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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.
# The product name that the CVE database uses. Defaults to BPN, but may need to
# be overriden per recipe (for example tiff.bb sets CVE_PRODUCT=libtiff).
CVE_PRODUCT ??= "${BPN}"
CVE_VERSION ??= "${PV}"
CVE_CHECK_DB_DIR ?= "${DL_DIR}/CVE_CHECK"
CVE_CHECK_DB_FILE ?= "${CVE_CHECK_DB_DIR}/nvdcve_1.1.db"
CVE_CHECK_DB_FILE_LOCK ?= "${CVE_CHECK_DB_FILE}.lock"
CVE_CHECK_LOG ?= "${T}/cve.log"
CVE_CHECK_TMP_FILE ?= "${TMPDIR}/cve_check"
CVE_CHECK_SUMMARY_DIR ?= "${LOG_DIR}/cve"
CVE_CHECK_SUMMARY_FILE_NAME ?= "cve-summary"
CVE_CHECK_SUMMARY_FILE ?= "${CVE_CHECK_SUMMARY_DIR}/${CVE_CHECK_SUMMARY_FILE_NAME}"
CVE_CHECK_DIR ??= "${DEPLOY_DIR}/cve"
CVE_CHECK_RECIPE_FILE ?= "${CVE_CHECK_DIR}/${PN}"
CVE_CHECK_MANIFEST ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.cve"
CVE_CHECK_COPY_FILES ??= "1"
CVE_CHECK_CREATE_MANIFEST ??= "1"
CVE_CHECK_REPORT_PATCHED ??= "1"
# Whitelist for packages (PN)
CVE_CHECK_PN_WHITELIST ?= ""
# Whitelist for CVE. If a CVE is found, then it is considered patched.
# The value is a string containing space separated CVE values:
#
# CVE_CHECK_WHITELIST = 'CVE-2014-2524 CVE-2018-1234'
#
CVE_CHECK_WHITELIST ?= ""
# Layers to be excluded
CVE_CHECK_LAYER_EXCLUDELIST ??= ""
# Layers to be included
CVE_CHECK_LAYER_INCLUDELIST ??= ""
# set to "alphabetical" for version using single alphabetical character as increament release
CVE_VERSION_SUFFIX ??= ""
python cve_save_summary_handler () {
import shutil
import datetime
cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE")
cve_summary_name = d.getVar("CVE_CHECK_SUMMARY_FILE_NAME")
cvelogpath = d.getVar("CVE_CHECK_SUMMARY_DIR")
bb.utils.mkdirhier(cvelogpath)
timestamp = datetime.datetime.now().strftime('%Y%m%d%H%M%S')
cve_summary_file = os.path.join(cvelogpath, "%s-%s.txt" % (cve_summary_name, timestamp))
if os.path.exists(cve_tmp_file):
shutil.copyfile(cve_tmp_file, cve_summary_file)
if cve_summary_file and os.path.exists(cve_summary_file):
cvefile_link = os.path.join(cvelogpath, cve_summary_name)
if os.path.exists(os.path.realpath(cvefile_link)):
os.remove(cvefile_link)
os.symlink(os.path.basename(cve_summary_file), cvefile_link)
}
addhandler cve_save_summary_handler
cve_save_summary_handler[eventmask] = "bb.event.BuildCompleted"
python do_cve_check () {
"""
Check recipe for patched and unpatched CVEs
"""
if os.path.exists(d.getVar("CVE_CHECK_DB_FILE")):
try:
patched_cves = get_patches_cves(d)
except FileNotFoundError:
bb.fatal("Failure in searching patches")
whitelisted, 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, whitelisted, cve_data)
else:
bb.note("No CVE database found, skipping CVE check")
}
addtask cve_check before do_build after do_fetch
do_cve_check[depends] = "cve-update-db-native:do_fetch"
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"))
}
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 d.getVar("CVE_CHECK_COPY_FILES") == "1":
deploy_file = d.getVar("CVE_CHECK_RECIPE_FILE")
if os.path.exists(deploy_file):
bb.utils.remove(deploy_file)
if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE")):
bb.note("Writing rootfs CVE manifest")
deploy_dir = d.getVar("DEPLOY_DIR_IMAGE")
link_name = d.getVar("IMAGE_LINK_NAME")
manifest_name = d.getVar("CVE_CHECK_MANIFEST")
cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE")
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 = "${@'cve_check_write_rootfs_manifest; ' if d.getVar('CVE_CHECK_CREATE_MANIFEST') == '1' else ''}"
do_rootfs[recrdeptask] += "${@'do_cve_check' if d.getVar('CVE_CHECK_CREATE_MANIFEST') == '1' else ''}"
def get_patches_cves(d):
"""
Get patches that solve CVEs using the "CVE: " tag.
