xmltooling/security/impl/AbstractPKIXTrustEngine.cpp

   1 /*
   2  *  Copyright 2001-2009 Internet2
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 /**
  18  * AbstractPKIXTrustEngine.cpp
  19  *
  20  * A trust engine that uses X.509 trust anchors and CRLs associated with a KeyInfoSource
  21  * to perform PKIX validation of signatures and certificates.
  22  */
  23
  24 #include "internal.h"
  25 #include "logging.h"
  26 #include "security/AbstractPKIXTrustEngine.h"
  27 #include "signature/KeyInfo.h"
  28 #include "signature/Signature.h"
  29
  30 #include <openssl/x509_vfy.h>
  31 #include <openssl/x509v3.h>
  32 #include <xmltooling/security/CredentialCriteria.h>
  33 #include <xmltooling/security/CredentialResolver.h>
  34 #include <xmltooling/security/KeyInfoResolver.h>
  35 #include <xmltooling/security/OpenSSLCryptoX509CRL.h>
  36 #include <xmltooling/security/X509Credential.h>
  37 #include <xmltooling/signature/SignatureValidator.h>
  38 #include <xmltooling/util/NDC.h>
  39 #include <xercesc/util/XMLUniDefs.hpp>
  40 #include <xsec/enc/OpenSSL/OpenSSLCryptoX509.hpp>
  41
  42 using namespace xmlsignature;
  43 using namespace xmltooling::logging;
  44 using namespace xmltooling;
  45 using namespace std;
  46
  47
  48 namespace {
  49     static int XMLTOOL_DLLLOCAL error_callback(int ok, X509_STORE_CTX* ctx)
  50     {
  51         if (!ok)
  52             Category::getInstance("OpenSSL").error("path validation failure: %s", X509_verify_cert_error_string(ctx->error));
  53         return ok;
  54     }
  55
  56     static bool XMLTOOL_DLLLOCAL validate(
  57         X509* EE,
  58         STACK_OF(X509)* untrusted,
  59         AbstractPKIXTrustEngine::PKIXValidationInfoIterator* pkixInfo,
  60         bool fullCRLChain,
  61         const vector<XSECCryptoX509CRL*>* inlineCRLs=NULL
  62         )
  63     {
  64         Category& log=Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine");
  65
  66         // First we build a stack of CA certs. These objects are all referenced in place.
  67         log.debug("supplying PKIX Validation information");
  68
  69         // We need this for CRL support.
  70         X509_STORE* store=X509_STORE_new();
  71         if (!store) {
  72             log_openssl();
  73             return false;
  74         }
  75
  76         STACK_OF(X509)* CAstack = sk_X509_new_null();
  77
  78         // This contains the state of the validate operation.
  79         int count=0;
  80         X509_STORE_CTX ctx;
  81
  82         const vector<XSECCryptoX509*>& CAcerts = pkixInfo->getTrustAnchors();
  83         for (vector<XSECCryptoX509*>::const_iterator i=CAcerts.begin(); i!=CAcerts.end(); ++i) {
  84             if ((*i)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL) {
  85                 sk_X509_push(CAstack,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
  86                 ++count;
  87             }
  88         }
  89
  90         log.debug("supplied (%d) CA certificate(s)", count);
  91
  92 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
  93         count=0;
  94         if (inlineCRLs) {
  95             for (vector<XSECCryptoX509CRL*>::const_iterator j=inlineCRLs->begin(); j!=inlineCRLs->end(); ++j) {
  96                 if ((*j)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL) {
  97                     // owned by store
  98                     X509_STORE_add_crl(store, X509_CRL_dup(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL()));
  99                     ++count;
 100                 }
 101             }
 102         }
 103         const vector<XSECCryptoX509CRL*>& crls = pkixInfo->getCRLs();
 104         for (vector<XSECCryptoX509CRL*>::const_iterator j=crls.begin(); j!=crls.end(); ++j) {
 105             if ((*j)->getProviderName()==DSIGConstants::s_unicodeStrPROVOpenSSL) {
 106                 // owned by store
 107                 X509_STORE_add_crl(store, X509_CRL_dup(static_cast<OpenSSLCryptoX509CRL*>(*j)->getOpenSSLX509CRL()));
 108                 ++count;
 109             }
 110         }
 111         log.debug("supplied (%d) CRL(s)", count);
 112         if (count > 0)
 113             X509_STORE_set_flags(store, fullCRLChain ? (X509_V_FLAG_CRL_CHECK|X509_V_FLAG_CRL_CHECK_ALL) : (X509_V_FLAG_CRL_CHECK));
 114 #else
 115         if ((inlineCRLs && !inlineCRLs->empty()) || !pkixInfo->getCRLs().empty()) {
 116             log.warn("OpenSSL versions < 0.9.7 do not support CRL checking");
 117         }
 118 #endif
 119
 120         // AFAICT, EE and untrusted are passed in but not owned by the ctx.
