Commit 5193a33d authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

efi/libstub: Move file I/O support code into separate file 



Split off the file I/O support code into a separate source file so
it ends up in a separate object file in the static library, allowing
the linker to omit it if the routines are not used.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent b8717454

drivers/firmware/efi/libstub/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ OBJECT_FILES_NON_STANDARD := y 
KCOV_INSTRUMENT			:= n



lib-y				:= efi-stub-helper.o gop.o secureboot.o tpm.o \

				   mem.o random.o randomalloc.o pci.o

				   file.o mem.o random.o randomalloc.o pci.o



# include the stub's generic dependencies from lib/ when building for ARM/arm64

arm-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c

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

+6 −288
Original line number Diff line number Diff line
@@ -12,23 +12,7 @@ 


#include "efistub.h"



/*

 * Some firmware implementations have problems reading files in one go.

 * A read chunk size of 1MB seems to work for most platforms.

 *

 * Unfortunately, reading files in chunks triggers *other* bugs on some

 * platforms, so we provide a way to disable this workaround, which can

 * be done by passing "efi=nochunk" on the EFI boot stub command line.

 *

 * If you experience issues with initrd images being corrupt it's worth

 * trying efi=nochunk, but chunking is enabled by default because there

 * are far more machines that require the workaround than those that

 * break with it enabled.

 */

#define EFI_READ_CHUNK_SIZE	(1024 * 1024)



static unsigned long efi_chunk_size = EFI_READ_CHUNK_SIZE;



static bool __efistub_global efi_nochunk;

static bool __efistub_global efi_nokaslr;

static bool __efistub_global efi_quiet;

static bool __efistub_global efi_novamap;
@@ -36,6 +20,10 @@ static bool __efistub_global efi_nosoftreserve; 
static bool __efistub_global efi_disable_pci_dma =

					IS_ENABLED(CONFIG_EFI_DISABLE_PCI_DMA);



bool __pure nochunk(void)

{

	return efi_nochunk;

}

bool __pure nokaslr(void)

{

	return efi_nokaslr;
@@ -53,11 +41,6 @@ bool __pure __efi_soft_reserve_enabled(void) 
	return !efi_nosoftreserve;

}



struct file_info {

	efi_file_protocol_t *handle;

	u64 size;

};



void efi_printk(char *str)

{

	char *s8;
@@ -75,90 +58,6 @@ void efi_printk(char *str) 
	}

}



static efi_status_t efi_file_size(void *__fh, efi_char16_t *filename_16,

				  void **handle, u64 *file_sz)

{

	efi_file_protocol_t *h, *fh = __fh;

	efi_file_info_t *info;

	efi_status_t status;

	efi_guid_t info_guid = EFI_FILE_INFO_ID;

	unsigned long info_sz;



	status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, 0);

	if (status != EFI_SUCCESS) {

		efi_printk("Failed to open file: ");

		efi_char16_printk(filename_16);

		efi_printk("\n");

		return status;

	}



	*handle = h;



	info_sz = 0;

	status = h->get_info(h, &info_guid, &info_sz, NULL);

	if (status != EFI_BUFFER_TOO_SMALL) {

		efi_printk("Failed to get file info size\n");

		return status;

	}



grow:

	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, info_sz,

			     (void **)&info);

	if (status != EFI_SUCCESS) {

		efi_printk("Failed to alloc mem for file info\n");

		return status;

	}



	status = h->get_info(h, &info_guid, &info_sz, info);

	if (status == EFI_BUFFER_TOO_SMALL) {

		efi_bs_call(free_pool, info);

		goto grow;

	}



	*file_sz = info->file_size;

	efi_bs_call(free_pool, info);



	if (status != EFI_SUCCESS)

		efi_printk("Failed to get initrd info\n");



	return status;

}



static efi_status_t efi_file_read(efi_file_protocol_t *handle,

				  unsigned long *size, void *addr)

{

	return handle->read(handle, size, addr);

}



static efi_status_t efi_file_close(efi_file_protocol_t *handle)

{

	return handle->close(handle);

}



static efi_status_t efi_open_volume(efi_loaded_image_t *image,

				    efi_file_protocol_t **__fh)

{

	efi_simple_file_system_protocol_t *io;

	efi_file_protocol_t *fh;

	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;

	efi_status_t status;

	efi_handle_t handle = image->device_handle;



	status = efi_bs_call(handle_protocol, handle, &fs_proto, (void **)&io);

	if (status != EFI_SUCCESS) {

		efi_printk("Failed to handle fs_proto\n");

		return status;

