[chargepoint] Fix AuthorizationKey handling (store received hexadecimal string but use bytes representation on connect)

Author: c-jimenez

.vscode/launch.json

@@ -38,6 +38,26 @@
             "target": "${workspaceRoot}/build_gcc_native/tests/chargepoint/smartcharging/test_smartcharging_setpoint",
             "cwd": "${workspaceRoot}",
             "valuesFormatting": "parseText"
+        },
+        {
+            "type": "cppdbg",
+            "request": "attach",
+            "name": "Join process",
+            "program": "${workspaceRoot}/bin/gcc_native/quick_start_chargepoint",
+            "processId": "${command:pickProcess}",
+            "MIMode": "gdb",
+            "setupCommands": [
+                {
+                    "description": "Activer l'impression en mode Pretty pour gdb",
+                    "text": "-enable-pretty-printing",
+                    "ignoreFailures": true
+                },
+                {
+                    "description": "Définir la version désassemblage sur Intel",
+                    "text": "-gdb-set disassembly-flavor intel",
+                    "ignoreFailures": true
+                }
+            ]
         }
     ]
 }

examples/security_centralsystem/CentralSystemEventsHandler.cpp

@@ -25,6 +25,7 @@ SOFTWARE.
 #include "CentralSystemEventsHandler.h"
 #include "ChargePointDatabase.h"
 
+#include <array>
 #include <iostream>
 #include <random>
 #include <sstream>
@@ -99,7 +100,8 @@ bool CentralSystemEventsHandler::checkCredentials(const std::string& chargepoint
 {
     bool ret = false;
 
-    cout << "Check credentials for [" << chargepoint_id << "] : " << password << endl;
+    std::string hex_encoded_password = ocpp::helpers::toHexString(password);
+    cout << "Check credentials for [" << chargepoint_id << "] : " << hex_encoded_password << endl;
 
     // HTTP Basic Authentication is for Charge Points configured with Security Profile 1 or 2 only
 
@@ -111,7 +113,7 @@ bool CentralSystemEventsHandler::checkCredentials(const std::string& chargepoint
     {
         if ((security_profile == 1u) || (security_profile == 2u))
         {
-            ret = (password == authent_key);
+            ret = (hex_encoded_password == authent_key);
         }
         else
         {
@@ -257,14 +259,18 @@ ocpp::types::RegistrationStatus CentralSystemEventsHandler::ChargePointRequestHa
     }
     else
     {
-        // Generate an authent key for the charge point : minimal 16 bytes, max : 20 bytes
-        std::stringstream ss_authent_key;
-        ss_authent_key << std::hex;
-        for (int i = 0; i < 5; i++)
+        // Generate an authent key for the charge point : minimal 8 bytes, max : 20 bytes
+        std::mt19937                                rand_gen;
+        std::uniform_int_distribution<unsigned int> rand_distrib;
+        std::random_device                          rd;
+        rand_gen.seed(rd());
+
+        std::array<uint8_t, 17u> authent_key_bytes;
+        for (auto& val : authent_key_bytes)
         {
-            ss_authent_key << std::setfill('0') << std::setw(4) << std::rand();
+            val = static_cast<uint8_t>(rand_distrib(rand_gen));
         }
-        m_authent_key = ss_authent_key.str();
+        m_authent_key = ocpp::helpers::toHexString(authent_key_bytes);
 
         // Add the charge point to the database
         m_chargepoint_db.addChargePoint(this->proxy()->identifier(), serial_number, vendor, model, 0, m_authent_key);

src/chargepoint/ChargePoint.cpp

@@ -1164,8 +1164,10 @@ bool ChargePoint::doConnect()
     std::string authorization_key = m_ocpp_config.authorizationKey();
     if (!authorization_key.empty() && (security_profile <= 2))
     {
-        credentials.user     = m_stack_config.chargePointIdentifier();
-        credentials.password = authorization_key;
+        auto authentication_key = ocpp::helpers::fromHexString(authorization_key);
+        credentials.user        = m_stack_config.chargePointIdentifier();
+        credentials.password    = std::string(reinterpret_cast<const char*>(authentication_key.data()), authorization_key.size());
+        credentials.password.resize(authentication_key.size());
     }
     if (security_profile != 1)
     {

src/chargepoint/security/SecurityManager.cpp

@@ -669,15 +669,16 @@ bool SecurityManager::handleMessage(const ocpp::messages::InstallCertificateReq&
 ocpp::types::ConfigurationStatus SecurityManager::checkAuthorizationKeyParameter(const std::string& key, const std::string& value)
 {
     (void)key;
-    ConfigurationStatus ret = ConfigurationStatus::Accepted;
+    ConfigurationStatus ret = ConfigurationStatus::Rejected;
 
