core: crypto: add support for SM2 PKE

Adds SM2 Public Key Encryption [1] using LibTomCrypt. The TA interface
complies with the GlobalPlatform TEE Internal Core API version 1.2.

SM2 is enabled with CFG_CRYPTO_SM2_PKE=y (default y) which currently
requires that CFG_CRYPTOLIB_NAME=tomcrypt. An Mbed TLS implementation
could be added later if needed.

[1] http://www.gmbz.org.cn/main/postDetail.html?id=20180724110812

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>

5 files changed, 80 insertions, 0 deletions

diff --git a/core/crypto.mk b/core/crypto.mk
index e9ae3b9a..d7b5a074 100644
--- a/core/crypto.mk
+++ b/core/crypto.mk
@@ -37,7 +37,14 @@ CFG_CRYPTO_SM3 ?= y
 CFG_CRYPTO_DSA ?= y
 CFG_CRYPTO_RSA ?= y
 CFG_CRYPTO_DH ?= y
+# ECC includes ECDSA and ECDH
 CFG_CRYPTO_ECC ?= y
+ifeq ($(CFG_CRYPTOLIB_NAME),tomcrypt)
+CFG_CRYPTO_SM2_PKE ?= y
+endif
+ifeq ($(CFG_CRYPTOLIB_NAME)-$(CFG_CRYPTO_SM2_PKE),mbedtls-y)
+$(error Error: CFG_CRYPTO_SM2_PKE=y requires CFG_CRYPTOLIB_NAME=tomcrypt)
+endif
 
 # Authenticated encryption
 CFG_CRYPTO_CCM ?= y
@@ -128,6 +135,8 @@ $(eval $(call cryp-dep-one, GCM, AES))
 $(eval $(call cryp-dep-one, AES, ECB CBC CTR CTS XTS))
 # If no DES cipher mode is left, disable DES
 $(eval $(call cryp-dep-one, DES, ECB CBC))
+# SM2 is Elliptic Curve Cryptography, it uses some generic ECC functions
+$(eval $(call cryp-dep-one, SM2_PKE, ECC))
 
 ###############################################################
 # libtomcrypt (LTC) specifics, phase #1
@@ -158,6 +167,7 @@ core-ltc-vars += AES_ARM64_CE AES_ARM32_CE
 core-ltc-vars += SHA1_ARM32_CE SHA1_ARM64_CE
 core-ltc-vars += SHA256_ARM32_CE SHA256_ARM64_CE
 core-ltc-vars += SIZE_OPTIMIZATION
+core-ltc-vars += SM2_PKE
 # Assigned selected CFG_CRYPTO_xxx as _CFG_CORE_LTC_xxx
 $(foreach v, $(core-ltc-vars), $(eval _CFG_CORE_LTC_$(v) := $(CFG_CRYPTO_$(v))))
 _CFG_CORE_LTC_MPI := $(CFG_CORE_MBEDTLS_MPI)
diff --git a/core/crypto/crypto.c b/core/crypto/crypto.c
index e4cbd6b3..eeaa269b 100644
--- a/core/crypto/crypto.c
+++ b/core/crypto/crypto.c
@@ -691,3 +691,23 @@ crypto_acipher_ecc_shared_secret(struct ecc_keypair *private_key __unused,
 	return TEE_ERROR_NOT_IMPLEMENTED;
 }
 #endif /*!CFG_CRYPTO_ECC*/
+
+#if !defined(CFG_CRYPTO_SM2_PKE)
+TEE_Result crypto_acipher_sm2_pke_decrypt(struct ecc_keypair *key __unused,
+					  const uint8_t *src __unused,
+					  size_t src_len __unused,
+					  uint8_t *dst __unused,
+					  size_t *dst_len __unused)
+{
+	return TEE_ERROR_NOT_IMPLEMENTED;
+}
+
+TEE_Result crypto_acipher_sm2_pke_encrypt(struct ecc_public_key *key __unused,
+					  const uint8_t *src __unused,
+					  size_t src_len __unused,
+					  uint8_t *dst __unused,
+					  size_t *dst_len __unused)
+{
+	return TEE_ERROR_NOT_IMPLEMENTED;
+}
+#endif /* !CFG_CRYPTO_SM2_PKE */
diff --git a/core/include/crypto/crypto.h b/core/include/crypto/crypto.h
index 1ca44d2b..7da74461 100644
--- a/core/include/crypto/crypto.h
+++ b/core/include/crypto/crypto.h
@@ -238,6 +238,12 @@ TEE_Result crypto_acipher_ecc_shared_secret(struct ecc_keypair *private_key,
 					    struct ecc_public_key *public_key,
 					    void *secret,
 					    unsigned long *secret_len);
+TEE_Result crypto_acipher_sm2_pke_decrypt(struct ecc_keypair *key,
+					  const uint8_t *src, size_t src_len,
+					  uint8_t *dst, size_t *dst_len);
+TEE_Result crypto_acipher_sm2_pke_encrypt(struct ecc_public_key *key,
+					  const uint8_t *src, size_t src_len,
+					  uint8_t *dst, size_t *dst_len);
 
