[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH] xen/arm: Avoid integer overflow using MIDR_IMPLEMENTOR_MASK
Hi Michal, On 25/02/2022 08:38, Michal Orzel wrote: Value of macro MIDR_IMPLEMENTOR_MASK exceeds the range of integer and can lead to overflow. Currently there is no issue as it is used in an expression implicitly casted to u32 in MIDR_IS_CPU_MODEL_RANGE. To avoid possible problems, fix the macro. Correct me if I am wrong, it sounds like this is only for hardening purpose at the moment. As this code is coming from Linux, I would prefer if we first upstream to Linux and then port to Xen once merged. Signed-off-by: Michal Orzel <michal.orzel@xxxxxxx> --- xen/arch/arm/include/asm/processor.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/xen/arch/arm/include/asm/processor.h b/xen/arch/arm/include/asm/processor.h index 8ab2940f68..149fae0d27 100644 --- a/xen/arch/arm/include/asm/processor.h +++ b/xen/arch/arm/include/asm/processor.h @@ -39,7 +39,7 @@ #define MIDR_VARIANT(midr) \ (((midr) & MIDR_VARIANT_MASK) >> MIDR_VARIANT_SHIFT) #define MIDR_IMPLEMENTOR_SHIFT 24 -#define MIDR_IMPLEMENTOR_MASK (0xff << MIDR_IMPLEMENTOR_SHIFT) +#define MIDR_IMPLEMENTOR_MASK (0xffu << MIDR_IMPLEMENTOR_SHIFT) NIT: We tend to use 0xffU. #define MIDR_IMPLEMENTOR(midr) \ (((midr) & MIDR_IMPLEMENTOR_MASK) >> MIDR_IMPLEMENTOR_SHIFT) Cheers, -- Julien Grall
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