[Buildroot] [PATCH v2 1/2] support/scripts/pkg-stats: add support for CVE reporting
Thomas De Schampheleire
patrickdepinguin+buildroot at gmail.com
Tue Feb 11 10:02:17 UTC 2020
Hi Titouan, Thomas,
El sáb., 8 feb. 2020 a las 22:58, Titouan Christophe
(<titouan.christophe at railnova.eu>) escribió:
>
> From: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
>
> This commit extends the pkg-stats script to grab information about the
> CVEs affecting the Buildroot packages.
>
> To do so, it downloads the NVD database from
> https://nvd.nist.gov/vuln/data-feeds in JSON format, and processes the
> JSON file to determine which of our packages is affected by which
> CVE. The information is then displayed in both the HTML output and the
> JSON output of pkg-stats.
>
> To use this feature, you have to pass the new --nvd-path option,
> pointing to a writable directory where pkg-stats will store the NVD
> database. If the local database is less than 24 hours old, it will not
> re-download it. If it is more than 24 hours old, it will re-download
> only the files that have really been updated by upstream NVD.
>
> Packages can use the newly introduced <pkg>_IGNORE_CVES variable to
> tell pkg-stats that some CVEs should be ignored: it can be because a
> patch we have is fixing the CVE, or because the CVE doesn't apply in
> our case.
>
> >From an implementation point of view:
>
> - A new class CVE implement most of the required functionalities:
> - Downloading the yearly NVD files
> - Reading and extracting relevant data from these files
> - Matching Packages against a CVE
> - Support for the format "1.0" of the NVD feeds, currently much more easier
> to process than the version "1.1", as the latter only provides CPE IDs.
> Both feed versions seem to provide the same data anyway.
>
> - The statistics are extended with the total number of CVEs, and the
> total number of packages that have at least one CVE pending.
>
> - The HTML output is extended with these new details. There are no
> changes to the code generating the JSON output because the existing
> code is smart enough to automatically expose the new information.
>
> This development is a collective effort with Titouan Christophe
> <titouan.christophe at railnova.eu> and Thomas De Schampheleire
> <thomas.de_schampheleire at nokia.com>.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
> Signed-off-by: Titouan Christophe <titouan.christophe at railnova.eu>
> ---
> Changes v1 -> v2 (Titouan):
> * Don't extract database files from gzip to json in downloader
> * Refactor CVEs traversal and matching in the CVE class
> * Simplify the NVD files downloader
> * Index the packages by name in a dict for faster CVE matching
> * Fix small typos and python idioms
Thanks for iterating on this..
> ---
> support/scripts/pkg-stats | 149 +++++++++++++++++++++++++++++++++++++-
> 1 file changed, 148 insertions(+), 1 deletion(-)
>
> diff --git a/support/scripts/pkg-stats b/support/scripts/pkg-stats
> index e477828f7b..2784a43d05 100755
> --- a/support/scripts/pkg-stats
> +++ b/support/scripts/pkg-stats
> @@ -26,10 +26,17 @@ import subprocess
> import requests # URL checking
> import json
> import certifi
> +import distutils.version
> +import time
> +import gzip
> from urllib3 import HTTPSConnectionPool
> from urllib3.exceptions import HTTPError
> from multiprocessing import Pool
>
> +NVD_START_YEAR = 2002
> +NVD_JSON_VERSION = "1.0"
> +NVD_BASE_URL = "https://nvd.nist.gov/feeds/json/cve/" + NVD_JSON_VERSION
> +
> INFRA_RE = re.compile(r"\$\(eval \$\(([a-z-]*)-package\)\)")
> URL_RE = re.compile(r"\s*https?://\S*\s*$")
>
> @@ -47,6 +54,7 @@ class Package:
> all_licenses = list()
> all_license_files = list()
> all_versions = dict()
> + all_ignored_cves = dict()
>
> def __init__(self, name, path):
> self.name = name
> @@ -61,6 +69,7 @@ class Package:
> self.url = None
> self.url_status = None
> self.url_worker = None
> + self.cves = list()
> self.latest_version = (RM_API_STATUS_ERROR, None, None)
>
> def pkgvar(self):
> @@ -152,6 +161,12 @@ class Package:
> self.warnings = int(m.group(1))
> return
>
> + def is_cve_ignored(self, cve):
> + """
> + Tells if the CVE is ignored by the package
> + """
> + return cve in self.all_ignored_cves.get(self.pkgvar(), [])
> +
> def __eq__(self, other):
> return self.path == other.path
>
> @@ -163,6 +178,103 @@ class Package:
> (self.name, self.path, self.has_license, self.has_license_files, self.has_hash, self.patch_count)
>
>
> +class CVE:
> + """An accessor class for CVE Items in NVD files"""
> + def __init__(self, nvd_cve):
> + """Initialize a CVE from its NVD JSON representation"""
> + self.nvd_cve = nvd_cve
> +
> + @staticmethod
> + def download_nvd_year(nvd_path, year):
> + metaf = "nvdcve-%s-%s.meta" % (NVD_JSON_VERSION, year)
> + path_metaf = os.path.join(nvd_path, metaf)
> + jsonf_gz = "nvdcve-%s-%s.json.gz" % (NVD_JSON_VERSION, year)
> + path_jsonf_gz = os.path.join(nvd_path, jsonf_gz)
> +
> + # If the database file is less than a day old, we assume the NVD data
> + # locally available is recent enough.