 121 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
 122         if (X509_STORE_CTX_init(&ctx,store,EE,untrusted)!=1) {
 123             log_openssl();
 124             log.error("unable to initialize X509_STORE_CTX");
 125             sk_X509_free(CAstack);
 126             X509_STORE_free(store);
 127             return false;
 128         }
 129 #else
 130         X509_STORE_CTX_init(&ctx,store,EE,untrusted);
 131 #endif
 132
 133         // Seems to be most efficient to just pass in the CA stack.
 134         X509_STORE_CTX_trusted_stack(&ctx,CAstack);
 135         X509_STORE_CTX_set_depth(&ctx,100);    // we check the depth down below
 136         X509_STORE_CTX_set_verify_cb(&ctx,error_callback);
 137
 138         int ret=X509_verify_cert(&ctx);
 139         if (ret==1) {
 140             // Now see if the depth was acceptable by counting the number of intermediates.
 141             int depth=sk_X509_num(ctx.chain)-2;
 142             if (pkixInfo->getVerificationDepth() < depth) {
 143                 log.error(
 144                     "certificate chain was too long (%d intermediates, only %d allowed)",
 145                     (depth==-1) ? 0 : depth,
 146                     pkixInfo->getVerificationDepth()
 147                     );
 148                 ret=0;
 149             }
 150         }
 151
 152         // Clean up...
 153         X509_STORE_CTX_cleanup(&ctx);
 154         X509_STORE_free(store);
 155         sk_X509_free(CAstack);
 156
 157         if (ret==1) {
 158             log.debug("successfully validated certificate chain");
 159             return true;
 160         }
 161
 162         return false;
 163     }
 164 };
 165
 166 AbstractPKIXTrustEngine::PKIXValidationInfoIterator::PKIXValidationInfoIterator()
 167 {
 168 }
 169
 170 AbstractPKIXTrustEngine::PKIXValidationInfoIterator::~PKIXValidationInfoIterator()
 171 {
 172 }
 173
 174 AbstractPKIXTrustEngine::AbstractPKIXTrustEngine(const xercesc::DOMElement* e) : TrustEngine(e), m_fullCRLChain(false)
 175 {
 176     static XMLCh fullCRLChain[] = UNICODE_LITERAL_12(f,u,l,l,C,R,L,C,h,a,i,n);
 177     const XMLCh* flag = e ? e->getAttributeNS(NULL, fullCRLChain) : NULL;
 178     m_fullCRLChain = (flag && (*flag == xercesc::chLatin_t || *flag == xercesc::chDigit_1));
 179 }
 180
 181 AbstractPKIXTrustEngine::~AbstractPKIXTrustEngine()
 182 {
 183 }
 184
 185 bool AbstractPKIXTrustEngine::checkEntityNames(
 186     X509* certEE, const CredentialResolver& credResolver, const CredentialCriteria& criteria
 187     ) const
 188 {
 189     Category& log=Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine.PKIX");
 190
 191     // We resolve to a set of trusted credentials.
 192     vector<const Credential*> creds;
 193     credResolver.resolve(creds,&criteria);
 194
 195     // Build a list of acceptable names.
