mirror of
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2025-08-05 16:54:27 +00:00
0dc1754e16
Remove EFI zboot's dependency on the decompression wrappers used by the legacy decompressor boot code, which can only process the input in one go, and this will not work for upcoming support for embedded ELF images. They also do some odd things like providing a barebones malloc() implementation, which is not needed in a hosted environment such as the EFI boot services. So instead, implement GZIP deflate and ZSTD decompression in terms of the underlying libraries. Support for other compression algoritms has already been dropped. Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
100 lines
2.7 KiB
C
100 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/efi.h>
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#include <linux/pe.h>
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#include <asm/efi.h>
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#include <linux/unaligned.h>
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#include "efistub.h"
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static unsigned long alloc_preferred_address(unsigned long alloc_size)
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{
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#ifdef EFI_KIMG_PREFERRED_ADDRESS
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efi_physical_addr_t efi_addr = EFI_KIMG_PREFERRED_ADDRESS;
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if (efi_bs_call(allocate_pages, EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
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alloc_size / EFI_PAGE_SIZE, &efi_addr) == EFI_SUCCESS)
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return efi_addr;
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#endif
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return ULONG_MAX;
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}
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void __weak efi_cache_sync_image(unsigned long image_base,
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unsigned long alloc_size)
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{
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// Provided by the arch to perform the cache maintenance necessary for
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// executable code loaded into memory to be safe for execution.
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}
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struct screen_info *alloc_screen_info(void)
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{
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return __alloc_screen_info();
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}
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asmlinkage efi_status_t __efiapi
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efi_zboot_entry(efi_handle_t handle, efi_system_table_t *systab)
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{
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char *cmdline_ptr __free(efi_pool) = NULL;
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unsigned long image_base, alloc_size;
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efi_loaded_image_t *image;
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efi_status_t status;
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WRITE_ONCE(efi_system_table, systab);
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status = efi_bs_call(handle_protocol, handle,
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&LOADED_IMAGE_PROTOCOL_GUID, (void **)&image);
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if (status != EFI_SUCCESS) {
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efi_err("Failed to locate parent's loaded image protocol\n");
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return status;
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}
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status = efi_handle_cmdline(image, &cmdline_ptr);
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if (status != EFI_SUCCESS)
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return status;
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efi_info("Decompressing Linux Kernel...\n");
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status = efi_zboot_decompress_init(&alloc_size);
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if (status != EFI_SUCCESS)
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return status;
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// If the architecture has a preferred address for the image,
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// try that first.
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image_base = alloc_preferred_address(alloc_size);
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if (image_base == ULONG_MAX) {
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unsigned long min_kimg_align = efi_get_kimg_min_align();
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u32 seed = U32_MAX;
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if (!IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
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// Setting the random seed to 0x0 is the same as
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// allocating as low as possible
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seed = 0;
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} else if (efi_nokaslr) {
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efi_info("KASLR disabled on kernel command line\n");
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} else {
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status = efi_get_random_bytes(sizeof(seed), (u8 *)&seed);
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if (status == EFI_NOT_FOUND) {
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efi_info("EFI_RNG_PROTOCOL unavailable\n");
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efi_nokaslr = true;
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} else if (status != EFI_SUCCESS) {
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efi_err("efi_get_random_bytes() failed (0x%lx)\n",
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status);
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efi_nokaslr = true;
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}
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}
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status = efi_random_alloc(alloc_size, min_kimg_align, &image_base,
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seed, EFI_LOADER_CODE, 0, EFI_ALLOC_LIMIT);
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if (status != EFI_SUCCESS) {
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efi_err("Failed to allocate memory\n");
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return status;
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}
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}
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// Decompress the payload into the newly allocated buffer
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status = efi_zboot_decompress((void *)image_base, alloc_size) ?:
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efi_stub_common(handle, image, image_base, cmdline_ptr);
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efi_free(alloc_size, image_base);
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return status;
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}
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