xmltooling/soap/impl/CURLSOAPTransport.cpp

   1 /*
   2  *  Copyright 2001-2007 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  * CURLSOAPTransport.cpp
  19  *
  20  * libcurl-based SOAPTransport implementation
  21  */
  22
  23 #include "internal.h"
  24 #include "exceptions.h"
  25 #include "logging.h"
  26 #include "security/CredentialCriteria.h"
  27 #include "security/OpenSSLTrustEngine.h"
  28 #include "security/OpenSSLCredential.h"
  29 #include "soap/HTTPSOAPTransport.h"
  30 #include "soap/OpenSSLSOAPTransport.h"
  31 #include "util/NDC.h"
  32 #include "util/Threads.h"
  33
  34 #include <list>
  35 #include <curl/curl.h>
  36 #include <openssl/x509_vfy.h>
  37
  38 using namespace xmltooling::logging;
  39 using namespace xmltooling;
  40 using namespace std;
  41
  42 namespace xmltooling {
  43
  44     // Manages cache of socket connections via CURL handles.
  45     class XMLTOOL_DLLLOCAL CURLPool
  46     {
  47     public:
  48         CURLPool() : m_size(0), m_lock(Mutex::create()),
  49             m_log(Category::getInstance(XMLTOOLING_LOGCAT".SOAPTransport.CURL")) {}
  50         ~CURLPool();
  51
  52         CURL* get(const SOAPTransport::Address& addr);
  53         void put(const char* from, const char* to, const char* endpoint, CURL* handle);
  54
  55     private:
  56         typedef map<string,vector<CURL*> > poolmap_t;
  57         poolmap_t m_bindingMap;
  58         list< vector<CURL*>* > m_pools;
  59         long m_size;
  60         Mutex* m_lock;
  61         Category& m_log;
  62     };
  63
  64     static XMLTOOL_DLLLOCAL CURLPool* g_CURLPool = NULL;
  65
  66     class XMLTOOL_DLLLOCAL CURLSOAPTransport : public HTTPSOAPTransport, public OpenSSLSOAPTransport
  67     {
  68     public:
  69         CURLSOAPTransport(const Address& addr)
  70             : m_sender(addr.m_from ? addr.m_from : ""), m_peerName(addr.m_to ? addr.m_to : ""), m_endpoint(addr.m_endpoint),
  71                 m_handle(NULL), m_headers(NULL),
  72 #ifndef XMLTOOLING_NO_XMLSEC
  73                     m_cred(NULL), m_trustEngine(NULL), m_peerResolver(NULL), m_mandatory(false),
  74 #endif
  75                     m_ssl_callback(NULL), m_ssl_userptr(NULL), m_chunked(true), m_authenticated(false) {
  76             m_handle = g_CURLPool->get(addr);
  77             curl_easy_setopt(m_handle,CURLOPT_URL,addr.m_endpoint);
  78             curl_easy_setopt(m_handle,CURLOPT_CONNECTTIMEOUT,15);
  79             curl_easy_setopt(m_handle,CURLOPT_TIMEOUT,30);
  80             curl_easy_setopt(m_handle,CURLOPT_HTTPAUTH,0);
  81             curl_easy_setopt(m_handle,CURLOPT_USERPWD,NULL);
  82             curl_easy_setopt(m_handle,CURLOPT_SSL_VERIFYHOST,2);
  83             curl_easy_setopt(m_handle,CURLOPT_HEADERDATA,this);
  84             m_headers=curl_slist_append(m_headers,"Content-Type: text/xml");
  85         }
  86
  87         virtual ~CURLSOAPTransport() {
  88             curl_slist_free_all(m_headers);
  89             curl_easy_setopt(m_handle,CURLOPT_ERRORBUFFER,NULL);
  90             curl_easy_setopt(m_handle,CURLOPT_PRIVATE,m_authenticated ? "secure" : NULL); // Save off security "state".
