xmltooling/security/impl/PKIXPathValidator.cpp

   1 /**
   2  * Licensed to the University Corporation for Advanced Internet
   3  * Development, Inc. (UCAID) under one or more contributor license
   4  * agreements. See the NOTICE file distributed with this work for
   5  * additional information regarding copyright ownership.
   6  *
   7  * UCAID licenses this file to you under the Apache License,
   8  * Version 2.0 (the "License"); you may not use this file except
   9  * in compliance with the License. You may obtain a copy of the
  10  * License at
  11  *
  12  * http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing,
  15  * software distributed under the License is distributed on an
  16  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
  17  * either express or implied. See the License for the specific
  18  * language governing permissions and limitations under the License.
  19  */
  20
  21 /**
  22  * PKIXPathValidator.cpp
  23  *
  24  * A path validator based on PKIX support in OpenSSL.
  25  */
  26
  27 #include "internal.h"
  28 #include "logging.h"
  29 #include "security/OpenSSLPathValidator.h"
  30 #include "security/OpenSSLCryptoX509CRL.h"
  31 #include "security/PKIXPathValidatorParams.h"
  32 #include "security/SecurityHelper.h"
  33 #include "util/NDC.h"
  34 #include "util/PathResolver.h"
  35 #include "util/Threads.h"
  36 #include "util/XMLHelper.h"
  37
  38 #include <memory>
  39 #include <algorithm>
  40 #include <fstream>
  41 #include <openssl/x509_vfy.h>
  42 #include <openssl/x509v3.h>
  43 #include <xsec/enc/OpenSSL/OpenSSLCryptoX509.hpp>
  44 #include <xercesc/util/XMLUniDefs.hpp>
  45
  46 using namespace xmltooling::logging;
  47 using namespace xmltooling;
  48 using namespace std;
  49
  50
  51 namespace {
  52     static int XMLTOOL_DLLLOCAL error_callback(int ok, X509_STORE_CTX* ctx)
  53     {
  54         if (!ok)
  55             Category::getInstance("OpenSSL").error("path validation failure: %s", X509_verify_cert_error_string(ctx->error));
  56         return ok;
  57     }
  58
  59     static string XMLTOOL_DLLLOCAL X509_NAME_to_string(X509_NAME* n)
  60     {
  61         string s;
  62         BIO* b = BIO_new(BIO_s_mem());
  63         X509_NAME_print_ex(b,n,0,XN_FLAG_RFC2253);
  64         BIO_flush(b);
  65         BUF_MEM* bptr=nullptr;
  66         BIO_get_mem_ptr(b, &bptr);
  67         if (bptr && bptr->length > 0) {
  68             s.append(bptr->data, bptr->length);
  69         }
  70         BIO_free(b);
  71         return s;
  72     }
  73
  74     static time_t XMLTOOL_DLLLOCAL getCRLTime(const ASN1_TIME *a)
  75     {
  76         struct tm t;
  77         memset(&t, 0, sizeof(t));
  78         // RFC 5280, sections 5.1.2.4 and 5.1.2.5 require thisUpdate and nextUpdate
  79         // to be encoded as UTCTime until 2049, and RFC 5280 section 4.1.2.5.1
  80         // further restricts the format to "YYMMDDHHMMSSZ" ("even where the number
  81         // of seconds is zero").
  82         // As long as OpenSSL doesn't provide any API to convert ASN1_TIME values
  83         // time_t, we therefore have to parse it ourselves, unfortunately.
  84         if (sscanf((const char*)a->data, "%2d%2d%2d%2d%2d%2dZ",
  85             &t.tm_year, &t.tm_mon, &t.tm_mday,
  86             &t.tm_hour, &t.tm_min, &t.tm_sec) == 6) {
  87             if (t.tm_year <= 50) {
  88                 // RFC 5280, section 4.1.2.5.1
  89                 t.tm_year += 100;
  90             }
  91             t.tm_mon--;
  92 #if defined(HAVE_TIMEGM)
  93             return timegm(&t);
  94 #else
  95             // Windows, and hopefully most others...?
