forked from quay/clair
/
nvd.go
280 lines (234 loc) · 7.49 KB
/
nvd.go
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// 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 nvd implements a vulnerability metadata appender using the NIST NVD
// database.
package nvd
import (
"bufio"
"compress/gzip"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"time"
log "github.com/sirupsen/logrus"
"github.com/coreos/clair/database"
"github.com/coreos/clair/ext/vulnmdsrc"
"github.com/coreos/clair/pkg/commonerr"
"github.com/coreos/clair/pkg/httputil"
)
const (
dataFeedURL string = "https://nvd.nist.gov/feeds/json/cve/1.0/nvdcve-1.0-%s.json.gz"
dataFeedMetaURL string = "https://nvd.nist.gov/feeds/json/cve/1.0/nvdcve-1.0-%s.meta"
appenderName string = "NVD"
logDataFeedName string = "data feed name"
)
type appender struct {
localPath string
dataFeedHashes map[string]string
metadata map[string]NVDMetadata
}
type NVDMetadata struct {
CVSSv2 NVDmetadataCVSSv2
CVSSv3 NVDmetadataCVSSv3
}
type NVDmetadataCVSSv2 struct {
PublishedDateTime string
Vectors string
Score float64
}
type NVDmetadataCVSSv3 struct {
Vectors string
Score float64
ExploitabilityScore float64
ImpactScore float64
}
func init() {
vulnmdsrc.RegisterAppender(appenderName, &appender{})
}
func (a *appender) BuildCache(datastore database.Datastore) error {
var err error
a.metadata = make(map[string]NVDMetadata)
// Init if necessary.
if a.localPath == "" {
// Create a temporary folder to store the NVD data and create hashes struct.
if a.localPath, err = ioutil.TempDir(os.TempDir(), "nvd-data"); err != nil {
return commonerr.ErrFilesystem
}
a.dataFeedHashes = make(map[string]string)
}
// Get data feeds.
dataFeedReaders, dataFeedHashes, err := getDataFeeds(a.dataFeedHashes, a.localPath)
if err != nil {
return err
}
a.dataFeedHashes = dataFeedHashes
// Parse data feeds.
for dataFeedName, dataFileName := range dataFeedReaders {
f, err := os.Open(dataFileName)
if err != nil {
log.WithError(err).WithField(logDataFeedName, dataFeedName).Error("could not open NVD data file")
return commonerr.ErrCouldNotParse
}
r := bufio.NewReader(f)
if err := a.parseDataFeed(r); err != nil {
log.WithError(err).WithField(logDataFeedName, dataFeedName).Error("could not parse NVD data file")
return err
}
f.Close()
}
return nil
}
func (a *appender) parseDataFeed(r io.Reader) error {
var nvd nvd
if err := json.NewDecoder(r).Decode(&nvd); err != nil {
return commonerr.ErrCouldNotParse
}
for _, nvdEntry := range nvd.Entries {
// Create metadata entry.
if metadata := nvdEntry.Metadata(); metadata != nil {
a.metadata[nvdEntry.Name()] = *metadata
}
}
return nil
}
func (a *appender) Append(vulnName string, appendFunc vulnmdsrc.AppendFunc) error {
if nvdMetadata, ok := a.metadata[vulnName]; ok {
appendFunc(appenderName, nvdMetadata, SeverityFromCVSS(nvdMetadata.CVSSv2.Score))
}
return nil
}
func (a *appender) PurgeCache() {
a.metadata = nil
}
func (a *appender) Clean() {
os.RemoveAll(a.localPath)
}
func getDataFeeds(dataFeedHashes map[string]string, localPath string) (map[string]string, map[string]string, error) {
var dataFeedNames []string
for y := 2002; y <= time.Now().Year(); y++ {
dataFeedNames = append(dataFeedNames, strconv.Itoa(y))
}
// Get hashes for these feeds.
