Hi,
On 3/30/21 8:32 PM, Alexandru Gagniuc wrote:
The STM32MP ROM provides several service. One of them is the ability to verify ecdsa256 signatures. Hook the ROM API into the ECDSA uclass.
Signed-off-by: Alexandru Gagniucmr.nuke.me@gmail.com
arch/arm/mach-stm32mp/Kconfig | 9 +++ arch/arm/mach-stm32mp/Makefile | 1 + arch/arm/mach-stm32mp/ecdsa_romapi.c | 106 +++++++++++++++++++++++++++ 3 files changed, 116 insertions(+) create mode 100644 arch/arm/mach-stm32mp/ecdsa_romapi.c
diff --git a/arch/arm/mach-stm32mp/Kconfig b/arch/arm/mach-stm32mp/Kconfig index 079d66a80c..92c4c5a7b0 100644 --- a/arch/arm/mach-stm32mp/Kconfig +++ b/arch/arm/mach-stm32mp/Kconfig @@ -121,6 +121,15 @@ config STM32_ETZPC help Say y to enable STM32 Extended TrustZone Protection
+config STM32_ECDSA_VERIFY
- bool "STM32 ECDSA verification via the ROM API"
- depends on SPL_ECDSA_VERIFY
- default y
- help
Say y to enable the uclass driver for ECDSA verification using theROM API provided on STM32MP.The ROM API is only available during SPL for now.- config CMD_STM32KEY bool "command stm32key to fuse public key hash" default y
diff --git a/arch/arm/mach-stm32mp/Makefile b/arch/arm/mach-stm32mp/Makefile index aa39867080..0942092d8e 100644 --- a/arch/arm/mach-stm32mp/Makefile +++ b/arch/arm/mach-stm32mp/Makefile @@ -10,6 +10,7 @@ obj-y += bsec.o
ifdef CONFIG_SPL_BUILD obj-y += spl.o +obj-$(CONFIG_STM32_ECDSA_VERIFY) += ecdsa_romapi.o else obj-y += cmd_stm32prog/ obj-$(CONFIG_CMD_STM32KEY) += cmd_stm32key.o diff --git a/arch/arm/mach-stm32mp/ecdsa_romapi.c b/arch/arm/mach-stm32mp/ecdsa_romapi.c new file mode 100644 index 0000000000..ca32925a12 --- /dev/null +++ b/arch/arm/mach-stm32mp/ecdsa_romapi.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*
- STM32MP ECDSA verification via the ROM API
- Implements ECDSA signature verification via the STM32MP ROM.
- */
#define LOG_CATEGORY UCLASS_ECDSA
to allow filtering with log command
+#include <asm/system.h> +#include <dm/device.h> +#include <linux/types.h> +#include <u-boot/ecdsa.h> +#include <crypto/ecdsa-uclass.h> +#include <linux/libfdt.h> +#include <dm/platdata.h>
+#define ROM_API_SUCCESS 0x77 +#define ROM_API_ECDSA_ALGO_PRIME_256V1 1 +#define ROM_API_ECDSA_ALGO_BRAINPOOL_256 2
+#define ROM_API_OFFSET_ECDSA_CHECK_KEY 0x5c +#define ROM_API_OFFSET_ECDSA_VERIFY 0x60
+struct ecdsa_rom_api {
- uint32_t (*ecdsa_check_key)(const void *pubkey_in, void *pubkey_out);
- uint32_t (*ecdsa_verify_signature)(const void *hash, const void *pubkey,
const void *signature,uint32_t ecc_algo);+};
+/*
- Without forcing the ".data" section, this would get saved in ".bss". BSS
- will be cleared soon after, so it's not suitable.
- */
+static uintptr_t rom_api_loc __section(".data");
+/*
- The ROM gives us the API location in r0 when starting. This is only available
- during SPL, as there isn't (yet) a mechanism to pass this on to u-boot.
- */
+void save_boot_params(unsigned long r0, unsigned long r1, unsigned long r2,
unsigned long r3)+{
- rom_api_loc = r0;
- save_boot_params_ret();
+}
+static void stm32mp_rom_get_ecdsa_functions(struct ecdsa_rom_api *rom) +{
- uintptr_t verify_ptr = rom_api_loc + ROM_API_OFFSET_ECDSA_VERIFY;
- uintptr_t check_key_ptr = rom_api_loc + ROM_API_OFFSET_ECDSA_CHECK_KEY;
- rom->ecdsa_verify_signature = *(void **)verify_ptr;
- rom->ecdsa_check_key = *(void **)check_key_ptr;
the check key API (rom->ecdsa_check_key at offset ROM_API_OFFSET_ECDSA_CHECK_KEY)
is never used...
Do you plan to use it in futures patches ?
if no, you can remove it.
PS: this API is no more used in recent TF-A downstrean version based on auth-framework
+}
+static int ecdsa_key_algo(const char *curve_name) +{
- if (!strcmp(curve_name, "prime256v1"))
return ROM_API_ECDSA_ALGO_PRIME_256V1;- else if (!strcmp(curve_name, "brainpool256"))
return ROM_API_ECDSA_ALGO_BRAINPOOL_256;- else
return -ENOPROTOOPT;+}
+static int romapi_ecdsa_verify(struct udevice *dev,
const struct ecdsa_public_key *pubkey,const void *hash, size_t hash_len,const void *signature, size_t sig_len)+{
- struct ecdsa_rom_api rom;
- uint8_t raw_key[64];
- uint32_t rom_ret;
- int algo;
- /* The ROM API can only handle 256-bit ECDSA keys. */
- if (sig_len != 64 || hash_len != 32 || pubkey->size_bits != 256)
return -EINVAL;- algo = ecdsa_key_algo(pubkey->curve_name);
- if (algo < 0)
return algo;- /* The ROM API wants the (X, Y) coordinates concatenated. */
- memcpy(raw_key, pubkey->x, 32);
- memcpy(raw_key + 32, pubkey->y, 32);
- stm32mp_rom_get_ecdsa_functions(&rom);
- rom_ret = rom.ecdsa_verify_signature(hash, raw_key, signature, algo);
- return rom_ret == ROM_API_SUCCESS ? 0 : -EPERM;
+}
+static const struct ecdsa_ops rom_api_ops = {
- .verify = romapi_ecdsa_verify,
+};
+U_BOOT_DRIVER(stm32mp_rom_api_ecdsa) = {
- .name = "stm32mp_rom_api_ecdsa",
- .id = UCLASS_ECDSA,
- .ops = &rom_api_ops,
- .flags = DM_FLAG_PRE_RELOC,
+};
+U_BOOT_DRVINFO(stm32mp_rom_api_ecdsa) = {
- .name = "stm32mp_rom_api_ecdsa",
+};
Regards
Patrick