  96             return mktime(&t) - timezone;
  97 #endif
  98         }
  99         return (time_t)-1;
 100     }
 101
 102     static const XMLCh minRefreshDelay[] =      UNICODE_LITERAL_15(m,i,n,R,e,f,r,e,s,h,D,e,l,a,y);
 103     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);
 104     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);
 105 };
 106
 107 namespace xmltooling {
 108
 109     class XMLTOOL_DLLLOCAL PKIXPathValidator : public OpenSSLPathValidator
 110     {
 111     public:
 112         PKIXPathValidator(const xercesc::DOMElement* e)
 113             : m_log(Category::getInstance(XMLTOOLING_LOGCAT".PathValidator.PKIX")),
 114               m_lock(XMLToolingConfig::getConfig().getNamedMutex(XMLTOOLING_LOGCAT".PathValidator.PKIX")),
 115               m_minRefreshDelay(XMLHelper::getAttrInt(e, 60, minRefreshDelay)),
 116               m_minSecondsRemaining(XMLHelper::getAttrInt(e, 86400, minSecondsRemaining)),
 117               m_minPercentRemaining(XMLHelper::getAttrInt(e, 10, minPercentRemaining)) {
 118         }
 119
 120         virtual ~PKIXPathValidator() {}
 121
 122         bool validate(
 123             XSECCryptoX509* certEE, const vector<XSECCryptoX509*>& certChain, const PathValidatorParams& params
 124             ) const;
 125         bool validate(
 126             X509* certEE, STACK_OF(X509)* certChain, const PathValidatorParams& params
 127             ) const;
 128
 129     private:
 130         XSECCryptoX509CRL* getRemoteCRLs(const char* cdpuri) const;
 131         bool isFreshCRL(XSECCryptoX509CRL *c, Category* log=nullptr) const;
 132
 133         Category& m_log;
 134         Mutex& m_lock;
 135         time_t m_minRefreshDelay,m_minSecondsRemaining;
 136         unsigned short m_minPercentRemaining;
 137
 138         static map<string,time_t> m_crlUpdateMap;
 139     };
 140
 141     PathValidator* XMLTOOL_DLLLOCAL PKIXPathValidatorFactory(const xercesc::DOMElement* const & e)
 142     {
 143         return new PKIXPathValidator(e);
 144     }
 145
 146 };
 147
 148 map<string,time_t> PKIXPathValidator::m_crlUpdateMap;
 149
 150 void XMLTOOL_API xmltooling::registerPathValidators()
 151 {
 152     XMLToolingConfig& conf=XMLToolingConfig::getConfig();
 153     conf.PathValidatorManager.registerFactory(PKIX_PATHVALIDATOR, PKIXPathValidatorFactory);
 154 }
 155
 156 PathValidator::PathValidator()
 157 {
 158 }
 159
 160 PathValidator::~PathValidator()
 161 {
 162 }
 163
 164 PathValidator::PathValidatorParams::PathValidatorParams()
 165 {
 166 }
 167
 168 PathValidator::PathValidatorParams::~PathValidatorParams()
 169 {
 170 }
 171
 172 PKIXPathValidatorParams::PKIXPathValidatorParams()
 173 {
 174 }
 175
 176 PKIXPathValidatorParams::~PKIXPathValidatorParams()
 177 {
 178 }
 179
 180 OpenSSLPathValidator::OpenSSLPathValidator()
 181 {
 182 }
 183
 184 OpenSSLPathValidator::~OpenSSLPathValidator()
 185 {
 186 }
 187
 188 bool PKIXPathValidator::validate(
 189     XSECCryptoX509* certEE, const vector<XSECCryptoX509*>& certChain, const PathValidatorParams& params
 190     ) const
 191 {
 192     if (certEE->getProviderName()!=DSIGConstants::s_unicodeStrPROVOpenSSL) {
 193         m_log.error("only the OpenSSL XSEC provider is supported");
 194         return false;
 195     }
 196
 197     STACK_OF(X509)* untrusted=sk_X509_new_null();
 198     for (vector<XSECCryptoX509*>::const_iterator i=certChain.begin(); i!=certChain.end(); ++i)
 199         sk_X509_push(untrusted,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
 200
 201     bool ret = validate(static_cast<OpenSSLCryptoX509*>(certEE)->getOpenSSLX509(), untrusted, params);
 202     sk_X509_free(untrusted);
 203     return ret;
 204 }
 205
 206 bool PKIXPathValidator::validate(X509* EE, STACK_OF(X509)* untrusted, const PathValidatorParams& params) const
 207 {
 208 #ifdef _DEBUG
 209     NDC ndc("validate");
 210 #endif
 211
 212     const PKIXPathValidatorParams* pkixParams = dynamic_cast<const PKIXPathValidatorParams*>(&params);
 213     if (!pkixParams) {
 214         m_log.error("input parameters were of incorrect type");
 215         return false;
 216     }
 217
 218     // First we build a stack of CA certs. These objects are all referenced in place.
