# This class is used to check recipes against public CVEs.
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#
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# In order to use this class just inherit the class in the
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# local.conf file and it will add the cve_check task for
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# every recipe. The task can be used per recipe, per image,
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# or using the special cases "world" and "universe". The
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# cve_check task will print a warning for every unpatched
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# CVE found and generate a file in the recipe WORKDIR/cve
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# directory. If an image is build it will generate a report
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# in DEPLOY_DIR_IMAGE for all the packages used.
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#
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# Example:
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# bitbake -c cve_check openssl
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# bitbake core-image-sato
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# bitbake -k -c cve_check universe
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#
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# DISCLAIMER
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#
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# This class/tool is meant to be used as support and not
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# the only method to check against CVEs. Running this tool
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# doesn't guarantee your packages are free of CVEs.
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# The product name that the CVE database uses defaults to BPN, but may need to
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# be overriden per recipe (for example tiff.bb sets CVE_PRODUCT=libtiff).
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CVE_PRODUCT ??= "${BPN}"
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CVE_VERSION ??= "${PV}"
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CVE_CHECK_DB_DIR ?= "${DL_DIR}/CVE_CHECK"
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CVE_CHECK_DB_FILE ?= "${CVE_CHECK_DB_DIR}/nvdcve_1.1.db"
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CVE_CHECK_DB_FILE_LOCK ?= "${CVE_CHECK_DB_FILE}.lock"
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CVE_CHECK_LOG ?= "${T}/cve.log"
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CVE_CHECK_TMP_FILE ?= "${TMPDIR}/cve_check"
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CVE_CHECK_SUMMARY_DIR ?= "${LOG_DIR}/cve"
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CVE_CHECK_SUMMARY_FILE_NAME ?= "cve-summary"
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CVE_CHECK_SUMMARY_FILE ?= "${CVE_CHECK_SUMMARY_DIR}/${CVE_CHECK_SUMMARY_FILE_NAME}"
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CVE_CHECK_DIR ??= "${DEPLOY_DIR}/cve"
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CVE_CHECK_RECIPE_FILE ?= "${CVE_CHECK_DIR}/${PN}"
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CVE_CHECK_MANIFEST ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.cve"
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CVE_CHECK_COPY_FILES ??= "1"
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CVE_CHECK_CREATE_MANIFEST ??= "1"
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CVE_CHECK_REPORT_PATCHED ??= "1"
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# Whitelist for packages (PN)
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CVE_CHECK_PN_WHITELIST ?= ""
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# Whitelist for CVE. If a CVE is found, then it is considered patched.
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# The value is a string containing space separated CVE values:
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#
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# CVE_CHECK_WHITELIST = 'CVE-2014-2524 CVE-2018-1234'
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#
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CVE_CHECK_WHITELIST ?= ""
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# Layers to be excluded
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CVE_CHECK_LAYER_EXCLUDELIST ??= ""
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# Layers to be included
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CVE_CHECK_LAYER_INCLUDELIST ??= ""
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# set to "alphabetical" for version using single alphabetical character as increment release
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CVE_VERSION_SUFFIX ??= ""
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python cve_save_summary_handler () {
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import shutil
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import datetime
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cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE")
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cve_summary_name = d.getVar("CVE_CHECK_SUMMARY_FILE_NAME")
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cvelogpath = d.getVar("CVE_CHECK_SUMMARY_DIR")
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bb.utils.mkdirhier(cvelogpath)
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timestamp = datetime.datetime.now().strftime('%Y%m%d%H%M%S')
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cve_summary_file = os.path.join(cvelogpath, "%s-%s.txt" % (cve_summary_name, timestamp))
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if os.path.exists(cve_tmp_file):
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shutil.copyfile(cve_tmp_file, cve_summary_file)
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if cve_summary_file and os.path.exists(cve_summary_file):
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cvefile_link = os.path.join(cvelogpath, cve_summary_name)
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if os.path.exists(os.path.realpath(cvefile_link)):
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os.remove(cvefile_link)
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os.symlink(os.path.basename(cve_summary_file), cvefile_link)
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}
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addhandler cve_save_summary_handler
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cve_save_summary_handler[eventmask] = "bb.event.BuildCompleted"
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python do_cve_check () {
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"""
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Check recipe for patched and unpatched CVEs
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"""
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from oe.cve_check import get_patched_cves
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if os.path.exists(d.getVar("CVE_CHECK_DB_FILE")):
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try:
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patched_cves = get_patched_cves(d)
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except FileNotFoundError:
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bb.fatal("Failure in searching patches")
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whitelisted, patched, unpatched = check_cves(d, patched_cves)
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if patched or unpatched:
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cve_data = get_cve_info(d, patched + unpatched)
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cve_write_data(d, patched, unpatched, whitelisted, cve_data)
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else:
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bb.note("No CVE database found, skipping CVE check")
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}
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addtask cve_check before do_build after do_fetch
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do_cve_check[lockfiles] += "${CVE_CHECK_DB_FILE_LOCK}"
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do_cve_check[depends] = "cve-update-db-native:do_fetch"
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do_cve_check[nostamp] = "1"
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python cve_check_cleanup () {
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"""
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Delete the file used to gather all the CVE information.
