clair/ext/vulnsrc/alpine/alpine.go
2017-05-11 15:18:37 -04:00

265 lines
6.2 KiB
Go

// Copyright 2017 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 alpine implements a vulnerability source updater using the
// alpine-secdb git repository.
package alpine
import (
"io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strings"
log "github.com/sirupsen/logrus"
"gopkg.in/yaml.v2"
"github.com/coreos/clair/database"
"github.com/coreos/clair/ext/versionfmt"
"github.com/coreos/clair/ext/versionfmt/dpkg"
"github.com/coreos/clair/ext/vulnsrc"
"github.com/coreos/clair/pkg/commonerr"
)
const (
secdbGitURL = "https://git.alpinelinux.org/cgit/alpine-secdb"
updaterFlag = "alpine-secdbUpdater"
nvdURLPrefix = "https://cve.mitre.org/cgi-bin/cvename.cgi?name="
)
func init() {
vulnsrc.RegisterUpdater("alpine", &updater{})
}
type updater struct {
repositoryLocalPath string
}
func (u *updater) Update(db database.Datastore) (resp vulnsrc.UpdateResponse, err error) {
log.WithField("package", "Alpine").Info("Start fetching vulnerabilities")
// Pull the master branch.
var commit string
commit, err = u.pullRepository()
if err != nil {
return
}
// Ask the database for the latest commit we successfully applied.
var dbCommit string
dbCommit, err = db.GetKeyValue(updaterFlag)
if err != nil {
return
}
// Set the updaterFlag to equal the commit processed.
resp.FlagName = updaterFlag
resp.FlagValue = commit
// Short-circuit if there have been no updates.
if commit == dbCommit {
log.WithField("package", "alpine").Debug("no update")
return
}
// Get the list of namespaces from the repository.
var namespaces []string
namespaces, err = ls(u.repositoryLocalPath, directoriesOnly)
if err != nil {
return
}
// Append any changed vulnerabilities to the response.
for _, namespace := range namespaces {
var vulns []database.Vulnerability
var note string
vulns, note, err = parseVulnsFromNamespace(u.repositoryLocalPath, namespace)
if err != nil {
return
}
if note != "" {
resp.Notes = append(resp.Notes, note)
}
resp.Vulnerabilities = append(resp.Vulnerabilities, vulns...)
}
return
}
func (u *updater) Clean() {
if u.repositoryLocalPath != "" {
os.RemoveAll(u.repositoryLocalPath)
}
}
type lsFilter int
const (
filesOnly lsFilter = iota
directoriesOnly
)
func ls(path string, filter lsFilter) ([]string, error) {
dir, err := os.Open(path)
if err != nil {
return nil, err
}
defer dir.Close()
finfos, err := dir.Readdir(0)
if err != nil {
return nil, err
}
var files []string
for _, info := range finfos {
if filter == directoriesOnly && !info.IsDir() {
continue
}
if filter == filesOnly && info.IsDir() {
continue
}
if strings.HasPrefix(info.Name(), ".") {
continue
}
files = append(files, info.Name())
}
return files, nil
}
func parseVulnsFromNamespace(repositoryPath, namespace string) (vulns []database.Vulnerability, note string, err error) {
nsDir := filepath.Join(repositoryPath, namespace)
var dbFilenames []string
dbFilenames, err = ls(nsDir, filesOnly)
if err != nil {
return
}
for _, filename := range dbFilenames {
var file io.ReadCloser
file, err = os.Open(filepath.Join(nsDir, filename))
if err != nil {
return
}
var fileVulns []database.Vulnerability
fileVulns, err = parseYAML(file)
if err != nil {
return
}
vulns = append(vulns, fileVulns...)
file.Close()
}
return
}
func (u *updater) pullRepository() (commit string, err error) {
// If the repository doesn't exist, clone it.
if _, pathExists := os.Stat(u.repositoryLocalPath); u.repositoryLocalPath == "" || os.IsNotExist(pathExists) {
if u.repositoryLocalPath, err = ioutil.TempDir(os.TempDir(), "alpine-secdb"); err != nil {
return "", vulnsrc.ErrFilesystem
}
cmd := exec.Command("git", "clone", secdbGitURL, ".")
cmd.Dir = u.repositoryLocalPath
if out, err := cmd.CombinedOutput(); err != nil {
u.Clean()
log.WithError(err).WithField("output", string(out)).Error("could not pull alpine-secdb repository")
return "", commonerr.ErrCouldNotDownload
}
} else {
// The repository already exists and it needs to be refreshed via a pull.
cmd := exec.Command("git", "pull")
cmd.Dir = u.repositoryLocalPath
if _, err := cmd.CombinedOutput(); err != nil {
return "", vulnsrc.ErrGitFailure
}
}
cmd := exec.Command("git", "rev-parse", "HEAD")
cmd.Dir = u.repositoryLocalPath
out, err := cmd.CombinedOutput()
if err != nil {
return "", vulnsrc.ErrGitFailure
}
commit = strings.TrimSpace(string(out))
return
}
type secDBFile struct {
Distro string `yaml:"distroversion"`
Packages []struct {
Pkg struct {
Name string `yaml:"name"`
Fixes map[string][]string `yaml:"secfixes"`
} `yaml:"pkg"`
} `yaml:"packages"`
}
func parseYAML(r io.Reader) (vulns []database.Vulnerability, err error) {
var rBytes []byte
rBytes, err = ioutil.ReadAll(r)
if err != nil {
return
}
var file secDBFile
err = yaml.Unmarshal(rBytes, &file)
if err != nil {
return
}
for _, pack := range file.Packages {
pkg := pack.Pkg
for version, vulnStrs := range pkg.Fixes {
err := versionfmt.Valid(dpkg.ParserName, version)
if err != nil {
log.WithError(err).WithField("version", version).Warning("could not parse package version. skipping")
continue
}
for _, vulnStr := range vulnStrs {
var vuln database.Vulnerability
vuln.Severity = database.UnknownSeverity
vuln.Name = vulnStr
vuln.Link = nvdURLPrefix + vulnStr
vuln.FixedIn = []database.FeatureVersion{
{
Feature: database.Feature{
Namespace: database.Namespace{
Name: "alpine:" + file.Distro,
VersionFormat: dpkg.ParserName,
},
Name: pkg.Name,
},
Version: version,
},
}
vulns = append(vulns, vuln)
}
}
}
return
}