 219     m_log.debug("supplying PKIX Validation information");
 220
 221     // We need this for CRL support.
 222     X509_STORE* store=X509_STORE_new();
 223     if (!store) {
 224         log_openssl();
 225         return false;
 226     }
 227
 228     // PKIX policy checking (cf. RFCs 3280/5280 section 6)
 229     if (pkixParams->isPolicyMappingInhibited() || pkixParams->isAnyPolicyInhibited() || (!pkixParams->getPolicies().empty())) {
 230 #if (OPENSSL_VERSION_NUMBER < 0x00908000L)
 231         m_log.error("PKIX policy checking option is configured, but OpenSSL version is less than 0.9.8");
 232         X509_STORE_free(store);
 233         return false;
 234 #else
 235         unsigned long pflags = 0;
 236         X509_VERIFY_PARAM *vpm = X509_VERIFY_PARAM_new();
 237         if (!vpm) {
 238             log_openssl();
 239             X509_STORE_free(store);
 240             return false;
 241         }
 242
 243         // populate the "user-initial-policy-set" input variable
 244         const set<string>& policies = pkixParams->getPolicies();
 245         if (!policies.empty()) {
 246             for (set<string>::const_iterator o=policies.begin(); o!=policies.end(); o++) {
 247                 ASN1_OBJECT *oid = OBJ_txt2obj(o->c_str(), 1);
 248                 if (oid && X509_VERIFY_PARAM_add0_policy(vpm, oid)) {
 249                     m_log.debug("OID (%s) added to set of acceptable policies", o->c_str());
 250                 }
 251                 else {
 252                     log_openssl();
 253                     m_log.error("unable to parse/configure policy OID value (%s)", o->c_str());
 254                     if (oid)
 255                         ASN1_OBJECT_free(oid);
 256                     X509_VERIFY_PARAM_free(vpm);
 257                     X509_STORE_free(store);
 258                     return false;
 259                 }
 260             }
 261             // when the user has supplied at least one policy OID, he obviously wants to check
 262             // for an explicit policy ("initial-explicit-policy")
 263             pflags |= X509_V_FLAG_EXPLICIT_POLICY;
 264         }
 265
 266         // "initial-policy-mapping-inhibit" input variable
 267         if (pkixParams->isPolicyMappingInhibited())
 268             pflags |= X509_V_FLAG_INHIBIT_MAP;
 269         // "initial-any-policy-inhibit" input variable
 270         if (pkixParams->isAnyPolicyInhibited())
 271             pflags |= X509_V_FLAG_INHIBIT_ANY;
 272
 273         if (!X509_VERIFY_PARAM_set_flags(vpm, pflags) || !X509_STORE_set1_param(store, vpm)) {
 274             log_openssl();
 275             m_log.error("unable to set PKIX policy checking parameters");
 276             X509_VERIFY_PARAM_free(vpm);
 277             X509_STORE_free(store);
 278             return false;
 279         }
 280
 281         X509_VERIFY_PARAM_free(vpm);
 282 #endif
 283     }
 284
 285     // This contains the state of the validate operation.
 286     int count=0;
 287     X509_STORE_CTX ctx;
 288
 289     // AFAICT, EE and untrusted are passed in but not owned by the ctx.
 290 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
 291     if (X509_STORE_CTX_init(&ctx,store,EE,untrusted)!=1) {
 292         log_openssl();
 293         m_log.error("unable to initialize X509_STORE_CTX");
 294         X509_STORE_free(store);
 295         return false;
 296     }
 297 #else
 298     X509_STORE_CTX_init(&ctx,store,EE,untrusted);
 299 #endif
 300
 301     STACK_OF(X509)* CAstack = sk_X509_new_null();
 302     const vector<XSECCryptoX509*>& CAcerts = pkixParams->getTrustAnchors();
 303     for (vector<XSECCryptoX509*>::const_iterator i=CAcerts.begin(); i!=CAcerts.end(); ++i) {
 304         if ((*i)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL) {
 305             sk_X509_push(CAstack,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
 306             ++count;
 307         }
 308     }
 309     m_log.debug("supplied (%d) CA certificate(s)", count);
 310
 311     // Seems to be most efficient to just pass in the CA stack.
