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