1# This class is used to check recipes against public CVEs. 2# 3# In order to use this class just inherit the class in the 4# local.conf file and it will add the cve_check task for 5# every recipe. The task can be used per recipe, per image, 6# or using the special cases "world" and "universe". The 7# cve_check task will print a warning for every unpatched 8# CVE found and generate a file in the recipe WORKDIR/cve 9# directory. If an image is build it will generate a report 10# in DEPLOY_DIR_IMAGE for all the packages used. 11# 12# Example: 13# bitbake -c cve_check openssl 14# bitbake core-image-sato 15# bitbake -k -c cve_check universe 16# 17# DISCLAIMER 18# 19# This class/tool is meant to be used as support and not 20# the only method to check against CVEs. Running this tool 21# doesn't guarantee your packages are free of CVEs. 22 23# The product name that the CVE database uses. Defaults to BPN, but may need to 24# be overriden per recipe (for example tiff.bb sets CVE_PRODUCT=libtiff). 25CVE_PRODUCT ??= "${BPN}" 26CVE_VERSION ??= "${PV}" 27 28CVE_CHECK_DB_DIR ?= "${DL_DIR}/CVE_CHECK" 29CVE_CHECK_DB_FILE ?= "${CVE_CHECK_DB_DIR}/nvd.db" 30 31CVE_CHECK_LOG ?= "${T}/cve.log" 32CVE_CHECK_TMP_FILE ?= "${TMPDIR}/cve_check" 33 34CVE_CHECK_DIR ??= "${DEPLOY_DIR}/cve" 35CVE_CHECK_MANIFEST ?= "${DEPLOY_DIR_IMAGE}/${IMAGE_NAME}${IMAGE_NAME_SUFFIX}.cve" 36CVE_CHECK_COPY_FILES ??= "1" 37CVE_CHECK_CREATE_MANIFEST ??= "1" 38 39# Whitelist for packages (PN) 40CVE_CHECK_PN_WHITELIST = "\ 41 glibc-locale \ 42" 43 44# Whitelist for CVE and version of package 45CVE_CHECK_CVE_WHITELIST = "{\ 46 'CVE-2014-2524': ('6.3','5.2',), \ 47}" 48 49python do_cve_check () { 50 """ 51 Check recipe for patched and unpatched CVEs 52 """ 53 54 if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE")): 55 patched_cves = get_patches_cves(d) 56 patched, unpatched = check_cves(d, patched_cves) 57 if patched or unpatched: 58 cve_data = get_cve_info(d, patched + unpatched) 59 cve_write_data(d, patched, unpatched, cve_data) 60 else: 61 bb.note("Failed to update CVE database, skipping CVE check") 62} 63 64addtask cve_check after do_unpack before do_build 65do_cve_check[depends] = "cve-check-tool-native:do_populate_sysroot cve-check-tool-native:do_populate_cve_db" 66do_cve_check[nostamp] = "1" 67 68python cve_check_cleanup () { 69 """ 70 Delete the file used to gather all the CVE information. 71 """ 72 73 bb.utils.remove(e.data.getVar("CVE_CHECK_TMP_FILE")) 74} 75 76addhandler cve_check_cleanup 77cve_check_cleanup[eventmask] = "bb.cooker.CookerExit" 78 79python cve_check_write_rootfs_manifest () { 80 """ 81 Create CVE manifest when building an image 82 """ 83 84 import shutil 85 86 if d.getVar("CVE_CHECK_COPY_FILES") == "1": 87 deploy_file = os.path.join(d.getVar("CVE_CHECK_DIR"), d.getVar("PN")) 88 if os.path.exists(deploy_file): 89 bb.utils.remove(deploy_file) 90 91 if os.path.exists(d.getVar("CVE_CHECK_TMP_FILE")): 92 bb.note("Writing rootfs CVE manifest") 93 deploy_dir = d.getVar("DEPLOY_DIR_IMAGE") 94 link_name = d.getVar("IMAGE_LINK_NAME") 95 manifest_name = d.getVar("CVE_CHECK_MANIFEST") 96 cve_tmp_file = d.getVar("CVE_CHECK_TMP_FILE") 97 98 shutil.copyfile(cve_tmp_file, manifest_name) 99 100 if manifest_name and os.path.exists(manifest_name): 101 manifest_link = os.path.join(deploy_dir, "%s.cve" % link_name) 102 # If we already have another manifest, update