  91             g_CURLPool->put(m_sender.c_str(), m_peerName.c_str(), m_endpoint.c_str(), m_handle);
  92         }
  93
  94         bool isConfidential() const {
  95             return m_endpoint.find("https")==0;
  96         }
  97
  98         bool setConnectTimeout(long timeout) {
  99             return (curl_easy_setopt(m_handle,CURLOPT_CONNECTTIMEOUT,timeout)==CURLE_OK);
 100         }
 101
 102         bool setTimeout(long timeout) {
 103             return (curl_easy_setopt(m_handle,CURLOPT_TIMEOUT,timeout)==CURLE_OK);
 104         }
 105
 106         bool setAuth(transport_auth_t authType, const char* username=NULL, const char* password=NULL);
 107
 108         bool setVerifyHost(bool verify) {
 109             return (curl_easy_setopt(m_handle,CURLOPT_SSL_VERIFYHOST,verify ? 2 : 0)==CURLE_OK);
 110         }
 111
 112 #ifndef XMLTOOLING_NO_XMLSEC
 113         bool setCredential(const Credential* cred=NULL) {
 114             const OpenSSLCredential* down = dynamic_cast<const OpenSSLCredential*>(cred);
 115             if (!down) {
 116                 m_cred = NULL;
 117                 return (cred==NULL);
 118             }
 119             m_cred = down;
 120             return true;
 121         }
 122
 123         bool setTrustEngine(
 124             const X509TrustEngine* trustEngine=NULL,
 125             const CredentialResolver* peerResolver=NULL,
 126             CredentialCriteria* criteria=NULL,
 127             bool mandatory=true
 128             ) {
 129             const OpenSSLTrustEngine* down = dynamic_cast<const OpenSSLTrustEngine*>(trustEngine);
 130             if (!down) {
 131                 m_trustEngine = NULL;
 132                 m_peerResolver = NULL;
 133                 m_criteria = NULL;
 134                 return (trustEngine==NULL);
 135             }
 136             m_trustEngine = down;
 137             m_peerResolver = peerResolver;
 138             m_criteria = criteria;
 139             m_mandatory = mandatory;
 140             return true;
 141         }
 142
 143 #endif
 144
 145         bool useChunkedEncoding(bool chunked=true) {
 146             m_chunked = chunked;
 147             return true;
 148         }
 149
 150         bool setProviderOption(const char* provider, const char* option, const char* value) {
 151             if (!provider || strcmp(provider, "CURL"))
 152                 return false;
 153             // For libcurl, the option is an enum and the value type depends on the option.
 154             CURLoption opt = static_cast<CURLoption>(strtol(option, NULL, 10));
 155             if (opt < CURLOPTTYPE_OBJECTPOINT)
 156                 return (curl_easy_setopt(m_handle, opt, strtol(value, NULL, 10)) == CURLE_OK);
 157 #ifdef CURLOPTTYPE_OFF_T
 158             else if (opt < CURLOPTTYPE_OFF_T)
 159                 return (curl_easy_setopt(m_handle, opt, value) == CURLE_OK);
 160             else if (sizeof(curl_off_t) == sizeof(long))
 161                 return (curl_easy_setopt(m_handle, opt, strtol(value, NULL, 10)) == CURLE_OK);
 162             return false;
 163 #else
 164             else
 165                 return (curl_easy_setopt(m_handle, opt, value) == CURLE_OK);
 166 #endif
 167         }
 168
 169         void send(istream& in) {
 170             send(&in);
 171         }
 172
 173         void send(istream* in=NULL);
 174
 175         istream& receive() {
 176             return m_stream;
 177         }
 178
 179         bool isAuthenticated() const {
 180             return m_authenticated;
 181         }
 182
 183         void setAuthenticated(bool auth) {
 184             m_authenticated = auth;
 185         }
 186
 187         string getContentType() const;
 188
 189         bool setRequestHeader(const char* name, const char* val) {
