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authorArd Biesheuvel <ard.biesheuvel@linaro.org>2016-11-12 21:32:33 +0000
committerIngo Molnar <mingo@kernel.org>2016-11-13 08:23:15 +0100
commit568bc4e87033d232c5fd00d5b0cd22a2ccc04944 (patch)
treef2bb9e8fa9445523c9c33a1afc5a9601fcf1f4ec
parenta6a144698db93a2c456d1e3811140cadef1ba0e3 (diff)
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>
-rw-r--r--drivers/firmware/efi/libstub/arm-stub.c2
-rw-r--r--drivers/firmware/efi/libstub/efistub.h2
-rw-r--r--drivers/firmware/efi/libstub/random.c48
-rw-r--r--include/linux/efi.h1
4 files changed, 53 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c
index 993aa56..b4f7d78 100644
--- a/drivers/firmware/efi/libstub/arm-stub.c
+++ b/drivers/firmware/efi/libstub/arm-stub.c
@@ -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,
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index fe1f225..b98824e 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -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
diff --git a/drivers/firmware/efi/libstub/random.c b/drivers/firmware/efi/libstub/random.c
index f8e2e5a..3a3feac 100644
--- a/drivers/firmware/efi/libstub/random.c
+++ b/drivers/firmware/efi/libstub/random.c
@@ -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;
+}
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 85e28b1..f5a821d 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -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)