	}



	status = io->open_volume(io, &fh);

	if (status != EFI_SUCCESS)

		efi_printk("Failed to open volume\n");

	else

		*__fh = fh;



	return status;

}



/*

 * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=

 * option, e.g. efi=nochunk.
@@ -197,7 +96,7 @@ efi_status_t efi_parse_options(char const *cmdline) 
	while (*str && *str != ' ') {

		if (!strncmp(str, "nochunk", 7)) {

			str += strlen("nochunk");

			efi_chunk_size = -1UL;

			efi_nochunk = true;

		}



		if (!strncmp(str, "novamap", 7)) {
@@ -232,187 +131,6 @@ efi_status_t efi_parse_options(char const *cmdline) 
	return EFI_SUCCESS;

}



/*

 * Check the cmdline for a LILO-style file= arguments.

 *

 * We only support loading a file from the same filesystem as

 * the kernel image.

 */

efi_status_t handle_cmdline_files(efi_loaded_image_t *image,

				  char *cmd_line, char *option_string,

				  unsigned long max_addr,

				  unsigned long *load_addr,

				  unsigned long *load_size)

{

	struct file_info *files;

	unsigned long file_addr;

	u64 file_size_total;

	efi_file_protocol_t *fh = NULL;

	efi_status_t status;

	int nr_files;

	char *str;

	int i, j, k;



	file_addr = 0;

	file_size_total = 0;



	str = cmd_line;



	j = 0;			/* See close_handles */



	if (!load_addr || !load_size)

		return EFI_INVALID_PARAMETER;



	*load_addr = 0;

	*load_size = 0;



	if (!str || !*str)

		return EFI_SUCCESS;



	for (nr_files = 0; *str; nr_files++) {

		str = strstr(str, option_string);

		if (!str)

			break;



		str += strlen(option_string);



		/* Skip any leading slashes */

		while (*str == '/' || *str == '\\')

			str++;



		while (*str && *str != ' ' && *str != '\n')

			str++;

	}



	if (!nr_files)

		return EFI_SUCCESS;



	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,

			     nr_files * sizeof(*files), (void **)&files);

	if (status != EFI_SUCCESS) {

		pr_efi_err("Failed to alloc mem for file handle list\n");

		goto fail;

	}



	str = cmd_line;

	for (i = 0; i < nr_files; i++) {

		struct file_info *file;

		efi_char16_t filename_16[256];

		efi_char16_t *p;



		str = strstr(str, option_string);

		if (!str)

			break;



		str += strlen(option_string);



		file = &files[i];

		p = filename_16;



		/* Skip any leading slashes */

		while (*str == '/' || *str == '\\')

			str++;



		while (*str && *str != ' ' && *str != '\n') {

			if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))

				break;



			if (*str == '/') {

				*p++ = '\\';

				str++;

			} else {

				*p++ = *str++;

			}

		}



		*p = '\0';



		/* Only open the volume once. */

		if (!i) {

			status = efi_open_volume(image, &fh);

			if (status != EFI_SUCCESS)

				goto free_files;

		}



		status = efi_file_size(fh, filename_16, (void **)&file->handle,

				       &file->size);

		if (status != EFI_SUCCESS)

			goto close_handles;



		file_size_total += file->size;

	}



	if (file_size_total) {

		unsigned long addr;



		/*

		 * Multiple files need to be at consecutive addresses in memory,

		 * so allocate enough memory for all the files.  This is used

		 * for loading multiple files.

		 */

		status = efi_allocate_pages(file_size_total, &file_addr, max_addr);

		if (status != EFI_SUCCESS) {

			pr_efi_err("Failed to alloc highmem for files\n");

			goto close_handles;

		}



		/* We've run out of free low memory. */

		if (file_addr > max_addr) {

			pr_efi_err("We've run out of free low memory\n");

			status = EFI_INVALID_PARAMETER;

			goto free_file_total;

		}



		addr = file_addr;

		for (j = 0; j < nr_files; j++) {

			unsigned long size;



			size = files[j].size;

			while (size) {

				unsigned long chunksize;



				if (IS_ENABLED(CONFIG_X86) && size > efi_chunk_size)

					chunksize = efi_chunk_size;

				else

					chunksize = size;



				status = efi_file_read(files[j].handle,

						       &chunksize,

						       (void *)addr);

				if (status != EFI_SUCCESS) {

					pr_efi_err("Failed to read file\n");

					goto free_file_total;