 190             string temp(name);
 191             temp=temp + ": " + val;
 192             m_headers=curl_slist_append(m_headers,temp.c_str());
 193             return true;
 194         }
 195
 196         const vector<string>& getResponseHeader(const char* val) const;
 197
 198         bool setSSLCallback(ssl_ctx_callback_fn fn, void* userptr=NULL) {
 199             m_ssl_callback=fn;
 200             m_ssl_userptr=userptr;
 201             return true;
 202         }
 203
 204     private:
 205         // per-call state
 206         string m_sender,m_peerName,m_endpoint,m_simplecreds;
 207         CURL* m_handle;
 208         stringstream m_stream;
 209         struct curl_slist* m_headers;
 210         map<string,vector<string> > m_response_headers;
 211 #ifndef XMLTOOLING_NO_XMLSEC
 212         const OpenSSLCredential* m_cred;
 213         const OpenSSLTrustEngine* m_trustEngine;
 214         const CredentialResolver* m_peerResolver;
 215         CredentialCriteria* m_criteria;
 216         bool m_mandatory;
 217 #endif
 218         ssl_ctx_callback_fn m_ssl_callback;
 219         void* m_ssl_userptr;
 220         bool m_chunked;
 221         bool m_authenticated;
 222
 223         friend size_t XMLTOOL_DLLLOCAL curl_header_hook(void* ptr, size_t size, size_t nmemb, void* stream);
 224         friend CURLcode XMLTOOL_DLLLOCAL xml_ssl_ctx_callback(CURL* curl, SSL_CTX* ssl_ctx, void* userptr);
 225         friend int XMLTOOL_DLLLOCAL verify_callback(X509_STORE_CTX* x509_ctx, void* arg);
 226     };
 227
 228     // libcurl callback functions
 229     size_t XMLTOOL_DLLLOCAL curl_header_hook(void* ptr, size_t size, size_t nmemb, void* stream);
 230     size_t XMLTOOL_DLLLOCAL curl_write_hook(void* ptr, size_t size, size_t nmemb, void* stream);
 231     size_t XMLTOOL_DLLLOCAL curl_read_hook( void *ptr, size_t size, size_t nmemb, void *stream);
 232     int XMLTOOL_DLLLOCAL curl_debug_hook(CURL* handle, curl_infotype type, char* data, size_t len, void* ptr);
 233     CURLcode XMLTOOL_DLLLOCAL xml_ssl_ctx_callback(CURL* curl, SSL_CTX* ssl_ctx, void* userptr);
 234 #ifndef XMLTOOLING_NO_XMLSEC
 235     int XMLTOOL_DLLLOCAL verify_callback(X509_STORE_CTX* x509_ctx, void* arg);
 236 #endif
 237
 238     SOAPTransport* CURLSOAPTransportFactory(const SOAPTransport::Address& addr)
 239     {
 240         return new CURLSOAPTransport(addr);
 241     }
 242 };
 243
 244 void xmltooling::registerSOAPTransports()
 245 {
 246     XMLToolingConfig& conf=XMLToolingConfig::getConfig();
 247     conf.SOAPTransportManager.registerFactory("http", CURLSOAPTransportFactory);
 248     conf.SOAPTransportManager.registerFactory("https", CURLSOAPTransportFactory);
 249 }
 250
 251 void xmltooling::initSOAPTransports()
 252 {
 253     g_CURLPool=new CURLPool();
 254 }
 255
 256 void xmltooling::termSOAPTransports()
 257 {
 258     delete g_CURLPool;
 259     g_CURLPool = NULL;
 260 }
 261
 262 CURLPool::~CURLPool()
 263 {
 264     for (poolmap_t::iterator i=m_bindingMap.begin(); i!=m_bindingMap.end(); i++) {
 265         for (vector<CURL*>::iterator j=i->second.begin(); j!=i->second.end(); j++)
 266             curl_easy_cleanup(*j);
 267     }
 268     delete m_lock;
 269 }
 270
 271 CURL* CURLPool::get(const SOAPTransport::Address& addr)
 272 {
 273 #ifdef _DEBUG
 274     xmltooling::NDC("get");
 275 #endif
 276     m_log.debug("getting connection handle to %s", addr.m_endpoint);
 277     string key(addr.m_endpoint);
 278     if (addr.m_from)
 279         key = key + '|' + addr.m_from;
 280     if (addr.m_to)
 281         key = key + '|' + addr.m_to;
 282     m_lock->lock();
 283     poolmap_t::iterator i=m_bindingMap.find(key);
 284
 285     if (i!=m_bindingMap.end()) {
 286         // Move this pool to the front of the list.
