OSX/libsecurity_ssl/lib/sslTransport.c

   1 /*
   2  * Copyright (c) 1999-2001,2005-2014 Apple Inc. All Rights Reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * sslTransport.c - SSL transport layer
  26  */
  27
  28 #include "ssl.h"
  29 #include "sslMemory.h"
  30 #include "sslContext.h"
  31 #include "sslRecord.h"
  32 #include "sslDebug.h"
  33 #include "sslCipherSpecs.h"
  34
  35 #include <assert.h>
  36 #include <string.h>
  37
  38 #include <utilities/SecIOFormat.h>
  39 #include <utilities/SecCFWrappers.h>
  40
  41 #include <CommonCrypto/CommonDigest.h>
  42 #include <Security/SecCertificatePriv.h>
  43
  44 #ifndef NDEBUG
  45 static inline void sslIoTrace(
  46     SSLContext *ctx,
  47         const char *op,
  48         size_t req,
  49         size_t moved,
  50         OSStatus stat)
  51 {
  52         sslLogRecordIo("[%p] ===%s: req %4lu moved %4lu status %d",
  53                 ctx, op, req, moved, (int)stat);
  54 }
  55 #else
  56 #define sslIoTrace(ctx, op, req, moved, stat)
  57 #endif  /* NDEBUG */
  58
  59 extern int kSplitDefaultValue;
  60
  61 static OSStatus SSLProcessProtocolMessage(SSLRecord *rec, SSLContext *ctx);
  62 static OSStatus SSLHandshakeProceed(SSLContext *ctx);
  63 static OSStatus SSLSendAlert(SSLContext *ctx, tls_alert_level_t level, tls_alert_t description);
  64
  65 OSStatus
  66 SSLWrite(
  67         SSLContext                      *ctx,
  68         const void *            data,
  69         size_t                          dataLength,
  70         size_t                          *bytesWritten)  /* RETURNED */
  71 {
  72         OSStatus        err;
  73     SSLRecord       rec;
  74     size_t          dataLen, processed;
  75
  76         sslLogRecordIo("[%p] SSLWrite top", ctx);
  77     if((ctx == NULL) || (bytesWritten == NULL)) {
  78         return errSecParam;
  79     }
  80     dataLen = dataLength;
  81     *bytesWritten = 0;
  82
  83     switch(ctx->state) {
  84         case SSL_HdskStateGracefulClose:
  85                 err = errSSLClosedGraceful;
  86                         goto abort;
  87         case SSL_HdskStateErrorClose:
  88         case SSL_HdskStateOutOfBandError:
  89                 err = errSSLClosedAbort;
  90                         goto abort;
  91             case SSL_HdskStateReady:
  92                         break;
  93         case SSL_HdskStateUninit:
  94             /* not ready for I/O, and handshake not in progress */
  95             sslIoTrace(ctx, "SSLWrite(1)", dataLength, 0, errSecBadReq);
  96             return errSecBadReq;
  97         default:
  98                         /* handshake in progress or done. Will call SSLHandshakeProceed below if necessary */
  99                         break;
 100         }
 101
 102     /* First, we have to wait until the session is ready to send data,
 103         so the encryption keys and such have been established. */
 104     while (!(ctx->writeCipher_ready))
 105     {   if ((err = SSLHandshakeProceed(ctx)) != 0)
 106             goto exit;
 107     }
 108
 109     /* Attempt to empty the write queue before queueing more data */
 110     if ((err = SSLServiceWriteQueue(ctx)) != 0)
 111         goto abort;
 112
 113     processed = 0;
 114
 115     /* Skip empty writes, fragmentation is done at the coreTLS layer */
 116     if(dataLen) {
 117         rec.contentType = SSL_RecordTypeAppData;
 118         rec.contents.data = ((uint8_t *)data) + processed;
 119         rec.contents.length = dataLen;
 120         if ((err = SSLWriteRecord(rec, ctx)) != 0)
 121             goto exit;
 122         processed += rec.contents.length;
 123     }
 124
 125     /* All the data has been advanced to the write queue */
 126     *bytesWritten = processed;
