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Merge pull request #2349 from erikwilson/fix-data-extract

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Fix race condition in data extraction
pull/2377/head
Erik Wilson 4 years ago committed by GitHub
parent c3c983198f 95b895038c
commit 154b395c03
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 205 additions and 4 deletions
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27
cmd/k3s/main.go
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@ -12,6 +12,8 @@ import (
"github.com/rancher/k3s/pkg/cli/cmds"
"github.com/rancher/k3s/pkg/data"
"github.com/rancher/k3s/pkg/datadir"
"github.com/rancher/k3s/pkg/dataverify"
"github.com/rancher/k3s/pkg/flock"
"github.com/rancher/k3s/pkg/untar"
"github.com/rancher/k3s/pkg/version"
"github.com/sirupsen/logrus"
@ -88,6 +90,7 @@ func stageAndRun(dataDir string, cmd string, args []string) error {
if err != nil {
return errors.Wrap(err, "extracting data")
}
logrus.Debugf("Asset dir %s", dir)
if err := os.Setenv("PATH", filepath.Join(dir, "bin")+":"+os.Getenv("PATH")+":"+filepath.Join(dir, "bin/aux")); err != nil {
return err
@ -102,6 +105,7 @@ func stageAndRun(dataDir string, cmd string, args []string) error {
}
logrus.Debugf("Running %s %v", cmd, args)
return syscall.Exec(cmd, args, os.Environ())
}
@ -115,13 +119,27 @@ func extract(dataDir string) (string, error) {
// first look for global asset folder so we don't create a HOME version if not needed
_, dir := getAssetAndDir(datadir.DefaultDataDir)
if _, err := os.Stat(dir); err == nil {
logrus.Debugf("Asset dir %s", dir)
return dir, nil
}
asset, dir := getAssetAndDir(dataDir)
// check if target directory already exists
if _, err := os.Stat(dir); err == nil {
return dir, nil
}
// acquire a data directory lock
os.MkdirAll(filepath.Join(dataDir, "data"), 0755)
lockFile := filepath.Join(dataDir, "data", ".lock")
logrus.Infof("Acquiring lock file %s", lockFile)
lock, err := flock.Acquire(lockFile)
if err != nil {
return "", err
}
defer flock.Release(lock)
// check again if target directory exists
if _, err := os.Stat(dir); err == nil {
logrus.Debugf("Asset dir %s", dir)
return dir, nil
}
@ -135,12 +153,14 @@ func extract(dataDir string) (string, error) {
tempDest := dir + "-tmp"
defer os.RemoveAll(tempDest)
os.RemoveAll(tempDest)
if err := untar.Untar(buf, tempDest); err != nil {
return "", err
}
if err := dataverify.Verify(filepath.Join(tempDest, "bin")); err != nil {
return "", err
}
currentSymLink := filepath.Join(dataDir, "data", "current")
previousSymLink := filepath.Join(dataDir, "data", "previous")
@ -152,6 +172,5 @@ func extract(dataDir string) (string, error) {
if err := os.Symlink(dir, currentSymLink); err != nil {
return "", err
}
return dir, os.Rename(tempDest, dir)
}

117
pkg/dataverify/dataverify.go
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@ -0,0 +1,117 @@
package dataverify
import (
"bufio"
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"os"
"path/filepath"
"strings"
"github.com/sirupsen/logrus"
)
// Verify will check the sha256sums and links from the files in a given directory
func Verify(dir string) error {
failed := false
if err := VerifySums(dir, ".sha256sums"); err != nil {
logrus.Errorf("Unable to verify sums: %s", err)
failed = true
}
if err := VerifyLinks(dir, ".links"); err != nil {
logrus.Errorf("Unable to verify links: %s", err)
failed = true
}
if failed {
return fmt.Errorf("failed to verify directory %s", dir)
}
return nil
}
// VerifySums will take a file which contains a list of hash sums for files and verify they match
func VerifySums(root, sumListFile string) error {
sums, err := fileMapFields(filepath.Join(root, sumListFile), 1, 0)
if err != nil {
return err
}
if len(sums) == 0 {
return fmt.Errorf("no entries found in %s", sumListFile)
}
numFailed := 0
for sumFile, sumExpected := range sums {
file := filepath.Join(root, sumFile)
sumActual, _ := sha256Sum(file)
if sumExpected != sumActual {
logrus.Errorf("Hash for file %s expected to be %s (fail)", sumFile, sumExpected)
numFailed++
} else {
logrus.Debugf("Verified hash %s is correct", sumFile)
}
}
if numFailed != 0 {
return fmt.Errorf("failed %d hash verifications", numFailed)
}
return nil
}
// VerifyLinks will take a file which contains a list of target links for files and verify they match
func VerifyLinks(root, linkListFile string) error {
links, err := fileMapFields(filepath.Join(root, linkListFile), 0, 1)
if err != nil {
return err
}
if len(links) == 0 {
return fmt.Errorf("no entries found in %s", linkListFile)
}
numFailed := 0
for linkFile, linkExpected := range links {
file := filepath.Join(root, linkFile)
linkActual, _ := os.Readlink(file)
if linkExpected != linkActual {
logrus.Errorf("Link for file %s expected to be %s (fail)", linkFile, linkExpected)
numFailed++
} else {
logrus.Debugf("Verified link %s is correct", linkFile)
}
}
if numFailed != 0 {
return fmt.Errorf("failed %d link verifications", numFailed)
}
return nil
}
func fileMapFields(fileName string, key, val int) (map[string]string, error) {
file, err := os.Open(fileName)
if err != nil {
return nil, err
}
defer file.Close()
result := map[string]string{}
scanner := bufio.NewScanner(file)
for scanner.Scan() {
fields := strings.Fields(scanner.Text())
if len(fields) == 0 {
continue
}
if len(fields) <= key || len(fields) <= val {
return nil, fmt.Errorf("fields for file %s (%d) smaller than required index (key: %d, val: %d)", fileName, len(fields), key, val)
}
result[fields[key]] = fields[val]
}
return result, scanner.Err()
}
func sha256Sum(filePath string) (string, error) {
file, err := os.Open(filePath)
if err != nil {
return "", err
}
defer file.Close()
hash := sha256.New()
if _, err := io.Copy(hash, file); err != nil {
return "", err
}
return hex.EncodeToString(hash.Sum(nil)), nil
}

29
pkg/flock/flock_other.go
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@ -0,0 +1,29 @@
// +build !linux,!darwin,!freebsd,!openbsd,!netbsd,!dragonfly
/*
Copyright 2016 The Kubernetes 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 flock
// Acquire is not implemented on non-unix systems.
func Acquire(path string) (int, error) {
return -1, nil
}
// Release is not implemented on non-unix systems.
func Release(lock int) error {
return nil
}

36
pkg/flock/flock_unix.go
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@ -0,0 +1,36 @@
// +build linux darwin freebsd openbsd netbsd dragonfly
/*
Copyright 2016 The Kubernetes 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 flock
import "golang.org/x/sys/unix"
// Acquire creates an exclusive lock on a file for the duration of the process, or until Release(d).
// This method is reentrant.
func Acquire(path string) (int, error) {
lock, err := unix.Open(path, unix.O_CREAT|unix.O_RDWR|unix.O_CLOEXEC, 0600)
if err != nil {
return -1, err
}
return lock, unix.Flock(lock, unix.LOCK_EX)
}
// Release removes an existing lock held by this process.
func Release(lock int) error {
return unix.Flock(lock, unix.LOCK_UN)
}
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