new(falco/config): add new configuration for http_output

Support for user provided CA certificate that can verify the remote server. Users
can provide path to the CA certiface store by providing a path to the dir or to the
CA store file. If needed users can decide to tell Falco to not verify the server.

Signed-off-by: Aldo Lacuku <aldo@lacuku.eu>

falco.yaml

@@ -408,6 +408,15 @@ http_output:
   enabled: false
   url: http://some.url
   user_agent: "falcosecurity/falco"
+  # Tell Falco to not verify the remote server.
+  insecure: false
+  # Path to the CA certificate that can verify the remote server. 
+  ca_cert: ""
+  # Path to a specific file that will be used as the CA certificate store.
+  ca_bundle: ""
+  # Path to a folder that will be used as the CA certificate store. CA certificate need to be
+  # stored as indivitual PEM files in this directory.
+  ca_path: "/etc/ssl/certs"
 
 # Falco supports running a gRPC server with two main binding types
 # 1. Over the network with mandatory mutual TLS authentication (mTLS)

userspace/falco/configuration.cpp

@@ -178,6 +178,22 @@ void falco_configuration::load_yaml(const std::string& config_name, const yaml_h
 		user_agent = config.get_scalar<std::string>("http_output.user_agent","falcosecurity/falco");
 		http_output.options["user_agent"] = user_agent;
 
+		bool insecure;
+		insecure = config.get_scalar<bool>("http_output.insecure", false);
+		http_output.options["insecure"] = insecure? std::string("true") : std::string("false");
+
+		std::string ca_cert;
+		ca_cert = config.get_scalar<std::string>("http_output.ca_cert", "");
+		http_output.options["ca_cert"] = ca_cert;
+
+		std::string ca_bundle;
+		ca_bundle = config.get_scalar<std::string>("http_output.ca_bundle", "");
+		http_output.options["ca_bundle"] = ca_bundle;
+
+		std::string ca_path;
+		ca_path = config.get_scalar<std::string>("http_output.ca_path", "/etc/ssl/certs");
+		http_output.options["ca_path"] = ca_path;
+
 		m_outputs.push_back(http_output);
 	}
 

userspace/falco/outputs_http.cpp

@@ -34,15 +34,58 @@ void falco::outputs::output_http::output(const message *msg)
 		} else {
 			slist1 = curl_slist_append(slist1, "Content-Type: text/plain");
 		}
+		res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist1);
 
-		curl_easy_setopt(curl, CURLOPT_HTTPHEADER, slist1);
-		curl_easy_setopt(curl, CURLOPT_URL, m_oc.options["url"].c_str());
-		curl_easy_setopt(curl, CURLOPT_POSTFIELDS, msg->msg.c_str());
-		curl_easy_setopt(curl, CURLOPT_USERAGENT, m_oc.options["user_agent"].c_str());
-		curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, -1L);
+		if(res == CURLE_OK)
+		{
+			res = curl_easy_setopt(curl, CURLOPT_URL, m_oc.options["url"].c_str());
+		}
+
+		if(res == CURLE_OK)
+		{
+			res = curl_easy_setopt(curl, CURLOPT_POSTFIELDS, msg->msg.c_str());
+		}
+
+		if(res == CURLE_OK)
+		{
+			res = curl_easy_setopt(curl, CURLOPT_USERAGENT, m_oc.options["user_agent"].c_str());
+		}
+
+		if(res == CURLE_OK)
+		{
+		   res = curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, -1L);
+		}
+
+		if(res == CURLE_OK)
+		{
+			if(m_oc.options["insecure"] == std::string("true"))
+			{
+				res = curl_easy_setopt(curl,CURLOPT_SSL_VERIFYPEER, 0L);
 
+				if(res == CURLE_OK)
+				{
+					res = curl_easy_setopt(curl, CURLOPT_SSL_VERIFYHOST, 0L);
+				}
+			}
+		}
 
-		res = curl_easy_perform(curl);
+		if(res == CURLE_OK)
+		{
+			if (!m_oc.options["ca_cert"].empty())
+			{
+				res = curl_easy_setopt(curl, CURLOPT_CAINFO, m_oc.options["ca_cert"].c_str());
+			}else if(!m_oc.options["ca_bundle"].empty())
+			{
+				res = curl_easy_setopt(curl, CURLOPT_CAINFO, m_oc.options["ca_bundle"].c_str());
+			}else{
+				res = curl_easy_setopt(curl, CURLOPT_CAPATH, m_oc.options["ca_path"].c_str());
+			}
+		}
+
+  		if(res == CURLE_OK)
+		{
+			res = curl_easy_perform(curl);
+		}
 
 		if(res != CURLE_OK)
 		{