symlinks 103 if os.path.exists(os.path.realpath(manifest_link)): 104 os.remove(manifest_link) 105 os.symlink(os.path.basename(manifest_name), manifest_link) 106 bb.plain("Image CVE report stored in: %s" % manifest_name) 107} 108 109ROOTFS_POSTPROCESS_COMMAND_prepend = "${@'cve_check_write_rootfs_manifest; ' if d.getVar('CVE_CHECK_CREATE_MANIFEST') == '1' else ''}" 110do_rootfs[recrdeptask] += "${@'do_cve_check' if d.getVar('CVE_CHECK_CREATE_MANIFEST') == '1' else ''}" 111 112def get_patches_cves(d): 113 """ 114 Get patches that solve CVEs using the "CVE: " tag. 115 """ 116 117 import re 118 119 pn = d.getVar("PN") 120 cve_match = re.compile("CVE:( CVE\-\d{4}\-\d+)+") 121 122 # Matches last CVE-1234-211432 in the file name, also if written 123 # with small letters. Not supporting multiple CVE id's in a single 124 # file name. 125 cve_file_name_match = re.compile(".*([Cc][Vv][Ee]\-\d{4}\-\d+)") 126 127 patched_cves = set() 128 bb.debug(2, "Looking for patches that solves CVEs for %s" % pn) 129 for url in src_patches(d): 130 patch_file = bb.fetch.decodeurl(url)[2] 131 132 # Check patch file name for CVE ID 133 fname_match = cve_file_name_match.search(patch_file) 134 if fname_match: 135 cve = fname_match.group(1).upper() 136 patched_cves.add(cve) 137 bb.debug(2, "Found CVE %s from patch file name %s" % (cve, patch_file)) 138 139 with open(patch_file, "r", encoding="utf-8") as f: 140 try: 141 patch_text = f.read() 142 except UnicodeDecodeError: 143 bb.debug(1, "Failed to read patch %s using UTF-8 encoding" 144 " trying with iso8859-1" % patch_file) 145 f.close() 146 with open(patch_file, "r", encoding="iso8859-1") as f: 147 patch_text = f.read() 148 149 # Search for one or more "CVE: " lines 150 text_match = False 151 for match in cve_match.finditer(patch_text): 152 # Get only the CVEs without the "CVE: " tag 153 cves = patch_text[match.start()+5:match.end()] 154 for cve in cves.split(): 155 bb.debug(2, "Patch %s solves %s" % (patch_file, cve)) 156 patched_cves.add(cve) 157 text_match = True 158 159 if not fname_match and not text_match: 160 bb.debug(2, "Patch %s doesn't solve CVEs" % patch_file) 161 162 return patched_cves 163 164def check_cves(d, patched_cves): 165 """ 166 Run cve-check-tool looking for patched and unpatched CVEs. 167 """ 168 169 import ast, csv, tempfile, subprocess, io 170 171 cves_patched = [] 172 cves_unpatched = [] 173 bpn = d.getVar("CVE_PRODUCT") 174 # If this has been unset then we're not scanning for CVEs here (for example, image recipes) 175 if not bpn: 176 return ([], []) 177 pv = d.getVar("CVE_VERSION").split("+git")[0] 178 cves = " ".join(patched_cves) 179 cve_db_dir = d.getVar("CVE_CHECK_DB_DIR") 180 cve_whitelist = ast.literal_eval(d.getVar("CVE_CHECK_CVE_WHITELIST")) 181 cve_cmd = "cve-check-tool" 182 cmd = [cve_cmd, "--no-html", "--skip-update", "--csv", "--not-affected", "-t", "faux", "-d", cve_db_dir] 183 184 # If the recipe has been whitlisted we return empty lists 185 if d.getVar("PN") in d.getVar("CVE_CHECK_PN_WHITELIST").split(): 186 bb.note("Recipe has been whitelisted, skipping check") 187 return ([], []) 188 189 try: 190 # Write the faux CSV file to be used with cve-check-tool 191 fd, faux = tempfile.mkstemp(prefix="cve-faux-") 192 with os.fdopen(fd, "w") as f: 193 for pn in bpn.split(): 194 f.write("%s,%s,%s,\n" % (pn, pv, cves)) 195 cmd.append(faux) 196 197 output = subprocess.check_output(cmd).decode("utf-8") 198 bb.debug(2, "Output of command %s:\n%s" % ("\n".join(cmd), output)) 199 except subprocess.CalledProcessError as e: 200 bb.warn("Couldn't check for CVEs: %s (output %s)" % (e, e.output)) 201 finally: 202 os.remove(faux) 203 204 for row in csv.reader(io.StringIO(output)): 205 # Third row has the unpatched CVEs 206 if row[2]: 207 for cve in row[2].split(): 208 # Skip if the CVE has been whitlisted for the current version 209 if pv in cve_whitelist.get(cve,[]): 210 bb.note("%s-%s has been whitelisted for %s" % (bpn, pv, cve)) 211 else: 212 cves_unpatched.append(cve) 213 bb.debug(2, "%s-%s is not patched for %s" % (bpn, pv, cve)) 214 # Fourth row has patched CVEs 215 if row[3]: 216 for cve in row[3].split(): 217 cves_patched.append(cve) 218 bb.debug(2, "%s-%s is patched for %s" % (bpn, pv, cve)) 219 220 return (cves_patched, cves_unpatched) 221 222def get_cve_info(d, cves): 223 """ 224 Get CVE information from the database used by cve-check-tool. 225 226 Unfortunately the only way to get CVE info is set the output to 227 html (hard to parse) or query directly the database. 228 """ 229 230 try: 231 import sqlite3 232 except ImportError: 233 from pysqlite2 import dbapi2 as sqlite3 234 235 cve_data = {} 236 db_file = d.getVar("CVE_CHECK_DB_FILE") 237 placeholder = ",".join("?" * len(cves)) 238 query = "SELECT * FROM NVD WHERE id IN (%s)" % placeholder 239 conn = sqlite3.connect(db_file) 240 cur = conn.cursor() 241 for row in cur.execute(query, tuple(cves)): 242 cve_data[row[0]] = {} 243 cve_data[row[0]]["summary"] = row[1] 244 cve_data[row[0]]["score"] = row[2] 245 cve_data[row[0]]["modified"] = row[3] 246 cve_data[row[0]]["vector"] = row[4] 247 conn.close() 248 249 return cve_data 250 251def cve_write_data(d, patched, unpatched, cve_data): 252 """ 253 Write CVE information in WORKDIR; and to CVE_CHECK_DIR, and 254 CVE manifest if enabled. 255 """ 256 257 cve_file = d.getVar("CVE_CHECK_LOG") 258 nvd_link = "https://web.nvd.nist.gov/view/vuln/detail?vulnId=" 259 write_string = "" 260 unpatched_cves = [] 261 bb.utils.mkdirhier(os.path.dirname(cve_file)) 262 263 for cve in sorted(cve_data): 264 write_string += "PACKAGE NAME: %s\n" % d.getVar("PN") 265 write_string += "PACKAGE VERSION: %s\n" % d.getVar("PV") 266 write_string += "CVE: %s\n" % cve 267 if cve in patched: 268 write_string += "CVE STATUS: Patched\n" 269 else: 270 unpatched_cves.append(cve) 271 write_string += "CVE STATUS: Unpatched\n" 272 write_string += "CVE SUMMARY: %s\n" % cve_data[cve]["summary"] 273 write_string += "CVSS v2 BASE SCORE: %s\n" % cve_data[cve]["score"] 274 write_string += "VECTOR: %s\n" % cve_data[cve]["vector"] 275 write_string += "MORE INFORMATION: %s%s\n\n" % (nvd_link, cve) 276 277 if unpatched_cves: 278 bb.warn("Found unpatched CVE (%s), for more information check %s" % (" ".join(unpatched_cves),cve_file)) 279 280 with open(cve_file, "w") as f: 281 bb.note("Writing file %s with CVE information" % cve_file) 282 f.write(write_string) 283 284 if d.getVar("CVE_CHECK_COPY_FILES") == "1": 285 cve_dir = d.getVar("CVE_CHECK_DIR") 286 bb.utils.mkdirhier(cve_dir) 287 deploy_file = os.path.join(cve_dir, d.getVar("PN")) 288 with open(deploy_file, "w") as f: 289 f.write(write_string) 290 291 if d.getVar("CVE_CHECK_CREATE_MANIFEST") == "1": 292 with open(d.getVar("CVE_CHECK_TMP_FILE"), "a") as f: 293 f.write("%s" % write_string) 294