> + if os.path.exists(path_jsonf_gz) and os.stat(path_jsonf_gz).st_mtime >= time.time() - 86400:
> + return path_jsonf_gz
> +
> + # If not, we download the meta file
> + url = "%s/%s" % (NVD_BASE_URL, metaf)
> + print("Getting %s" % url)
> + page_meta = requests.get(url)
> + page_meta.raise_for_status()
> + if os.path.exists(path_metaf):
> + # If the meta file already existed, we compare the existing
> + # one with the data newly downloaded. If they are different,
> + # we need to re-download the database.
> + meta_known = open(path_metaf, "r").read()
> + if page_meta.text == meta_known:
> + return path_jsonf_gz
While I was testing and playing around, I found that the when the
json.gz file is removed, it is not redownloaded.
This is because here, the json.gz path is returned without checking
that it exists.
(I have some patch for this and next suggestions at the end of this mail).
> +
> + # Grab the compressed JSON NVD, and write files to disk
> + url = "%s/%s" % (NVD_BASE_URL, jsonf_gz)
> + print("Getting %s" % url)
> + page_data = requests.get(url)
> + page_data.raise_for_status()
> + open(path_jsonf_gz, "wb").write(page_data.content)
> + open(path_metaf, "w").write(page_meta.text)
> + return path_jsonf_gz
> +
> + @classmethod
> + def read_nvd_dir(cls, nvd_dir):
> + """
> + Iterate over all the CVEs contained in NIST Vulnerability Database
> + feeds since NVD_START_YEAR. If the files are missing or outdated in
> + nvd_dir, a fresh copy will be downloaded, and kept in .json.gz
> + """
> + for year in range(NVD_START_YEAR, datetime.datetime.now().year + 1):
> + filename = CVE.download_nvd_year(nvd_dir, year)
> + content = json.load(gzip.GzipFile(filename))
During testing I initially got an error in the 2017 file:
Traceback (most recent call last):
File "support/scripts/pkg-stats", line 917, in <module>
__main__()
File "support/scripts/pkg-stats", line 906, in __main__
check_package_cves(args.nvd_path, {p.name: p for p in packages})
File "support/scripts/pkg-stats", line 484, in check_package_cves
for cve in CVE.read_nvd_dir(nvd_path):
File "support/scripts/pkg-stats", line 231, in read_nvd_dir
content = json.load(gzip.GzipFile(filename))
File "/usr/lib64/python2.7/json/__init__.py", line 287, in load
return loads(fp.read(),
File "/usr/lib64/python2.7/gzip.py", line 260, in read
self._read(readsize)
File "/usr/lib64/python2.7/gzip.py", line 314, in _read
self._read_eof()
File "/usr/lib64/python2.7/gzip.py", line 353, in _read_eof
hex(self.crc)))
IOError: CRC check failed 0x9b7b00d7 != 0x790947a4L
I'm not sure how this happened, but after removing the file and
redownloading it got fixed.