 196     set<string> trustednames;
 197     trustednames.insert(criteria.getPeerName());
 198     for (vector<const Credential*>::const_iterator cred = creds.begin(); cred!=creds.end(); ++cred)
 199         trustednames.insert((*cred)->getKeyNames().begin(), (*cred)->getKeyNames().end());
 200
 201     X509_NAME* subject=X509_get_subject_name(certEE);
 202     if (subject) {
 203         // One way is a direct match to the subject DN.
 204         // Seems that the way to do the compare is to write the X509_NAME into a BIO.
 205         BIO* b = BIO_new(BIO_s_mem());
 206         BIO* b2 = BIO_new(BIO_s_mem());
 207         // The flags give us LDAP order instead of X.500, with a comma separator.
 208         X509_NAME_print_ex(b,subject,0,XN_FLAG_RFC2253);
 209         BIO_flush(b);
 210         // The flags give us LDAP order instead of X.500, with a comma plus space separator.
 211         X509_NAME_print_ex(b2,subject,0,XN_FLAG_RFC2253 + XN_FLAG_SEP_CPLUS_SPC - XN_FLAG_SEP_COMMA_PLUS);
 212         BIO_flush(b2);
 213
 214         BUF_MEM* bptr=NULL;
 215         BUF_MEM* bptr2=NULL;
 216         BIO_get_mem_ptr(b, &bptr);
 217         BIO_get_mem_ptr(b2, &bptr2);
 218
 219         if (bptr && bptr->length > 0 && log.isDebugEnabled()) {
 220             string subjectstr(bptr->data, bptr->length);
 221             log.debug("certificate subject: %s", subjectstr.c_str());
 222         }
 223
 224         // Check each keyname.
 225         for (set<string>::const_iterator n=trustednames.begin(); bptr && bptr2 && n!=trustednames.end(); n++) {
 226 #ifdef HAVE_STRCASECMP
 227             if ((n->length() == bptr->length && !strncasecmp(n->c_str(), bptr->data, bptr->length)) ||
 228                 (n->length() == bptr2->length && !strncasecmp(n->c_str(), bptr2->data, bptr2->length))) {
 229 #else
 230             if ((n->length() == bptr->length && !strnicmp(n->c_str(), bptr->data, bptr->length)) ||
 231                 (n->length() == bptr2->length && !strnicmp(n->c_str(), bptr2->data, bptr2->length))) {
 232 #endif
 233                 log.debug("matched full subject DN to a key name (%s)", n->c_str());
 234                 BIO_free(b);
 235                 BIO_free(b2);
 236                 return true;
 237             }
 238         }
 239         BIO_free(b);
 240         BIO_free(b2);
 241
 242         log.debug("unable to match DN, trying TLS subjectAltName match");
 243         STACK_OF(GENERAL_NAME)* altnames=(STACK_OF(GENERAL_NAME)*)X509_get_ext_d2i(certEE, NID_subject_alt_name, NULL, NULL);
 244         if (altnames) {
 245             int numalts = sk_GENERAL_NAME_num(altnames);
 246             for (int an=0; an<numalts; an++) {
 247                 const GENERAL_NAME* check = sk_GENERAL_NAME_value(altnames, an);
 248                 if (check->type==GEN_DNS || check->type==GEN_URI) {
 249                     const char* altptr = (char*)ASN1_STRING_data(check->d.ia5);
 250                     const int altlen = ASN1_STRING_length(check->d.ia5);
 251                     for (set<string>::const_iterator n=trustednames.begin(); n!=trustednames.end(); n++) {
 252 #ifdef HAVE_STRCASECMP
 253                         if ((check->type==GEN_DNS && n->length()==altlen && !strncasecmp(altptr,n->c_str(),altlen))
 254 #else
 255                         if ((check->type==GEN_DNS && n->length()==altlen && !strnicmp(altptr,n->c_str(),altlen))
 256 #endif
 257                                 || (check->type==GEN_URI && n->length()==altlen && !strncmp(altptr,n->c_str(),altlen))) {
 258                             log.debug("matched DNS/URI subjectAltName to a key name (%s)", n->c_str());
 259                             GENERAL_NAMES_free(altnames);
 260                             return true;
 261                         }
 262                     }
 263                 }
 264             }
 265         }
 266         GENERAL_NAMES_free(altnames);
 267
 268         log.debug("unable to match subjectAltName, trying TLS CN match");
 269
 270         // Fetch the last CN RDN.
