arm64: add sentinel to kpti_safe_list

commit 71c751f2a43fa03fae3cf5f0067ed3001a397013 upstream.

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>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 60066315d66997bec106d7d19735c44f16fc227d..ae28979676c18bb47e1cab613fac0bb772a4c83f 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -836,6 +836,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry,
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A57),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A72),
                MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
+               { /* sentinel */ }
        };
        char const *str = "kpti command line option";
        bool meltdown_safe;