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"""
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bb.utils.remove(e.data.getVar("CVE_CHECK_TMP_FILE"))
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}
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addhandler cve_check_cleanup
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cve_check_cleanup[eventmask] = "bb.cooker.CookerExit"
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python cve_check_write_rootfs_manifest () {
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"""
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Create CVE manifest when building an image
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"""
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import shutil
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if d.getVar("CVE_CHECK_COPY_FILES") == "1":
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deploy_file = d.getVar("CVE_CHECK_RECIPE_FILE")
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if os.path.exists(deploy_file):
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bb.utils.remove(deploy_file)
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if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE")):
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bb.note("Writing rootfs CVE manifest")
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deploy_dir = d.getVar("DEPLOY_DIR_IMAGE")
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link_name = d.getVar("IMAGE_LINK_NAME")
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manifest_name = d.getVar("CVE_CHECK_MANIFEST")
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cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE")
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shutil.copyfile(cve_tmp_file, manifest_name)
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if manifest_name and os.path.exists(manifest_name):
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manifest_link = os.path.join(deploy_dir, "%s.cve" % link_name)
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# If we already have another manifest, update symlinks
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if os.path.exists(os.path.realpath(manifest_link)):
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os.remove(manifest_link)
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os.symlink(os.path.basename(manifest_name), manifest_link)
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bb.plain("Image CVE report stored in: %s" % manifest_name)
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}
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ROOTFS_POSTPROCESS_COMMAND:prepend = "${@'cve_check_write_rootfs_manifest; ' if d.getVar('CVE_CHECK_CREATE_MANIFEST') == '1' else ''}"
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do_rootfs[recrdeptask] += "${@'do_cve_check' if d.getVar('CVE_CHECK_CREATE_MANIFEST') == '1' else ''}"
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def check_cves(d, patched_cves):
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"""
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Connect to the NVD database and find unpatched cves.
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"""
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from oe.cve_check import Version
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pn = d.getVar("PN")
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real_pv = d.getVar("PV")
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suffix = d.getVar("CVE_VERSION_SUFFIX")
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cves_unpatched = []
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# CVE_PRODUCT can contain more than one product (eg. curl/libcurl)
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products = d.getVar("CVE_PRODUCT").split()
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# If this has been unset then we're not scanning for CVEs here (for example, image recipes)
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if not products:
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return ([], [], [])
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pv = d.getVar("CVE_VERSION").split("+git")[0]
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# If the recipe has been whitelisted we return empty lists
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if pn in d.getVar("CVE_CHECK_PN_WHITELIST").split():
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bb.note("Recipe has been whitelisted, skipping check")
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return ([], [], [])
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cve_whitelist = d.getVar("CVE_CHECK_WHITELIST").split()
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import sqlite3
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db_file = d.expand("file:${CVE_CHECK_DB_FILE}?mode=ro")
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conn = sqlite3.connect(db_file, uri=True)
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# For each of the known product names (e.g. curl has CPEs using curl and libcurl)...
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for product in products:
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if ":" in product:
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vendor, product = product.split(":", 1)
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else:
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vendor = "%"
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# Find all relevant CVE IDs.
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for cverow in conn.execute("SELECT DISTINCT ID FROM PRODUCTS WHERE PRODUCT IS ? AND VENDOR LIKE ?", (product, vendor)):
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cve = cverow[0]
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if cve in cve_whitelist:
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bb.note("%s-%s has been whitelisted for %s" % (product, pv, cve))
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# TODO: this should be in the report as 'whitelisted'
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patched_cves.add(cve)
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continue
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elif cve in patched_cves:
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bb.note("%s has been patched" % (cve))
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continue
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vulnerable = False
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for row in conn.execute("SELECT * FROM PRODUCTS WHERE ID IS ? AND PRODUCT IS ? AND VENDOR LIKE ?", (cve, product, vendor)):
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(_, _, _, version_start, operator_start, version_end, operator_end) = row
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#bb.debug(2, "Evaluating row " + str(row))
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if (operator_start == '=' and pv == version_start) or version_start == '-':
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vulnerable = True
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else:
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if operator_start:
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try:
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vulnerable_start = (operator_start == '>=' and Version(pv,suffix) >= Version(version_start,suffix))
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vulnerable_start |= (operator_start == '>' and Version(pv,suffix) > Version(version_start,suffix))
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except:
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bb.warn("%s: Failed to compare %s %s %s for %s" %
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(product, pv, operator_start, version_start, cve))
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vulnerable_start = False
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else:
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vulnerable_start = False
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if operator_end:
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try:
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vulnerable_end = (operator_end == '<=' and Version(pv,suffix) <= Version(version_end,suffix) )
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vulnerable_end |= (operator_end == '<' and Version(pv,suffix) < Version(version_end,suffix) )
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except:
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bb.warn("%s: Failed to compare %s %s %s for %s" %
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(product, pv, operator_end, version_end, cve))
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vulnerable_end = False
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else:
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vulnerable_end = False
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if operator_start and operator_end:
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vulnerable = vulnerable_start and vulnerable_end
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else:
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vulnerable = vulnerable_start or vulnerable_end
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if vulnerable:
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bb.note("%s-%s is vulnerable to %s" % (pn, real_pv, cve))
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cves_unpatched.append(cve)
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break
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if not vulnerable:
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bb.note("%s-%s is not vulnerable to %s" % (pn, real_pv, cve))
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# TODO: not patched but not vulnerable
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patched_cves.add(cve)
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conn.close()
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return (list(cve_whitelist), list(patched_cves), cves_unpatched)
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def get_cve_info(d, cves):
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"""
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Get CVE information from the database.
