resultcollector.go

/*
Copyright © 2019 Red Hat Inc.

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 manager

import (
	"bufio"
	"bytes"
	"context"
	"crypto/tls"
	"crypto/x509"
	goerrors "errors"
	"flag"
	"fmt"
	"io"
	"net/http"
	"net/http/httputil"
	"os"
	"path/filepath"
	"strings"
	"sync"
	"time"

	backoff "github.com/cenkalti/backoff/v4"
	"github.com/dsnet/compress/bzip2"
	libgocrypto "github.com/openshift/library-go/pkg/crypto"
	"github.com/spf13/cobra"
	"k8s.io/apimachinery/pkg/api/errors"
	"k8s.io/apimachinery/pkg/types"
	"sigs.k8s.io/controller-runtime/pkg/client/config"
	logf "sigs.k8s.io/controller-runtime/pkg/log"
	"sigs.k8s.io/controller-runtime/pkg/log/zap"

	compv1alpha1 "github.com/ComplianceAsCode/compliance-operator/pkg/apis/compliance/v1alpha1"
	"github.com/ComplianceAsCode/compliance-operator/pkg/controller/common"
	"github.com/ComplianceAsCode/compliance-operator/pkg/utils"
)

var ResultcollectorCmd = &cobra.Command{
	Use:   "resultscollector",
	Short: "A tool to do an OpenSCAP scan from a pod.",
	Long:  "A tool to do an OpenSCAP scan from a pod.",
	Run:   resultCollectorMain,
}

var (
	timeoutErr = goerrors.New("Timed out waiting for results file")
)

func init() {
	defineResultcollectorFlags(ResultcollectorCmd)
}

type scapresultsConfig struct {
	ArfFile            string
	XccdfFile          string
	ExitCodeFile       string
	CmdOutputFile      string
	WarningsOutputFile string
	ScanName           string
	ConfigMapName      string
	NodeName           string
	Namespace          string
	ResultServerURI    string
	Timeout            int64
	Cert               string
	Key                string
	CA                 string
}

func defineResultcollectorFlags(cmd *cobra.Command) {
	cmd.Flags().String("arf-file", "", "The ARF file to watch.")
	cmd.Flags().String("results-file", "", "The XCCDF results file to watch.")
	cmd.Flags().String("exit-code-file", "", "A file containing the oscap command's exit code.")
	cmd.Flags().String("oscap-output-file", "", "A file containing the oscap command's output.")
	cmd.Flags().String("warnings-output-file", "", "A file containing the warnings to output.")
	cmd.Flags().String("owner", "", "The compliance scan that owns the configMap objects.")
	cmd.Flags().String("config-map-name", "", "The configMap to upload to, typically the podname.")
	cmd.Flags().String("node-name", "", "The node that was scanned.")
	cmd.Flags().String("namespace", "openshift-compliance", "Running pod namespace.")
	cmd.Flags().Int64("timeout", 3600, "How long to wait for the file.")
	cmd.Flags().String("resultserveruri", "", "The resultserver URI name.")
	cmd.Flags().String("tls-client-cert", "", "The path to the client and CA PEM cert bundle.")
	cmd.Flags().String("tls-client-key", "", "The path to the client PEM key.")
	cmd.Flags().String("tls-ca", "", "The path to the CA certificate.")

	flags := cmd.Flags()

	// Add flags registered by imported packages (e.g. glog and
	// controller-runtime)
	flags.AddGoFlagSet(flag.CommandLine)
}

func parseConfig(cmd *cobra.Command) *scapresultsConfig {
	var conf scapresultsConfig
	conf.ArfFile = getValidStringArg(cmd, "arf-file")
	conf.XccdfFile = getValidStringArg(cmd, "results-file")
	conf.ExitCodeFile = getValidStringArg(cmd, "exit-code-file")
	conf.CmdOutputFile = getValidStringArg(cmd, "oscap-output-file")
	conf.ScanName = getValidStringArg(cmd, "owner")
	conf.ConfigMapName = getValidStringArg(cmd, "config-map-name")
	conf.Namespace = getValidStringArg(cmd, "namespace")
	conf.Cert = getValidStringArg(cmd, "tls-client-cert")
	conf.Key = getValidStringArg(cmd, "tls-client-key")
	conf.CA = getValidStringArg(cmd, "tls-ca")
	conf.Timeout, _ = cmd.Flags().GetInt64("timeout")
	conf.ResultServerURI, _ = cmd.Flags().GetString("resultserveruri")
	// Set default if needed
	if conf.ResultServerURI == "" {
		conf.ResultServerURI = "http://" + conf.ScanName + "-rs:8080/"
	}
	conf.WarningsOutputFile, _ = cmd.Flags().GetString("warnings-output-file")