 271         char* peer_CN = NULL;
 272         int j,i = -1;
 273         while ((j=X509_NAME_get_index_by_NID(subject, NID_commonName, i)) >= 0)
 274             i = j;
 275         if (i >= 0) {
 276             ASN1_STRING* tmp = X509_NAME_ENTRY_get_data(X509_NAME_get_entry(subject, i));
 277             // Copied in from libcurl.
 278             /* In OpenSSL 0.9.7d and earlier, ASN1_STRING_to_UTF8 fails if the input
 279                is already UTF-8 encoded. We check for this case and copy the raw
 280                string manually to avoid the problem. */
 281             if(tmp && ASN1_STRING_type(tmp) == V_ASN1_UTF8STRING) {
 282                 j = ASN1_STRING_length(tmp);
 283                 if(j >= 0) {
 284                     peer_CN = (char*)OPENSSL_malloc(j + 1);
 285                     memcpy(peer_CN, ASN1_STRING_data(tmp), j);
 286                     peer_CN[j] = '\0';
 287                 }
 288             }
 289             else /* not a UTF8 name */ {
 290                 j = ASN1_STRING_to_UTF8(reinterpret_cast<unsigned char**>(&peer_CN), tmp);
 291             }
 292
 293             for (set<string>::const_iterator n=trustednames.begin(); n!=trustednames.end(); n++) {
 294 #ifdef HAVE_STRCASECMP
 295                 if (n->length() == j && !strncasecmp(peer_CN, n->c_str(), j)) {
 296 #else
 297                 if (n->length() == j && !strnicmp(peer_CN, n->c_str(), j)) {
 298 #endif
 299                     log.debug("matched subject CN to a key name (%s)", n->c_str());
 300                     if(peer_CN)
 301                         OPENSSL_free(peer_CN);
 302                     return true;
 303                 }
 304             }
 305             if(peer_CN)
 306                 OPENSSL_free(peer_CN);
 307         }
 308         else {
 309             log.warn("no common name in certificate subject");
 310         }
 311     }
 312     else {
 313         log.error("certificate has no subject?!");
 314     }
 315
 316     return false;
 317 }
 318
 319 bool AbstractPKIXTrustEngine::validateWithCRLs(
 320     X509* certEE,
 321     STACK_OF(X509)* certChain,
 322     const CredentialResolver& credResolver,
 323     CredentialCriteria* criteria,
 324     const std::vector<XSECCryptoX509CRL*>* inlineCRLs
 325     ) const
 326 {
 327 #ifdef _DEBUG
 328     NDC ndc("validateWithCRLs");
 329 #endif
 330     Category& log=Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine.PKIX");
 331
 332     if (!certEE) {
 333         log.error("X.509 credential was NULL, unable to perform validation");
 334         return false;
 335     }
 336
 337     if (criteria && criteria->getPeerName() && *(criteria->getPeerName())) {
 338         log.debug("checking that the certificate name is acceptable");
 339         if (criteria->getUsage()==Credential::UNSPECIFIED_CREDENTIAL)
 340             criteria->setUsage(Credential::SIGNING_CREDENTIAL);
 341         if (!checkEntityNames(certEE,credResolver,*criteria)) {
 342             log.error("certificate name was not acceptable");
 343             return false;
 344         }
 345     }
 346
 347     log.debug("performing certificate path validation...");
 348
 349     auto_ptr<PKIXValidationInfoIterator> pkix(getPKIXValidationInfoIterator(credResolver, criteria));
 350     while (pkix->next()) {
 351         if (::validate(certEE,certChain,pkix.get(),m_fullCRLChain,inlineCRLs)) {
