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// Copyright 2015 The appc 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
/*
This validator tool is intended to be run within an App Container Executor
(ACE), and verifies that the ACE has been set up correctly.
This verifies the _apps perspective_ of the execution environment.
Changes to the validator need to be reflected in app_manifest.json, and vice-versa
The App Container Execution spec defines the following expectations within the execution environment:
- Working Directory defaults to the root of the application image, overridden with "workingDirectory"
- PATH /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
- AC_APP_NAME the entrypoint that this process was defined from
In addition, we validate:
- The expected mount points are mounted
- metadata service reachable at http://169.254.169.255
TODO(jonboulle):
- should we validate Isolators? (e.g. MemoryLimit + malloc, or capabilities)
- should we validate ports? (e.g. that they are available to bind to within the network namespace of the pod)
*/
import (
"bufio"
"bytes"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"os"
"reflect"
"strings"
"time"
"github.com/appc/spec/schema"
"github.com/appc/spec/schema/types"
)
const (
standardPath = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"
appNameEnv = "AC_APP_NAME"
metadataPathBase = "/acMetadata/v1"
// marker files to validate
prestartFile = "/prestart"
mainFile = "/main"
poststopFile = "/poststop"
mainVolFile = "/db/main"
sidekickVolFile = "/db/sidekick"
timeout = 5 * time.Second
)
var (
// Expected values must be kept in sync with app_manifest.json
workingDirectory = "/opt/acvalidator"
// "Environment"
env = map[string]string{
"IN_ACE_VALIDATOR": "correct",
}
// "MountPoints"
mps = map[string]types.MountPoint{
"database": types.MountPoint{
Path: "/db",
ReadOnly: false,
},
}
// "Name"
an = "ace-validator-main"
)
type results []error
// main outputs diagnostic information to stderr and exits 1 if validation fails
func main() {
if len(os.Args) != 2 {
stderr("usage: %s [main|sidekick|preStart|postStop]", os.Args[0])
os.Exit(64)
}
mode := os.Args[1]
var res results
switch strings.ToLower(mode) {
case "main":
res = validateMain()
case "sidekick":
res = validateSidekick()
case "prestart":
res = validatePrestart()
case "poststop":
res = validatePoststop()
default:
stderr("unrecognized mode: %s", mode)
os.Exit(64)
}
if len(res) == 0 {
fmt.Printf("%s OK\n", mode)
os.Exit(0)
}
fmt.Printf("%s FAIL\n", mode)
for _, err := range res {
fmt.Fprintln(os.Stderr, "==>", err)
}
os.Exit(1)
}
func validateMain() (errs results) {
errs = append(errs, assertExists(prestartFile)...)
errs = append(errs, assertNotExistsAndCreate(mainFile)...)
errs = append(errs, assertNotExists(poststopFile)...)
errs = append(errs, ValidatePath(standardPath)...)
errs = append(errs, ValidateWorkingDirectory(workingDirectory)...)
errs = append(errs, ValidateEnvironment(env)...)
errs = append(errs, ValidateMountpoints(mps)...)
errs = append(errs, ValidateAppNameEnv(an)...)
errs = append(errs, ValidateMetadataSvc()...)
errs = append(errs, waitForFile(sidekickVolFile, timeout)...)
errs = append(errs, assertNotExistsAndCreate(mainVolFile)...)
return
}
func validateSidekick() (errs results) {
errs = append(errs, assertNotExistsAndCreate(sidekickVolFile)...)
errs = append(errs, waitForFile(mainVolFile, timeout)...)
return
}
func validatePrestart() (errs results) {
errs = append(errs, assertNotExistsAndCreate(prestartFile)...)
errs = append(errs, assertNotExists(mainFile)...)
errs = append(errs, assertNotExists(poststopFile)...)
return
}
func validatePoststop() (errs results) {
errs = append(errs, assertExists(prestartFile)...)
errs = append(errs, assertExists(mainFile)...)
