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22 * PKIXPathValidator.cpp
24 * A path validator based on PKIX support in OpenSSL.
29 #include "security/OpenSSLPathValidator.h"
30 #include "security/OpenSSLCryptoX509CRL.h"
31 #include "security/PKIXPathValidatorParams.h"
32 #include "security/SecurityHelper.h"
34 #include "util/PathResolver.h"
35 #include "util/Threads.h"
36 #include "util/XMLHelper.h"
41 #include <openssl/x509_vfy.h>
42 #include <openssl/x509v3.h>
43 #include <xsec/enc/OpenSSL/OpenSSLCryptoX509.hpp>
44 #include <xercesc/util/XMLUniDefs.hpp>
46 using namespace xmltooling::logging;
47 using namespace xmltooling;
52 static int XMLTOOL_DLLLOCAL error_callback(int ok, X509_STORE_CTX* ctx)
55 Category::getInstance("OpenSSL").error(
56 "path validation failure at depth(%d): %s", ctx->error_depth, X509_verify_cert_error_string(ctx->error)
62 static string XMLTOOL_DLLLOCAL X509_NAME_to_string(X509_NAME* n)
65 BIO* b = BIO_new(BIO_s_mem());
66 X509_NAME_print_ex(b,n,0,XN_FLAG_RFC2253);
68 BUF_MEM* bptr=nullptr;
69 BIO_get_mem_ptr(b, &bptr);
70 if (bptr && bptr->length > 0) {
71 s.append(bptr->data, bptr->length);
77 static time_t XMLTOOL_DLLLOCAL getCRLTime(const ASN1_TIME *a)
80 memset(&t, 0, sizeof(t));
81 // RFC 5280, sections 5.1.2.4 and 5.1.2.5 require thisUpdate and nextUpdate
82 // to be encoded as UTCTime until 2049, and RFC 5280 section 4.1.2.5.1
83 // further restricts the format to "YYMMDDHHMMSSZ" ("even where the number
84 // of seconds is zero").
85 // As long as OpenSSL doesn't provide any API to convert ASN1_TIME values
86 // time_t, we therefore have to parse it ourselves, unfortunately.
87 if (sscanf((const char*)a->data, "%2d%2d%2d%2d%2d%2dZ",
88 &t.tm_year, &t.tm_mon, &t.tm_mday,
89 &t.tm_hour, &t.tm_min, &t.tm_sec) == 6) {
90 if (t.tm_year <= 50) {
91 // RFC 5280, section 4.1.2.5.1
95 #if defined(HAVE_TIMEGM)
98 // Windows, and hopefully most others...?
99 return mktime(&t) - timezone;
105 static const XMLCh minRefreshDelay[] = UNICODE_LITERAL_15(m,i,n,R,e,f,r,e,s,h,D,e,l,a,y);
106 static const XMLCh minSecondsRemaining[] = UNICODE_LITERAL_19(m,i,n,S,e,c,o,n,d,s,R,e,m,a,i,n,i,n,g);
107 static const XMLCh minPercentRemaining[] = UNICODE_LITERAL_19(m,i,n,P,e,r,c,e,n,t,R,e,m,a,i,n,i,n,g);
110 namespace xmltooling {
112 class XMLTOOL_DLLLOCAL PKIXPathValidator : public OpenSSLPathValidator
115 PKIXPathValidator(const xercesc::DOMElement* e)
116 : m_log(Category::getInstance(XMLTOOLING_LOGCAT".PathValidator.PKIX")),
117 m_lock(XMLToolingConfig::getConfig().getNamedMutex(XMLTOOLING_LOGCAT".PathValidator.PKIX")),
118 m_minRefreshDelay(XMLHelper::getAttrInt(e, 60, minRefreshDelay)),
119 m_minSecondsRemaining(XMLHelper::getAttrInt(e, 86400, minSecondsRemaining)),
120 m_minPercentRemaining(XMLHelper::getAttrInt(e, 10, minPercentRemaining)) {
123 virtual ~PKIXPathValidator() {}
126 XSECCryptoX509* certEE, const vector<XSECCryptoX509*>& certChain, const PathValidatorParams& params
129 X509* certEE, STACK_OF(X509)* certChain, const PathValidatorParams& params
133 XSECCryptoX509CRL* getRemoteCRLs(const char* cdpuri) const;
134 bool isFreshCRL(XSECCryptoX509CRL *c, Category* log=nullptr) const;
138 time_t m_minRefreshDelay,m_minSecondsRemaining;
139 unsigned short m_minPercentRemaining;
141 static map<string,time_t> m_crlUpdateMap;
144 PathValidator* XMLTOOL_DLLLOCAL PKIXPathValidatorFactory(const xercesc::DOMElement* const & e)
146 return new PKIXPathValidator(e);
151 map<string,time_t> PKIXPathValidator::m_crlUpdateMap;
153 void XMLTOOL_API xmltooling::registerPathValidators()
