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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}${IMAGE_NAME_SUFFIX}.cve"
CVE_CHECK_COPY_FILES ??= "1"
CVE_CHECK_CREATE_MANIFEST ??= "1"
# Whitelist for packages (PN)
CVE_CHECK_PN_WHITELIST = "\
glibc-locale \
"
# Whitelist for CVE and version of package
CVE_CHECK_CVE_WHITELIST = "{\
'CVE-2014-2524': ('6.3','5.2',), \
}"
python do_cve_check () {
"""
Check recipe for patched and unpatched CVEs
"""
if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE", True)):
patched_cves = get_patches_cves(d)
patched, unpatched = check_cves(d, patched_cves)
if patched or unpatched:
cve_data = get_cve_info(d, patched + unpatched)
cve_write_data(d, patched, unpatched, cve_data)
else:
bb.note("Failed to update CVE database, skipping CVE check")
}
addtask cve_check after do_unpack before do_build
do_cve_check[depends] = "cve-check-tool-native:do_populate_cve_db"
do_cve_check[nostamp] = "1"
python cve_check_cleanup () {
"""
Delete the file used to gather all the CVE information.
"""
bb.utils.remove(e.data.getVar("CVE_CHECK_TMP_FILE", True))
}
addhandler cve_check_cleanup
cve_check_cleanup[eventmask] = "bb.cooker.CookerExit"
python cve_check_write_rootfs_manifest () {
"""
Create CVE manifest when building an image
"""
import shutil
if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE", True)):
bb.note("Writing rootfs CVE manifest")
deploy_dir = d.getVar("DEPLOY_DIR_IMAGE", True)
link_name = d.getVar("IMAGE_LINK_NAME", True)
manifest_name = d.getVar("CVE_CHECK_MANIFEST", True)
cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE", True)
shutil.copyfile(cve_tmp_file, manifest_name)
if manifest_name and os.path.exists(manifest_name):
manifest_link = os.path.join(deploy_dir, "%s.cve" % link_name)
# If we already have another manifest, update symlinks
if os.path.exists(os.path.realpath(manifest_link)):
os.remove(manifest_link)
os.symlink(os.path.basename(manifest_name), manifest_link)
bb.plain("Image CVE report stored in: %s" % manifest_name)
}
ROOTFS_POSTPROCESS_COMMAND_prepend = "${@'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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