driver core: platform: Annotate struct irq_affinity_devres 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
irq_affinity_devres.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-hardening@vger.kernel.org
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20231006201749.work.432-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 828908d1d5b9492f38888fa54ea7e10ff8c3c0da..10c5779634182815cb76cc01eb7de7121b0532da 100644 (file)
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -292,7 +292,7 @@ EXPORT_SYMBOL_GPL(platform_irq_count);
 
 struct irq_affinity_devres {
        unsigned int count;
-       unsigned int irq[];
+       unsigned int irq[] __counted_by(count);
 };
 
 static void platform_disable_acpi_irq(struct platform_device *pdev, int index)