Splitting cmd_xxx() functions in separate files.

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

src/hsm/cmd_derive_asym.c

@@ -0,0 +1,102 @@
+/* 
+ * 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 "common.h"
+#include "mbedtls/ecdsa.h" 
+#include "crypto_utils.h"
+#include "sc_hsm.h"
+
+
+#define MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED -0x006E
+#define MOD_ADD( N )                                                    \
+    while( mbedtls_mpi_cmp_mpi( &(N), &grp->P ) >= 0 )                  \
+        MBEDTLS_MPI_CHK( mbedtls_mpi_sub_abs( &(N), &(N), &grp->P ) )
+static inline int mbedtls_mpi_add_mod( const mbedtls_ecp_group *grp,
+                                       mbedtls_mpi *X,
+                                       const mbedtls_mpi *A,
+                                       const mbedtls_mpi *B )
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    MBEDTLS_MPI_CHK( mbedtls_mpi_add_mpi( X, A, B ) );
+    MOD_ADD( *X );
+cleanup:
+    return( ret );
+}
+
+int cmd_derive_asym() {
+    uint8_t key_id = P1(apdu);
+    uint8_t dest_id = P2(apdu);
+    file_t *fkey;
+    if (!isUserAuthenticated)
+        return SW_SECURITY_STATUS_NOT_SATISFIED();
+    if (!(fkey = search_dynamic_file((KEY_PREFIX << 8) | key_id)) || !fkey->data || file_get_size(fkey) == 0) 
+        return SW_FILE_NOT_FOUND();
+    if (key_has_purpose(fkey, ALGO_EC_DERIVE) == false)
+        return SW_CONDITIONS_NOT_SATISFIED();
+    if (apdu.nc == 0)
+        return SW_WRONG_LENGTH();
+    if (apdu.data[0] == ALGO_EC_DERIVE) {
+        mbedtls_ecdsa_context ctx;
+        mbedtls_ecdsa_init(&ctx);
+        
+        int r;
+        r = load_private_key_ecdsa(&ctx, fkey);
+        if (r != CCID_OK) {
+            mbedtls_ecdsa_free(&ctx);
+            if (r == CCID_VERIFICATION_FAILED)
+                return SW_SECURE_MESSAGE_EXEC_ERROR();
+            return SW_EXEC_ERROR();
+        }
+        mbedtls_mpi a, nd;
+        mbedtls_mpi_init(&a);
+        mbedtls_mpi_init(&nd);
+        r = mbedtls_mpi_read_binary(&a, apdu.data+1, apdu.nc-1);
+        if (r != 0) {
+            mbedtls_ecdsa_free(&ctx);
+            mbedtls_mpi_free(&a);
+            mbedtls_mpi_free(&nd);
+            return SW_DATA_INVALID();
+        }
+        r = mbedtls_mpi_add_mod(&ctx.grp, &nd, &ctx.d, &a);
+        if (r != 0) {
+            mbedtls_ecdsa_free(&ctx);
+            mbedtls_mpi_free(&a);
+            mbedtls_mpi_free(&nd);
+            return SW_EXEC_ERROR();
+        }
+        r = mbedtls_mpi_copy(&ctx.d, &nd);
+        if (r != 0) {
+            mbedtls_ecdsa_free(&ctx);
+            mbedtls_mpi_free(&a);
+            mbedtls_mpi_free(&nd);
+            return SW_EXEC_ERROR();
+        }
+        r = store_keys(&ctx, HSM_KEY_EC, dest_id);
+        if (r != CCID_OK) {
+            mbedtls_ecdsa_free(&ctx);
+            mbedtls_mpi_free(&a);
+            mbedtls_mpi_free(&nd);
+            return SW_EXEC_ERROR();
+        }
+        mbedtls_ecdsa_free(&ctx);
+        mbedtls_mpi_free(&a);
+        mbedtls_mpi_free(&nd);
+    }
+    else 
+        return SW_WRONG_DATA();
+    return SW_OK();
+}