blob: 8e76f42f0da6e2ba3566ea46004d685c9eab1e1c (
about) (
plain)
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
|
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2015, 2016 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
(define-module (guix cve)
#:use-module (guix utils)
#:use-module (guix http-client)
#:use-module (sxml ssax)
#:use-module (web uri)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-19)
#:use-module (ice-9 match)
#:use-module (ice-9 regex)
#:use-module (ice-9 vlist)
#:export (vulnerability?
vulnerability-id
vulnerability-packages
xml->vulnerabilities
current-vulnerabilities
vulnerabilities->lookup-proc))
;;; Commentary:
;;;
;;; This modules provides the tools to fetch, parse, and digest part of the
;;; Common Vulnerabilities and Exposures (CVE) feeds provided by the US NIST
;;; at <https://nvd.nist.gov/download.cfm#CVE_FEED>.
;;;
;;; Code:
(define-record-type <vulnerability>
(vulnerability id packages)
vulnerability?
(id vulnerability-id)
(packages vulnerability-packages))
(define %now
(current-date))
(define %current-year
(date-year %now))
(define %past-year
(- %current-year 1))
(define (yearly-feed-uri year)
"Return the URI for the CVE feed for YEAR."
(string->uri
(string-append "https://static.nvd.nist.gov/feeds/xml/cve/nvdcve-2.0-"
(number->string year) ".xml.gz")))
(define %current-year-ttl
;; According to <https://nvd.nist.gov/download.cfm#CVE_FEED>, feeds are
;; updated "approximately every two hours."
(* 3600 3))
(define %past-year-ttl
;; Update the previous year's database more and more infrequently.
(* 3600 24 2 (date-month %now)))
(define (call-with-cve-port uri ttl proc)
"Pass PROC an input port from which to read the CVE stream."
(let ((port (http-fetch/cached uri #:ttl ttl)))
(dynamic-wind
(const #t)
(lambda ()
(call-with-decompressed-port 'gzip port
(lambda (port)
(setvbuf port _IOFBF 65536)
(proc port))))
(lambda ()
(close-port port)))))
(define %cpe-package-rx
;; For applications: "cpe:/a:VENDOR:PACKAGE:VERSION", or sometimes
;; "cpe/a:VENDOR:PACKAGE:VERSION:PATCH-LEVEL".
(make-regexp "^cpe:/a:([^:]+):([^:]+):([^:]+)((:.+)?)"))
(define (cpe->package-name cpe)
"Converts the Common Platform Enumeration (CPE) string CPE to a package
name, in a very naive way. Return #f if CPE does not look like an application
CPE string."
(and=> (regexp-exec %cpe-package-rx (string-trim-both cpe))
(lambda (matches)
(cons (match:substring matches 2)
(string-append (match:substring matches 3)
(match (match:substring matches 4)
("" "")
(patch-level
;; Drop the colon from things like
;; "cpe:/a:openbsd:openssh:6.8:p1".
(string-drop patch-level 1))))))))
(define %parse-vulnerability-feed
;; Parse the XML vulnerability feed from
;; <https://nvd.nist.gov/download.cfm#CVE_FEED> and return a list of
;; vulnerability objects.
(ssax:make-parser NEW-LEVEL-SEED
(lambda (elem-gi attributes namespaces expected-content
seed)
(match elem-gi
((name-space . 'entry)
(cons (assoc-ref attributes 'id) seed))
((name-space . 'vulnerable-software-list)
(cons '() seed))
((name-space . 'product)
(cons 'product seed))
(x seed)))
FINISH-ELEMENT
(lambda (elem-gi attributes namespaces parent-seed
seed)
(match elem-gi
((name-space . 'entry)
(match seed
(((? string? id) . rest)
;; Some entries have no vulnerable-software-list.
rest)
((products id . rest)
(match (filter-map cpe->package-name products)
(()
;; No application among PRODUCTS.
rest)
(packages
(cons (vulnerability id (reverse packages))
rest))))))
(x
seed)))
CHAR-DATA-HANDLER
(lambda (str _ seed)
(match seed
(('product software-list . rest)
;; Add STR to the vulnerable software list this
;; <product> tag is part of.
(cons (cons str software-list) rest))
(x x)))))
(define (xml->vulnerabilities port)
"Read from PORT an XML feed of vulnerabilities and return a list of
vulnerability objects."
(reverse (%parse-vulnerability-feed port '())))
(define (current-vulnerabilities)
"Return the current list of Common Vulnerabilities and Exposures (CVE) as
published by the US NIST."
(define (read-vulnerabilities uri ttl)
(call-with-cve-port uri ttl
(lambda (port)
;; XXX: The SSAX "error port" is used to send pointless warnings such as
;; "warning: Skipping PI". Turn that off.
(parameterize ((current-ssax-error-port (%make-void-port "w")))
(xml->vulnerabilities port)))))
(append-map read-vulnerabilities
(list (yearly-feed-uri %past-year)
(yearly-feed-uri %current-year))
(list %past-year-ttl
%current-year-ttl)))
(define (vulnerabilities->lookup-proc vulnerabilities)
"Return a lookup procedure built from VULNERABILITIES that takes a package
name and optionally a version number. When the version is omitted, the lookup
procedure returns a list of version/vulnerability pairs; otherwise, it returns
a list of vulnerabilities affection the given package version."
(define table
;; Map package names to lists of version/vulnerability pairs.
(fold (lambda (vuln table)
(match vuln
(($ <vulnerability> id packages)
(fold (lambda (package table)
(match package
((name . version)
(vhash-cons name (cons version vuln)
table))))
table
packages))))
vlist-null
vulnerabilities))
(lambda* (package #:optional version)
(vhash-fold* (if version
(lambda (pair result)
(match pair
((v . vuln)
(if (string=? v version)
(cons vuln result)
result))))
cons)
'()
package table)))
;;; Local Variables:
;;; eval: (put 'call-with-cve-port 'scheme-indent-function 2)
;;; End:
;;; cve.scm ends here
|
