akhtar <[email protected]>

Cc Linus Walleij <[email protected]>

Cc "Gustavo A. R. Silva" <[email protected]>

Cc [email protected]

Cc [email protected]

Cc [email protected]

Cc [email protected]

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

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

---
  drivers/pinctrl/samsung/pinctrl-exynos.c | 2 +-
  drivers/pinctrl/samsung/pinctrl-exynos.h | 2 +-
  2 files changed, 2 insertions(+), 2 deletions(-)

drivers/pinctrl/samsung/pinctrl-exynos.c +1 -1

index a8212fc126bf..6b58ec84e34b 100644
@@ -616,6 +616,7 @@ __init int exynos_eint_wkup_init(struct samsung_pinctrl_drv_data *d)
  		+ muxed_banks*sizeof(struct samsung_pin_bank *), GFP_KERNEL);
  	if (!muxed_data)
  		return -ENOMEM;
+	muxed_data->nr_banks = muxed_banks;
 
  	irq_set_chained_handler_and_data(irq, exynos_irq_demux_eint16_31,
  					 muxed_data);

@@ -628,7 +629,6 @@ __init int exynos_eint_wkup_init(struct samsung_pinctrl_drv_data *d)
 
  		muxed_data->banks[idx++] = bank;
  	}
-	muxed_data->nr_banks = muxed_banks;
 
  	return 0;
  }

drivers/pinctrl/samsung/pinctrl-exynos.h +1 -1

index 7bd6d82c9f36..3ac52c2cf998 100644
@@ -159,7 +159,7 @@ struct exynos_weint_data {
   */
  struct exynos_muxed_weint_data {
  	unsigned int nr_banks;
-	struct samsung_pin_bank *banks[];
+	struct samsung_pin_bank *banks[] __counted_by(nr_banks);
  };
 
  int exynos_eint_gpio_init(struct samsung_pinctrl_drv_data *d);

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 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 exynos_muxed_weint_data. Additionally, since the element count member must be set before accessing the annotated flexible array member, move its initialization earlier.

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