# 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 increment 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 """ from oe.cve_check import get_patched_cves if os.path.exists(d.getVar("CVE_CHECK_DB_FILE")): try: patched_cves = get_patched_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") bb.utils.mkdirhier(os.path.dirname(manifest_name)) 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 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 whitelisted we return empty lists if pn in d.getVar("CVE_CHECK_PN_WHITELIST").split(): bb.note("Recipe has been whitelisted, skipping check") return ([], [], []) 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 = {} db_file = d.expand("file:${CVE_CHECK_DB_FILE}?mode=ro") conn = sqlite3.connect(db_file, uri=True) 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://nvd.nist.gov/vuln/detail/" 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)