Commit 55203550 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

Merge tag 'efi-urgent-for-v5.14-rc4' of... 

Merge tag 'efi-urgent-for-v5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi into efi/urgent

Pull EFI fixes from Ard Biesheuvel:

 A batch of fixes for the arm64 stub image loader:

 - fix a logic bug that can make the random page allocator fail
   spuriously
 - force reallocation of the Image when it overlaps with firmware
   reserved memory regions
 - fix an oversight that defeated on optimization introduced earlier
   where images loaded at a suitable offset are never moved if booting
   without randomization
 - complain about images that were not loaded at the right offset by the
   firmware image loader.

Link: https://lore.kernel.org/r/20210803091215.2566-1-ardb@kernel.org
parents ddab1e71 c32ac11d

drivers/firmware/efi/libstub/arm64-stub.c

+61 −10
Original line number Diff line number Diff line
@@ -35,15 +35,48 @@ efi_status_t check_platform_features(void) 
}



/*

 * Although relocatable kernels can fix up the misalignment with respect to

 * MIN_KIMG_ALIGN, the resulting virtual text addresses are subtly out of

 * sync with those recorded in the vmlinux when kaslr is disabled but the

 * image required relocation anyway. Therefore retain 2M alignment unless

 * KASLR is in use.

 * Distro versions of GRUB may ignore the BSS allocation entirely (i.e., fail

 * to provide space, and fail to zero it). Check for this condition by double

 * checking that the first and the last byte of the image are covered by the

 * same EFI memory map entry.

 */

static u64 min_kimg_align(void)

static bool check_image_region(u64 base, u64 size)

{

	return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;

	unsigned long map_size, desc_size, buff_size;

	efi_memory_desc_t *memory_map;

	struct efi_boot_memmap map;

	efi_status_t status;

	bool ret = false;

	int map_offset;



	map.map =	&memory_map;

	map.map_size =	&map_size;

	map.desc_size =	&desc_size;

	map.desc_ver =	NULL;

	map.key_ptr =	NULL;

	map.buff_size =	&buff_size;



	status = efi_get_memory_map(&map);

	if (status != EFI_SUCCESS)

		return false;



	for (map_offset = 0; map_offset < map_size; map_offset += desc_size) {

		efi_memory_desc_t *md = (void *)memory_map + map_offset;

		u64 end = md->phys_addr + md->num_pages * EFI_PAGE_SIZE;



		/*

		 * Find the region that covers base, and return whether

		 * it covers base+size bytes.

		 */

		if (base >= md->phys_addr && base < end) {

			ret = (base + size) <= end;

			break;

		}

	}



	efi_bs_call(free_pool, memory_map);



	return ret;

}



efi_status_t handle_kernel_image(unsigned long *image_addr,
@@ -56,6 +89,16 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, 
	unsigned long kernel_size, kernel_memsize = 0;

	u32 phys_seed = 0;



	/*

	 * Although relocatable kernels can fix up the misalignment with

	 * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are

	 * subtly out of sync with those recorded in the vmlinux when kaslr is

	 * disabled but the image required relocation anyway. Therefore retain

	 * 2M alignment if KASLR was explicitly disabled, even if it was not

	 * going to be activated to begin with.

	 */

	u64 min_kimg_align = efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;



	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {

		if (!efi_nokaslr) {

			status = efi_get_random_bytes(sizeof(phys_seed),
@@ -76,6 +119,10 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, 
	if (image->image_base != _text)

		efi_err("FIRMWARE BUG: efi_loaded_image_t::image_base has bogus value\n");



	if (!IS_ALIGNED((u64)_text, EFI_KIMG_ALIGN))

		efi_err("FIRMWARE BUG: kernel image not aligned on %ldk boundary\n",

			EFI_KIMG_ALIGN >> 10);



	kernel_size = _edata - _text;

	kernel_memsize = kernel_size + (_end - _edata);

	*reserve_size = kernel_memsize;
@@ -85,14 +132,18 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, 
		 * If KASLR is enabled, and we have some randomness available,

		 * locate the kernel at a randomized offset in physical memory.

		 */

		status = efi_random_alloc(*reserve_size, min_kimg_align(),

		status = efi_random_alloc(*reserve_size, min_kimg_align,

					  reserve_addr, phys_seed);

		if (status != EFI_SUCCESS)

			efi_warn("efi_random_alloc() failed: 0x%lx\n", status);

	} else {

		status = EFI_OUT_OF_RESOURCES;

	}



	if (status != EFI_SUCCESS) {

		if (IS_ALIGNED((u64)_text, min_kimg_align())) {

		if (!check_image_region((u64)_text, kernel_memsize)) {

			efi_err("FIRMWARE BUG: Image BSS overlaps adjacent EFI memory region\n");

		} else if (IS_ALIGNED((u64)_text, min_kimg_align)) {

			/*

			 * Just execute from wherever we were loaded by the

			 * UEFI PE/COFF loader if the alignment is suitable.
@@ -103,7 +154,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr, 
		}



		status = efi_allocate_pages_aligned(*reserve_size, reserve_addr,

						    ULONG_MAX, min_kimg_align());

						    ULONG_MAX, min_kimg_align);



		if (status != EFI_SUCCESS) {

			efi_err("Failed to relocate kernel\n");

drivers/firmware/efi/libstub/randomalloc.c

+2 −0
Original line number Diff line number Diff line
@@ -30,6 +30,8 @@ static unsigned long get_entry_num_slots(efi_memory_desc_t *md, 


	region_end = min(md->phys_addr + md->num_pages * EFI_PAGE_SIZE - 1,

			 (u64)ULONG_MAX);

	if (region_end < size)

		return 0;



	first_slot = round_up(md->phys_addr, align);

	last_slot = round_down(region_end - size + 1, align);