	// platform scans have no node name
	conf.NodeName, _ = cmd.Flags().GetString("node-name")

	logf.SetLogger(zap.New())

	return &conf
}

func getOpenSCAPScanInstance(name, namespace string, client *complianceCrClient) (*compv1alpha1.ComplianceScan, error) {
	key := types.NamespacedName{Name: name, Namespace: namespace}
	scan := &compv1alpha1.ComplianceScan{}
	err := client.client.Get(context.TODO(), key, scan)
	if err != nil {
		cmdLog.Error(err, "Error getting scan instance", "ComplianceScan.Name", scan.Name, "ComplianceScan.Namespace", scan.Namespace)
		return nil, err
	}

	return scan, nil
}

func resultsFileReady(fname string, fFound chan *os.File) (bool, error) {
	// Note that we're cleaning the filename path above.
	// Also note that the file is not being closed here and should
	// be closed by the channel receiver.
	// #nosec
	file, err := os.Open(fname)
	if err == nil {
		fileinfo, statErr := file.Stat()
		// Only try to use the file if it already has contents.
		// This way we avoid race conditions between the side-car and
		// this script.
		if statErr == nil && fileinfo.Size() > 0 {
			fFound <- file
			return true, nil
		} else {
			return false, file.Close()
		}
	} else if !os.IsNotExist(err) {
		cmdLog.Error(err, "Couldn't open results file")
		// We mark this as "ready" as there's nothing else to do.
		// This will stop the go-routine
		return true, fmt.Errorf("couldn't open result file: %w", err)
	}
	return false, nil
}

func probeResultsFile(fname string, fFound chan *os.File, errs chan error) {
	for {
		ready, err := resultsFileReady(fname, fFound)
		if err != nil {
			errs <- err
		}
		if ready {
			return
		}
		time.Sleep(1 * time.Second)
	}
}

func waitForResultsFile(filename string, timeout int64) (*os.File, error) {
	readFileTimeoutChan := make(chan *os.File, 1)
	errs := make(chan error)
	// G304 (CWE-22) is addressed by this.
	cleanFileName := filepath.Clean(filename)

	go probeResultsFile(cleanFileName, readFileTimeoutChan, errs)

	select {
	case file := <-readFileTimeoutChan:
		cmdLog.Info("Results file found, will upload it.", "resuts-file", filename)
		close(readFileTimeoutChan)
		return file, nil
	case err := <-errs:
		outErr := fmt.Errorf("error reading result file: %w", err)
		cmdLog.Error(outErr, "Timeout. Aborting.")
		return nil, outErr
	case <-time.After(time.Duration(timeout) * time.Second):
		cmdLog.Error(timeoutErr, "Timeout. Aborting.")
		return nil, timeoutErr
	}
}

func resultNeedsCompression(size int64) bool {
	return size > 1048570
}

func compressResults(contents io.Reader) (io.Reader, error) {
	// Encode the contents ascii, compress it with gzip, b64encode it so it
	// can be stored in the configmap.
	var buffer bytes.Buffer
	w, err := bzip2.NewWriter(&buffer, &bzip2.WriterConfig{Level: bzip2.BestCompression})
	if err != nil {
		return nil, err
	}
	defer w.Close()
	_, err = io.Copy(w, contents)
	if err != nil {
		return nil, err
	}
	return &buffer, nil
}

type resultFileContents struct {
	contents   io.Reader
	compressed bool
	close      func() error
}

func readResultsFile(filename string, timeout int64) (*resultFileContents, error) {
	var err error
	var rfContents resultFileContents

	cleanFileName := filepath.Clean(filename)
	handle, err := waitForResultsFile(cleanFileName, timeout)
	if err != nil {
		return nil, fmt.Errorf("error waiting for results file: %w", err)
	}
	// #nosec
	defer handle.Close()

	// #nosec
	contentsfile, err := os.Open(cleanFileName)
	if err != nil {
		return nil, err
	}
	rfContents.contents = bufio.NewReader(contentsfile)

