Added an event for default rule read shell configuration file

Signed-off-by: GLVS Kiriti <[email protected]>

Author: GLVSKiriti

events/syscall/read_shell_configuration_file.go

@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: Apache-2.0
+/*
+Copyright (C) 2024 The Falco Authors.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package syscall
+
+import (
+	"os"
+
+	"github.com/falcosecurity/event-generator/events"
+)
+
+var _ = events.Register(
+	ReadShellConfigurationFile,
+	events.WithDisabled(), // this rules is not included in falco_rules.yaml (stable rules), so disable the action
+)
+
+func ReadShellConfigurationFile(h events.Helper) error {
+	shellConfigFiles := []string{
+		"/etc/bashrc",
+		"/etc/profile",
+		"/etc/csh.cshrc",
+		"/etc/csh.login",
+	}
+
+	var errRead error
+
+	// Iterate over shellConfigFiles until a file is successfully opened.
+	for _, configFile := range shellConfigFiles {
+		file, err := os.Open(configFile)
+		if err == nil {
+			h.Log().Infof("A shell configuration file %s was read by a non-shell program", configFile)
+			defer file.Close()
+			return err
+		} else if !os.IsNotExist(err) {
+			errRead = err
+		}
+	}
+
+	return errRead
+}