Re: [PATCH] irqchip/irq-bcm7038-l1: Prefer struct_size over open coded arithmetic

From: Kees Cook
Date: Fri Feb 09 2024 - 19:20:25 EST


On Fri, Feb 09, 2024 at 07:31:28PM +0100, Erick Archer wrote:
> This is an effort to get rid of all multiplications from allocation
> functions in order to prevent integer overflows [1].
>
> As the cpu variable is a pointer to "struct bcm7038_l1_cpu" and this
> structure ends in a flexible array:
>
> struct bcm7038_l1_cpu {
> void __iomem *map_base;
> u32 mask_cache[];
> };
>
> the preferred way in the kernel is to use the struct_size() helper to
> do the arithmetic instead of the argument "size + count * size" in the
> kzalloc() function.
>
> This way, the code is more readable and more safer.
>
> Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/162 [2]
>
> Signed-off-by: Erick Archer <erick.archer@xxxxxxx>

Yeah, looks right to me.

Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>

--
Kees Cook