On Fri, May 17, 2019 at 11:24:27AM +0200, Ard Biesheuvel wrote: > If efi_call_phys_prolog() returns NULL, the calling function should > abort and never call efi_call_phys_epilog(). Hi Ard, I edit the patch and it is as following. Returning EFI_ABORTED would be proper, because the return value (status) is checked in __efi_enter_virtual_mode(). And returning EFI_ABORTED can abort the process. Thanks Gen save_pgd is allocated by kmalloc_array. And it is dereferenced in the following codes. However, memory allocation functions such as kmalloc_array may fail. Dereferencing this save_pgd null pointer may cause the kernel go wrong. Thus we should check this allocation. Signed-off-by: Gen Zhang <blackgod016574@xxxxxxxxx> --- diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index e1cb01a..a7189a3 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -85,6 +85,8 @@ static efi_status_t __init phys_efi_set_virtual_address_map( pgd_t *save_pgd; save_pgd = efi_call_phys_prolog(); + if (!save_pgd) + return EFI_ABORTED; /* Disable interrupts around EFI calls: */ local_irq_save(flags); diff --git a/arch/x86/platform/efi/efi_64.c b/arch/x86/platform/efi/efi_64.c index cf0347f..828460a 100644 --- a/arch/x86/platform/efi/efi_64.c +++ b/arch/x86/platform/efi/efi_64.c @@ -91,6 +91,8 @@ pgd_t * __init efi_call_phys_prolog(void) n_pgds = DIV_ROUND_UP((max_pfn << PAGE_SHIFT), PGDIR_SIZE); save_pgd = kmalloc_array(n_pgds, sizeof(*save_pgd), GFP_KERNEL); + if (!save_pgd) + return NULL; /* * Build 1:1 identity mapping for efi=old_map usage. Note that ---