155 XMLToolingConfig& conf=XMLToolingConfig::getConfig();
156 conf.PathValidatorManager.registerFactory(PKIX_PATHVALIDATOR, PKIXPathValidatorFactory);
159 PathValidator::PathValidator()
163 PathValidator::~PathValidator()
167 PathValidator::PathValidatorParams::PathValidatorParams()
171 PathValidator::PathValidatorParams::~PathValidatorParams()
175 PKIXPathValidatorParams::PKIXPathValidatorParams()
179 PKIXPathValidatorParams::~PKIXPathValidatorParams()
183 OpenSSLPathValidator::OpenSSLPathValidator()
187 OpenSSLPathValidator::~OpenSSLPathValidator()
191 bool PKIXPathValidator::validate(
192 XSECCryptoX509* certEE, const vector<XSECCryptoX509*>& certChain, const PathValidatorParams& params
195 if (certEE->getProviderName()!=DSIGConstants::s_unicodeStrPROVOpenSSL) {
196 m_log.error("only the OpenSSL XSEC provider is supported");
200 STACK_OF(X509)* untrusted=sk_X509_new_null();
201 for (vector<XSECCryptoX509*>::const_iterator i=certChain.begin(); i!=certChain.end(); ++i)
202 sk_X509_push(untrusted,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
204 bool ret = validate(static_cast<OpenSSLCryptoX509*>(certEE)->getOpenSSLX509(), untrusted, params);
205 sk_X509_free(untrusted);
209 bool PKIXPathValidator::validate(X509* EE, STACK_OF(X509)* untrusted, const PathValidatorParams& params) const
215 const PKIXPathValidatorParams* pkixParams = dynamic_cast<const PKIXPathValidatorParams*>(¶ms);
217 m_log.error("input parameters were of incorrect type");
221 // First we build a stack of CA certs. These objects are all referenced in place.
222 m_log.debug("supplying PKIX Validation information");
224 // We need this for CRL support.
225 X509_STORE* store=X509_STORE_new();
231 // PKIX policy checking (cf. RFCs 3280/5280 section 6)
232 if (pkixParams->isPolicyMappingInhibited() || pkixParams->isAnyPolicyInhibited() || (!pkixParams->getPolicies().empty())) {
233 #if (OPENSSL_VERSION_NUMBER < 0x00908000L)
234 m_log.error("PKIX policy checking option is configured, but OpenSSL version is less than 0.9.8");
235 X509_STORE_free(store);
238 unsigned long pflags = 0;
239 X509_VERIFY_PARAM *vpm = X509_VERIFY_PARAM_new();
242 X509_STORE_free(store);
246 // populate the "user-initial-policy-set" input variable
247 const set<string>& policies = pkixParams->getPolicies();
248 if (!policies.empty()) {
249 for (set<string>::const_iterator o=policies.begin(); o!=policies.end(); o++) {
250 ASN1_OBJECT *oid = OBJ_txt2obj(o->c_str(), 1);
251 if (oid && X509_VERIFY_PARAM_add0_policy(vpm, oid)) {
252 m_log.debug("OID (%s) added to set of acceptable policies", o->c_str());
256 m_log.error("unable to parse/configure policy OID value (%s)", o->c_str());
258 ASN1_OBJECT_free(oid);
259 X509_VERIFY_PARAM_free(vpm);
260 X509_STORE_free(store);
264 // when the user has supplied at least one policy OID, he obviously wants to check
265 // for an explicit policy ("initial-explicit-policy")
266 pflags |= X509_V_FLAG_EXPLICIT_POLICY;
269 // "initial-policy-mapping-inhibit" input variable
270 if (pkixParams->isPolicyMappingInhibited())
271 pflags |= X509_V_FLAG_INHIBIT_MAP;
272 // "initial-any-policy-inhibit" input variable
273 if (pkixParams->isAnyPolicyInhibited())
274 pflags |= X509_V_FLAG_INHIBIT_ANY;
276 if (!X509_VERIFY_PARAM_set_flags(vpm, pflags) || !X509_STORE_set1_param(store, vpm)) {
278 m_log.error("unable to set PKIX policy checking parameters");
279 X509_VERIFY_PARAM_free(vpm);
280 X509_STORE_free(store);
284 X509_VERIFY_PARAM_free(vpm);
288 // This contains the state of the validate operation.
