From ebdea88d57d5e67b8f6e6cf615300eedbc7200a9 Mon Sep 17 00:00:00 2001 From: Ilias Apalodimas Date: Mon, 11 Oct 2021 15:10:23 +0300 Subject: [PATCH] efi_loader: Fix loaded image alignment MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit We are ignoring the alignment communicated via the PE/COFF header. Starting 5.10 the Linux kernel will loudly complain about it. For more details look at [1] (in linux kernel). So add a function that can allocate aligned EFI memory and use it for our relocated loaded image. [1] c32ac11da3f83 ("efi/libstub: arm64: Double check image alignment at entry") Signed-off-by: Ilias Apalodimas Tested-by: Vincent Stehlé Acked-by: Ard Biesheuvel Reviewed-by: Heinrich Schuchardt --- include/efi_loader.h | 2 ++ lib/efi_loader/efi_image_loader.c | 12 +++---- lib/efi_loader/efi_memory.c | 52 +++++++++++++++++++++++++++++++ 3 files changed, 60 insertions(+), 6 deletions(-) diff --git a/include/efi_loader.h b/include/efi_loader.h index c440962fe5..5cdc72345e 100644 --- a/include/efi_loader.h +++ b/include/efi_loader.h @@ -675,6 +675,8 @@ struct efi_device_path *efi_get_dp_from_boot(const efi_guid_t guid); #define efi_size_in_pages(size) (((size) + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT) /* Generic EFI memory allocator, call this to get memory */ void *efi_alloc(uint64_t len, int memory_type); +/* Allocate pages on the specified alignment */ +void *efi_alloc_aligned_pages(u64 len, int memory_type, size_t align); /* More specific EFI memory allocator, called by EFI payloads */ efi_status_t efi_allocate_pages(enum efi_allocate_type type, enum efi_memory_type memory_type, diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index e9572d4d5d..eb95580538 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -898,9 +898,9 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, image_base = opt->ImageBase; efi_set_code_and_data_type(loaded_image_info, opt->Subsystem); handle->image_type = opt->Subsystem; - virt_size = ALIGN(virt_size, opt->SectionAlignment); - efi_reloc = efi_alloc(virt_size, - loaded_image_info->image_code_type); + efi_reloc = efi_alloc_aligned_pages(virt_size, + loaded_image_info->image_code_type, + opt->SectionAlignment); if (!efi_reloc) { log_err("Out of memory\n"); ret = EFI_OUT_OF_RESOURCES; @@ -914,9 +914,9 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, image_base = opt->ImageBase; efi_set_code_and_data_type(loaded_image_info, opt->Subsystem); handle->image_type = opt->Subsystem; - virt_size = ALIGN(virt_size, opt->SectionAlignment); - efi_reloc = efi_alloc(virt_size, - loaded_image_info->image_code_type); + efi_reloc = efi_alloc_aligned_pages(virt_size, + loaded_image_info->image_code_type, + opt->SectionAlignment); if (!efi_reloc) { log_err("Out of memory\n"); ret = EFI_OUT_OF_RESOURCES; diff --git a/lib/efi_loader/efi_memory.c b/lib/efi_loader/efi_memory.c index f4acbee4f9..7f0b507281 100644 --- a/lib/efi_loader/efi_memory.c +++ b/lib/efi_loader/efi_memory.c @@ -549,6 +549,58 @@ efi_status_t efi_free_pages(uint64_t memory, efi_uintn_t pages) return ret; } +/** + * efi_alloc_aligned_pages - allocate + * + * @len: len in bytes + * @memory_type: usage type of the allocated memory + * @align: alignment in bytes + * Return: aligned memory or NULL + */ +void *efi_alloc_aligned_pages(u64 len, int memory_type, size_t align) +{ + u64 req_pages = efi_size_in_pages(len); + u64 true_pages = req_pages + efi_size_in_pages(align) - 1; + u64 free_pages; + u64 aligned_mem; + efi_status_t r; + u64 mem; + + /* align must be zero or a power of two */ + if (align & (align - 1)) + return NULL; + + /* Check for overflow */ + if (true_pages < req_pages) + return NULL; + + if (align < EFI_PAGE_SIZE) { + r = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES, memory_type, + req_pages, &mem); + return (r == EFI_SUCCESS) ? (void *)(uintptr_t)mem : NULL; + } + + r = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES, memory_type, + true_pages, &mem); + if (r != EFI_SUCCESS) + return NULL; + + aligned_mem = ALIGN(mem, align); + /* Free pages before alignment */ + free_pages = efi_size_in_pages(aligned_mem - mem); + if (free_pages) + efi_free_pages(mem, free_pages); + + /* Free trailing pages */ + free_pages = true_pages - (req_pages + free_pages); + if (free_pages) { + mem = aligned_mem + req_pages * EFI_PAGE_SIZE; + efi_free_pages(mem, free_pages); + } + + return (void *)(uintptr_t)aligned_mem; +} + /** * efi_allocate_pool - allocate memory from pool * -- 2.39.5