| # 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_LOG ?= "${T}/cve.log" |
| CVE_CHECK_TMP_FILE ?= "${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 ?= "" |
| |
| # 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 ?= "" |
| |
| 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_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")) |
| } |
| |
| 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 = os.path.join(d.getVar("CVE_CHECK_DIR"), d.getVar("PN")) |
| 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 distutils.version import LooseVersion |
| |
| 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 d.getVar("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 LooseVersion(pv) >= LooseVersion(version_start)) |
| vulnerable_start |= (operator_start == '>' and LooseVersion(pv) > LooseVersion(version_start)) |
| 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 LooseVersion(pv) <= LooseVersion(version_end)) |
| vulnerable_end |= (operator_end == '<' and LooseVersion(pv) < LooseVersion(version_end)) |
| 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" % (product, pv, cve)) |
| cves_unpatched.append(cve) |
| break |
| |
| if not vulnerable: |
| bb.note("%s-%s is not vulnerable to %s" % (product, 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") |
| 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): |
| write_string += "PACKAGE NAME: %s\n" % d.getVar("PN") |
| write_string += "PACKAGE VERSION: %s\n" % d.getVar("PV") |
| write_string += "CVE: %s\n" % cve |
| if cve in whitelisted: |
| write_string += "CVE STATUS: Whitelisted\n" |
| elif cve in 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)) |
| |
| 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": |
| cve_dir = d.getVar("CVE_CHECK_DIR") |
| bb.utils.mkdirhier(cve_dir) |
| deploy_file = os.path.join(cve_dir, d.getVar("PN")) |
| with open(deploy_file, "w") as f: |
| f.write(write_string) |
| |
| if d.getVar("CVE_CHECK_CREATE_MANIFEST") == "1": |
| with open(d.getVar("CVE_CHECK_TMP_FILE"), "a") as f: |
| f.write("%s" % write_string) |