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Diffstat (limited to 'meta/classes/cve-check.bbclass')
| -rw-r--r-- | meta/classes/cve-check.bbclass | 267 |
1 files changed, 267 insertions, 0 deletions
diff --git a/meta/classes/cve-check.bbclass b/meta/classes/cve-check.bbclass new file mode 100644 index 00000000000..8251ca7c97b --- /dev/null +++ b/meta/classes/cve-check.bbclass @@ -0,0 +1,267 @@ +# 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)): + if d.getVar('RM_OLD_IMAGE', True) == "1": + os.remove(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) |