"""
import re
pn = d.getVar("PN")
cve_match = re.compile("CVE:( CVE\-\d{4}\-\d+)+")
# Matches last CVE-1234-211432 in the file name, also if written
# with small letters. Not supporting multiple CVE id's in a single
# file name.
cve_file_name_match = re.compile(".*([Cc][Vv][Ee]\-\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]
if not os.path.isfile(patch_file):
bb.error("File Not found: %s" % patch_file)
raise FileNotFoundError
# Check patch file name for CVE ID
fname_match = cve_file_name_match.search(patch_file)
if fname_match:
cve = fname_match.group(1).upper()
patched_cves.add(cve)
bb.debug(2, "Found CVE %s from patch file name %s" % (cve, patch_file))
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 one or more "CVE: " lines
text_match = False
for match in cve_match.finditer(patch_text):
# 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)
text_match = True
if not fname_match and not text_match:
bb.debug(2, "Patch %s doesn't solve CVEs" % patch_file)
return patched_cves
def check_cves(d, patched_cves):
"""
Connect to the NVD database and find unpatched cves.
"""
from oe.cve_check import Version
pn = d.getVar("PN")
real_pv = d.getVar("PV")
suffix = d.getVar("CVE_VERSION_SUFFIX")
cves_unpatched = []
# CVE_PRODUCT can contain more than one product (eg. curl/libcurl)
products = d.getVar("CVE_PRODUCT").split()
# If this has been unset then we're not scanning for CVEs here (for example, image recipes)
if not products:
return ([], [], [])
pv = d.getVar("CVE_VERSION").split("+git")[0]
# If the recipe has been whitlisted we return empty lists
if pn in d.getVar("CVE_CHECK_PN_WHITELIST").split():
bb.note("Recipe has been whitelisted, skipping check")
return ([], [], [])
old_cve_whitelist = d.getVar("CVE_CHECK_CVE_WHITELIST")
if old_cve_whitelist:
bb.warn("CVE_CHECK_CVE_WHITELIST is deprecated, please use CVE_CHECK_WHITELIST.")
cve_whitelist = d.getVar("CVE_CHECK_WHITELIST").split()
import sqlite3
db_file = d.expand("file:${CVE_CHECK_DB_FILE}?mode=ro")
conn = sqlite3.connect(db_file, uri=True)
# For each of the known product names (e.g. curl has CPEs using curl and libcurl)...
for product in products:
if ":" in product:
vendor, product = product.split(":", 1)
else:
vendor = "%"
# Find all relevant CVE IDs.
for cverow in conn.execute("SELECT DISTINCT ID FROM PRODUCTS WHERE PRODUCT IS ? AND VENDOR LIKE ?", (product, vendor)):
cve = cverow[0]
if cve in cve_whitelist:
bb.note("%s-%s has been whitelisted for %s" % (product, pv, cve))
# TODO: this should be in the report as 'whitelisted'
patched_cves.add(cve)
continue
elif cve in patched_cves:
bb.note("%s has been patched" % (cve))
continue
vulnerable = False
for row in conn.execute("SELECT * FROM PRODUCTS WHERE ID IS ? AND PRODUCT IS ? AND VENDOR LIKE ?", (cve, product, vendor)):
(_, _, _, version_start, operator_start, version_end, operator_end) = row
#bb.debug(2, "Evaluating row " + str(row))
if (operator_start == '=' and pv == version_start) or version_start == '-':
vulnerable = True
else:
if operator_start:
try:
vulnerable_start = (operator_start == '>=' and Version(pv,suffix) >= Version(version_start,suffix))
vulnerable_start |= (operator_start == '>' and Version(pv,suffix) > Version(version_start,suffix))
except:
bb.warn("%s: Failed to compare %s %s %s for %s" %
(product, pv, operator_start, version_start, cve))
vulnerable_start = False
else:
vulnerable_start = False
if operator_end:
try:
vulnerable_end = (operator_end == '<=' and Version(pv,suffix) <= Version(version_end,suffix) )
vulnerable_end |= (operator_end == '<' and Version(pv,suffix) < Version(version_end,suffix) )
except:
bb.warn("%s: Failed to compare %s %s %s for %s" %
(product, pv, operator_end, version_end, cve))
vulnerable_end = False
else:
vulnerable_end = False
if operator_start and operator_end:
vulnerable = vulnerable_start and vulnerable_end
else:
vulnerable = vulnerable_start or vulnerable_end
if vulnerable:
bb.note("%s-%s is vulnerable to %s" % (pn, real_pv, cve))
cves_unpatched.append(cve)
break
if not vulnerable:
bb.note("%s-%s is not vulnerable to %s" % (pn, real_pv, cve))
# TODO: not patched but not vulnerable
patched_cves.add(cve)
conn.close()
return (list(cve_whitelist), list(patched_cves), cves_unpatched)
def get_cve_info(d, cves):
"""
Get CVE information from the database.
