[OperationalCredentials]: Support read TrustedRootCertificates attribute

src/app/clusters/operational-credentials-server/operational-credentials-server.cpp

@@ -69,6 +69,7 @@ class OperationalCredentialsAttrAccess : public AttributeAccessInterface
 
 private:
     CHIP_ERROR ReadFabricsList(EndpointId endpoint, AttributeValueEncoder & aEncoder);
+    CHIP_ERROR ReadRootCertificates(EndpointId endpoint, AttributeValueEncoder & aEncoder);
 };
 
 CHIP_ERROR OperationalCredentialsAttrAccess::ReadFabricsList(EndpointId endpoint, AttributeValueEncoder & aEncoder)
@@ -96,6 +97,24 @@ CHIP_ERROR OperationalCredentialsAttrAccess::ReadFabricsList(EndpointId endpoint
     });
 }
 
+CHIP_ERROR OperationalCredentialsAttrAccess::ReadRootCertificates(EndpointId endpoint, AttributeValueEncoder & aEncoder)
+{
+    return aEncoder.EncodeList([](const TagBoundEncoder & encoder) -> CHIP_ERROR {
+        for (auto & fabricInfo : Server::GetInstance().GetFabricTable())
+        {
+            ByteSpan cert;
+
+            if (!fabricInfo.IsInitialized())
+                continue;
+
+            ReturnErrorOnFailure(fabricInfo.GetRootCert(cert));
+            ReturnErrorOnFailure(encoder.Encode(cert));
+        }
+
+        return CHIP_NO_ERROR;
+    });
+}
+
 OperationalCredentialsAttrAccess gAttrAccess;
 
 CHIP_ERROR OperationalCredentialsAttrAccess::Read(const ConcreteAttributePath & aPath, AttributeValueEncoder & aEncoder)
@@ -107,6 +126,9 @@ CHIP_ERROR OperationalCredentialsAttrAccess::Read(const ConcreteAttributePath &
     case Attributes::FabricsList::Id: {
         return ReadFabricsList(aPath.mEndpointId, aEncoder);
     }
+    case Attributes::TrustedRootCertificates::Id: {
+        return ReadRootCertificates(aPath.mEndpointId, aEncoder);
+    }
     default:
         break;
     }

src/controller/data_model/controller-clusters.zap

@@ -5137,6 +5137,21 @@
               "maxInterval": 65344,
               "reportableChange": 0
             },
+            {
+              "name": "TrustedRootCertificates",
+              "code": 4,
+              "mfgCode": null,
+              "side": "server",
+              "included": 1,
+              "storageOption": "RAM",
+              "singleton": 0,
+              "bounded": 0,
+              "defaultValue": "",
+              "reportable": 0,
+              "minInterval": 1,
+              "maxInterval": 65534,
+              "reportableChange": 0
+            },
             {
               "name": "ClusterRevision",
               "code": 65533,