 312     X509_STORE_CTX_trusted_stack(&ctx,CAstack);
 313     X509_STORE_CTX_set_depth(&ctx,100);    // we check the depth down below
 314     X509_STORE_CTX_set_verify_cb(&ctx,error_callback);
 315
 316     // Do a first pass verify. If CRLs aren't used, this is the only pass.
 317     int ret=X509_verify_cert(&ctx);
 318     if (ret==1) {
 319         // Now see if the depth was acceptable by counting the number of intermediates.
 320         int depth=sk_X509_num(ctx.chain)-2;
 321         if (pkixParams->getVerificationDepth() < depth) {
 322             m_log.error(
 323                 "certificate chain was too long (%d intermediates, only %d allowed)",
 324                 (depth==-1) ? 0 : depth,
 325                 pkixParams->getVerificationDepth()
 326                 );
 327             ret=0;
 328         }
 329     }
 330
 331     if (pkixParams->getRevocationChecking() != PKIXPathValidatorParams::REVOCATION_OFF) {
 332 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
 333         // When we add CRLs, we have to be sure the nextUpdate hasn't passed, because OpenSSL won't accept
 334         // the CRL in that case. If we end up not adding a CRL for a particular link in the chain, the
 335         // validation will fail (if the fullChain option was set).
 336         set<string> crlissuers;
 337         time_t now = time(nullptr);
 338
 339         const vector<XSECCryptoX509CRL*>& crls = pkixParams->getCRLs();
 340         for (vector<XSECCryptoX509CRL*>::const_iterator j=crls.begin(); j!=crls.end(); ++j) {
 341             if ((*j)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL &&
 342                 (X509_cmp_time(X509_CRL_get_nextUpdate(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL()), &now) > 0)) {
 343                 // owned by store
 344                 X509_STORE_add_crl(store, X509_CRL_dup(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL()));
 345                 string crlissuer(X509_NAME_to_string(X509_CRL_get_issuer(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL())));
 346                 if (!crlissuer.empty()) {
 347                     m_log.debug("added CRL issued by (%s)", crlissuer.c_str());
 348                     crlissuers.insert(crlissuer);
 349                 }
 350             }
 351         }
 352
 353         for (int i = 0; i < sk_X509_num(untrusted); ++i) {
 354             X509 *cert = sk_X509_value(untrusted, i);
 355             string crlissuer(X509_NAME_to_string(X509_get_issuer_name(cert)));
 356             if (crlissuers.count(crlissuer)) {
 357                // We already have a CRL for this cert, so skip CRLDP processing for this one.
 358                continue;
 359             }
 360
 361             bool foundUsableCDP = false;
 362             STACK_OF(DIST_POINT)* dps = (STACK_OF(DIST_POINT)*)X509_get_ext_d2i(cert, NID_crl_distribution_points, nullptr, nullptr);
 363             for (int ii = 0; !foundUsableCDP && ii < sk_DIST_POINT_num(dps); ++ii) {
 364                 DIST_POINT* dp = sk_DIST_POINT_value(dps, ii);
 365                 if (!dp->distpoint || dp->distpoint->type != 0)
 366                     continue;
 367                 for (int iii = 0; !foundUsableCDP && iii < sk_GENERAL_NAME_num(dp->distpoint->name.fullname); ++iii) {
 368                     GENERAL_NAME* gen = sk_GENERAL_NAME_value(dp->distpoint->name.fullname, iii);
 369                     // Only consider HTTP URIs, and stop after the first one we find.
 370 #ifdef HAVE_STRCASECMP
 371                     if (gen->type == GEN_URI && (!strncasecmp((const char*)gen->d.ia5->data, "http:", 5))) {
 372 #else
 373                     if (gen->type == GEN_URI && (!strnicmp((const char*)gen->d.ia5->data, "http:", 5))) {
 374 #endif
 375                         const char* cdpuri = (const char*)gen->d.ia5->data;
 376                         auto_ptr<XSECCryptoX509CRL> crl(getRemoteCRLs(cdpuri));
 377                         if (crl.get() && crl->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL &&
 378                             (isFreshCRL(crl.get()) || (ii == sk_DIST_POINT_num(dps)-1 && iii == sk_GENERAL_NAME_num(dp->distpoint->name.fullname)-1))) {
 379                             // owned by store
 380                             X509_STORE_add_crl(store, X509_CRL_dup(static_cast<OpenSSLCryptoX509CRL*>(crl.get())->getOpenSSLX509CRL()));
 381                             m_log.debug("added CRL issued by (%s)", crlissuer.c_str());
 382                             crlissuers.insert(crlissuer);
 383                             foundUsableCDP = true;
 384                         }
 385                     }
 386                 }
 387             }
 388             sk_DIST_POINT_free(dps);
 389         }
 390
 391         // Do a second pass verify with CRLs in place.