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"""
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import sqlite3
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cve_data = {}
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conn = sqlite3.connect(d.getVar("CVE_CHECK_DB_FILE"))
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for cve in cves:
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for row in conn.execute("SELECT * FROM NVD WHERE ID IS ?", (cve,)):
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cve_data[row[0]] = {}
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cve_data[row[0]]["summary"] = row[1]
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cve_data[row[0]]["scorev2"] = row[2]
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cve_data[row[0]]["scorev3"] = row[3]
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cve_data[row[0]]["modified"] = row[4]
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cve_data[row[0]]["vector"] = row[5]
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conn.close()
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return cve_data
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def cve_write_data(d, patched, unpatched, whitelisted, cve_data):
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"""
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Write CVE information in WORKDIR; and to CVE_CHECK_DIR, and
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CVE manifest if enabled.
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"""
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cve_file = d.getVar("CVE_CHECK_LOG")
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fdir_name = d.getVar("FILE_DIRNAME")
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layer = fdir_name.split("/")[-3]
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include_layers = d.getVar("CVE_CHECK_LAYER_INCLUDELIST").split()
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exclude_layers = d.getVar("CVE_CHECK_LAYER_EXCLUDELIST").split()
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if exclude_layers and layer in exclude_layers:
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return
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if include_layers and layer not in include_layers:
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return
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nvd_link = "https://nvd.nist.gov/vuln/detail/"
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write_string = ""
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unpatched_cves = []
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bb.utils.mkdirhier(os.path.dirname(cve_file))
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for cve in sorted(cve_data):
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is_patched = cve in patched
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if is_patched and (d.getVar("CVE_CHECK_REPORT_PATCHED") != "1"):
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continue
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write_string += "LAYER: %s\n" % layer
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write_string += "PACKAGE NAME: %s\n" % d.getVar("PN")
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write_string += "PACKAGE VERSION: %s%s\n" % (d.getVar("EXTENDPE"), d.getVar("PV"))
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write_string += "CVE: %s\n" % cve
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if cve in whitelisted:
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write_string += "CVE STATUS: Whitelisted\n"
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elif is_patched:
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write_string += "CVE STATUS: Patched\n"
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else:
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unpatched_cves.append(cve)
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write_string += "CVE STATUS: Unpatched\n"
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write_string += "CVE SUMMARY: %s\n" % cve_data[cve]["summary"]
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write_string += "CVSS v2 BASE SCORE: %s\n" % cve_data[cve]["scorev2"]
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write_string += "CVSS v3 BASE SCORE: %s\n" % cve_data[cve]["scorev3"]
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write_string += "VECTOR: %s\n" % cve_data[cve]["vector"]
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write_string += "MORE INFORMATION: %s%s\n\n" % (nvd_link, cve)
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if unpatched_cves:
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bb.warn("Found unpatched CVE (%s), for more information check %s" % (" ".join(unpatched_cves),cve_file))
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if write_string:
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with open(cve_file, "w") as f:
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bb.note("Writing file %s with CVE information" % cve_file)
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f.write(write_string)
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if d.getVar("CVE_CHECK_COPY_FILES") == "1":
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deploy_file = d.getVar("CVE_CHECK_RECIPE_FILE")
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bb.utils.mkdirhier(os.path.dirname(deploy_file))
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with open(deploy_file, "w") as f:
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f.write(write_string)
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if d.getVar("CVE_CHECK_CREATE_MANIFEST") == "1":
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cvelogpath = d.getVar("CVE_CHECK_SUMMARY_DIR")
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bb.utils.mkdirhier(cvelogpath)
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with open(d.getVar("CVE_CHECK_TMP_FILE"), "a") as f:
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f.write("%s" % write_string)
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