 352             return true;
 353         }
 354     }
 355
 356     log.debug("failed to validate certificate chain using supplied PKIX information");
 357     return false;
 358 }
 359
 360 bool AbstractPKIXTrustEngine::validate(
 361     X509* certEE,
 362     STACK_OF(X509)* certChain,
 363     const CredentialResolver& credResolver,
 364     CredentialCriteria* criteria
 365     ) const
 366 {
 367     return validateWithCRLs(certEE,certChain,credResolver,criteria);
 368 }
 369
 370 bool AbstractPKIXTrustEngine::validate(
 371     XSECCryptoX509* certEE,
 372     const vector<XSECCryptoX509*>& certChain,
 373     const CredentialResolver& credResolver,
 374     CredentialCriteria* criteria
 375     ) const
 376 {
 377 #ifdef _DEBUG
 378         NDC ndc("validate");
 379 #endif
 380     if (!certEE) {
 381         Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine.PKIX").error("X.509 credential was NULL, unable to perform validation");
 382         return false;
 383     }
 384     else if (certEE->getProviderName()!=DSIGConstants::s_unicodeStrPROVOpenSSL) {
 385         Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine.PKIX").error("only the OpenSSL XSEC provider is supported");
 386         return false;
 387     }
 388
 389     STACK_OF(X509)* untrusted=sk_X509_new_null();
 390     for (vector<XSECCryptoX509*>::const_iterator i=certChain.begin(); i!=certChain.end(); ++i)
 391         sk_X509_push(untrusted,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
 392
 393     bool ret = validate(static_cast<OpenSSLCryptoX509*>(certEE)->getOpenSSLX509(), untrusted, credResolver, criteria);
 394     sk_X509_free(untrusted);
 395     return ret;
 396 }
 397
 398 bool AbstractPKIXTrustEngine::validate(
 399     Signature& sig,
 400     const CredentialResolver& credResolver,
 401     CredentialCriteria* criteria
 402     ) const
 403 {
 404 #ifdef _DEBUG
 405     NDC ndc("validate");
 406 #endif
 407     Category& log=Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine.PKIX");
 408
 409     const KeyInfoResolver* inlineResolver = m_keyInfoResolver;
 410     if (!inlineResolver)
 411         inlineResolver = XMLToolingConfig::getConfig().getKeyInfoResolver();
 412     if (!inlineResolver) {
 413         log.error("unable to perform PKIX validation, no KeyInfoResolver available");
 414         return false;
 415     }
 416
 417     // Pull the certificate chain out of the signature.
 418     X509Credential* x509cred;
 419     auto_ptr<Credential> cred(inlineResolver->resolve(&sig,X509Credential::RESOLVE_CERTS|X509Credential::RESOLVE_CRLS));
 420     if (!cred.get() || !(x509cred=dynamic_cast<X509Credential*>(cred.get()))) {
 421         log.error("unable to perform PKIX validation, signature does not contain any certificates");
 422         return false;
 423     }
 424     const vector<XSECCryptoX509*>& certs = x509cred->getEntityCertificateChain();
 425     if (certs.empty()) {
 426         log.error("unable to perform PKIX validation, signature does not contain any certificates");
 427         return false;
 428     }
 429
 430     log.debug("validating signature using certificate from within the signature");
 431
 432     // Find and save off a pointer to the certificate that unlocks the object.
 433     // Most of the time, this will be the first one anyway.
