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Commit 568bc4e8 authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Ingo Molnar
Browse files

efi/arm*/libstub: Invoke EFI_RNG_PROTOCOL to seed the UEFI RNG table 



Invoke the EFI_RNG_PROTOCOL protocol in the context of the stub and
install the Linux-specific RNG seed UEFI config table. This will be
picked up by the EFI routines in the core kernel to seed the kernel
entropy pool.

Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarMatt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20161112213237.8804-6-matt@codeblueprint.co.uk


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent a6a14469

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

+2 −0
Original line number Diff line number Diff line
@@ -340,6 +340,8 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, 
	if (status != EFI_SUCCESS)

		pr_efi_err(sys_table, "Failed initrd from command line!\n");



	efi_random_get_seed(sys_table);



	new_fdt_addr = fdt_addr;

	status = allocate_new_fdt_and_exit_boot(sys_table, handle,

				&new_fdt_addr, dram_base + MAX_FDT_OFFSET,

drivers/firmware/efi/libstub/efistub.h

+2 −0
Original line number Diff line number Diff line
@@ -71,4 +71,6 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, 


efi_status_t check_platform_features(efi_system_table_t *sys_table_arg);



efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg);



#endif

drivers/firmware/efi/libstub/random.c

+48 −0
Original line number Diff line number Diff line
@@ -143,3 +143,51 @@ efi_status_t efi_random_alloc(efi_system_table_t *sys_table_arg, 


	return status;

}



#define RANDOM_SEED_SIZE	32



efi_status_t efi_random_get_seed(efi_system_table_t *sys_table_arg)

{

	efi_guid_t rng_proto = EFI_RNG_PROTOCOL_GUID;

	efi_guid_t rng_algo_raw = EFI_RNG_ALGORITHM_RAW;

	efi_guid_t rng_table_guid = LINUX_EFI_RANDOM_SEED_TABLE_GUID;

	struct efi_rng_protocol *rng;

	struct linux_efi_random_seed *seed;

	efi_status_t status;



	status = efi_call_early(locate_protocol, &rng_proto, NULL,

				(void **)&rng);

	if (status != EFI_SUCCESS)

		return status;



	status = efi_call_early(allocate_pool, EFI_RUNTIME_SERVICES_DATA,

				sizeof(*seed) + RANDOM_SEED_SIZE,

				(void **)&seed);

	if (status != EFI_SUCCESS)

		return status;



	status = rng->get_rng(rng, &rng_algo_raw, RANDOM_SEED_SIZE,

			      seed->bits);

	if (status == EFI_UNSUPPORTED)

		/*

		 * Use whatever algorithm we have available if the raw algorithm

		 * is not implemented.

		 */

		status = rng->get_rng(rng, NULL, RANDOM_SEED_SIZE,

				      seed->bits);



	if (status != EFI_SUCCESS)

		goto err_freepool;



	seed->size = RANDOM_SEED_SIZE;

	status = efi_call_early(install_configuration_table, &rng_table_guid,

				seed);

	if (status != EFI_SUCCESS)

		goto err_freepool;



	return EFI_SUCCESS;



err_freepool:

	efi_call_early(free_pool, seed);

	return status;

}

include/linux/efi.h

+1 −0
Original line number Diff line number Diff line
@@ -589,6 +589,7 @@ void efi_native_runtime_setup(void); 
#define DEVICE_TREE_GUID			EFI_GUID(0xb1b621d5, 0xf19c, 0x41a5,  0x83, 0x0b, 0xd9, 0x15, 0x2c, 0x69, 0xaa, 0xe0)

#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)

#define EFI_RNG_ALGORITHM_RAW			EFI_GUID(0xe43176d7, 0xb6e8, 0x4827,  0xb7, 0x84, 0x7f, 0xfd, 0xc4, 0xb6, 0x85, 0x61)

#define EFI_MEMORY_ATTRIBUTES_TABLE_GUID	EFI_GUID(0xdcfa911d, 0x26eb, 0x469f,  0xa2, 0x20, 0x38, 0xb7, 0xdc, 0x46, 0x12, 0x20)

#define EFI_CONSOLE_OUT_DEVICE_GUID		EFI_GUID(0xd3b36f2c, 0xd551, 0x11d4,  0x9a, 0x46, 0x00, 0x90, 0x27, 0x3f, 0xc1, 0x4d)