errs = append(errs, assertNotExistsAndCreate(poststopFile)...)
return
}
// ValidatePath ensures that the PATH has been set up correctly within the
// environment in which this process is being run
func ValidatePath(wp string) results {
r := results{}
gp := os.Getenv("PATH")
if wp != gp {
r = append(r, fmt.Errorf("PATH not set appropriately (need %q, got %q)", wp, gp))
}
return r
}
// ValidateWorkingDirectory ensures that the process working directory is set
// to the desired path.
func ValidateWorkingDirectory(wwd string) (r results) {
gwd, err := os.Getwd()
if err != nil {
r = append(r, fmt.Errorf("error getting working directory: %v", err))
return
}
if gwd != wwd {
r = append(r, fmt.Errorf("working directory not set appropriately (need %q, got %v)", wwd, gwd))
}
return
}
// ValidateEnvironment ensures that the given environment contains the
// necessary/expected environment variables.
func ValidateEnvironment(wenv map[string]string) (r results) {
for wkey, wval := range wenv {
gval := os.Getenv(wkey)
if gval != wval {
err := fmt.Errorf("environment variable %q not set appropriately (need %q, got %q)", wkey, wval, gval)
r = append(r, err)
}
}
return
}
// ValidateAppNameEnv ensures that the environment variable specifying the
// entrypoint of this process is set correctly.
func ValidateAppNameEnv(want string) (r results) {
if got := os.Getenv(appNameEnv); got != want {
r = append(r, fmt.Errorf("%s not set appropriately (need %q, got %q)", appNameEnv, want, got))
}
return
}
// ValidateMountpoints ensures that the given mount points are present in the
// environment in which this process is running
func ValidateMountpoints(wmp map[string]types.MountPoint) results {
r := results{}
// TODO(jonboulle): verify actual source
for _, mp := range wmp {
if err := checkMount(mp.Path, mp.ReadOnly); err != nil {
r = append(r, err)
}
}
return r
}
func metadataRequest(req *http.Request, expectedContentType string) ([]byte, error) {
cli := http.Client{
Timeout: 100 * time.Millisecond,
}
req.Header["Metadata-Flavor"] = []string{"AppContainer"}
resp, err := cli.Do(req)
if err != nil {
return nil, err
}
if resp.StatusCode != 200 {
return nil, fmt.Errorf("Get %s failed with %v", req.URL, resp.StatusCode)
}
if respContentType := resp.Header.Get("Content-Type"); respContentType != expectedContentType {
return nil, fmt.Errorf("`%v` did not respond with expected Content-Type header. Expected %s, received %s",
req.URL, expectedContentType, respContentType)
}
body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return nil, fmt.Errorf("Get %s failed on body read: %v", req.URL, err)
}
return body, nil
}
func metadataGet(metadataURL, path string, expectedContentType string) ([]byte, error) {
uri := metadataURL + metadataPathBase + path
req, err := http.NewRequest("GET", uri, nil)
if err != nil {
panic(err)
}
return metadataRequest(req, expectedContentType)
}
func metadataPost(metadataURL, path string, body []byte, expectedContentType string) ([]byte, error) {
uri := metadataURL + metadataPathBase + path
req, err := http.NewRequest("POST", uri, bytes.NewBuffer(body))
if err != nil {
panic(err)
}
req.Header.Set("Content-Type", "text/plain")
return metadataRequest(req, expectedContentType)
}
func metadataPostForm(metadataURL, path string, data url.Values, expectedContentType string) ([]byte, error) {
uri := metadataURL + metadataPathBase + path
req, err := http.NewRequest("POST", uri, strings.NewReader(data.Encode()))
if err != nil {
panic(err)
}
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
return metadataRequest(req, expectedContentType)
}
func validatePodAnnotations(metadataURL string, pm *schema.PodManifest) results {
r := results{}
var actualAnnots types.Annotations
annotJson, err := metadataGet(metadataURL, "/pod/annotations", "application/json")
if err != nil {
return append(r, err)
}
err = json.Unmarshal(annotJson, &actualAnnots)
if err != nil {
return append(r, err)
}
if !reflect.DeepEqual(actualAnnots, pm.Annotations) {
r = append(r, fmt.Errorf("pod annotations mismatch: %v vs %v", actualAnnots, pm.Annotations))
}
return r
}
func validatePodMetadata(metadataURL string, pm *schema.PodManifest) results {
r := results{}
uuid, err := metadataGet(metadataURL, "/pod/uuid", "text/plain; charset=us-ascii")
if err != nil {
return append(r, err)
}
_, err = types.NewUUID(string(uuid))
if err != nil {
return append(r, fmt.Errorf("malformed UUID returned (%v): %v", string(uuid), err))
}
return append(r, validatePodAnnotations(metadataURL, pm)...)