 392         if (pkixParams->getRevocationChecking() == PKIXPathValidatorParams::REVOCATION_FULLCHAIN)
 393             X509_STORE_CTX_set_flags(&ctx, X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL);
 394         else
 395             X509_STORE_CTX_set_flags(&ctx, X509_V_FLAG_CRL_CHECK);
 396         ret=X509_verify_cert(&ctx);
 397 #else
 398         m_log.warn("CRL checking is enabled, but OpenSSL version is too old");
 399         ret = 0;
 400 #endif
 401     }
 402
 403     // Clean up...
 404     X509_STORE_CTX_cleanup(&ctx);
 405     X509_STORE_free(store);
 406     sk_X509_free(CAstack);
 407
 408     if (ret==1) {
 409         m_log.debug("successfully validated certificate chain");
 410         return true;
 411     }
 412
 413     return false;
 414 }
 415
 416 XSECCryptoX509CRL* PKIXPathValidator::getRemoteCRLs(const char* cdpuri) const
 417 {
 418     // This is a filesystem-based CRL cache using a shared lock across all instances
 419     // of this class.
 420
 421     // The filenames for the CRL cache are based on a hash of the CRL location.
 422     string cdpfile = SecurityHelper::doHash("SHA1", cdpuri, strlen(cdpuri)) + ".crl";
 423     XMLToolingConfig::getConfig().getPathResolver()->resolve(cdpfile, PathResolver::XMLTOOLING_RUN_FILE);
 424     string cdpstaging = cdpfile + ".tmp";
 425
 426     time_t now = time(nullptr);
 427     vector<XSECCryptoX509CRL*> crls;
 428
 429     try {
 430         // While holding the lock, check for a cached copy of the CRL, and remove "expired" ones.
 431         Lock glock(m_lock);
 432 #ifdef WIN32
 433         struct _stat stat_buf;
 434         if (_stat(cdpfile.c_str(), &stat_buf) == 0) {
 435 #else
 436         struct stat stat_buf;
 437         if (stat(cdpfile.c_str(), &stat_buf) == 0) {
 438 #endif
 439             SecurityHelper::loadCRLsFromFile(crls, cdpfile.c_str());
 440             if (crls.empty() || crls.front()->getProviderName() != DSIGConstants::s_unicodeStrPROVOpenSSL ||
 441                 X509_cmp_time(X509_CRL_get_nextUpdate(static_cast<OpenSSLCryptoX509CRL*>(crls.front())->getOpenSSLX509CRL()), &now) < 0) {
 442                 for_each(crls.begin(), crls.end(), xmltooling::cleanup<XSECCryptoX509CRL>());
 443                 crls.clear();
 444                 remove(cdpfile.c_str());    // may as well delete the local copy
 445                 m_crlUpdateMap.erase(cdpuri);
 446                 m_log.info("deleting cached CRL from %s with nextUpdate field in the past", cdpuri);
 447             }
 448         }
 449     }
 450     catch (exception& ex) {
 451         m_log.error("exception loading cached copy of CRL from %s: %s", cdpuri, ex.what());
 452     }
 453
 454     if (crls.empty() || !isFreshCRL(crls.front(), &m_log)) {
 455         bool updateTimestamp = true;
 456         try {
 457             // If we get here, the cached copy didn't exist yet, or it's time to refresh.
 458             // To limit the rate of unsuccessful attempts when a CRLDP is unreachable,
 459             // we remember the timestamp of the last attempt (both successful/unsuccessful).