I then tried reproducing such problem by manually messing with the
json.gz file, and this created another error:
Traceback (most recent call last):
File "support/scripts/pkg-stats", line 919, in <module>
__main__()
File "support/scripts/pkg-stats", line 908, in __main__
check_package_cves(args.nvd_path, {p.name: p for p in packages})
File "support/scripts/pkg-stats", line 486, in check_package_cves
for cve in CVE.read_nvd_dir(nvd_path):
File "support/scripts/pkg-stats", line 233, in read_nvd_dir
content = json.load(gzip.GzipFile(filename))
File "/usr/lib64/python2.7/json/__init__.py", line 287, in load
return loads(fp.read(),
File "/usr/lib64/python2.7/gzip.py", line 260, in read
self._read(readsize)
File "/usr/lib64/python2.7/gzip.py", line 318, in _read
uncompress = self.decompress.decompress(buf)
zlib.error: Error -3 while decompressing: invalid distance too far back
I suggest a better error handling for such case (see below).
> + for cve in content["CVE_Items"]:
> + yield cls(cve['cve'])
> +
> + def each_product(self):
> + """Iterate over each product section of this cve"""
> + for vendor in self.nvd_cve['affects']['vendor']['vendor_data']:
> + for product in vendor['product']['product_data']:
> + yield product
> +
> + @property
> + def identifier(self):
> + """The CVE unique identifier"""
> + return self.nvd_cve['CVE_data_meta']['ID']
> +
> + @property
> + def pkg_names(self):
> + """The set of package names referred by this CVE definition"""
> + return set(p['product_name'] for p in self.each_product())
> +
> + def affects(self, br_pkg):
> + """
> + True if the Buildroot Package object passed as argument is affected
> + by this CVE.
> + """
> + for product in self.each_product():
> + if product['product_name'] != br_pkg.name:
> + continue
> +
> + for v in product['version']['version_data']:
> + if v["version_affected"] == "=":
> + if br_pkg.current_version == v["version_value"]:
> + return True
> + elif v["version_affected"] == "<=":
> + pkg_version = distutils.version.LooseVersion(br_pkg.current_version)
> + if not hasattr(pkg_version, "version"):
> + print("Cannot parse package '%s' version '%s'" % (br_pkg.name, br_pkg.current_version))
> + continue
> + cve_affected_version = distutils.version.LooseVersion(v["version_value"])
> + if not hasattr(cve_affected_version, "version"):
> + print("Cannot parse CVE affected version '%s'" % v["version_value"])
> + continue
> + return pkg_version <= cve_affected_version
> + else:
> + print("version_affected: %s" % v['version_affected'])
> + return False
> +
> +
> def get_pkglist(npackages, package_list):
> """
> Builds the list of Buildroot packages, returning a list of Package
> @@ -227,7 +339,7 @@ def get_pkglist(npackages, package_list):
> def package_init_make_info():
> # Fetch all variables at once
> variables = subprocess.check_output(["make", "BR2_HAVE_DOT_CONFIG=y", "-s", "printvars",
> - "VARS=%_LICENSE %_LICENSE_FILES %_VERSION"])
> + "VARS=%_LICENSE %_LICENSE_FILES %_VERSION %_IGNORE_CVES"])
> variable_list = variables.splitlines()
>
> # We process first the host package VERSION, and then the target
> @@ -261,6 +373,10 @@ def package_init_make_info():
> pkgvar = pkgvar[:-8]
> Package.all_versions[pkgvar] = value
>
> + elif pkgvar.endswith("_IGNORE_CVES"):
> + pkgvar = pkgvar[:-12]
> + Package.all_ignored_cves[pkgvar] = value.split(" ")
> +
>
> def check_url_status_worker(url, url_status):
> if url_status != "Missing" and url_status != "No Config.in":
> @@ -355,6 +471,13 @@ def check_package_latest_version(packages):
> del http_pool
>
>
> +def check_package_cves(nvd_path, packages):
> + for cve in CVE.read_nvd_dir(nvd_path):
> + for pkg_name in cve.pkg_names:
> + if pkg_name in packages and cve.affects(packages[pkg_name]):
> + packages[pkg_name].cves.append(cve.identifier)
> +
> +
> def calculate_stats(packages):
> stats = defaultdict(int)
> for pkg in packages:
> @@ -390,6 +513,9 @@ def calculate_stats(packages):
> else:
> stats["version-not-uptodate"] += 1
> stats["patches"] += pkg.patch_count
> + stats["total-cves"] += len(pkg.cves)
> + if len(pkg.cves) != 0:
> + stats["pkg-cves"] += 1
