x86, efi: Check table header length in efi_bgrt_init()

Header length should be validated for all ACPI tables before accessing
any non-header field.

Signed-off-by: Jan Beulich <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Acked-by: Matt Fleming <[email protected]>
Signed-off-by: H. Peter Anvin <[email protected]>

diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
index f6a0c1b8e518f91ef4992be10a3091e514cc5a50..d9c1b95af17c1ead797783eed225c94c9aa7fe5f 100644 (file)
--- a/arch/x86/platform/efi/efi-bgrt.c
+++ b/arch/x86/platform/efi/efi-bgrt.c
@@ -39,6 +39,8 @@ void efi_bgrt_init(void)
        if (ACPI_FAILURE(status))
                return;
 
+       if (bgrt_tab->header.length < sizeof(*bgrt_tab))
+               return;
        if (bgrt_tab->version != 1)
                return;
        if (bgrt_tab->image_type != 0 || !bgrt_tab->image_address)