				}

				addr += chunksize;

				size -= chunksize;

			}



			efi_file_close(files[j].handle);

		}



	}



	efi_bs_call(free_pool, files);



	*load_addr = file_addr;

	*load_size = file_size_total;



	return status;



free_file_total:

	efi_free(file_size_total, file_addr);



close_handles:

	for (k = j; k < i; k++)

		efi_file_close(files[k].handle);

free_files:

	efi_bs_call(free_pool, files);

fail:

	*load_addr = 0;

	*load_size = 0;



	return status;

}

/*

 * Get the number of UTF-8 bytes corresponding to an UTF-16 character.

 * This overestimates for surrogates, but that is okay.

drivers/firmware/efi/libstub/efistub.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#define __efistub_global

#endif



extern bool __pure nochunk(void);

extern bool __pure nokaslr(void);

extern bool __pure is_quiet(void);

extern bool __pure novamap(void);

drivers/firmware/efi/libstub/file.c

0 → 100644
+303 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Helper functions used by the EFI stub on multiple

 * architectures. This should be #included by the EFI stub

 * implementation files.

 *

 * Copyright 2011 Intel Corporation; author Matt Fleming

 */



#include <linux/efi.h>

#include <asm/efi.h>



#include "efistub.h"



/*

 * Some firmware implementations have problems reading files in one go.

 * A read chunk size of 1MB seems to work for most platforms.

 *

 * Unfortunately, reading files in chunks triggers *other* bugs on some

 * platforms, so we provide a way to disable this workaround, which can

 * be done by passing "efi=nochunk" on the EFI boot stub command line.

 *

 * If you experience issues with initrd images being corrupt it's worth

 * trying efi=nochunk, but chunking is enabled by default on x86 because

 * there are far more machines that require the workaround than those that

 * break with it enabled.

 */

#define EFI_READ_CHUNK_SIZE	SZ_1M



struct file_info {

	efi_file_protocol_t *handle;

	u64 size;

};



static efi_status_t efi_file_size(void *__fh, efi_char16_t *filename_16,

				  void **handle, u64 *file_sz)

{

	efi_file_protocol_t *h, *fh = __fh;

	efi_file_info_t *info;

	efi_status_t status;

	efi_guid_t info_guid = EFI_FILE_INFO_ID;

	unsigned long info_sz;



	status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, 0);

	if (status != EFI_SUCCESS) {

		efi_printk("Failed to open file: ");

		efi_char16_printk(filename_16);

		efi_printk("\n");

		return status;

	}



	*handle = h;



	info_sz = 0;

	status = h->get_info(h, &info_guid, &info_sz, NULL);

	if (status != EFI_BUFFER_TOO_SMALL) {

		efi_printk("Failed to get file info size\n");

		return status;

	}



grow:

	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, info_sz,

			     (void **)&info);

	if (status != EFI_SUCCESS) {

		efi_printk("Failed to alloc mem for file info\n");

		return status;

	}



	status = h->get_info(h, &info_guid, &info_sz, info);

	if (status == EFI_BUFFER_TOO_SMALL) {

		efi_bs_call(free_pool, info);

		goto grow;

	}



	*file_sz = info->file_size;

	efi_bs_call(free_pool, info);



	if (status != EFI_SUCCESS)

		efi_printk("Failed to get initrd info\n");



	return status;

}



static efi_status_t efi_file_read(efi_file_protocol_t *handle,

				  unsigned long *size, void *addr)

{

	return handle->read(handle, size, addr);

}



static efi_status_t efi_file_close(efi_file_protocol_t *handle)

{

	return handle->close(handle);

}



static efi_status_t efi_open_volume(efi_loaded_image_t *image,

				    efi_file_protocol_t **__fh)

{

	efi_simple_file_system_protocol_t *io;

	efi_file_protocol_t *fh;

	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;

	efi_status_t status;

	efi_handle_t handle = image->device_handle;



	status = efi_bs_call(handle_protocol, handle, &fs_proto, (void **)&io);

	if (status != EFI_SUCCESS) {

		efi_printk("Failed to handle fs_proto\n");

		return status;

	}



	status = io->open_volume(io, &fh);

	if (status != EFI_SUCCESS)

		efi_printk("Failed to open volume\n");

	else

		*__fh = fh;



	return status;

}



/*

 * Check the cmdline for a LILO-style file= arguments.