292 // AFAICT, EE and untrusted are passed in but not owned by the ctx.
293 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
294 if (X509_STORE_CTX_init(&ctx,store,EE,untrusted)!=1) {
296 m_log.error("unable to initialize X509_STORE_CTX");
297 X509_STORE_free(store);
301 X509_STORE_CTX_init(&ctx,store,EE,untrusted);
304 STACK_OF(X509)* CAstack = sk_X509_new_null();
305 const vector<XSECCryptoX509*>& CAcerts = pkixParams->getTrustAnchors();
306 for (vector<XSECCryptoX509*>::const_iterator i=CAcerts.begin(); i!=CAcerts.end(); ++i) {
307 if ((*i)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL) {
308 sk_X509_push(CAstack,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
312 m_log.debug("supplied (%d) CA certificate(s)", count);
314 // Seems to be most efficient to just pass in the CA stack.
315 X509_STORE_CTX_trusted_stack(&ctx,CAstack);
316 X509_STORE_CTX_set_depth(&ctx,100); // we check the depth down below
317 X509_STORE_CTX_set_verify_cb(&ctx,error_callback);
319 // Do a first pass verify. If CRLs aren't used, this is the only pass.
320 int ret=X509_verify_cert(&ctx);
322 // Now see if the depth was acceptable by counting the number of intermediates.
323 int depth=sk_X509_num(ctx.chain)-2;
324 if (pkixParams->getVerificationDepth() < depth) {
326 "certificate chain was too long (%d intermediates, only %d allowed)",
327 (depth==-1) ? 0 : depth,
328 pkixParams->getVerificationDepth()
334 if (pkixParams->getRevocationChecking() != PKIXPathValidatorParams::REVOCATION_OFF) {
335 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
336 // When we add CRLs, we have to be sure the nextUpdate hasn't passed, because OpenSSL won't accept
337 // the CRL in that case. If we end up not adding a CRL for a particular link in the chain, the
338 // validation will fail (if the fullChain option was set).
339 set<string> crlissuers;
340 time_t now = time(nullptr);
342 // Pull CRLs from external CDP first, since an attacker is likely to stick an old but valid CRL into
344 for (int i = 0; i < sk_X509_num(untrusted); ++i) {
345 X509 *cert = sk_X509_value(untrusted, i);
346 string crlissuer(X509_NAME_to_string(X509_get_issuer_name(cert)));
347 if (crlissuers.count(crlissuer)) {
348 // We already have a CRL for this cert, so skip CRLDP processing for this one.
351 bool foundUsableCDP = false;
352 STACK_OF(DIST_POINT)* dps = (STACK_OF(DIST_POINT)*)X509_get_ext_d2i(cert, NID_crl_distribution_points, nullptr, nullptr);
353 for (int ii = 0; !foundUsableCDP && ii < sk_DIST_POINT_num(dps); ++ii) {
354 DIST_POINT* dp = sk_DIST_POINT_value(dps, ii);
355 if (!dp->distpoint || dp->distpoint->type != 0)
357 for (int iii = 0; !foundUsableCDP && iii < sk_GENERAL_NAME_num(dp->distpoint->name.fullname); ++iii) {
358 GENERAL_NAME* gen = sk_GENERAL_NAME_value(dp->distpoint->name.fullname, iii);
359 // Only consider URIs, and stop after the first one we find.
360 if (gen->type == GEN_URI) {
361 const char* cdpuri = (const char*)gen->d.ia5->data;
362 auto_ptr<XSECCryptoX509CRL> crl(getRemoteCRLs(cdpuri));
363 if (crl.get() && crl->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL &&
364 (isFreshCRL(crl.get()) || (ii == sk_DIST_POINT_num(dps)-1 && iii == sk_GENERAL_NAME_num(dp->distpoint->name.fullname)-1))) {
366 X509_STORE_add_crl(store, X509_CRL_dup(static_cast<OpenSSLCryptoX509CRL*>(crl.get())->getOpenSSLX509CRL()));
367 m_log.debug("added CRL issued by (%s)", crlissuer.c_str());
368 crlissuers.insert(crlissuer);
369 foundUsableCDP = true;
374 sk_DIST_POINT_free(dps);
377 // Pick up any valid CRLs inline.
