Make available the default random number generator in barebox to EFI applications during boot time.
Signed-off-by: Ahmad Fatoum <[email protected]> --- efi/loader/protocols/Kconfig | 8 ++ efi/loader/protocols/Makefile | 1 + efi/loader/protocols/rng.c | 165 ++++++++++++++++++++++++++++++++++ 3 files changed, 174 insertions(+) create mode 100644 efi/loader/protocols/rng.c diff --git a/efi/loader/protocols/Kconfig b/efi/loader/protocols/Kconfig index 8c8bfabd7c0f..7d5e203d121a 100644 --- a/efi/loader/protocols/Kconfig +++ b/efi/loader/protocols/Kconfig @@ -31,4 +31,12 @@ config EFI_LOADER_UNICODE_CAPITALIZATION set, only the the correct handling of the letters of the codepage used by the FAT file system is ensured. +config EFI_LOADER_RNG + bool "EFI_RNG_PROTOCOL support" + depends on HWRNG + default y + help + Provide a EFI_RNG_PROTOCOL implementation using the hardware random + number generator of the platform. + endmenu diff --git a/efi/loader/protocols/Makefile b/efi/loader/protocols/Makefile index b6e39b0666da..ecc0fc392856 100644 --- a/efi/loader/protocols/Makefile +++ b/efi/loader/protocols/Makefile @@ -6,3 +6,4 @@ obj-$(CONFIG_VIDEO) += gop.o obj-$(CONFIG_CONSOLE_FULL) += console.o obj-$(CONFIG_EFI_LOADER_HII) += hii.o hii_config.o obj-$(CONFIG_EFI_LOADER_UNICODE_COLLATION_PROTOCOL2) += unicode_collation.o +obj-$(CONFIG_EFI_LOADER_RNG) += rng.o diff --git a/efi/loader/protocols/rng.c b/efi/loader/protocols/rng.c new file mode 100644 index 000000000000..9c3caa82f884 --- /dev/null +++ b/efi/loader/protocols/rng.c @@ -0,0 +1,165 @@ +// SPDX-License-Identifier: GPL-2.0+ +// SPDX-Comment: Origin-URL: https://github.com/u-boot/u-boot/blob/58da850c87240c397242ebd47341c69aa6278119/lib/efi_loader/efi_rng.c +/* + * Copyright (c) 2019, Linaro Limited + */ + +#include <linux/hw_random.h> +#include <stdlib.h> +#include <efi/loader.h> +#include <efi/protocol/rng.h> +#include <efi/devicepath.h> +#include <efi/loader/devicepath.h> +#include <efi/loader/object.h> +#include <efi/loader/trace.h> +#include <efi/guid.h> +#include <efi/error.h> +#include <xfuncs.h> + +struct efi_rng_obj { + struct efi_object header; + struct hwrng *hwrng; + struct efi_rng_protocol ops; +}; + +#define to_efi_rng_obj(this) container_of(this, struct efi_rng_obj, ops) + +/** + * rng_getinfo() - get information about random number generation + * + * This function implement the GetInfo() service of the EFI random number + * generator protocol. See the UEFI spec for details. + * + * @this: random number generator protocol instance + * @rng_algorithm_list_size: number of random number generation algorithms + * @rng_algorithm_list: descriptions of random number generation + * algorithms + * Return: status code + */ +static efi_status_t EFIAPI rng_getinfo(struct efi_rng_protocol *this, + efi_uintn_t *rng_algorithm_list_size, + efi_guid_t *rng_algorithm_list) +{ + efi_status_t ret = EFI_SUCCESS; + efi_guid_t rng_algo_guid = EFI_RNG_ALGORITHM_RAW; + + EFI_ENTRY("%p, %p, %p", this, rng_algorithm_list_size, + rng_algorithm_list); + + if (!this || !rng_algorithm_list_size) { + ret = EFI_INVALID_PARAMETER; + goto back; + } + + if (!rng_algorithm_list || + *rng_algorithm_list_size < sizeof(*rng_algorithm_list)) { + *rng_algorithm_list_size = sizeof(*rng_algorithm_list); + ret = EFI_BUFFER_TOO_SMALL; + goto back; + } + + /* + * For now, use EFI_RNG_ALGORITHM_RAW as the default + * algorithm. If a new algorithm gets added in the + * future through a Kconfig, rng_algo_guid will be set + * based on that Kconfig option + */ + *rng_algorithm_list_size = sizeof(*rng_algorithm_list); + *rng_algorithm_list = rng_algo_guid; + +back: + return EFI_EXIT(ret); +} + +/** + * rng_getval() - get random value + * + * This function implement the GetRng() service of the EFI random number + * generator protocol. See the UEFI spec for details. + * + * @this: random number generator protocol instance + * @rng_algorithm: random number generation algorithm + * @rng_value_length: number of random bytes to generate, buffer length + * @rng_value: buffer to receive random bytes + * Return: status code + */ +static efi_status_t EFIAPI rng_getval(struct efi_rng_protocol *this, + efi_guid_t *rng_algorithm, + efi_uintn_t rng_value_length, + uint8_t *rng_value) +{ + int ret; + efi_status_t status = EFI_SUCCESS; + const efi_guid_t rng_raw_guid = EFI_RNG_ALGORITHM_RAW; + struct efi_rng_obj *rngobj = to_efi_rng_obj(this); + + EFI_ENTRY("%p, %p, %zu, %p", this, rng_algorithm, rng_value_length, + rng_value); + + if (!this || !rng_value || !rng_value_length) { + status = EFI_INVALID_PARAMETER; + goto back; + } + + if (rng_algorithm) { + EFI_PRINT("RNG algorithm %pUl\n", rng_algorithm); + if (efi_guidcmp(*rng_algorithm, rng_raw_guid)) { + status = EFI_UNSUPPORTED; + goto back; + } + } + + ret = hwrng_get_crypto_bytes(rngobj->hwrng, rng_value, rng_value_length); + if (ret < 0) { + EFI_PRINT("Rng device read failed\n"); + status = EFI_DEVICE_ERROR; + goto back; + } + +back: + return EFI_EXIT(status); +} + +/** + * efi_rng_register() - register EFI_RNG_PROTOCOL + * + * If a HWRNG device is available, the Random Number Generator Protocol is + * registered. + * + * Return: An EFI error status + */ +static efi_status_t efi_rng_register(void *data) +{ + struct efi_rng_obj *rngobj; + struct hwrng *rng; + struct efi_device_path *dp; + efi_handle_t handle; + + rng = hwrng_get_first(); + if (IS_ERR(rng)) + return EFI_UNSUPPORTED; + + rngobj = xzalloc(sizeof(*rngobj)); + + rngobj->hwrng = rng; + rngobj->ops.get_info = rng_getinfo; + rngobj->ops.get_rng = rng_getval; + + dp = efi_dp_from_cdev(&rng->cdev, true); + + efi_add_handle(&rngobj->header); + + handle = &rngobj->header; + + return efi_install_multiple_protocol_interfaces(&handle, + &efi_device_path_protocol_guid, dp, + &efi_rng_protocol_guid, &rngobj->ops, + NULL); +} + +static int efi_rng_init(void) +{ + efi_register_deferred_init(efi_rng_register, NULL); + return 0; +} +device_initcall(efi_rng_init); -- 2.47.3
