clair/contrib/analyze-local-images/main.go

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// Copyright 2015 clair 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 main
import (
"bufio"
"bytes"
"encoding/json"
"errors"
"flag"
"fmt"
"io/ioutil"
"net"
"net/http"
"os"
"os/exec"
"strconv"
"strings"
"time"
"github.com/coreos/clair/api/v1"
"github.com/coreos/clair/utils/types"
"github.com/fatih/color"
)
const (
postLayerURI = "/v1/layers"
getLayerFeaturesURI = "/v1/layers/%s?vulnerabilities"
httpPort = 9279
)
var (
endpoint = flag.String("endpoint", "http://127.0.0.1:6060", "Address to Clair API")
myAddress = flag.String("my-address", "127.0.0.1", "Address from the point of view of Clair")
minimumSeverity = flag.String("minimum-severity", "Negligible", "Minimum severity of vulnerabilities to show (Unknown, Negligible, Low, Medium, High, Critical, Defcon1)")
flagNoColor = flag.Bool("no-color", false, "Disable color output")
)
func main() {
// Parse command-line arguments.
flag.Usage = func() {
fmt.Fprintf(os.Stderr, "Usage: %s [options] image-id\n\nOptions:\n", os.Args[0])
flag.PrintDefaults()
}
flag.Parse()
if len(flag.Args()) != 1 {
flag.Usage()
os.Exit(1)
}
imageName := flag.Args()[0]
minSeverity := types.Priority(*minimumSeverity)
if !minSeverity.IsValid() {
flag.Usage()
os.Exit(1)
}
if *flagNoColor {
color.NoColor = true
}
// Save image.
fmt.Printf("Saving %s\n", imageName)
path, err := save(imageName)
defer os.RemoveAll(path)
if err != nil {
fmt.Printf("- Could not save image: %s\n", err)
os.Exit(1)
}
// Retrieve history.
fmt.Println("Getting image's history")
layerIDs, err := historyFromManifest(path)
if err != nil {
layerIDs, err = historyFromCommand(imageName)
}
if err != nil || len(layerIDs) == 0 {
fmt.Printf("- Could not get image's history: %s\n", err)
os.Exit(1)
}
// Setup a simple HTTP server if Clair is not local.
if !strings.Contains(*endpoint, "127.0.0.1") && !strings.Contains(*endpoint, "localhost") {
allowedHost := strings.TrimPrefix(*endpoint, "http://")
portIndex := strings.Index(allowedHost, ":")
if portIndex >= 0 {
allowedHost = allowedHost[:portIndex]
}
go listenHTTP(path, allowedHost)
path = "http://" + *myAddress + ":" + strconv.Itoa(httpPort)
time.Sleep(200 * time.Millisecond)
}
// Analyze layers.
fmt.Printf("Analyzing %d layers\n", len(layerIDs))
for i := 0; i < len(layerIDs); i++ {
fmt.Printf("- Analyzing %s\n", layerIDs[i])
var err error
if i > 0 {
err = analyzeLayer(*endpoint, path+"/"+layerIDs[i]+"/layer.tar", layerIDs[i], layerIDs[i-1])
} else {
err = analyzeLayer(*endpoint, path+"/"+layerIDs[i]+"/layer.tar", layerIDs[i], "")
}
if err != nil {
fmt.Printf("- Could not analyze layer: %s\n", err)
os.Exit(1)
}
}
// Get vulnerabilities.
fmt.Println("Getting image's vulnerabilities")
layer, err := getLayer(*endpoint, layerIDs[len(layerIDs)-1])
if err != nil {
fmt.Printf("- Could not get layer information: %s\n", err)
os.Exit(1)
}
// Print report.
fmt.Printf("\n# Clair report for image %s (%s)\n", imageName, time.Now().UTC())
if len(layer.Features) == 0 {
fmt.Println("No feature has been detected on the image.")
fmt.Println("This usually means that the image isn't supported by Clair.")
os.Exit(0)
}
isSafe := true
for _, feature := range layer.Features {
if len(feature.Vulnerabilities) > 0 {
isFirstVulnerability := true
for _, vulnerability := range feature.Vulnerabilities {
severity := types.Priority(vulnerability.Severity)
if minSeverity.Compare(severity) > 0 {
continue
}
if isFirstVulnerability {
isSafe = false
isFirstVulnerability = false
fmt.Printf("## Feature: %s %s (%s)\n", feature.Name, feature.Version, feature.NamespaceName)
fmt.Printf("- Added by layer: %s\n", feature.AddedBy)
}
fmt.Printf("### (%s) %s\n", coloredSeverity(severity), vulnerability.Name)
if vulnerability.Description != "" {
fmt.Printf("- Link: %s\n", vulnerability.Link)
}
if vulnerability.Link != "" {
fmt.Printf("- Description: %s\n", vulnerability.Description)
}
if vulnerability.FixedBy != "" {
fmt.Printf("- Fixed version: %s\n", vulnerability.FixedBy)
}
if len(vulnerability.Metadata) > 0 {
fmt.Printf("- Metadata: %+v\n", vulnerability.Metadata)
}
}
}
}
if isSafe {
fmt.Println("\nBravo, your image looks SAFE !")