378 const vector<XSECCryptoX509CRL*>& crls = pkixParams->getCRLs();
379 for (vector<XSECCryptoX509CRL*>::const_iterator j=crls.begin(); j!=crls.end(); ++j) {
380 if ((*j)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL &&
381 (X509_cmp_time(X509_CRL_get_nextUpdate(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL()), &now) > 0)) {
382 string crlissuer(X509_NAME_to_string(X509_CRL_get_issuer(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL())));
383 if (crlissuer.empty() || crlissuers.count(crlissuer)) {
384 // We already have a CRL for this cert, so skip this one.
387 m_log.debug("added CRL issued by (%s)", crlissuer.c_str());
388 crlissuers.insert(crlissuer);
390 X509_STORE_add_crl(store, X509_CRL_dup(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL()));
394 // Do a second pass verify with CRLs in place.
395 if (pkixParams->getRevocationChecking() == PKIXPathValidatorParams::REVOCATION_FULLCHAIN)
396 X509_STORE_CTX_set_flags(&ctx, X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
398 X509_STORE_CTX_set_flags(&ctx, X509_V_FLAG_CRL_CHECK);
399 ret=X509_verify_cert(&ctx);
401 m_log.warn("CRL checking is enabled, but OpenSSL version is too old");
407 m_log.debug("successfully validated certificate chain");
409 #if defined(X509_V_ERR_NO_EXPLICIT_POLICY) && (OPENSSL_VERSION_NUMBER < 0x10000000L)
410 else if (X509_STORE_CTX_get_error(&ctx) == X509_V_ERR_NO_EXPLICIT_POLICY && !pkixParams->isPolicyMappingInhibited()) {
411 m_log.warn("policy mapping requires OpenSSL 1.0.0 or later");
416 X509_STORE_CTX_cleanup(&ctx);
417 X509_STORE_free(store);
418 sk_X509_free(CAstack);
423 XSECCryptoX509CRL* PKIXPathValidator::getRemoteCRLs(const char* cdpuri) const
425 // This is a filesystem-based CRL cache using a shared lock across all instances
428 // The filenames for the CRL cache are based on a hash of the CRL location.
429 string cdpfile = SecurityHelper::doHash("SHA1", cdpuri, strlen(cdpuri)) + ".crl";
430 XMLToolingConfig::getConfig().getPathResolver()->resolve(cdpfile, PathResolver::XMLTOOLING_CACHE_FILE);
431 string cdpstaging = cdpfile + ".tmp";
433 time_t now = time(nullptr);
434 vector<XSECCryptoX509CRL*> crls;
437 // While holding the lock, check for a cached copy of the CRL, and remove "expired" ones.
440 struct _stat stat_buf;
441 if (_stat(cdpfile.c_str(), &stat_buf) == 0) {
443 struct stat stat_buf;
444 if (stat(cdpfile.c_str(), &stat_buf) == 0) {
446 SecurityHelper::loadCRLsFromFile(crls, cdpfile.c_str());
447 if (crls.empty() || crls.front()->getProviderName() != DSIGConstants::s_unicodeStrPROVOpenSSL ||
448 X509_cmp_time(X509_CRL_get_nextUpdate(static_cast<OpenSSLCryptoX509CRL*>(crls.front())->getOpenSSLX509CRL()), &now) < 0) {
449 for_each(crls.begin(), crls.end(), xmltooling::cleanup<XSECCryptoX509CRL>());
451 remove(cdpfile.c_str()); // may as well delete the local copy
452 m_crlUpdateMap.erase(cdpuri);
453 m_log.info("deleting cached CRL from %s with nextUpdate field in the past", cdpuri);
457 catch (exception& ex) {
458 m_log.error("exception loading cached copy of CRL from %s: %s", cdpuri, ex.what());
461 if (crls.empty() || !isFreshCRL(crls.front(), &m_log)) {
462 bool updateTimestamp = true;
464 // If we get here, the cached copy didn't exist yet, or it's time to refresh.
