mirror of
https://github.com/aquasecurity/kube-bench.git
synced 2024-10-31 20:39:14 +00:00
39d94df81b
If people are trying to use the Docker image to check their cluster, there's a big likelyhood of them hitting the error message saying that either `kubectl` or `kubelet` need to be found in order for `kube-bench` to be able to determine the Kubernetes version in use. This adds a tip that the version can be specified manually with the `--version` flag which is a lot easier than having to make a new Docker image with the right version of `kubelet`/`kubectl` in order for `kube-bench` to work.
284 lines
7.0 KiB
Go
284 lines
7.0 KiB
Go
package cmd
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import (
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"fmt"
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"os"
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"os/exec"
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"regexp"
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"strings"
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"github.com/aquasecurity/kube-bench/check"
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"github.com/fatih/color"
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"github.com/golang/glog"
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"github.com/spf13/viper"
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)
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var (
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// Print colors
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colors = map[check.State]*color.Color{
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check.PASS: color.New(color.FgGreen),
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check.FAIL: color.New(color.FgRed),
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check.WARN: color.New(color.FgYellow),
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check.INFO: color.New(color.FgBlue),
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}
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)
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var psFunc func(string) string
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var statFunc func(string) (os.FileInfo, error)
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func init() {
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psFunc = ps
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statFunc = os.Stat
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}
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func printlnWarn(msg string) {
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fmt.Fprintf(os.Stderr, "[%s] %s\n",
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colors[check.WARN].Sprintf("%s", check.WARN),
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msg,
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)
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}
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func sprintlnWarn(msg string) string {
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return fmt.Sprintf("[%s] %s",
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colors[check.WARN].Sprintf("%s", check.WARN),
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msg,
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)
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}
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func exitWithError(err error) {
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fmt.Fprintf(os.Stderr, "\n%v\n", err)
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os.Exit(1)
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}
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func continueWithError(err error, msg string) string {
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if err != nil {
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glog.V(2).Info(err)
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}
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if msg != "" {
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fmt.Fprintf(os.Stderr, "%s\n", msg)
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}
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return ""
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}
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func cleanIDs(list string) []string {
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list = strings.Trim(list, ",")
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ids := strings.Split(list, ",")
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for _, id := range ids {
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id = strings.Trim(id, " ")
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}
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return ids
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}
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// ps execs out to the ps command; it's separated into a function so we can write tests
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func ps(proc string) string {
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cmd := exec.Command("ps", "-C", proc, "-o", "cmd", "--no-headers")
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out, err := cmd.Output()
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if err != nil {
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continueWithError(fmt.Errorf("%s: %s", cmd.Args, err), "")
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}
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return string(out)
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}
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// getBinaries finds which of the set of candidate executables are running
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func getBinaries(v *viper.Viper) map[string]string {
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binmap := make(map[string]string)
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for _, component := range v.GetStringSlice("components") {
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s := v.Sub(component)
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if s == nil {
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continue
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}
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optional := s.GetBool("optional")
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bins := s.GetStringSlice("bins")
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if len(bins) > 0 {
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bin, err := findExecutable(bins)
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if err != nil && !optional {
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exitWithError(fmt.Errorf("need %s executable but none of the candidates are running", component))
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}
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// Default the executable name that we'll substitute to the name of the component
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if bin == "" {
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bin = component
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glog.V(2).Info(fmt.Sprintf("Component %s not running", component))
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} else {
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glog.V(2).Info(fmt.Sprintf("Component %s uses running binary %s", component, bin))
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}
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binmap[component] = bin
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}
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}
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return binmap
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}
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// getConfigFiles finds which of the set of candidate config files exist
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// accepts a string 't' which indicates the type of config file, conf,
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// podspec or untifile.