"""
import sqlite3
cve_data = {}
conn = sqlite3.connect(d.getVar("CVE_CHECK_DB_FILE"))
for cve in cves:
for row in conn.execute("SELECT * FROM NVD WHERE ID IS ?", (cve,)):
cve_data[row[0]] = {}
cve_data[row[0]]["summary"] = row[1]
cve_data[row[0]]["scorev2"] = row[2]
cve_data[row[0]]["scorev3"] = row[3]
cve_data[row[0]]["modified"] = row[4]
cve_data[row[0]]["vector"] = row[5]
conn.close()
return cve_data
def cve_write_data(d, patched, unpatched, whitelisted, cve_data):
"""
Write CVE information in WORKDIR; and to CVE_CHECK_DIR, and
CVE manifest if enabled.
"""
cve_file = d.getVar("CVE_CHECK_LOG")
fdir_name = d.getVar("FILE_DIRNAME")
layer = fdir_name.split("/")[-3]
include_layers = d.getVar("CVE_CHECK_LAYER_INCLUDELIST").split()
exclude_layers = d.getVar("CVE_CHECK_LAYER_EXCLUDELIST").split()
if exclude_layers and layer in exclude_layers:
return
if include_layers and layer not in include_layers:
return
nvd_link = "https://web.nvd.nist.gov/view/vuln/detail?vulnId="
write_string = ""
unpatched_cves = []
bb.utils.mkdirhier(os.path.dirname(cve_file))
for cve in sorted(cve_data):
is_patched = cve in patched
if is_patched and (d.getVar("CVE_CHECK_REPORT_PATCHED") != "1"):
continue
write_string += "LAYER: %s\n" % layer
write_string += "PACKAGE NAME: %s\n" % d.getVar("PN")
write_string += "PACKAGE VERSION: %s%s\n" % (d.getVar("EXTENDPE"), d.getVar("PV"))
write_string += "CVE: %s\n" % cve
if cve in whitelisted:
write_string += "CVE STATUS: Whitelisted\n"
elif is_patched:
write_string += "CVE STATUS: Patched\n"
else:
unpatched_cves.append(cve)
write_string += "CVE STATUS: Unpatched\n"
write_string += "CVE SUMMARY: %s\n" % cve_data[cve]["summary"]
write_string += "CVSS v2 BASE SCORE: %s\n" % cve_data[cve]["scorev2"]
write_string += "CVSS v3 BASE SCORE: %s\n" % cve_data[cve]["scorev3"]
write_string += "VECTOR: %s\n" % cve_data[cve]["vector"]
write_string += "MORE INFORMATION: %s%s\n\n" % (nvd_link, cve)
if unpatched_cves:
bb.warn("Found unpatched CVE (%s), for more information check %s" % (" ".join(unpatched_cves),cve_file))
if write_string:
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") == "1":
deploy_file = d.getVar("CVE_CHECK_RECIPE_FILE")
bb.utils.mkdirhier(os.path.dirname(deploy_file))
with open(deploy_file, "w") as f:
f.write(write_string)
if d.getVar("CVE_CHECK_CREATE_MANIFEST") == "1":
cvelogpath = d.getVar("CVE_CHECK_SUMMARY_DIR")
bb.utils.mkdirhier(cvelogpath)
with open(d.getVar("CVE_CHECK_TMP_FILE"), "a") as f:
f.write("%s" % write_string)
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