	// Using stat avoids us having to read the file's contents
	statInfo, err := os.Stat(cleanFileName)
	if err != nil {
		return nil, err
	}
	if resultNeedsCompression(statInfo.Size()) {
		// #nosec
		defer contentsfile.Close()
		rfContents.close = func() error {
			return nil
		}
		rfContents.contents, err = compressResults(rfContents.contents)
		cmdLog.Info("File needs compression", "results-file", filename)
		if err != nil {
			cmdLog.Error(err, "Error: Compression failed")
			return nil, err
		}
		rfContents.compressed = true
		cmdLog.Info("Compressed results")
	} else {
		rfContents.close = func() error {
			return contentsfile.Close()
		}
	}
	return &rfContents, nil
}

func readWarningsFile(filename string) string {
	// No warnings file provided, no need to parse anything
	if filename == "" {
		return ""
	}
	contents, err := os.ReadFile(filepath.Clean(filename))
	if os.IsNotExist(err) {
		// warnings file provided, but no warnings were generated
		return ""
	}
	if err != nil {
		DBG("Error while reading warnings file: %v", err)
		return ""
	}

	return strings.Trim(string(contents), "\n")
}

func uploadToResultServer(arfContents *resultFileContents, scapresultsconf *scapresultsConfig) error {
	return backoff.Retry(func() error {
		url := scapresultsconf.ResultServerURI
		cmdLog.Info("Trying to upload to resultserver", "url", url)
		transport, err := getMutualHttpsTransport(scapresultsconf)
		if err != nil {
			cmdLog.Error(err, "Failed to get https transport")
			return err
		}
		client := &http.Client{Transport: transport}
		req, _ := http.NewRequest("POST", url, arfContents.contents)
		req.Header.Add("Content-Type", "application/xml")
		req.Header.Add("X-Report-Name", scapresultsconf.ConfigMapName)
		if arfContents.compressed {
			req.Header.Add("Content-Encoding", "bzip2")
		}
		resp, err := client.Do(req)
		if err != nil {
			cmdLog.Error(err, "Failed to upload results to server")
			return err
		}
		defer resp.Body.Close()
		bytesresp, err := httputil.DumpResponse(resp, true)
		if err != nil {
			cmdLog.Error(err, "Failed to parse response")
			return err
		}
		cmdLog.Info(string(bytesresp))
		return nil
	}, backoff.WithMaxRetries(backoff.NewExponentialBackOff(), maxRetries))
}

func uploadResultConfigMap(xccdfContents *resultFileContents, exitcode string,
	scapresultsconf *scapresultsConfig, client *complianceCrClient) error {
	warnings := readWarningsFile(scapresultsconf.WarningsOutputFile)

	return backoff.Retry(func() error {
		cmdLog.Info("Trying to upload results ConfigMap")
		openscapScan, err := getOpenSCAPScanInstance(scapresultsconf.ScanName, scapresultsconf.Namespace, client)
		if err != nil {
			return err
		}
		confMap := utils.GetResultConfigMap(openscapScan, scapresultsconf.ConfigMapName, "results",
			scapresultsconf.NodeName, xccdfContents.contents, xccdfContents.compressed, exitcode, warnings)
		err = client.client.Create(context.TODO(), confMap)

		if errors.IsAlreadyExists(err) {
			return nil
		}
		return err
	}, backoff.WithMaxRetries(backoff.NewExponentialBackOff(), maxRetries))
}

func uploadErrorConfigMap(errorMsg *resultFileContents, exitcode string,
	scapresultsconf *scapresultsConfig, client *complianceCrClient) error {
	warnings := readWarningsFile(scapresultsconf.WarningsOutputFile)

	return backoff.Retry(func() error {
		cmdLog.Info("Trying to upload error ConfigMap")
		openscapScan, err := getOpenSCAPScanInstance(scapresultsconf.ScanName, scapresultsconf.Namespace, client)
		if err != nil {
			return err
		}
		confMap := utils.GetResultConfigMap(openscapScan, scapresultsconf.ConfigMapName, "error-msg",
			scapresultsconf.NodeName, errorMsg.contents, errorMsg.compressed, exitcode, warnings)
		err = client.client.Create(context.TODO(), confMap)

		if errors.IsAlreadyExists(err) {
			return nil
		}
		return err
	}, backoff.WithMaxRetries(backoff.NewExponentialBackOff(), maxRetries))
}