-    // Authorization key length for security profiles 1 and 2 must be between 32 and 40 bytes
-    unsigned int security_profile = m_ocpp_config.securityProfile();
-    if ((security_profile == 1) || (security_profile == 2))
+    // Authorization key length for security profiles 1 and 2 must be between 16 and 40 bytes
+    // and must be a valid hexadecimal representation
+    if ((value.size() >= 16u) && (value.size() <= 40u))
     {
-        if ((value.size() < 32u) || (value.size() > 40u))
+        auto key_bytes = ocpp::helpers::fromHexString(value);
+        if (key_bytes.size() == (value.size() / 2u))
         {
-            ret = ConfigurationStatus::Rejected;
+            ret = ConfigurationStatus::Accepted;
         }
     }
 

src/tools/helpers/StringHelpers.cpp

@@ -18,6 +18,9 @@ along with OpenOCPP. If not, see <http://www.gnu.org/licenses/>.
 
 #include "StringHelpers.h"
 
+#include <iomanip>
+#include <sstream>
+
 namespace ocpp
 {
 namespace helpers
@@ -114,5 +117,50 @@ bool endsWith(const std::string& str, const std::string& substr)
     return ret;
 }
 
+/** @brief Helper function to convert a buffer to an hexadecimal string representation */
+std::string toHexString(const void* buffer, size_t size)
+{
+    std::stringstream ss;
+    const uint8_t*    data = reinterpret_cast<const uint8_t*>(buffer);
+    if (data)
+    {
+        ss << std::hex;
+        for (size_t i = 0; i < size; i++)
+        {
+            ss << std::setw(2) << std::setfill('0') << static_cast<int>(data[i]) << "";
+        }
+    }
+    return ss.str();
+}
+
+/** @brief Helper function to convert an hexadecimal string representation into an array of bytes */
+std::vector<uint8_t> fromHexString(const std::string& hex_string)
+{
+    std::vector<uint8_t> ret;
+    if ((hex_string.size() & 1) == 0)
+    {
+        try
+        {
+            for (size_t i = 0; i < hex_string.size(); i += 2u)
+            {
+                std::string ss = hex_string.substr(i, 2u);
+                for (const auto& c : ss)
+                {
+                    if (!((c >= '0') && (c <= '9')) && !((c >= 'a') && (c <= 'f')) && !((c >= 'A') && (c <= 'F')))
+                    {
+                        throw std::out_of_range(ss);
+                    }
+                }
+                ret.push_back(static_cast<uint8_t>(std::stoul(ss, nullptr, 16)));
+            }
+        }
+        catch (...)
+        {
+            ret.clear();
+        }
+    }
+    return ret;
+}
+
 } // namespace helpers
 } // namespace ocpp

src/tools/helpers/StringHelpers.h

@@ -19,8 +19,10 @@ along with OpenOCPP. If not, see <http://www.gnu.org/licenses/>.
 #ifndef OPENOCPP_STRING_H
 #define OPENOCPP_STRING_H
 
+#include <cstdint>
 #include <string>
 #include <vector>
+
 namespace ocpp
 {
 namespace helpers
@@ -87,6 +89,32 @@ bool startsWith(const std::string& str, const std::string& substr);
  */
 bool endsWith(const std::string& str, const std::string& substr);
 
+/**
+ * @brief Helper function to convert a buffer to an hexadecimal string representation
+ * @param buffer Buffer to convert
+ * @param size Size of the buffer in bytes
+ * @return Buffer contents as an hexadecimal string
+ */
+std::string toHexString(const void* buffer, size_t size);
+
+/**
+ * @brief Helper function to convert a ContiguousContainer to an hexadecimal string representation
+ * @param cont container to convert
+ * @return Container contents as an hexadecimal string
+ */
+template <typename ContiguousContainer>
+std::string toHexString(const ContiguousContainer& cont)
+{
+    return toHexString(&cont[0], cont.size() * sizeof(cont[0]));
+}
+
+/**
+ * @brief Helper function to convert an hexadecimal string representation into an array of bytes
+ * @param hex_string Hexadecimal string to convert
+ * @return Corresponding array of bytes, empty if the input string is invalid
+ */
+std::vector<uint8_t> fromHexString(const std::string& hex_string);
+
 } // namespace helpers
 } // namespace ocpp