 *

 * We only support loading a file from the same filesystem as

 * the kernel image.

 */

efi_status_t handle_cmdline_files(efi_loaded_image_t *image,

				  char *cmd_line, char *option_string,

				  unsigned long max_addr,

				  unsigned long *load_addr,

				  unsigned long *load_size)

{

	unsigned long efi_chunk_size = ULONG_MAX;

	struct file_info *files;

	unsigned long file_addr;

	u64 file_size_total;

	efi_file_protocol_t *fh = NULL;

	efi_status_t status;

	int nr_files;

	char *str;

	int i, j, k;



	if (IS_ENABLED(CONFIG_X86) && !nochunk())

		efi_chunk_size = EFI_READ_CHUNK_SIZE;



	file_addr = 0;

	file_size_total = 0;



	str = cmd_line;



	j = 0;			/* See close_handles */



	if (!load_addr || !load_size)

		return EFI_INVALID_PARAMETER;



	*load_addr = 0;

	*load_size = 0;



	if (!str || !*str)

		return EFI_SUCCESS;



	for (nr_files = 0; *str; nr_files++) {

		str = strstr(str, option_string);

		if (!str)

			break;



		str += strlen(option_string);



		/* Skip any leading slashes */

		while (*str == '/' || *str == '\\')

			str++;



		while (*str && *str != ' ' && *str != '\n')

			str++;

	}



	if (!nr_files)

		return EFI_SUCCESS;



	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,

			     nr_files * sizeof(*files), (void **)&files);

	if (status != EFI_SUCCESS) {

		pr_efi_err("Failed to alloc mem for file handle list\n");

		goto fail;

	}



	str = cmd_line;

	for (i = 0; i < nr_files; i++) {

		struct file_info *file;

		efi_char16_t filename_16[256];

		efi_char16_t *p;



		str = strstr(str, option_string);

		if (!str)

			break;



		str += strlen(option_string);



		file = &files[i];

		p = filename_16;



		/* Skip any leading slashes */

		while (*str == '/' || *str == '\\')

			str++;



		while (*str && *str != ' ' && *str != '\n') {

			if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))

				break;



			if (*str == '/') {

				*p++ = '\\';

				str++;

			} else {

				*p++ = *str++;

			}

		}



		*p = '\0';



		/* Only open the volume once. */

		if (!i) {

			status = efi_open_volume(image, &fh);

			if (status != EFI_SUCCESS)

				goto free_files;

		}



		status = efi_file_size(fh, filename_16, (void **)&file->handle,

				       &file->size);

		if (status != EFI_SUCCESS)

			goto close_handles;



		file_size_total += file->size;

	}



	if (file_size_total) {

		unsigned long addr;



		/*

		 * Multiple files need to be at consecutive addresses in memory,

		 * so allocate enough memory for all the files.  This is used

		 * for loading multiple files.

		 */

		status = efi_allocate_pages(file_size_total, &file_addr, max_addr);

		if (status != EFI_SUCCESS) {

			pr_efi_err("Failed to alloc highmem for files\n");

			goto close_handles;

		}



		/* We've run out of free low memory. */

		if (file_addr > max_addr) {

			pr_efi_err("We've run out of free low memory\n");

			status = EFI_INVALID_PARAMETER;

			goto free_file_total;

		}



		addr = file_addr;

		for (j = 0; j < nr_files; j++) {

			unsigned long size;



			size = files[j].size;

			while (size) {

				unsigned long chunksize;



				if (size > efi_chunk_size)

					chunksize = efi_chunk_size;

				else

					chunksize = size;



				status = efi_file_read(files[j].handle,

						       &chunksize,

						       (void *)addr);

				if (status != EFI_SUCCESS) {

					pr_efi_err("Failed to read file\n");

					goto free_file_total;

				}

				addr += chunksize;

				size -= chunksize;

			}



			efi_file_close(files[j].handle);

		}



	}



	efi_bs_call(free_pool, files);



	*load_addr = file_addr;

	*load_size = file_size_total;



	return status;



free_file_total:

	efi_free(file_size_total, file_addr);



close_handles:

	for (k = j; k < i; k++)

		efi_file_close(files[k].handle);

free_files:

	efi_bs_call(free_pool, files);

fail:

	*load_addr = 0;

	*load_size = 0;



	return status;

}

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