}
}
func save(imageName string) (string, error) {
path, err := ioutil.TempDir("", "analyze-local-image-")
if err != nil {
return "", err
}
var stderr bytes.Buffer
save := exec.Command("docker", "save", imageName)
save.Stderr = &stderr
extract := exec.Command("tar", "xf", "-", "-C"+path)
extract.Stderr = &stderr
pipe, err := extract.StdinPipe()
if err != nil {
return "", err
}
save.Stdout = pipe
err = extract.Start()
if err != nil {
return "", errors.New(stderr.String())
}
err = save.Run()
if err != nil {
return "", errors.New(stderr.String())
}
err = pipe.Close()
if err != nil {
return "", err
}
err = extract.Wait()
if err != nil {
return "", errors.New(stderr.String())
}
return path, nil
}
func historyFromManifest(path string) ([]string, error) {
mf, err := os.Open(path + "/manifest.json")
if err != nil {
return nil, err
}
defer mf.Close()
// https://github.com/docker/docker/blob/master/image/tarexport/tarexport.go#L17
type manifestItem struct {
Config string
RepoTags []string
Layers []string
}
var manifest []manifestItem
if err = json.NewDecoder(mf).Decode(&manifest); err != nil {
return nil, err
} else if len(manifest) != 1 {
return nil, err
}
var layers []string
for _, layer := range manifest[0].Layers {
layers = append(layers, strings.TrimSuffix(layer, "/layer.tar"))
}
return layers, nil
}
func historyFromCommand(imageName string) ([]string, error) {
var stderr bytes.Buffer
cmd := exec.Command("docker", "history", "-q", "--no-trunc", imageName)
cmd.Stderr = &stderr
stdout, err := cmd.StdoutPipe()
if err != nil {
return []string{}, err
}
err = cmd.Start()
if err != nil {
return []string{}, errors.New(stderr.String())
}
var layers []string
scanner := bufio.NewScanner(stdout)
for scanner.Scan() {
layers = append(layers, scanner.Text())
}
for i := len(layers)/2 - 1; i >= 0; i-- {
opp := len(layers) - 1 - i
layers[i], layers[opp] = layers[opp], layers[i]
}
return layers, nil
}
func listenHTTP(path, allowedHost string) {
fmt.Printf("Setting up HTTP server (allowing: %s)\n", allowedHost)
restrictedFileServer := func(path, allowedHost string) http.Handler {
fc := func(w http.ResponseWriter, r *http.Request) {
host, _, err := net.SplitHostPort(r.RemoteAddr)
if err == nil && strings.EqualFold(host, allowedHost) {
http.FileServer(http.Dir(path)).ServeHTTP(w, r)
return
}
w.WriteHeader(403)
}
return http.HandlerFunc(fc)
}
err := http.ListenAndServe(":"+strconv.Itoa(httpPort), restrictedFileServer(path, allowedHost))
if err != nil {
fmt.Printf("- An error occurs with the HTTP server: %s\n", err)
os.Exit(1)
}
}
func analyzeLayer(endpoint, path, layerName, parentLayerName string) error {
payload := v1.LayerEnvelope{
Layer: &v1.Layer{
Name: layerName,
Path: path,
ParentName: parentLayerName,
Format: "Docker",
},
}
jsonPayload, err := json.Marshal(payload)
if err != nil {
return err
}
request, err := http.NewRequest("POST", endpoint+postLayerURI, bytes.NewBuffer(jsonPayload))
if err != nil {
return err
}
request.Header.Set("Content-Type", "application/json")
client := &http.Client{}
response, err := client.Do(request)
if err != nil {
return err
}
defer response.Body.Close()
if response.StatusCode != 201 {
body, _ := ioutil.ReadAll(response.Body)
return fmt.Errorf("- Got response %d with message %s", response.StatusCode, string(body))
}
return nil
}
func getLayer(endpoint, layerID string) (v1.Layer, error) {
response, err := http.Get(endpoint + fmt.Sprintf(getLayerFeaturesURI, layerID))
if err != nil {
return v1.Layer{}, err
}
defer response.Body.Close()
if response.StatusCode != 200 {
body, _ := ioutil.ReadAll(response.Body)
err := fmt.Errorf("- Got response %d with message %s", response.StatusCode, string(body))
return v1.Layer{}, err
}
var apiResponse v1.LayerEnvelope
if err = json.NewDecoder(response.Body).Decode(&apiResponse); err != nil {
return v1.Layer{}, err
} else if apiResponse.Error != nil {
return v1.Layer{}, errors.New(apiResponse.Error.Message)
}
return *apiResponse.Layer, nil
}
func coloredSeverity(severity types.Priority) string {
red := color.New(color.FgRed).SprintFunc()
yellow := color.New(color.FgYellow).SprintFunc()
white := color.New(color.FgWhite).SprintFunc()
switch severity {
case types.High, types.Critical:
return red(severity)
case types.Medium:
return yellow(severity)
default:
return white(severity)
}
}