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func getConfigFiles(v *viper.Viper) map[string]string {
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confmap := make(map[string]string)
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for _, component := range v.GetStringSlice("components") {
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s := v.Sub(component)
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if s == nil {
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continue
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}
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// See if any of the candidate config files exist
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conf := findConfigFile(s.GetStringSlice("confs"))
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if conf == "" {
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if s.IsSet("defaultconf") {
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conf = s.GetString("defaultconf")
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glog.V(2).Info(fmt.Sprintf("Using default config file name '%s' for component %s", conf, component))
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} else {
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// Default the config file name that we'll substitute to the name of the component
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glog.V(2).Info(fmt.Sprintf("Missing config file for %s", component))
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conf = component
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}
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} else {
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glog.V(2).Info(fmt.Sprintf("Component %s uses config file '%s'", component, conf))
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}
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confmap[component] = conf
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}
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return confmap
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}
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// verifyBin checks that the binary specified is running
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func verifyBin(bin string) bool {
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// Strip any quotes
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bin = strings.Trim(bin, "'\"")
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// bin could consist of more than one word
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// We'll search for running processes with the first word, and then check the whole
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// proc as supplied is included in the results
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proc := strings.Fields(bin)[0]
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out := psFunc(proc)
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// There could be multiple lines in the ps output
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// The binary needs to be the first word in the ps output, except that it could be preceded by a path
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// e.g. /usr/bin/kubelet is a match for kubelet
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// but apiserver is not a match for kube-apiserver
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reFirstWord := regexp.MustCompile(`^(\S*\/)*` + bin)
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lines := strings.Split(out, "\n")
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for _, l := range lines {
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if reFirstWord.Match([]byte(l)) {
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return true
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}
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}
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return false
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}
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// fundConfigFile looks through a list of possible config files and finds the first one that exists
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func findConfigFile(candidates []string) string {
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for _, c := range candidates {
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_, err := statFunc(c)
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if err == nil {
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return c
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}
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if !os.IsNotExist(err) {
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exitWithError(fmt.Errorf("error looking for file %s: %v", c, err))
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}
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}
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return ""
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}
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// findExecutable looks through a list of possible executable names and finds the first one that's running
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func findExecutable(candidates []string) (string, error) {
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for _, c := range candidates {
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if verifyBin(c) {
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return c, nil
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}
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glog.V(1).Info(fmt.Sprintf("executable '%s' not running", c))
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}
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return "", fmt.Errorf("no candidates running")
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}
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func multiWordReplace(s string, subname string, sub string) string {
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f := strings.Fields(sub)
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if len(f) > 1 {
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sub = "'" + sub + "'"
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}
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return strings.Replace(s, subname, sub, -1)
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}
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func getKubeVersion() string {
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// These executables might not be on the user's path.
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_, err := exec.LookPath("kubectl")
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if err != nil {
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_, err = exec.LookPath("kubelet")
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if err != nil {
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exitWithError(fmt.Errorf("Version check failed: need kubectl or kubelet binaries to get kubernetes version.\nAlternately, you can specify the version with --version"))
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}
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return getKubeVersionFromKubelet()
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}
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return getKubeVersionFromKubectl()
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}
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func getKubeVersionFromKubectl() string {
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cmd := exec.Command("kubectl", "version", "--short")
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out, err := cmd.CombinedOutput()
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if err != nil {
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continueWithError(fmt.Errorf("%s", out), "")
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}
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return getVersionFromKubectlOutput(string(out))
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}
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func getKubeVersionFromKubelet() string {
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cmd := exec.Command("kubelet", "--version")
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out, err := cmd.CombinedOutput()
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if err != nil {
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continueWithError(fmt.Errorf("%s", out), "")
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}
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return getVersionFromKubeletOutput(string(out))
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}
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func getVersionFromKubectlOutput(s string) string {
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serverVersionRe := regexp.MustCompile(`Server Version: v(\d+.\d+)`)
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subs := serverVersionRe.FindStringSubmatch(s)
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if len(subs) < 2 {
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printlnWarn(fmt.Sprintf("Unable to get kubectl version, using default version: %s", defaultKubeVersion))
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return defaultKubeVersion
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}
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return subs[1]
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}
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func getVersionFromKubeletOutput(s string) string {
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serverVersionRe := regexp.MustCompile(`Kubernetes v(\d+.\d+)`)
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subs := serverVersionRe.FindStringSubmatch(s)
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if len(subs) < 2 {
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printlnWarn(fmt.Sprintf("Unable to get kubelet version, using default version: %s", defaultKubeVersion))
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return defaultKubeVersion
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}
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return subs[1]
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}
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func makeSubstitutions(s string, ext string, m map[string]string) string {
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for k, v := range m {
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subst := "$" + k + ext
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if v == "" {
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glog.V(2).Info(fmt.Sprintf("No subsitution for '%s'\n", subst))
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continue
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}
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glog.V(1).Info(fmt.Sprintf("Substituting %s with '%s'\n", subst, v))
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s = multiWordReplace(s, subst, v)
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}
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return s
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}
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