arm64: add sentinel to kpti_safe_list

We're missing a sentinel entry in kpti_safe_list. Thus is_midr_in_range_list()
can walk past the end of kpti_safe_list. Depending on the contents of memory,
this could erroneously match a CPU's MIDR, cause a data abort, or other bad
outcomes.

Add the sentinel entry to avoid this.

Fixes: be5b299830c63ed7 ("arm64: capabilities: Add support for checks based on a list of MIDRs")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reported-by: Jan Kiszka <jan.kiszka@siemens.com>
Tested-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 536d572e55967286b65457631251c842c1951353..9d1b06d67c53d4addacf97dd96207aa91d2ba04b 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
        static const struct midr_range kpti_safe_list[] = {
                MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
                MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
+               { /* sentinel */ }
        };
        char const *str = "command line option";