 287         m_pools.remove(&(i->second));
 288         m_pools.push_front(&(i->second));
 289
 290         // If a free connection exists, return it.
 291         if (!(i->second.empty())) {
 292             CURL* handle=i->second.back();
 293             i->second.pop_back();
 294             m_size--;
 295             m_lock->unlock();
 296             m_log.debug("returning existing connection handle from pool");
 297             return handle;
 298         }
 299     }
 300
 301     m_lock->unlock();
 302     m_log.debug("nothing free in pool, returning new connection handle");
 303
 304     // Create a new connection and set non-varying options.
 305     CURL* handle=curl_easy_init();
 306     if (!handle)
 307         return NULL;
 308     curl_easy_setopt(handle,CURLOPT_NOPROGRESS,1);
 309     curl_easy_setopt(handle,CURLOPT_NOSIGNAL,1);
 310     curl_easy_setopt(handle,CURLOPT_FAILONERROR,1);
 311     curl_easy_setopt(handle,CURLOPT_SSLVERSION,CURL_SSLVERSION_SSLv3);
 312     curl_easy_setopt(handle,CURLOPT_SSL_CIPHER_LIST,"ALL:!aNULL:!LOW:!EXPORT:!SSLv2");
 313     // Verification of the peer is via TrustEngine only.
 314     curl_easy_setopt(handle,CURLOPT_SSL_VERIFYPEER,0);
 315     curl_easy_setopt(handle,CURLOPT_HEADERFUNCTION,&curl_header_hook);
 316     curl_easy_setopt(handle,CURLOPT_WRITEFUNCTION,&curl_write_hook);
 317     curl_easy_setopt(handle,CURLOPT_DEBUGFUNCTION,&curl_debug_hook);
 318
 319     return handle;
 320 }
 321
 322 void CURLPool::put(const char* from, const char* to, const char* endpoint, CURL* handle)
 323 {
 324     string key(endpoint);
 325     if (from)
 326         key = key + '|' + from;
 327     if (to)
 328         key = key + '|' + to;
 329     m_lock->lock();
 330     poolmap_t::iterator i=m_bindingMap.find(key);
 331     if (i==m_bindingMap.end())
 332         m_pools.push_front(&(m_bindingMap.insert(poolmap_t::value_type(key,vector<CURL*>(1,handle))).first->second));
 333     else
 334         i->second.push_back(handle);
 335
 336     CURL* killit=NULL;
 337     if (++m_size > 256) {
 338         // Kick a handle out from the back of the bus.
 339         while (true) {
 340             vector<CURL*>* corpse=m_pools.back();
 341             if (!corpse->empty()) {
 342                 killit=corpse->back();
 343                 corpse->pop_back();
 344                 m_size--;
 345                 break;
 346             }
 347
 348             // Move an empty pool up to the front so we don't keep hitting it.