 127     if ((err = SSLServiceWriteQueue(ctx)) == 0) {
 128                 err = errSecSuccess;
 129         }
 130 exit:
 131         switch(err) {
 132                 case errSecSuccess:
 133                 case errSSLWouldBlock:
 134         case errSSLUnexpectedRecord:
 135                 case errSSLServerAuthCompleted: /* == errSSLClientAuthCompleted */
 136                 case errSSLClientCertRequested:
 137         case errSSLClientHelloReceived:
 138         case errSSLClosedGraceful:
 139             break;
 140         default:
 141             sslErrorLog("SSLWrite: going to state errorClose due to err %d\n",
 142                         (int)err);
 143             SSLChangeHdskState(ctx, SSL_HdskStateErrorClose);
 144             break;
 145     }
 146 abort:
 147         sslIoTrace(ctx, "SSLWrite(2)", dataLength, *bytesWritten, err);
 148     return err;
 149 }
 150
 151 OSStatus
 152 SSLRead (
 153         SSLContext                      *ctx,
 154         void *                          data,
 155         size_t                          dataLength,
 156         size_t                          *processed)             /* RETURNED */
 157 {
 158         OSStatus        err;
 159     uint8_t         *charPtr;
 160     size_t          bufSize, remaining, count;
 161     SSLRecord       rec;
 162
 163         sslLogRecordIo("[%p] SSLRead top (dataLength=%ld)", ctx, dataLength);
 164     if((ctx == NULL) || (data == NULL) || (processed == NULL)) {
 165         return errSecParam;
 166     }
 167     bufSize = dataLength;
 168     *processed = 0;        /* Initialize in case we return with errSSLWouldBlock */
 169
 170 readRetry:
 171         /* first handle cases in which we know we're finished */
 172         switch(ctx->state) {
 173                 case SSL_HdskStateGracefulClose:
 174                         err = errSSLClosedGraceful;
 175                         goto abort;
 176                 case SSL_HdskStateErrorClose:
 177         case SSL_HdskStateOutOfBandError:
 178                         err = errSSLClosedAbort;
 179                         goto abort;
 180                 case SSL_HdskStateNoNotifyClose:
 181                         err = errSSLClosedNoNotify;
 182                         goto abort;
 183                 default:
 184                         break;
 185         }
 186
 187     /* First, we have to wait until the session is ready to receive data,
 188         so the encryption keys and such have been established. */
 189     while (ctx->readCipher_ready == 0) {
 190                 if ((err = SSLHandshakeProceed(ctx)) != 0) {
 191             goto exit;
 192                 }
 193     }
 194
 195     /* Need this to handle the case were SSLRead returned
 196        errSSLClientHelloReceived as readCipher_ready is not set yet in that case */
 197     if ((err = tls_handshake_continue(ctx->hdsk)) != 0)
 198         return err;
 199
 200     /* Attempt to service the write queue */
 201     if ((err = SSLServiceWriteQueue(ctx)) != 0) {
 202                 if (err != errSSLWouldBlock) {
 203             goto exit;
 204                 }
 205     }
 206
 207     remaining = bufSize;
 208     charPtr = (uint8_t *)data;
 209
 210     /* If we have data in the buffer, use that first */
 211     if (ctx->receivedDataBuffer.data)
 212     {
 213         count = ctx->receivedDataBuffer.length - ctx->receivedDataPos;
 214         if (count > bufSize)
 215             count = bufSize;
 216         memcpy(data, ctx->receivedDataBuffer.data + ctx->receivedDataPos, count);
 217         remaining -= count;
 218         charPtr += count;
 219         *processed += count;
 220         ctx->receivedDataPos += count;
 221     }
 222
 223     assert(ctx->receivedDataPos <= ctx->receivedDataBuffer.length);
