Commit e4fbf476 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Catalin Marinas
Browse files

efi: stub: implement efi_get_random_bytes() based on EFI_RNG_PROTOCOL 



This exposes the firmware's implementation of EFI_RNG_PROTOCOL via a new
function efi_get_random_bytes().

Reviewed-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent c031a421

drivers/firmware/efi/libstub/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \ 
				   $(patsubst %.c,lib-%.o,$(arm-deps))



lib-$(CONFIG_ARM)		+= arm32-stub.o

lib-$(CONFIG_ARM64)		+= arm64-stub.o

lib-$(CONFIG_ARM64)		+= arm64-stub.o random.o

CFLAGS_arm64-stub.o 		:= -DTEXT_OFFSET=$(TEXT_OFFSET)



#

drivers/firmware/efi/libstub/efistub.h

+3 −0
Original line number Diff line number Diff line
@@ -43,4 +43,7 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size, 
		     unsigned long desc_size, efi_memory_desc_t *runtime_map,

		     int *count);



efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table,

				  unsigned long size, u8 *out);



#endif

drivers/firmware/efi/libstub/random.c

0 → 100644
+35 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2016 Linaro Ltd;  <ard.biesheuvel@linaro.org>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 *

 */



#include <linux/efi.h>

#include <asm/efi.h>



#include "efistub.h"



struct efi_rng_protocol {

	efi_status_t (*get_info)(struct efi_rng_protocol *,

				 unsigned long *, efi_guid_t *);

	efi_status_t (*get_rng)(struct efi_rng_protocol *,

				efi_guid_t *, unsigned long, u8 *out);

};



efi_status_t efi_get_random_bytes(efi_system_table_t *sys_table_arg,

				  unsigned long size, u8 *out)

{

	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;

	efi_status_t status;

	struct efi_rng_protocol *rng;



	status = efi_call_early(locate_protocol, &rng_proto, NULL,

				(void **)&rng);

	if (status != EFI_SUCCESS)

		return status;



	return rng->get_rng(rng, NULL, size, out);

}

include/linux/efi.h

+5 −1
Original line number Diff line number Diff line
@@ -299,7 +299,7 @@ typedef struct { 
	void *open_protocol_information;

	void *protocols_per_handle;

	void *locate_handle_buffer;

	void *locate_protocol;

	efi_status_t (*locate_protocol)(efi_guid_t *, void *, void **);

	void *install_multiple_protocol_interfaces;

	void *uninstall_multiple_protocol_interfaces;

	void *calculate_crc32;
@@ -599,6 +599,10 @@ void efi_native_runtime_setup(void); 
#define EFI_PROPERTIES_TABLE_GUID \

    EFI_GUID(  0x880aaca3, 0x4adc, 0x4a04, 0x90, 0x79, 0xb7, 0x47, 0x34, 0x08, 0x25, 0xe5 )



#define EFI_RNG_PROTOCOL_GUID \

	EFI_GUID(0x3152bca5, 0xeade, 0x433d, \

		 0x86, 0x2e, 0xc0, 0x1c, 0xdc, 0x29, 0x1f, 0x44)



typedef struct {

	efi_guid_t guid;

	u64 table;