Add WiFi command to configure ECC slot

  - This is used to configure client certificate and client key in the ssl client
    The certificate is sent as buffer via AT command and the key is read from
    secure element nvs namespace

Author: pennam

UNOR4USBBridge/at_handler.cpp

@@ -8,11 +8,11 @@
 #include "cmds_wifi_station.h"
 #include "cmds_wifi_softAP.h"
 #include "cmds_wifi_netif.h"
+#include "cmds_preferences.h"
 #include "cmds_wifi_SSL.h"
 #include "cmds_wifi_udp.h"
 #include "cmds_ble_bridge.h"
 #include "cmds_ota.h"
-#include "cmds_preferences.h"
 #include "cmds_se.h"
 
 using namespace SudoMaker;

UNOR4USBBridge/at_handler.h

@@ -86,6 +86,8 @@ class CAtHandler {
 public:
    std::vector<std::uint8_t> cert_buf;
    std::vector<std::uint8_t> se_buf;
+   std::vector<std::uint8_t> client_cert_pem;
+   std::vector<std::uint8_t> client_key_pem;
    CAtHandler(HardwareSerial *s);
    CAtHandler() = delete ;
    static void onWiFiEvent(WiFiEvent_t event);

UNOR4USBBridge/cmds_wifi_SSL.h

@@ -11,6 +11,8 @@ INCBIN(x509_crt_bundle, PATH_CERT_BUNDLE);
 #endif
 
 #include "at_handler.h"
+#include "mbedtls/pem.h"
+#include "SSE.h"
 
 void CAtHandler::add_cmds_wifi_SSL() {
    /* ....................................................................... */
@@ -106,6 +108,105 @@ void CAtHandler::add_cmds_wifi_SSL() {
             return chAT::CommandStatus::ERROR;
       }
    };
+
+   /* ....................................................................... */
+   command_table[_SETECCSLOT] = [this](auto & srv, auto & parser) {
+   /* ....................................................................... */
+      switch (parser.cmd_mode) {
+         case chAT::CommandMode::Write: {
+            if (parser.args.size() != 3) {
+               return chAT::CommandStatus::ERROR;
+            }
+
+            auto &sock_num = parser.args[0];
+            auto &slot_num = parser.args[1];
+            auto &cert_len = parser.args[2];
+            if (sock_num.empty() || slot_num.empty() || cert_len.empty()) {
+               return chAT::CommandStatus::ERROR;
+            }
+
+            int sock = atoi(sock_num.c_str());
+            int size = atoi(cert_len.c_str());
+
+            CClientWrapper the_client = getClient(sock);
+            if (the_client.sslclient == nullptr) {
+               return chAT::CommandStatus::ERROR;
+            }
+
+            std::vector<unsigned char> client_cert_der;
+            client_cert_der = srv.inhibit_read(size);
+            size_t offset = client_cert_der.size();
+
+            if(offset < size) {
+               client_cert_der.resize(size);
+               do {
+                  offset += serial->read(client_cert_der.data() + offset, size - offset);
+               } while (offset < size);
+            }
+            srv.continue_read();
+
+#if ECC_DEBUG_ENABLED
+            log_v("_SETECCSLOT: input cert");
+            log_buf_v((const uint8_t *)client_cert_der.data(), size);
+#endif
+
+            /* Convert client certificate DER buffer into PEM */
+            client_cert_pem.resize(1024);
+            size_t olen;
+            mbedtls_pem_write_buffer("-----BEGIN CERTIFICATE-----\n",
+                                     "-----END CERTIFICATE-----\n",
+                                     client_cert_der.data(), size,
+                                     client_cert_pem.data(), 1024,
+                                     &olen);
+            client_cert_pem.resize(olen);
+
+#if ECC_DEBUG_ENABLED
+            log_v("_SETECCSLOT: output cert");
+            log_v("\n%s", client_cert_pem.data());
+#endif
+
+            /* Set client certificate */
+            the_client.sslclient->setCertificate((const char *)client_cert_pem.data());
+
+            /* Read private key from non volatile storage in DER format */
+            std::vector<unsigned char> client_key_der;
+            int len = sse.getBytesLength(slot_num.c_str());
+            int ret = -1;
+            client_key_der.resize(len);
+            if ((ret = sse.getBytes(slot_num.c_str(), client_key_der.data(), len)) < len) {
+               log_e(" failed\n  !  sse.getBytes returned -0x%04x", (unsigned int) -ret);
+               return chAT::CommandStatus::ERROR;
+            }
+
+#if ECC_DEBUG_ENABLED
+            log_v("_SETECCSLOT: input key");
+            log_buf_v((const uint8_t *)client_key_der.data(), ret);
+#endif
+
+            /* Convert private key in PEM format */
+            client_key_pem.resize(1024);
+            mbedtls_pem_write_buffer("-----BEGIN EC PRIVATE KEY-----\n",
+                                     "-----END EC PRIVATE KEY-----\n",
+                                     client_key_der.data(), len,
+                                     client_key_pem.data(), 1024,
+                                     &olen);
+            client_key_pem.resize(olen);
+
+#if ECC_DEBUG_ENABLED
+            log_v("_SETECCSLOT: output key");
+            log_v("\n%s", client_key_pem.data());
+#endif
+
+            /* Set client key */
+            the_client.sslclient->setPrivateKey((const char *)client_key_pem.data());
+
+            return chAT::CommandStatus::OK;
+         }
+         default:
+            return chAT::CommandStatus::ERROR;
+      }
+   };
+
    /* ....................................................................... */
    command_table[_SSLCLIENTSTATE] = [this](auto & srv, auto & parser) {
    /* ....................................................................... */     

UNOR4USBBridge/commands.h

@@ -57,6 +57,7 @@ enum {
 #define _CLIENTCONNECTED         "+CLIENTCONNECTED"
 #define _SSLBEGINCLIENT          "+SSLBEGINCLIENT"
 #define _SETCAROOT               "+SETCAROOT"
+#define _SETECCSLOT              "+SETECCSLOT"
 #define _SSLCLIENTSTATE          "+SSLCLIENTSTATE"
 #define _SSLCLIENTCONNECTNAME    "+SSLCLIENTCONNECTNAME"
 #define _SETIP                   "+SETIP"