 349             m_pools.pop_back();
 350             m_pools.push_front(corpse);
 351         }
 352     }
 353     m_lock->unlock();
 354     if (killit) {
 355         curl_easy_cleanup(killit);
 356 #ifdef _DEBUG
 357         xmltooling::NDC("put");
 358 #endif
 359         m_log.info("conn_pool_max limit reached, dropping an old connection");
 360     }
 361 }
 362
 363 bool CURLSOAPTransport::setAuth(transport_auth_t authType, const char* username, const char* password)
 364 {
 365     if (authType==transport_auth_none) {
 366         if (curl_easy_setopt(m_handle,CURLOPT_HTTPAUTH,0)!=CURLE_OK)
 367             return false;
 368         return (curl_easy_setopt(m_handle,CURLOPT_USERPWD,NULL)==CURLE_OK);
 369     }
 370     long flag=0;
 371     switch (authType) {
 372         case transport_auth_basic:    flag = CURLAUTH_BASIC; break;
 373         case transport_auth_digest:   flag = CURLAUTH_DIGEST; break;
 374         case transport_auth_ntlm:     flag = CURLAUTH_NTLM; break;
 375         case transport_auth_gss:      flag = CURLAUTH_GSSNEGOTIATE; break;
 376         default:            return false;
 377     }
 378     if (curl_easy_setopt(m_handle,CURLOPT_HTTPAUTH,flag)!=CURLE_OK)
 379         return false;
 380     m_simplecreds = string(username ? username : "") + ':' + (password ? password : "");
 381     return (curl_easy_setopt(m_handle,CURLOPT_USERPWD,m_simplecreds.c_str())==CURLE_OK);
 382 }
 383
 384 const vector<string>& CURLSOAPTransport::getResponseHeader(const char* name) const
 385 {
 386     static vector<string> emptyVector;
 387
 388     map<string,vector<string> >::const_iterator i=m_response_headers.find(name);
 389     if (i!=m_response_headers.end())
 390         return i->second;
 391
 392     for (map<string,vector<string> >::const_iterator j=m_response_headers.begin(); j!=m_response_headers.end(); j++) {
 393 #ifdef HAVE_STRCASECMP
 394         if (!strcasecmp(j->first.c_str(), name))
 395 #else
 396         if (!stricmp(j->first.c_str(), name))
 397 #endif
 398             return j->second;
 399     }
 400
 401     return emptyVector;
 402 }
 403
 404 string CURLSOAPTransport::getContentType() const
 405 {
 406     char* content_type=NULL;
 407     curl_easy_getinfo(m_handle,CURLINFO_CONTENT_TYPE,&content_type);
 408     return content_type ? content_type : "";
 409 }
 410
 411 void CURLSOAPTransport::send(istream* in)
 412 {
 413 #ifdef _DEBUG
 414     xmltooling::NDC ndc("send");
 415 #endif
 416     Category& log=Category::getInstance(XMLTOOLING_LOGCAT".SOAPTransport.CURL");
 417     Category& log_curl=Category::getInstance(XMLTOOLING_LOGCAT".libcurl");
 418
 419     // For this implementation, it's sufficient to check for https as a sign of transport security.
 420     if (m_mandatory && !isConfidential())
 421         throw IOException("Blocking unprotected HTTP request, transport authentication by server required.");
 422
 423     string msg;
 424
 425     // By this time, the handle has been prepared with the URL to use and the
 426     // caller should have executed any set functions to manipulate it.
 427
 428     // Setup standard per-call curl properties.
 429     curl_easy_setopt(m_handle,CURLOPT_DEBUGDATA,&log_curl);
 430     curl_easy_setopt(m_handle,CURLOPT_FILE,&m_stream);
 431     if (m_chunked && in) {
 432         curl_easy_setopt(m_handle,CURLOPT_POST,1);
 433         m_headers=curl_slist_append(m_headers,"Transfer-Encoding: chunked");
 434         curl_easy_setopt(m_handle,CURLOPT_READFUNCTION,&curl_read_hook);
 435         curl_easy_setopt(m_handle,CURLOPT_READDATA,in);
 436     }
 437     else if (in) {
 438         char buf[1024];
 439         while (*in) {
 440             in->read(buf,1024);
 441             msg.append(buf,in->gcount());
 442         }
 443         curl_easy_setopt(m_handle,CURLOPT_POST,1);
 444         curl_easy_setopt(m_handle,CURLOPT_READFUNCTION,NULL);
 445         curl_easy_setopt(m_handle,CURLOPT_POSTFIELDS,msg.c_str());
 446         curl_easy_setopt(m_handle,CURLOPT_POSTFIELDSIZE,msg.length());
 447     }
 448     else {
 449         curl_easy_setopt(m_handle,CURLOPT_HTTPGET,1);
 450     }
 451
 452     char curl_errorbuf[CURL_ERROR_SIZE];
 453     curl_errorbuf[0]=0;
 454     curl_easy_setopt(m_handle,CURLOPT_ERRORBUFFER,curl_errorbuf);
 455     if (log_curl.isDebugEnabled())
 456         curl_easy_setopt(m_handle,CURLOPT_VERBOSE,1);
 457
 458     // Set request headers.