}
func validateAppAnnotations(metadataURL string, pm *schema.PodManifest, app *schema.RuntimeApp, img *schema.ImageManifest) results {
r := results{}
// build a map of expected annotations by merging img.Annotations
// with PodManifest overrides
expectedAnnots := img.Annotations
for _, annot := range app.Annotations {
expectedAnnots.Set(annot.Name, annot.Value)
}
if len(expectedAnnots) == 0 {
expectedAnnots = nil
}
var actualAnnots types.Annotations
annotJson, err := metadataGet(metadataURL, "/apps/"+string(app.Name)+"/annotations", "application/json")
if err != nil {
return append(r, err)
}
err = json.Unmarshal(annotJson, &actualAnnots)
if err != nil {
return append(r, err)
}
if len(actualAnnots) == 0 {
actualAnnots = nil
}
if !reflect.DeepEqual(actualAnnots, expectedAnnots) {
err := fmt.Errorf("%v annotations mismatch: %v vs %v", app.Name, actualAnnots, expectedAnnots)
r = append(r, err)
}
return r
}
func validateAppMetadata(metadataURL string, pm *schema.PodManifest, app *schema.RuntimeApp) results {
r := results{}
am, err := metadataGet(metadataURL, "/apps/"+app.Name.String()+"/image/manifest", "application/json")
if err != nil {
return append(r, err)
}
img := &schema.ImageManifest{}
if err = json.Unmarshal(am, img); err != nil {
return append(r, fmt.Errorf("failed to JSON-decode %q manifest: %v", app.Name.String(), err))
}
id, err := metadataGet(metadataURL, "/apps/"+app.Name.String()+"/image/id", "text/plain; charset=us-ascii")
if err != nil {
r = append(r, err)
}
if string(id) != app.Image.ID.String() {
err = fmt.Errorf("%q's image id mismatch: %v vs %v", app.Name.String(), id, app.Image.ID)
r = append(r, err)
}
return append(r, validateAppAnnotations(metadataURL, pm, app, img)...)
}
func validateSigning(metadataURL string, pm *schema.PodManifest) results {
r := results{}
// Get our UUID
uuid, err := metadataGet(metadataURL, "/pod/uuid", "text/plain; charset=us-ascii")
if err != nil {
return append(r, err)
}
plaintext := "Old MacDonald Had A Farm"
// Sign
sig, err := metadataPostForm(metadataURL, "/pod/hmac/sign", url.Values{
"content": []string{plaintext},
}, "text/plain; charset=us-ascii")
if err != nil {
return append(r, err)
}
// Verify
_, err = metadataPostForm(metadataURL, "/pod/hmac/verify", url.Values{
"content": []string{plaintext},
"uuid": []string{string(uuid)},
"signature": []string{string(sig)},
}, "text/plain; charset=us-ascii")
if err != nil {
return append(r, err)
}
return r
}
func ValidateMetadataSvc() results {
r := results{}
metadataURL := os.Getenv("AC_METADATA_URL")
if metadataURL == "" {
return append(r, fmt.Errorf("AC_METADATA_URL is not set"))
}
pod, err := metadataGet(metadataURL, "/pod/manifest", "application/json")
if err != nil {
return append(r, err)
}
pm := &schema.PodManifest{}
if err = json.Unmarshal(pod, pm); err != nil {
return append(r, fmt.Errorf("failed to JSON-decode pod manifest: %v", err))
}
r = append(r, validatePodMetadata(metadataURL, pm)...)
