From: Jan Beulich Date: Mon, 4 Nov 2013 09:10:04 +0000 (+0100) Subject: x86/ACPI/x2APIC: guard against out of range ACPI or APIC IDs X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~6081 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=2c24cdcce3269f3286790c63821951a1de93c66a;p=xen.git x86/ACPI/x2APIC: guard against out of range ACPI or APIC IDs Other than for the legacy APIC, the x2APIC MADT entries have valid ranges possibly extending beyond what our internal arrays can handle, and hence we need to guard ourselves against corrupting memory here. Signed-off-by: Jan Beulich Reviewed-by: Keir Fraser --- diff --git a/xen/arch/x86/acpi/boot.c b/xen/arch/x86/acpi/boot.c index 0e1d570c29..df264233cd 100644 --- a/xen/arch/x86/acpi/boot.c +++ b/xen/arch/x86/acpi/boot.c @@ -97,7 +97,20 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end) acpi_table_print_madt_entry(header); - /* Record local apic id only when enabled */ + /* Record local apic id only when enabled and fitting. */ + if (processor->local_apic_id >= MAX_APICS || + processor->uid >= MAX_MADT_ENTRIES) { + printk("%sAPIC ID %#x and/or ACPI ID %#x beyond limit" + " - processor ignored\n", + processor->lapic_flags & ACPI_MADT_ENABLED ? + KERN_WARNING "WARNING: " : KERN_INFO, + processor->local_apic_id, processor->uid); + /* + * Must not return an error here, to prevent + * acpi_table_parse_entries() from terminating early. + */ + return 0 /* -ENOSPC */; + } if (processor->lapic_flags & ACPI_MADT_ENABLED) { x86_acpiid_to_apicid[processor->uid] = processor->local_apic_id;