 460             time_t ts = 0;
 461             m_lock.lock();
 462             map<string,time_t>::const_iterator tsit = m_crlUpdateMap.find(cdpuri);
 463             if (tsit != m_crlUpdateMap.end())
 464                 ts = tsit->second;
 465             m_lock.unlock();
 466
 467             if (difftime(now, ts) > m_minRefreshDelay) {
 468                 SOAPTransport::Address addr("AbstractPKIXTrustEngine", cdpuri, cdpuri);
 469                 string scheme(addr.m_endpoint, strchr(addr.m_endpoint,':') - addr.m_endpoint);
 470                 auto_ptr<SOAPTransport> soap(XMLToolingConfig::getConfig().SOAPTransportManager.newPlugin(scheme.c_str(), addr));
 471                 soap->send();
 472                 istream& msg = soap->receive();
 473                 Lock glock(m_lock);
 474                 ofstream out(cdpstaging.c_str(), fstream::trunc|fstream::binary);
 475                 out << msg.rdbuf();
 476                 out.close();
 477                 SecurityHelper::loadCRLsFromFile(crls, cdpstaging.c_str());
 478                 if (crls.empty() || crls.front()->getProviderName() != DSIGConstants::s_unicodeStrPROVOpenSSL ||
 479                     X509_cmp_time(X509_CRL_get_nextUpdate(static_cast<OpenSSLCryptoX509CRL*>(crls.front())->getOpenSSLX509CRL()), &now) < 0) {
 480                     // The "new" CRL wasn't usable, so get rid of it.
 481                     for_each(crls.begin(), crls.end(), xmltooling::cleanup<XSECCryptoX509CRL>());
 482                     crls.clear();
 483                     remove(cdpstaging.c_str());
 484                     m_log.error("ignoring CRL retrieved from %s with nextUpdate field in the past", cdpuri);
 485                 }
 486                 else {
 487                     // "Commit" the new CRL. Note that we might add a CRL which doesn't pass
 488                     // isFreshCRL, but that's preferrable over adding none at all.
 489                     m_log.info("CRL refreshed from %s", cdpuri);
 490                     remove(cdpfile.c_str());
 491                     if (rename(cdpstaging.c_str(), cdpfile.c_str()) != 0)
 492                         m_log.error("unable to rename CRL staging file");
 493                 }
 494             }
 495             else {
 496                 updateTimestamp = false;    // don't update if we're within the backoff window
 497             }
 498         }
 499         catch (exception& ex) {
 500             m_log.error("exception downloading/caching CRL from %s: %s", cdpuri, ex.what());
 501         }
 502
 503         if (updateTimestamp) {
 504             Lock glock(m_lock);
 505             m_crlUpdateMap[cdpuri] = now;
 506         }
 507     }
 508
 509     if (crls.empty())
 510         return nullptr;
 511     for_each(crls.begin() + 1, crls.end(), xmltooling::cleanup<XSECCryptoX509CRL>());
 512     return crls.front();
 513 }
 514
 515 bool PKIXPathValidator::isFreshCRL(XSECCryptoX509CRL *c, Category* log) const
 516 {
 517     if (c) {
 518         const X509_CRL* crl = static_cast<OpenSSLCryptoX509CRL*>(c)->getOpenSSLX509CRL();
 519         time_t thisUpdate = getCRLTime(X509_CRL_get_lastUpdate(crl));
 520         time_t nextUpdate = getCRLTime(X509_CRL_get_nextUpdate(crl));
 521         time_t now = time(nullptr);
 522
 523         if (thisUpdate < 0 || nextUpdate < 0) {
 524             // we failed to parse at least one of the fields (they were not encoded
 525             // as required by RFC 5280, actually)
 526             time_t exp = now + m_minSecondsRemaining;
 527             if (log) {
 528                 log->warn("isFreshCRL (issuer '%s'): improperly encoded thisUpdate or nextUpdate field - falling back to simple time comparison",
 529                           (X509_NAME_to_string(X509_CRL_get_issuer(crl))).c_str());
 530             }
 531             return (X509_cmp_time(X509_CRL_get_nextUpdate(crl), &exp) > 0) ? true : false;
 532         }
 533         else {
 534             if (log && log->isDebugEnabled()) {
 535                 log->debug("isFreshCRL (issuer '%s'): %.0f seconds until nextUpdate (%3.2f%% elapsed since thisUpdate)",
 536                           (X509_NAME_to_string(X509_CRL_get_issuer(crl))).c_str(),
 537                           difftime(nextUpdate, now), (difftime(now, thisUpdate) * 100) / difftime(nextUpdate, thisUpdate));
 538             }
 539
 540             // consider it recent enough if there are at least MIN_SECS_REMAINING
 541             // to the nextUpdate, and at least MIN_PERCENT_REMAINING of its
 542             // overall "validity" are remaining to the nextUpdate
 543             return (now + m_minSecondsRemaining < nextUpdate) &&
 544                     ((difftime(nextUpdate, now) * 100) / difftime(nextUpdate, thisUpdate) > m_minPercentRemaining);
 545         }
 546     }
 547     return false;
 548 }