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- # This class is used to check recipes against public CVEs.
- #
- # In order to use this class just inherit the class in the
- # local.conf file and it will add the cve_check task for
- # every recipe. The task can be used per recipe, per image,
- # or using the special cases "world" and "universe". The
- # cve_check task will print a warning for every unpatched
- # CVE found and generate a file in the recipe WORKDIR/cve
- # directory. If an image is build it will generate a report
- # in DEPLOY_DIR_IMAGE for all the packages used.
- #
- # Example:
- # bitbake -c cve_check openssl
- # bitbake core-image-sato
- # bitbake -k -c cve_check universe
- #
- # DISCLAIMER
- #
- # This class/tool is meant to be used as support and not
- # the only method to check against CVEs. Running this tool
- # doesn't guarantee your packages are free of CVEs.
- CVE_CHECK_DB_DIR ?= "${DL_DIR}/CVE_CHECK"
- CVE_CHECK_DB_FILE ?= "${CVE_CHECK_DB_DIR}/nvd.db"
- CVE_CHECK_LOCAL_DIR ?= "${WORKDIR}/cve"
- CVE_CHECK_LOCAL_FILE ?= "${CVE_CHECK_LOCAL_DIR}/cve.log"
- CVE_CHECK_TMP_FILE ?= "${TMPDIR}/cve_check"
- CVE_CHECK_DIR ??= "${DEPLOY_DIR}/cve"
- CVE_CHECK_MANIFEST ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.cve"
- CVE_CHECK_COPY_FILES ??= "1"
- CVE_CHECK_CREATE_MANIFEST ??= "1"
- # Whitelist for packages (PN)
- CVE_CHECK_PN_WHITELIST = "\
- glibc-locale \
- "
- # Whitelist for CVE and version of package
- CVE_CHECK_CVE_WHITELIST = "{\
- 'CVE-2014-2524': ('6.3',), \
- }"
- python do_cve_check () {
- """
- Check recipe for patched and unpatched CVEs
- """
- if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE", True)):
- patched_cves = get_patches_cves(d)
- patched, unpatched = check_cves(d, patched_cves)
- if patched or unpatched:
- cve_data = get_cve_info(d, patched + unpatched)
- cve_write_data(d, patched, unpatched, cve_data)
- else:
- bb.note("Failed to update CVE database, skipping CVE check")
- }
- addtask cve_check after do_unpack before do_build
- do_cve_check[depends] = "cve-check-tool-native:do_populate_cve_db"
- do_cve_check[nostamp] = "1"
- python cve_check_cleanup () {
- """
- Delete the file used to gather all the CVE information.
- """
- bb.utils.remove(e.data.getVar("CVE_CHECK_TMP_FILE", True))
- }
- addhandler cve_check_cleanup
- cve_check_cleanup[eventmask] = "bb.cooker.CookerExit"
- python cve_check_write_rootfs_manifest () {
- """
- Create CVE manifest when building an image
- """
- import shutil
- if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE", True)):
- bb.note("Writing rootfs CVE manifest")
- deploy_dir = d.getVar("DEPLOY_DIR_IMAGE", True)
- link_name = d.getVar("IMAGE_LINK_NAME", True)
- manifest_name = d.getVar("CVE_CHECK_MANIFEST", True)
- cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE", True)
- shutil.copyfile(cve_tmp_file, manifest_name)
- if manifest_name and os.path.exists(manifest_name):
- manifest_link = os.path.join(deploy_dir, "%s.cve" % link_name)
- # If we already have another manifest, update symlinks
- if os.path.exists(os.path.realpath(manifest_link)):
- os.remove(manifest_link)
- os.symlink(os.path.basename(manifest_name), manifest_link)
- bb.plain("Image CVE report stored in: %s" % manifest_name)
- }
- ROOTFS_POSTPROCESS_COMMAND_prepend = "${@'cve_check_write_rootfs_manifest; ' if d.getVar('CVE_CHECK_CREATE_MANIFEST', True) == '1' else ''}"
- def get_patches_cves(d):
- """
- Get patches that solve CVEs using the "CVE: " tag.
- """
- import re
- pn = d.getVar("PN", True)
- cve_match = re.compile("CVE:( CVE\-\d{4}\-\d+)+")
- patched_cves = set()
- bb.debug(2, "Looking for patches that solves CVEs for %s" % pn)
- for url in src_patches(d):
- patch_file = bb.fetch.decodeurl(url)[2]
- with open(patch_file, "r", encoding="utf-8") as f:
- try:
- patch_text = f.read()
- except UnicodeDecodeError:
- bb.debug(1, "Failed to read patch %s using UTF-8 encoding"
- " trying with iso8859-1" % patch_file)
- f.close()
- with open(patch_file, "r", encoding="iso8859-1") as f:
- patch_text = f.read()
- # Search for the "CVE: " line
- match = cve_match.search(patch_text)
- if match:
- # Get only the CVEs without the "CVE: " tag
- cves = patch_text[match.start()+5:match.end()]
- for cve in cves.split():
- bb.debug(2, "Patch %s solves %s" % (patch_file, cve))
- patched_cves.add(cve)
- else:
- bb.debug(2, "Patch %s doesn't solve CVEs" % patch_file)
- return patched_cves
- def check_cves(d, patched_cves):
- """
- Run cve-check-tool looking for patched and unpatched CVEs.