465 // To limit the rate of unsuccessful attempts when a CRLDP is unreachable,
466 // we remember the timestamp of the last attempt (both successful/unsuccessful).
469 map<string,time_t>::const_iterator tsit = m_crlUpdateMap.find(cdpuri);
470 if (tsit != m_crlUpdateMap.end())
474 if (difftime(now, ts) > m_minRefreshDelay) {
475 SOAPTransport::Address addr("AbstractPKIXTrustEngine", cdpuri, cdpuri);
476 string scheme(addr.m_endpoint, strchr(addr.m_endpoint,':') - addr.m_endpoint);
477 auto_ptr<SOAPTransport> soap(XMLToolingConfig::getConfig().SOAPTransportManager.newPlugin(scheme.c_str(), addr));
479 istream& msg = soap->receive();
481 ofstream out(cdpstaging.c_str(), fstream::trunc|fstream::binary);
484 SecurityHelper::loadCRLsFromFile(crls, cdpstaging.c_str());
485 if (crls.empty() || crls.front()->getProviderName() != DSIGConstants::s_unicodeStrPROVOpenSSL ||
486 X509_cmp_time(X509_CRL_get_nextUpdate(static_cast<OpenSSLCryptoX509CRL*>(crls.front())->getOpenSSLX509CRL()), &now) < 0) {
487 // The "new" CRL wasn't usable, so get rid of it.
488 for_each(crls.begin(), crls.end(), xmltooling::cleanup<XSECCryptoX509CRL>());
490 remove(cdpstaging.c_str());
491 m_log.error("ignoring CRL retrieved from %s with nextUpdate field in the past", cdpuri);
494 // "Commit" the new CRL. Note that we might add a CRL which doesn't pass
495 // isFreshCRL, but that's preferrable over adding none at all.
496 m_log.info("CRL refreshed from %s", cdpuri);
497 remove(cdpfile.c_str());
498 if (rename(cdpstaging.c_str(), cdpfile.c_str()) != 0)
499 m_log.error("unable to rename CRL staging file");
503 updateTimestamp = false; // don't update if we're within the backoff window
506 catch (exception& ex) {
507 m_log.error("exception downloading/caching CRL from %s: %s", cdpuri, ex.what());
510 if (updateTimestamp) {
512 m_crlUpdateMap[cdpuri] = now;
518 for_each(crls.begin() + 1, crls.end(), xmltooling::cleanup<XSECCryptoX509CRL>());
522 bool PKIXPathValidator::isFreshCRL(XSECCryptoX509CRL *c, Category* log) const
525 const X509_CRL* crl = static_cast<OpenSSLCryptoX509CRL*>(c)->getOpenSSLX509CRL();
526 time_t thisUpdate = getCRLTime(X509_CRL_get_lastUpdate(crl));
527 time_t nextUpdate = getCRLTime(X509_CRL_get_nextUpdate(crl));
528 time_t now = time(nullptr);
530 if (thisUpdate < 0 || nextUpdate < 0) {
531 // we failed to parse at least one of the fields (they were not encoded
532 // as required by RFC 5280, actually)
533 time_t exp = now + m_minSecondsRemaining;
535 log->warn("isFreshCRL (issuer '%s'): improperly encoded thisUpdate or nextUpdate field - falling back to simple time comparison",
536 (X509_NAME_to_string(X509_CRL_get_issuer(crl))).c_str());
538 return (X509_cmp_time(X509_CRL_get_nextUpdate(crl), &exp) > 0) ? true : false;
541 if (log && log->isDebugEnabled()) {
542 log->debug("isFreshCRL (issuer '%s'): %.0f seconds until nextUpdate (%3.2f%% elapsed since thisUpdate)",
543 (X509_NAME_to_string(X509_CRL_get_issuer(crl))).c_str(),
544 difftime(nextUpdate, now), (difftime(now, thisUpdate) * 100) / difftime(nextUpdate, thisUpdate));
547 // consider it recent enough if there are at least MIN_SECS_REMAINING
548 // to the nextUpdate, and at least MIN_PERCENT_REMAINING of its
549 // overall "validity" are remaining to the nextUpdate
550 return (now + m_minSecondsRemaining < nextUpdate) &&
551 ((difftime(nextUpdate, now) * 100) / difftime(nextUpdate, thisUpdate) > m_minPercentRemaining);