func handleCompleteSCAPResults(exitcode string, scapresultsconf *scapresultsConfig, client *complianceCrClient) {
	arfContents, err := readResultsFile(scapresultsconf.ArfFile, scapresultsconf.Timeout)
	if err != nil {
		cmdLog.Error(err, "Failed to read ARF file")
		os.Exit(1)
	}
	defer arfContents.close()

	xccdfContents, err := readResultsFile(scapresultsconf.XccdfFile, scapresultsconf.Timeout)
	if err != nil {
		cmdLog.Error(err, "Failed to read XCCDF file")
		os.Exit(1)
	}
	defer xccdfContents.close()

	var wg sync.WaitGroup
	wg.Add(2)
	go func() {
		serverUploadErr := uploadToResultServer(arfContents, scapresultsconf)
		if serverUploadErr != nil {
			cmdLog.Error(serverUploadErr, "Failed to upload results to server")
			os.Exit(1)
		}
		cmdLog.Info("Uploaded to resultserver")
		wg.Done()
	}()

	go func() {
		cmUploadErr := uploadResultConfigMap(xccdfContents, exitcode, scapresultsconf, client)
		if cmUploadErr != nil {
			cmdLog.Error(cmUploadErr, "Failed to upload ConfigMap")
			os.Exit(1)
		}
		cmdLog.Info("Uploaded ConfigMap")
		wg.Done()
	}()
	wg.Wait()
}

func handleErrorInOscapRun(exitcode string, scapresultsconf *scapresultsConfig, client *complianceCrClient) {
	errorMsg, err := readResultsFile(scapresultsconf.CmdOutputFile, scapresultsconf.Timeout)
	if err != nil {
		cmdLog.Error(err, "Failed to read error message output from oscap run")
		os.Exit(1)
	}
	defer errorMsg.close()

	err = uploadErrorConfigMap(errorMsg, exitcode, scapresultsconf, client)
	if err != nil {
		cmdLog.Error(err, "Failed to upload error ConfigMap")
		os.Exit(1)
	}
	cmdLog.Info("Uploaded ConfigMap")
}

func getOscapExitCode(scapresultsconf *scapresultsConfig) string {
	exitcodeContent, err := readResultsFile(scapresultsconf.ExitCodeFile, scapresultsconf.Timeout)
	if err != nil {
		cmdLog.Error(err, "Failed to read oscap error code")
		os.Exit(1)
	}
	defer exitcodeContent.close()

	exitcode, _ := io.ReadAll(exitcodeContent.contents)
	return strings.Trim(string(exitcode), "\n")
}

func getMutualHttpsTransport(c *scapresultsConfig) (*http.Transport, error) {
	cert, err := tls.LoadX509KeyPair(c.Cert, c.Key)
	if err != nil {
		return nil, err
	}
	ca, err := os.ReadFile(c.CA)
	if err != nil {
		return nil, err
	}
	pool := x509.NewCertPool()
	pool.AppendCertsFromPEM(ca)

	tlsConfig := &tls.Config{
		MinVersion: tls.VersionTLS12,
	}
	// Configures TLS 1.2
	tlsConfig = libgocrypto.SecureTLSConfig(tlsConfig)
	tlsConfig.RootCAs = pool
	tlsConfig.Certificates = []tls.Certificate{cert}

	return &http.Transport{
		TLSClientConfig: tlsConfig,
	}, nil
}

// an exit code of 0 means that the scan returned compliant
// an exit code of 2 means that the scan returned non-compliant
// an exit code of 1 means that the scan encountered an error
func exitCodeIsError(exitcode string) bool {
	return exitcode != common.OpenSCAPExitCodeCompliant && exitcode != common.OpenSCAPExitCodeNonCompliant
}

func resultCollectorMain(cmd *cobra.Command, args []string) {
	scapresultsconf := parseConfig(cmd)

	cfg, err := config.GetConfig()
	if err != nil {
		cmdLog.Error(err, "")
		os.Exit(1)
	}

	crclient, err := createCrClient(cfg)
	if err != nil {
		cmdLog.Error(err, "Cannot create kube client for our types\n")
		os.Exit(1)
	}

	exitcode := getOscapExitCode(scapresultsconf)
	cmdLog.Info("Got exit-code from file", "exit-code", exitcode)

	if exitCodeIsError(exitcode) {
		handleErrorInOscapRun(exitcode, scapresultsconf, crclient)
		return
	}
	handleCompleteSCAPResults(exitcode, scapresultsconf, crclient)
}