 459     curl_easy_setopt(m_handle,CURLOPT_HTTPHEADER,m_headers);
 460
 461 #ifndef XMLTOOLING_NO_XMLSEC
 462     if (m_ssl_callback || m_cred || m_trustEngine) {
 463 #else
 464     if (m_ssl_callback) {
 465 #endif
 466         curl_easy_setopt(m_handle,CURLOPT_SSL_CTX_FUNCTION,xml_ssl_ctx_callback);
 467         curl_easy_setopt(m_handle,CURLOPT_SSL_CTX_DATA,this);
 468
 469         // Restore security "state". Necessary because the callback only runs
 470         // when handshakes occur. Even new TCP connections won't execute it.
 471         char* priv=NULL;
 472         curl_easy_getinfo(m_handle,CURLINFO_PRIVATE,&priv);
 473         if (priv)
 474             m_authenticated=true;
 475     }
 476     else {
 477         curl_easy_setopt(m_handle,CURLOPT_SSL_CTX_FUNCTION,NULL);
 478         curl_easy_setopt(m_handle,CURLOPT_SSL_CTX_DATA,NULL);
 479     }
 480
 481     // Make the call.
 482     log.debug("sending SOAP message to %s", m_endpoint.c_str());
 483     if (curl_easy_perform(m_handle) != CURLE_OK) {
 484         throw IOException(
 485             string("CURLSOAPTransport failed while contacting SOAP endpoint (") + m_endpoint + "): " +
 486                 (curl_errorbuf[0] ? curl_errorbuf : "no further information available"));
 487     }
 488 }
 489
 490 // callback to buffer headers from server
 491 size_t xmltooling::curl_header_hook(void* ptr, size_t size, size_t nmemb, void* stream)
 492 {
 493     // only handle single-byte data
 494     if (size!=1)
 495         return 0;
 496     CURLSOAPTransport* ctx = reinterpret_cast<CURLSOAPTransport*>(stream);
 497     char* buf = (char*)malloc(nmemb + 1);
 498     if (buf) {
 499         memset(buf,0,nmemb + 1);
 500         memcpy(buf,ptr,nmemb);
 501         char* sep=(char*)strchr(buf,':');
 502         if (sep) {
 503             *(sep++)=0;
 504             while (*sep==' ')
 505                 *(sep++)=0;
 506             char* white=buf+nmemb-1;
 507             while (isspace(*white))
 508                 *(white--)=0;
 509             ctx->m_response_headers[buf].push_back(sep);
 510         }
 511         free(buf);
 512         return nmemb;
 513     }
 514     return 0;
 515 }
 516
 517 // callback to send data to server
 518 size_t xmltooling::curl_read_hook(void* ptr, size_t size, size_t nmemb, void* stream)
 519 {
 520     // stream is actually an istream pointer
 521     istream* buf=reinterpret_cast<istream*>(stream);
 522     buf->read(reinterpret_cast<char*>(ptr),size*nmemb);
 523     return buf->gcount();
 524 }
 525
 526 // callback to buffer data from server
 527 size_t xmltooling::curl_write_hook(void* ptr, size_t size, size_t nmemb, void* stream)
 528 {
 529     size_t len = size*nmemb;
 530     reinterpret_cast<stringstream*>(stream)->write(reinterpret_cast<const char*>(ptr),len);
 531     return len;
 532 }
 533
 534 // callback for curl debug data
 535 int xmltooling::curl_debug_hook(CURL* handle, curl_infotype type, char* data, size_t len, void* ptr)
 536 {
 537     // *ptr is actually a logging object
 538     if (!ptr) return 0;
 539     CategoryStream log=reinterpret_cast<Category*>(ptr)->debugStream();
 540     for (unsigned char* ch=(unsigned char*)data; len && (isprint(*ch) || isspace(*ch)); len--)
 541         log << *ch++;
 542     return 0;
 543 }
 544
 545 #ifndef XMLTOOLING_NO_XMLSEC
 546 int xmltooling::verify_callback(X509_STORE_CTX* x509_ctx, void* arg)
 547 {
 548     Category& log=Category::getInstance(XMLTOOLING_LOGCAT".SOAPTransport.CURL");
 549     log.debug("invoking custom X.509 verify callback");
 550 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
 551     CURLSOAPTransport* ctx = reinterpret_cast<CURLSOAPTransport*>(arg);
 552 #else
 553     // Yes, this sucks. I'd use TLS, but there's no really obvious spot to put the thread key
 554     // and global variables suck too. We can't access the X509_STORE_CTX depth directly because
 555     // OpenSSL only copies it into the context if it's >=0, and the unsigned pointer may be
 556     // negative in the SSL structure's int member.