> return stats
>
>
> @@ -601,6 +727,17 @@ def dump_html_pkg(f, pkg):
> f.write(" <td class=\"%s\">%s</td>\n" %
> (" ".join(td_class), url_str))
>
> + # CVEs
> + td_class = ["centered"]
> + if len(pkg.cves) == 0:
> + td_class.append("correct")
> + else:
> + td_class.append("wrong")
> + f.write(" <td class=\"%s\">\n" % " ".join(td_class))
> + for cve in pkg.cves:
> + f.write(" <a href=\"https://security-tracker.debian.org/tracker/%s\">%s<br/>\n" % (cve, cve))
> + f.write(" </td>\n")
> +
> f.write(" </tr>\n")
>
>
> @@ -618,6 +755,7 @@ def dump_html_all_pkgs(f, packages):
> <td class=\"centered\">Latest version</td>
> <td class=\"centered\">Warnings</td>
> <td class=\"centered\">Upstream URL</td>
> +<td class=\"centered\">CVEs</td>
> </tr>
> """)
> for pkg in sorted(packages):
> @@ -656,6 +794,10 @@ def dump_html_stats(f, stats):
> stats["version-not-uptodate"])
> f.write("<tr><td>Packages with no known upstream version</td><td>%s</td></tr>\n" %
> stats["version-unknown"])
> + f.write("<tr><td>Packages affected by CVEs</td><td>%s</td></tr>\n" %
> + stats["pkg-cves"])
> + f.write("<tr><td>Total number of CVEs affecting all packages</td><td>%s</td></tr>\n" %
> + stats["total-cves"])
> f.write("</table>\n")
>
>
> @@ -714,6 +856,8 @@ def parse_args():
> help='Number of packages')
> packages.add_argument('-p', dest='packages', action='store',
> help='List of packages (comma separated)')
> + parser.add_argument('--nvd-path', dest='nvd_path',
> + help='Path to the local NVD database')
> args = parser.parse_args()
> if not args.html and not args.json:
> parser.error('at least one of --html or --json (or both) is required')
> @@ -746,6 +890,9 @@ def __main__():
> check_package_urls(packages)
> print("Getting latest versions ...")
> check_package_latest_version(packages)
> + if args.nvd_path:
> + print("Checking packages CVEs")
> + check_package_cves(args.nvd_path, {p.name: p for p in packages})
If the the passed nvd path does not exist, the script will fail. I
suggest creating the dir automatically.
The below changes implement the suggestions above:
diff --git a/support/scripts/pkg-stats b/support/scripts/pkg-stats
index 2784a43d05..e8f708537e 100755
--- a/support/scripts/pkg-stats
+++ b/support/scripts/pkg-stats
@@ -27,8 +27,10 @@ import requests # URL checking
import json
import certifi
import distutils.version
+import sys
import time
import gzip
+import zlib
from urllib3 import HTTPSConnectionPool
from urllib3.exceptions import HTTPError
from multiprocessing import Pool
@@ -201,10 +203,12 @@ class CVE:
print("Getting %s" % url)
page_meta = requests.get(url)
page_meta.raise_for_status()
- if os.path.exists(path_metaf):
- # If the meta file already existed, we compare the existing
- # one with the data newly downloaded. If they are different,
- # we need to re-download the database.
+ # If the meta file already existed, we compare the existing
+ # one with the data newly downloaded. If they are different,
+ # we need to re-download the database.
+ # If the database does not exist locally, we need to redownload it in
+ # any case.
+ if os.path.exists(path_metaf) and os.path.exists(path_jsonf_gz):
meta_known = open(path_metaf, "r").read()
if page_meta.text == meta_known:
return path_jsonf_gz
@@ -227,7 +231,13 @@ class CVE:
"""
for year in range(NVD_START_YEAR, datetime.datetime.now().year + 1):
filename = CVE.download_nvd_year(nvd_dir, year)
- content = json.load(gzip.GzipFile(filename))
+ try:
+ content = json.load(gzip.GzipFile(filename))
+ except (zlib.error, IOError) as e:
+ print('ERROR: problem reading %s, please remove the
file and rerun this script.' % filename)
+ print(e)
+ sys.exit(1)
+
for cve in content["CVE_Items"]:
yield cls(cve['cve'])
@@ -892,6 +902,8 @@ def __main__():
check_package_latest_version(packages)
if args.nvd_path:
print("Checking packages CVEs")
+ if not os.path.exists(args.nvd_path):
+ os.makedirs(args.nvd_path)
check_package_cves(args.nvd_path, {p.name: p for p in packages})
print("Calculate stats")
stats = calculate_stats(packages)
Best regards,
Thomas
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