On 32bit systems (pages << EFI_PAGE_SHIFT) may lead to an overflow which does not occur in 64bit arithmetics.
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; switch (type) { case EFI_ALLOCATE_ANY_PAGES: -- 2.40.1