 557     CURLSOAPTransport* ctx = reinterpret_cast<CURLSOAPTransport*>(
 558         SSL_get_verify_depth(
 559             reinterpret_cast<SSL*>(X509_STORE_CTX_get_ex_data(x509_ctx,SSL_get_ex_data_X509_STORE_CTX_idx()))
 560             )
 561         );
 562 #endif
 563
 564     bool success=false;
 565     if (ctx->m_criteria) {
 566         ctx->m_criteria->setUsage(Credential::TLS_CREDENTIAL);
 567         // Bypass name check (handled for us by curl).
 568         ctx->m_criteria->setPeerName(NULL);
 569         success = ctx->m_trustEngine->validate(x509_ctx->cert,x509_ctx->untrusted,*(ctx->m_peerResolver),ctx->m_criteria);
 570     }
 571     else {
 572         // Bypass name check (handled for us by curl).
 573         CredentialCriteria cc;
 574         cc.setUsage(Credential::TLS_CREDENTIAL);
 575         success = ctx->m_trustEngine->validate(x509_ctx->cert,x509_ctx->untrusted,*(ctx->m_peerResolver),&cc);
 576     }
 577
 578     if (!success) {
 579         log.error("supplied TrustEngine failed to validate SSL/TLS server certificate");
 580         x509_ctx->error=X509_V_ERR_APPLICATION_VERIFICATION;     // generic error, check log for plugin specifics
 581         ctx->setAuthenticated(false);
 582         return ctx->m_mandatory ? 0 : 1;
 583     }
 584
 585     // Signal success. Hopefully it doesn't matter what's actually in the structure now.
 586     ctx->setAuthenticated(true);
 587     return 1;
 588 }
 589 #endif
 590
 591 // callback to invoke a caller-defined SSL callback
 592 CURLcode xmltooling::xml_ssl_ctx_callback(CURL* curl, SSL_CTX* ssl_ctx, void* userptr)
 593 {
 594     CURLSOAPTransport* conf = reinterpret_cast<CURLSOAPTransport*>(userptr);
 595
 596 #ifndef XMLTOOLING_NO_XMLSEC
 597     if (conf->m_cred)
 598         conf->m_cred->attach(ssl_ctx);
 599
 600     if (conf->m_trustEngine) {
 601         SSL_CTX_set_verify(ssl_ctx,SSL_VERIFY_PEER,NULL);
 602 #if (OPENSSL_VERSION_NUMBER >= 0x00907000L)
 603         // With 0.9.7, we can pass a callback argument directly.
 604         SSL_CTX_set_cert_verify_callback(ssl_ctx,verify_callback,userptr);
 605 #else
 606         // With 0.9.6, there's no argument, so we're going to use a really embarrassing hack and
 607         // stuff the argument in the depth property where it will get copied to the context object
 608         // that's handed to the callback.
 609         SSL_CTX_set_cert_verify_callback(ssl_ctx,reinterpret_cast<int (*)()>(verify_callback),NULL);
 610         SSL_CTX_set_verify_depth(ssl_ctx,reinterpret_cast<int>(userptr));
 611 #endif
 612     }
 613 #endif
 614
 615     if (conf->m_ssl_callback && !conf->m_ssl_callback(conf, ssl_ctx, conf->m_ssl_userptr))
 616         return CURLE_SSL_CERTPROBLEM;
 617
 618     return CURLE_OK;
 619 }