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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: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Kees 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: Ingo Molnar <mingo@kernel.org>
hifive-unleashed-5.1
Ard Biesheuvel 2016-11-12 21:32:33 +00:00 committed by Ingo Molnar
parent a6a144698d
commit 568bc4e870
4 changed files with 53 additions and 0 deletions
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2
drivers/firmware/efi/libstub/arm-stub.c
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@ -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,

2
drivers/firmware/efi/libstub/efistub.h
View File

@ -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

48
drivers/firmware/efi/libstub/random.c
View File

@ -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;
}

1
include/linux/efi.h
View File

@ -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)