Hi Heinrich, On Sun, 30 Jul 2023 at 13:51, Heinrich Schuchardt <[email protected]> wrote: > > On 32bit systems (pages << EFI_PAGE_SHIFT) may lead to an overflow which > does not occur in 64bit arithmetics.
You mean this cant happen in 32 bits but can in 64bit right? > > An overflow of (pages << EFI_PAGE_SHIFT) on 64bit systems should be treated > as an error. > > Signed-off-by: Heinrich Schuchardt <[email protected]> > --- > v2: > %s/size/sizeof/ > lib/efi_loader/efi_memory.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c > index e2ca78d935..9de6cf6010 100644 > --- a/lib/efi_loader/efi_memory.c > +++ b/lib/efi_loader/efi_memory.c > @@ -487,7 +487,7 @@ efi_status_t efi_allocate_pages(enum efi_allocate_type > type, > enum efi_memory_type memory_type, > efi_uintn_t pages, uint64_t *memory) > { > - u64 len = pages << EFI_PAGE_SHIFT; > + u64 len; > efi_status_t ret; > uint64_t addr; > > @@ -497,6 +497,11 @@ efi_status_t efi_allocate_pages(enum efi_allocate_type > type, > return EFI_INVALID_PARAMETER; > if (!memory) > return EFI_INVALID_PARAMETER; > + len = (u64)pages << EFI_PAGE_SHIFT; > + /* Catch possible overflow on 64bit systems */ > + if (sizeof(efi_uintn_t) == sizeof(u64) && > + (len >> EFI_PAGE_SHIFT) != (u64)pages) > + return EFI_OUT_OF_RESOURCES; EFI_INVALID_PARAMETER is better here, since no allocation actually takes place. > > switch (type) { > case EFI_ALLOCATE_ANY_PAGES: > -- > 2.40.1 > Regards /Ilias
