forked from quay/clair
/
debian.go
256 lines (216 loc) · 7.29 KB
/
debian.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
// 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 debian implements a vulnerability source updater using the Debian
// Security Tracker.
package debian
import (
"crypto/sha1"
"encoding/hex"
"encoding/json"
"fmt"
"io"
"net/http"
"strings"
log "github.com/sirupsen/logrus"
"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 (
url = "https://security-tracker.debian.org/tracker/data/json"
cveURLPrefix = "https://security-tracker.debian.org/tracker"
updaterFlag = "debianUpdater"
)
type jsonData map[string]map[string]jsonVuln
type jsonVuln struct {
Description string `json:"description"`
Releases map[string]jsonRel `json:"releases"`
}
type jsonRel struct {
FixedVersion string `json:"fixed_version"`
Status string `json:"status"`
Urgency string `json:"urgency"`
}
type updater struct{}
func init() {
vulnsrc.RegisterUpdater("debian", &updater{})
}
func (u *updater) Update(datastore database.Datastore) (resp vulnsrc.UpdateResponse, err error) {
log.WithField("package", "Debian").Info("Start fetching vulnerabilities")
// Download JSON.
r, err := http.Get(url)
if err != nil {
log.WithError(err).Error("could not download Debian's update")
return resp, commonerr.ErrCouldNotDownload
}
// Get the SHA-1 of the latest update's JSON data
latestHash, err := datastore.GetKeyValue(updaterFlag)
if err != nil {
return resp, err
}
// Parse the JSON.
resp, err = buildResponse(r.Body, latestHash)
if err != nil {
return resp, err
}
return resp, nil
}
func (u *updater) Clean() {}
func buildResponse(jsonReader io.Reader, latestKnownHash string) (resp vulnsrc.UpdateResponse, err error) {
hash := latestKnownHash
// Defer the addition of flag information to the response.
defer func() {
if err == nil {
resp.FlagName = updaterFlag
resp.FlagValue = hash
}
}()
// Create a TeeReader so that we can unmarshal into JSON and write to a SHA-1
// digest at the same time.
jsonSHA := sha1.New()
teedJSONReader := io.TeeReader(jsonReader, jsonSHA)
// Unmarshal JSON.
var data jsonData
err = json.NewDecoder(teedJSONReader).Decode(&data)
if err != nil {
log.WithError(err).Error("could not unmarshal Debian's JSON")
return resp, commonerr.ErrCouldNotParse
}
// Calculate the hash and skip updating if the hash has been seen before.
hash = hex.EncodeToString(jsonSHA.Sum(nil))
if latestKnownHash == hash {
log.WithField("package", "Debian").Debug("no update")
return resp, nil
}
// Extract vulnerability data from Debian's JSON schema.
var unknownReleases map[string]struct{}
resp.Vulnerabilities, unknownReleases = parseDebianJSON(&data)
// Log unknown releases
for k := range unknownReleases {
note := fmt.Sprintf("Debian %s is not mapped to any version number (eg. Jessie->8). Please update me.", k)
resp.Notes = append(resp.Notes, note)
log.Warning(note)
}
return resp, nil
}
func parseDebianJSON(data *jsonData) (vulnerabilities []database.Vulnerability, unknownReleases map[string]struct{}) {
mvulnerabilities := make(map[string]*database.Vulnerability)
unknownReleases = make(map[string]struct{})
for pkgName, pkgNode := range *data {
for vulnName, vulnNode := range pkgNode {
for releaseName, releaseNode := range vulnNode.Releases {
// Attempt to detect the release number.
if _, isReleaseKnown := database.DebianReleasesMapping[releaseName]; !isReleaseKnown {
unknownReleases[releaseName] = struct{}{}
continue
}
// Skip if the status is not determined or the vulnerability is a temporary one.
if !strings.HasPrefix(vulnName, "CVE-") || releaseNode.Status == "undetermined" {
continue
}
// Get or create the vulnerability.
vulnerability, vulnerabilityAlreadyExists := mvulnerabilities[vulnName]
if !vulnerabilityAlreadyExists {
vulnerability = &database.Vulnerability{
Name: vulnName,
Link: strings.Join([]string{cveURLPrefix, "/", vulnName}, ""),
Severity: database.UnknownSeverity,
Description: vulnNode.Description,
}
}
// Set the priority of the vulnerability.
// In the JSON, a vulnerability has one urgency per package it affects.
severity := SeverityFromUrgency(releaseNode.Urgency)
if severity.Compare(vulnerability.Severity) > 0 {
// The highest urgency should be the one set.
vulnerability.Severity = severity
}
// Determine the version of the package the vulnerability affects.
var version string
var err error
if releaseNode.FixedVersion == "0" {
// This means that the package is not affected by this vulnerability.
version = versionfmt.MinVersion
} else if releaseNode.Status == "open" {
// Open means that the package is currently vulnerable in the latest
// version of this Debian release.
version = versionfmt.MaxVersion
} else if releaseNode.Status == "resolved" {
// Resolved means that the vulnerability has been fixed in
// "fixed_version" (if affected).
err = versionfmt.Valid(dpkg.ParserName, releaseNode.FixedVersion)
if err != nil {
log.WithError(err).WithField("version", version).Warning("could not parse package version. skipping")
continue
}
version = releaseNode.FixedVersion
}
// Create and add the feature version.
pkg := database.FeatureVersion{
Feature: database.Feature{
Name: pkgName,
Namespace: database.Namespace{
Name: "debian:" + database.DebianReleasesMapping[releaseName],
VersionFormat: dpkg.ParserName,
},
},
Version: version,
}
vulnerability.FixedIn = append(vulnerability.FixedIn, pkg)
// Store the vulnerability.
mvulnerabilities[vulnName] = vulnerability
}
}
}
// Convert the vulnerabilities map to a slice
for _, v := range mvulnerabilities {
vulnerabilities = append(vulnerabilities, *v)
}
return
}
// SeverityFromUrgency converts the urgency scale used by the Debian Security
// Bug Tracker into a database.Severity.
func SeverityFromUrgency(urgency string) database.Severity {
switch urgency {
case "not yet assigned":
return database.UnknownSeverity
case "end-of-life":
fallthrough
case "unimportant":
return database.NegligibleSeverity
case "low":
fallthrough
case "low*":
fallthrough
case "low**":
return database.LowSeverity
case "medium":
fallthrough
case "medium*":
fallthrough
case "medium**":
return database.MediumSeverity
case "high":
fallthrough
case "high*":
fallthrough
case "high**":
return database.HighSeverity
default:
log.WithField("urgency", urgency).Warning("could not determine vulnerability severity from urgency")
return database.UnknownSeverity
}
}