- """
- import ast, csv, tempfile, subprocess, io
- cves_patched = []
- cves_unpatched = []
- bpn = d.getVar("BPN", True)
- pv = d.getVar("PV", True).split("git+")[0]
- cves = " ".join(patched_cves)
- cve_db_dir = d.getVar("CVE_CHECK_DB_DIR", True)
- cve_whitelist = ast.literal_eval(d.getVar("CVE_CHECK_CVE_WHITELIST", True))
- cve_cmd = "cve-check-tool"
- cmd = [cve_cmd, "--no-html", "--csv", "--not-affected", "-t", "faux", "-d", cve_db_dir]
- # If the recipe has been whitlisted we return empty lists
- if d.getVar("PN", True) in d.getVar("CVE_CHECK_PN_WHITELIST", True).split():
- bb.note("Recipe has been whitelisted, skipping check")
- return ([], [])
- # It is needed to export the proxies to download the database using HTTP
- bb.utils.export_proxies(d)
- try:
- # Write the faux CSV file to be used with cve-check-tool
- fd, faux = tempfile.mkstemp(prefix="cve-faux-")
- with os.fdopen(fd, "w") as f:
- f.write("%s,%s,%s," % (bpn, pv, cves))
- cmd.append(faux)
- output = subprocess.check_output(cmd, stderr=subprocess.STDOUT).decode("utf-8")
- bb.debug(2, "Output of command %s:\n%s" % ("\n".join(cmd), output))
- except subprocess.CalledProcessError as e:
- bb.warn("Couldn't check for CVEs: %s (output %s)" % (e, e.output))
- finally:
- os.remove(faux)
- for row in csv.reader(io.StringIO(output)):
- # Third row has the unpatched CVEs
- if row[2]:
- for cve in row[2].split():
- # Skip if the CVE has been whitlisted for the current version
- if pv in cve_whitelist.get(cve,[]):
- bb.note("%s-%s has been whitelisted for %s" % (bpn, pv, cve))
- else:
- cves_unpatched.append(cve)
- bb.debug(2, "%s-%s is not patched for %s" % (bpn, pv, cve))
- # Fourth row has patched CVEs
- if row[3]:
- for cve in row[3].split():
- cves_patched.append(cve)
- bb.debug(2, "%s-%s is patched for %s" % (bpn, pv, cve))
- return (cves_patched, cves_unpatched)
- def get_cve_info(d, cves):
- """
- Get CVE information from the database used by cve-check-tool.
- Unfortunately the only way to get CVE info is set the output to
- html (hard to parse) or query directly the database.
- """
- try:
- import sqlite3
- except ImportError:
- from pysqlite2 import dbapi2 as sqlite3
- cve_data = {}
- db_file = d.getVar("CVE_CHECK_DB_FILE", True)
- placeholder = ",".join("?" * len(cves))
- query = "SELECT * FROM NVD WHERE id IN (%s)" % placeholder
- conn = sqlite3.connect(db_file)
- cur = conn.cursor()
- for row in cur.execute(query, tuple(cves)):
- cve_data[row[0]] = {}
- cve_data[row[0]]["summary"] = row[1]
- cve_data[row[0]]["score"] = row[2]
- cve_data[row[0]]["modified"] = row[3]
- cve_data[row[0]]["vector"] = row[4]
- conn.close()
- return cve_data
- def cve_write_data(d, patched, unpatched, cve_data):
- """
- Write CVE information in WORKDIR; and to CVE_CHECK_DIR, and
- CVE manifest if enabled.
- """
- cve_file = d.getVar("CVE_CHECK_LOCAL_FILE", True)
- nvd_link = "https://web.nvd.nist.gov/view/vuln/detail?vulnId="
- write_string = ""
- first_alert = True
- bb.utils.mkdirhier(d.getVar("CVE_CHECK_LOCAL_DIR", True))
- for cve in sorted(cve_data):
- write_string += "PACKAGE NAME: %s\n" % d.getVar("PN", True)
- write_string += "PACKAGE VERSION: %s\n" % d.getVar("PV", True)
- write_string += "CVE: %s\n" % cve
- if cve in patched:
- write_string += "CVE STATUS: Patched\n"
- else:
- write_string += "CVE STATUS: Unpatched\n"
- if first_alert:
- bb.warn("Found unpatched CVE, for more information check %s" % cve_file)
- first_alert = False
- write_string += "CVE SUMMARY: %s\n" % cve_data[cve]["summary"]
- write_string += "CVSS v2 BASE SCORE: %s\n" % cve_data[cve]["score"]
- write_string += "VECTOR: %s\n" % cve_data[cve]["vector"]
- write_string += "MORE INFORMATION: %s%s\n\n" % (nvd_link, cve)
- with open(cve_file, "w") as f:
- bb.note("Writing file %s with CVE information" % cve_file)
- f.write(write_string)
- if d.getVar("CVE_CHECK_COPY_FILES", True) == "1":
- cve_dir = d.getVar("CVE_CHECK_DIR", True)
- bb.utils.mkdirhier(cve_dir)
- deploy_file = os.path.join(cve_dir, d.getVar("PN", True))
- with open(deploy_file, "w") as f:
- f.write(write_string)
- if d.getVar("CVE_CHECK_CREATE_MANIFEST", True) == "1":
- with open(d.getVar("CVE_CHECK_TMP_FILE", True), "a") as f:
- f.write("%s" % write_string)
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