for _, dataFeedName := range dataFeedNames {
hash, err := getHashFromMetaURL(fmt.Sprintf(dataFeedMetaURL, dataFeedName))
if err != nil {
log.WithError(err).WithField(logDataFeedName, dataFeedName).Warning("could not get NVD data feed hash")
// It's not a big deal, no need interrupt, we're just going to download it again then.
continue
}
dataFeedHashes[dataFeedName] = hash
}
// Create map containing the name and filename for every data feed.
dataFeedReaders := make(map[string]string)
for _, dataFeedName := range dataFeedNames {
fileName := filepath.Join(localPath, fmt.Sprintf("%s.json", dataFeedName))
if h, ok := dataFeedHashes[dataFeedName]; ok && h == dataFeedHashes[dataFeedName] {
// The hash is known, the disk should contains the feed. Try to read from it.
if localPath != "" {
if f, err := os.Open(fileName); err == nil {
f.Close()
dataFeedReaders[dataFeedName] = fileName
continue
}
}
err := downloadFeed(dataFeedName, fileName)
if err != nil {
return dataFeedReaders, dataFeedHashes, err
}
dataFeedReaders[dataFeedName] = fileName
}
}
return dataFeedReaders, dataFeedHashes, nil
}
func downloadFeed(dataFeedName, fileName string) error {
// Download data feed.
r, err := httputil.GetWithUserAgent(fmt.Sprintf(dataFeedURL, dataFeedName))
if err != nil {
log.WithError(err).WithField(logDataFeedName, dataFeedName).Error("could not download NVD data feed")
return commonerr.ErrCouldNotDownload
}
defer r.Body.Close()
if !httputil.Status2xx(r) {
log.WithFields(log.Fields{"StatusCode": r.StatusCode, "DataFeedName": dataFeedName}).Error("Failed to download NVD data feed")
return commonerr.ErrCouldNotDownload
}
// Un-gzip it.
gr, err := gzip.NewReader(r.Body)
if err != nil {
log.WithError(err).WithFields(log.Fields{"StatusCode": r.StatusCode, "DataFeedName": dataFeedName}).Error("could not read NVD data feed")
return commonerr.ErrCouldNotDownload
}
// Store it to a file at the same time if possible.
f, err := os.Create(fileName)
if err != nil {
log.WithError(err).WithField("Filename", fileName).Warning("could not store NVD data feed to filesystem")
return commonerr.ErrFilesystem
}
defer f.Close()
_, err = io.Copy(f, gr)
if err != nil {
log.WithError(err).WithField("Filename", fileName).Warning("could not stream NVD data feed to filesystem")
return commonerr.ErrFilesystem
}
return nil
}
func getHashFromMetaURL(metaURL string) (string, error) {
r, err := httputil.GetWithUserAgent(metaURL)
if err != nil {
return "", err
}
defer r.Body.Close()
if !httputil.Status2xx(r) {
return "", fmt.Errorf("%v failed status code: %d", metaURL, r.StatusCode)
}
scanner := bufio.NewScanner(r.Body)
for scanner.Scan() {
line := scanner.Text()
if strings.HasPrefix(line, "sha256:") {
return strings.TrimPrefix(line, "sha256:"), nil
}
}
if err := scanner.Err(); err != nil {
return "", err
}
return "", errors.New("invalid .meta file format")
}
// SeverityFromCVSS converts the CVSS Score (0.0 - 10.0) into a
// database.Severity following the qualitative rating scale available in the
// CVSS v3.0 specification (https://www.first.org/cvss/specification-document),
// Table 14.
//
// The Negligible level is set for CVSS scores between [0, 1), replacing the
// specified None level, originally used for a score of 0.
func SeverityFromCVSS(score float64) database.Severity {
switch {
case score < 1.0:
return database.NegligibleSeverity
case score < 3.9:
return database.LowSeverity
case score < 6.9:
return database.MediumSeverity
case score < 8.9:
return database.HighSeverity
case score <= 10:
return database.CriticalSeverity
}
return database.UnknownSeverity
}