In efi_call_phys_prolog(), 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. Further, if efi_call_phys_prolog() returns NULL, we should abort the process in phys_efi_set_virtual_address_map(), and return EFI_ABORTED. 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 ---
