irqdomain: Annotate struct irq_domain 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 irq_domain.

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

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20230922175127.work.214-kees@kernel.org

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 51c254b7fec273550f17742e53bf28923cc561c8..ee0a82c6050838dcd3f62264b0693f844013d1fb 100644 (file)
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -174,7 +174,7 @@ struct irq_domain {
        irq_hw_number_t                 hwirq_max;
        unsigned int                    revmap_size;
        struct radix_tree_root          revmap_tree;
-       struct irq_data __rcu           *revmap[];
+       struct irq_data __rcu           *revmap[] __counted_by(revmap_size);
 };
 
 /* Irq domain flags */