Moving all SM stuff to EAC.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

src/hsm/eac.c

@@ -0,0 +1,67 @@
+/* 
+ * This file is part of the Pico HSM distribution (https://github.com/polhenarejos/pico-hsm).
+ * Copyright (c) 2022 Pol Henarejos.
+ * 
+ * This program is free software: you can redistribute it and/or modify  
+ * it under the terms of the GNU General Public License as published by  
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but 
+ * WITHOUT ANY WARRANTY; without even the implied warranty of 
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License 
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "eac.h"
+#include "crypto_utils.h"
+#include "random.h"
+#include "mbedtls/cmac.h"
+
+static uint8_t nonce[8];
+static uint8_t auth_token[8];
+static uint8_t sm_kmac[16];
+static uint8_t sm_kenc[16];
+static MSE_protocol sm_protocol;
+
+bool is_secured_apdu() {
+    return (CLA(apdu) & 0xC);
+}
+
+void sm_derive_key(const uint8_t *input, size_t input_len, uint8_t counter, const uint8_t *nonce, size_t nonce_len, uint8_t *out) {
+    uint8_t *b = (uint8_t *)calloc(1, input_len+nonce_len+4);
+    if (input)
+        memcpy(b, input, input_len);
+    if (nonce)
+        memcpy(b+input_len, nonce, nonce_len);
+    b[input_len+nonce_len+3] = counter;
+    uint8_t digest[20];
+    generic_hash(MBEDTLS_MD_SHA1, b, input_len+nonce_len+4, digest);
+    memcpy(out, digest, 16);
+    free(b);
+}
+
+void sm_derive_all_keys(const uint8_t *derived, size_t derived_len) {
+    memcpy(nonce, random_bytes_get(8), 8);
+    sm_derive_key(derived, derived_len, 1, nonce, sizeof(nonce), sm_kenc);
+    sm_derive_key(derived, derived_len, 2, nonce, sizeof(nonce), sm_kmac);
+}
+
+void sm_set_protocol(MSE_protocol proto) {
+    sm_protocol = proto;
+}
+
+MSE_protocol sm_get_protocol() {
+    return sm_protocol;
+}
+
+uint8_t *sm_get_nonce() {
+    return nonce;
+}
+
+int sm_sign(uint8_t *in, size_t in_len, uint8_t *out) {
+    return mbedtls_cipher_cmac(mbedtls_cipher_info_from_type(MBEDTLS_CIPHER_AES_128_ECB), sm_kmac, 128, in, in_len, out);
+}
+