Add schema validator for Alpine linux

Signed-off-by: Shivam Sandbhor <shivam.sandbhor@gmail.com>

Author: sbs2001

vulnerabilities/scraper/alpine_linux.py

@@ -1,42 +1,75 @@
 import itertools
 import saneyaml
+from schema import Regex, Or, Schema
 from urllib.request import urlopen
 from io import BytesIO
 from zipfile import ZipFile
 
-ALPINE_DB_URL = 'https://gitlab.alpinelinux.org/alpine/infra/alpine-secdb/-/\
-archive/master/alpine-secdb-master.zip'
+ALPINE_DB_URL = "https://gitlab.alpinelinux.org/alpine/infra/alpine-secdb/-/\
+archive/master/alpine-secdb-master.zip"
 
 
 def alpine_advisories(url):
     with urlopen(url) as response:
         with ZipFile(BytesIO(response.read())) as zf:
             for path in zf.namelist():
-                if path.endswith('main.yaml'):
+                if path.endswith("main.yaml"):
                     yield saneyaml.load(zf.open(path))
 
 
+def validate_schema(advisory_dict):
+    scheme = {
+        "distroversion": Regex(r"v\d.\d*"),
+        "reponame": "main",
+        "archs": list,
+        "packages": [
+            {
+                "pkg": {
+                    "name": str,
+                    "secfixes": {
+                        str: Or(
+                            [
+                                Or(
+                                    Regex(r"CVE.\d+-\d+"),
+                                    Regex(r"XSA-\d{3}"),
+                                    Regex(r"ZBX-\d{4}"),
+                                    Regex(r"wnpa-sec-\d{4}-\d{2}"),
+                                )
+                            ],
+                            "",
+                        ),
+                    },
+                }
+            }
+        ],
+        object: object,
+    }
+    Schema(scheme).validate(advisory_dict)
+
+
 def import_vulnerabilities():
     vulnerability_package_dicts = []
     for vulnerability in alpine_advisories(ALPINE_DB_URL):
-        for pkg_details in vulnerability['packages']:
-            package_name = pkg_details['pkg']['name']
-            for version, fixed_cves in pkg_details['pkg']['secfixes'].items():
+        validate_schema(vulnerability)
+        for pkg_details in vulnerability["packages"]:
+            package_name = pkg_details["pkg"]["name"]
+            for version, fixed_cves in pkg_details["pkg"]["secfixes"].items():
                 # ['CVE-2016-9932  XSA-200', 'CVE-2016-9815','CVE-????-?????'] after mapping
                 # the split  function to above list
                 all_cves = list(map(lambda x: x.split(), fixed_cves))
                 # it becomes   [['CVE-2016-9932','XSA-200'], ['CVE-2016-9815'],['CVE-????-?????']]
                 for index, vuln_grp in enumerate(all_cves):
                     all_cves[index] = list(
-                        filter(lambda x: 'CVE-????-?????' not in x, vuln_grp))
+                        filter(lambda x: "CVE-????-?????" not in x, vuln_grp)
+                    )
                 all_cves = [i for i in all_cves if i and len(i) <= 2]
                 # this data consists lots of 'CVE-????-?????' to denote vulnerabilities
                 # with unassigned  CVE ids , we filter out these as well as other garbage data
                 vulnerability_package_dicts.append(
                     {
-                        'package_name': package_name,
-                        'vuln_ids': all_cves,
-                        'fixed_version': version,
+                        "package_name": package_name,
+                        "vuln_ids": all_cves,
+                        "fixed_version": version,
                     }
                 )
     return vulnerability_package_dicts