 /*
  * Verifies a SHA-256 hash, doesn't require crypto_init() to be called in
diff --git a/core/lib/libtomcrypt/ecc.c b/core/lib/libtomcrypt/ecc.c
index 8322ba2e..051da77e 100644
--- a/core/lib/libtomcrypt/ecc.c
+++ b/core/lib/libtomcrypt/ecc.c
@@ -124,6 +124,13 @@ static TEE_Result ecc_get_curve_info(uint32_t curve, uint32_t algo,
 		    (algo != TEE_ALG_ECDH_P521))
 			return TEE_ERROR_BAD_PARAMETERS;
 		break;
+	case TEE_ECC_CURVE_SM2:
+		size_bits = 256;
+		size_bytes = 32;
+		name = "SM2";
+		if ((algo != 0) && (algo != TEE_ALG_SM2_PKE))
+			return TEE_ERROR_BAD_PARAMETERS;
+		break;
 	default:
 		return TEE_ERROR_NOT_SUPPORTED;
 	}
diff --git a/core/tee/tee_svc_cryp.c b/core/tee/tee_svc_cryp.c
index 80892f29..622fd299 100644
--- a/core/tee/tee_svc_cryp.c
+++ b/core/tee/tee_svc_cryp.c
@@ -486,6 +486,14 @@ static const struct tee_cryp_obj_type_props tee_cryp_obj_props[] = {
 	PROP(TEE_TYPE_ECDH_KEYPAIR, 1, 192, 521,
 		sizeof(struct ecc_keypair),
 		tee_cryp_obj_ecc_keypair_attrs),
+
+	PROP(TEE_TYPE_SM2_PKE_PUBLIC_KEY, 1, 256, 256,
+	     sizeof(struct ecc_public_key),
+	     tee_cryp_obj_ecc_pub_key_attrs),
+
+	PROP(TEE_TYPE_SM2_PKE_KEYPAIR, 1, 256, 256,
+	     sizeof(struct ecc_keypair),
+	     tee_cryp_obj_ecc_keypair_attrs),
 };
 
 struct attr_ops {
@@ -1137,6 +1145,9 @@ TEE_Result tee_obj_attr_copy_from(struct tee_obj *o, const struct tee_obj *src)
 		} else if (o->info.objectType == TEE_TYPE_ECDH_PUBLIC_KEY) {
 			if (src->info.objectType != TEE_TYPE_ECDH_KEYPAIR)
 				return TEE_ERROR_BAD_PARAMETERS;
+		} else if (o->info.objectType == TEE_TYPE_SM2_PKE_PUBLIC_KEY) {
+			if (src->info.objectType != TEE_TYPE_SM2_PKE_KEYPAIR)
+				return TEE_ERROR_BAD_PARAMETERS;
 		} else {
 			return TEE_ERROR_BAD_PARAMETERS;
 		}
@@ -1225,11 +1236,13 @@ TEE_Result tee_obj_set_type(struct tee_obj *o, uint32_t obj_type,
 		break;
 	case TEE_TYPE_ECDSA_PUBLIC_KEY:
 	case TEE_TYPE_ECDH_PUBLIC_KEY:
+	case TEE_TYPE_SM2_PKE_PUBLIC_KEY:
 		res = crypto_acipher_alloc_ecc_public_key(o->attr,
 							  max_key_size);
 		break;
 	case TEE_TYPE_ECDSA_KEYPAIR:
 	case TEE_TYPE_ECDH_KEYPAIR:
+	case TEE_TYPE_SM2_PKE_KEYPAIR:
 		res = crypto_acipher_alloc_ecc_keypair(o->attr, max_key_size);
 		break;
 	default:
@@ -1480,6 +1493,9 @@ static TEE_Result get_ec_key_size(uint32_t curve, size_t *key_size)
 	case TEE_ECC_CURVE_NIST_P521:
 		*key_size = 521;
 		break;
+	case TEE_ECC_CURVE_SM2:
+		*key_size = 256;
+		break;
 	default:
 		return TEE_ERROR_NOT_SUPPORTED;
 	}
@@ -1880,6 +1896,7 @@ TEE_Result syscall_obj_generate_key(unsigned long obj, unsigned long key_size,
 
 	case TEE_TYPE_ECDSA_KEYPAIR:
 	case TEE_TYPE_ECDH_KEYPAIR:
+	case TEE_TYPE_SM2_PKE_KEYPAIR:
 		res = tee_svc_obj_generate_key_ecc(o, type_props, key_size,
 						  params, param_count);
 		if (res != TEE_SUCCESS)
@@ -2010,6 +2027,12 @@ static TEE_Result tee_svc_cryp_check_key_type(const struct tee_obj *o,
 	case TEE_MAIN_ALGO_ECDH:
 		req_key_type = TEE_TYPE_ECDH_KEYPAIR;
 		break;
+	case TEE_MAIN_ALGO_SM2_PKE:
+		if (mode == TEE_MODE_ENCRYPT)
+			req_key_type = TEE_TYPE_SM2_PKE_PUBLIC_KEY;
+		else
+			req_key_type = TEE_TYPE_SM2_PKE_KEYPAIR;
+		break;
 #if defined(CFG_CRYPTO_HKDF)
 	case TEE_MAIN_ALGO_HKDF:
 		req_key_type = TEE_TYPE_HKDF_IKM;
@@ -3402,6 +3425,20 @@ TEE_Result syscall_asymm_operate(unsigned long state,
 		}
 		break;
 
+	case TEE_ALG_SM2_PKE:
+		if (cs->mode == TEE_MODE_ENCRYPT) {
+			res = crypto_acipher_sm2_pke_encrypt(o->attr, src_data,
+							     src_len, dst_data,
+							     &dlen);
+		} else if (cs->mode == TEE_MODE_DECRYPT) {
+			res = crypto_acipher_sm2_pke_decrypt(o->attr, src_data,
+							     src_len, dst_data,
+							     &dlen);
+		} else {
+			res = TEE_ERROR_GENERIC;
+		}
+		break;
+
 	case TEE_ALG_RSAES_PKCS1_V1_5:
 	case TEE_ALG_RSAES_PKCS1_OAEP_MGF1_SHA1:
 	case TEE_ALG_RSAES_PKCS1_OAEP_MGF1_SHA224: