diff --git a/src/interface/efi/efi_init.c b/src/interface/efi/efi_init.c index 284c39b35..e1041a5ec 100644 --- a/src/interface/efi/efi_init.c +++ b/src/interface/efi/efi_init.c @@ -21,6 +21,7 @@ FILE_LICENCE ( GPL2_OR_LATER ); #include #include +#include #include #include #include @@ -128,6 +129,13 @@ efi_stack_cookie ( EFI_HANDLE handle ) { */ cookie <<= 8; + /* Ensure that the NUL byte is placed at the bottom of the + * stack cookie, to avoid potential disclosure via an + * unterminated string. + */ + if ( __BYTE_ORDER == __BIG_ENDIAN ) + cookie >>= 8; + return cookie; }