for _, app := range pm.Apps {
app := app
r = append(r, validateAppMetadata(metadataURL, pm, &app)...)
}
return append(r, validateSigning(metadataURL, pm)...)
}
// checkMount checks that the given string is a mount point, and that it is
// mounted appropriately read-only or not according to the given bool
func checkMount(d string, readonly bool) error {
return checkMountImpl(d, readonly)
}
// parseMountinfo parses a Reader representing a /proc/PID/mountinfo file and
// returns whether dir is mounted and if so, whether it is read-only or not
func parseMountinfo(mountinfo io.Reader, dir string) (isMounted bool, readOnly bool, err error) {
sc := bufio.NewScanner(mountinfo)
for sc.Scan() {
var (
mountID int
parentID int
majorMinor string
root string
mountPoint string
mountOptions string
)
_, err := fmt.Sscanf(sc.Text(), "%d %d %s %s %s %s",
&mountID, &parentID, &majorMinor, &root, &mountPoint, &mountOptions)
if err != nil {
return false, false, err
}
if mountPoint == dir {
isMounted = true
optionsParts := strings.Split(mountOptions, ",")
for _, o := range optionsParts {
switch o {
case "ro":
readOnly = true
case "rw":
readOnly = false
}
}
}
}
return
}
// assertNotExistsAndCreate asserts that a file at the given path does not
// exist, and then proceeds to create (touch) the file. It returns any errors
// encountered at either of these steps.
func assertNotExistsAndCreate(p string) []error {
var errs []error
errs = append(errs, assertNotExists(p)...)
if err := touchFile(p); err != nil {
errs = append(errs, fmt.Errorf("error touching file %q: %v", p, err))
}
return errs
}
// assertNotExists asserts that a file at the given path does not exist. A
// non-empty list of errors is returned if the file exists or any error is
// encountered while checking.
func assertNotExists(p string) []error {
var errs []error
e, err := fileExists(p)
if err != nil {
errs = append(errs, fmt.Errorf("error checking %q exists: %v", p, err))
}
if e {
errs = append(errs, fmt.Errorf("file %q exists unexpectedly", p))
}
return errs
}
// assertExists asserts that a file exists at the given path. A non-empty
// list of errors is returned if the file does not exist or any error is
// encountered while checking.
func assertExists(p string) []error {
var errs []error
e, err := fileExists(p)
if err != nil {
errs = append(errs, fmt.Errorf("error checking %q exists: %v", p, err))
}
if !e {
errs = append(errs, fmt.Errorf("file %q does not exist as expected", p))
}
return errs
}
// touchFile creates an empty file, returning any error encountered
func touchFile(p string) error {
_, err := os.Create(p)
return err
}
// fileExists checks whether a file exists at the given path
func fileExists(p string) (bool, error) {
_, err := os.Stat(p)
if err == nil {
return true, nil
}
if os.IsNotExist(err) {
return false, nil
}
return false, err
}
// waitForFile waits for the file at the given path to appear
func waitForFile(p string, to time.Duration) []error {
done := time.After(to)
for {
select {
case <-done:
return []error{
fmt.Errorf("timed out waiting for %s", p),
}
case <-time.After(1):
if ok, _ := fileExists(p); ok {
return nil
}
}
}
}
func stderr(format string, a ...interface{}) {
out := fmt.Sprintf(format, a...)
fmt.Fprintln(os.Stderr, strings.TrimSuffix(out, "\n"))
}
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