 434     XSECCryptoX509* certEE=NULL;
 435     SignatureValidator keyValidator;
 436     for (vector<XSECCryptoX509*>::const_iterator i=certs.begin(); !certEE && i!=certs.end(); ++i) {
 437         try {
 438             auto_ptr<XSECCryptoKey> key((*i)->clonePublicKey());
 439             keyValidator.setKey(key.get());
 440             keyValidator.validate(&sig);
 441             log.debug("signature verified with key inside signature, attempting certificate validation...");
 442             certEE=(*i);
 443         }
 444         catch (ValidationException& ex) {
 445             log.debug(ex.what());
 446         }
 447     }
 448
 449     if (!certEE) {
 450         log.debug("failed to verify signature with embedded certificates");
 451         return false;
 452     }
 453     else if (certEE->getProviderName()!=DSIGConstants::s_unicodeStrPROVOpenSSL) {
 454         log.error("only the OpenSSL XSEC provider is supported");
 455         return false;
 456     }
 457
 458     STACK_OF(X509)* untrusted=sk_X509_new_null();
 459     for (vector<XSECCryptoX509*>::const_iterator i=certs.begin(); i!=certs.end(); ++i)
 460         sk_X509_push(untrusted,static_cast<OpenSSLCryptoX509*>(*i)->getOpenSSLX509());
 461     const vector<XSECCryptoX509CRL*>& crls = x509cred->getCRLs();
 462     bool ret = validateWithCRLs(static_cast<OpenSSLCryptoX509*>(certEE)->getOpenSSLX509(), untrusted, credResolver, criteria, &crls);
 463     sk_X509_free(untrusted);
 464     return ret;
 465 }
 466
 467 bool AbstractPKIXTrustEngine::validate(
 468     const XMLCh* sigAlgorithm,
 469     const char* sig,
 470     KeyInfo* keyInfo,
 471     const char* in,
 472     unsigned int in_len,
 473     const CredentialResolver& credResolver,
 474     CredentialCriteria* criteria
 475     ) const
 476 {
 477 #ifdef _DEBUG
 478     NDC ndc("validate");
 479 #endif
 480     Category& log=Category::getInstance(XMLTOOLING_LOGCAT".TrustEngine.PKIX");
 481
 482     if (!keyInfo) {
 483         log.error("unable to perform PKIX validation, KeyInfo not present");
 484         return false;
 485     }
 486
 487     const KeyInfoResolver* inlineResolver = m_keyInfoResolver;
 488     if (!inlineResolver)
 489         inlineResolver = XMLToolingConfig::getConfig().getKeyInfoResolver();
 490     if (!inlineResolver) {
 491         log.error("unable to perform PKIX validation, no KeyInfoResolver available");
 492         return false;
 493     }
 494
 495     // Pull the certificate chain out of the signature.
 496     X509Credential* x509cred;
 497     auto_ptr<Credential> cred(inlineResolver->resolve(keyInfo,X509Credential::RESOLVE_CERTS));
 498     if (!cred.get() || !(x509cred=dynamic_cast<X509Credential*>(cred.get()))) {
 499         log.error("unable to perform PKIX validation, KeyInfo does not contain any certificates");
 500         return false;
 501     }
 502     const vector<XSECCryptoX509*>& certs = x509cred->getEntityCertificateChain();
 503     if (certs.empty()) {
 504         log.error("unable to perform PKIX validation, KeyInfo does not contain any certificates");
 505         return false;
 506     }
 507
 508     log.debug("validating signature using certificate from within KeyInfo");
 509
 510     // Find and save off a pointer to the certificate that unlocks the object.
 511     // Most of the time, this will be the first one anyway.
 512     XSECCryptoX509* certEE=NULL;
 513     for (vector<XSECCryptoX509*>::const_iterator i=certs.begin(); !certEE && i!=certs.end(); ++i) {
 514         try {
 515             auto_ptr<XSECCryptoKey> key((*i)->clonePublicKey());
 516             if (Signature::verifyRawSignature(key.get(), sigAlgorithm, sig, in, in_len)) {
 517                 log.debug("signature verified with key inside signature, attempting certificate validation...");
 518                 certEE=(*i);
 519             }
 520         }
 521         catch (SignatureException& ex) {
 522             log.debug(ex.what());
 523         }
 524     }
 525
 526     if (certEE)
 527         return validate(certEE,certs,credResolver,criteria);
 528
 529     log.debug("failed to verify signature with embedded certificates");
 530     return false;
 531 }