 224     assert(*processed + remaining == bufSize);
 225     assert(charPtr == ((uint8_t *)data) + *processed);
 226
 227     if (ctx->receivedDataBuffer.data != 0 &&
 228         ctx->receivedDataPos >= ctx->receivedDataBuffer.length)
 229     {
 230         SSLFreeBuffer(&ctx->receivedDataBuffer);
 231         ctx->receivedDataBuffer.data = 0;
 232         ctx->receivedDataPos = 0;
 233     }
 234
 235         /*
 236      * If we didnt fill up the users buffer, get some more data
 237          */
 238     if (remaining > 0 && ctx->state != SSL_HdskStateGracefulClose)
 239     {
 240         assert(ctx->receivedDataBuffer.data == 0);
 241         if ((err = SSLReadRecord(&rec, ctx)) != 0) {
 242             goto exit;
 243         }
 244         if (rec.contentType == SSL_RecordTypeAppData ||
 245             rec.contentType == SSL_RecordTypeV2_0)
 246         {
 247             if (rec.contents.length <= remaining)
 248             {   /* Copy all we got in the user's buffer */
 249                 memcpy(charPtr, rec.contents.data, rec.contents.length);
 250                 *processed += rec.contents.length;
 251                 {
 252                     if ((err = SSLFreeRecord(rec, ctx))) {
 253                         goto exit;
 254                     }
 255                 }
 256             }
 257             else
 258             {   /* Copy what we can in the user's buffer, keep the rest for next SSLRead. */
 259                 memcpy(charPtr, rec.contents.data, remaining);
 260                 *processed += remaining;
 261                 ctx->receivedDataBuffer = rec.contents;
 262                 ctx->receivedDataPos = remaining;
 263             }
 264         }
 265         else {
 266             if ((err = SSLProcessProtocolMessage(&rec, ctx)) != 0) {
 267                 /* This may not make much sense, but this is required so that we
 268                  process the write queue. This replicate exactly the behavior
 269                  before the coreTLS adoption */
 270                 if(err == errSSLClosedGraceful) {
 271                     SSLClose(ctx);
 272                 } else {
 273                     goto exit;
 274                 }
 275                         }
 276             if ((err = SSLFreeRecord(rec, ctx))) {
 277                 goto exit;
 278                         }
 279         }
 280     }
 281
 282     err = errSecSuccess;
 283
 284 exit:
 285         /* test for renegotiate: loop until something useful happens */
 286         if(((err == errSecSuccess)  && (*processed == 0) && dataLength) || (err == errSSLUnexpectedRecord)) {
 287                 sslLogNegotiateDebug("SSLRead recursion");
 288                 goto readRetry;
 289         }
 290         /* shut down on serious errors */
 291     switch(err) {
 292         case errSecSuccess:
 293         case errSSLWouldBlock:
 294         case errSSLUnexpectedRecord:
 295         case errSSLServerAuthCompleted: /* == errSSLClientAuthCompleted */
 296         case errSSLClientCertRequested:
 297         case errSSLClientHelloReceived:
 298         case errSSLClosedGraceful:
 299         case errSSLClosedNoNotify:
 300             break;
 301         default:
 302             sslErrorLog("SSLRead: going to state errorClose due to err %d\n",
 303                         (int)err);
 304             SSLChangeHdskState(ctx, SSL_HdskStateErrorClose);
 305             break;
 306     }
 307 abort:
 308         sslIoTrace(ctx, "SSLRead returns", dataLength, *processed, err);
 309     return err;
 310 }
 311
 312 #if     SSL_DEBUG
 313 #include "sslCrypto.h"
 314 #endif
 315
 316
 317
 318 static void get_extended_peer_id(SSLContext *ctx, tls_buffer *extended_peer_id)
 319 {
 320     uint8_t md[CC_SHA256_DIGEST_LENGTH];
 321     __block CC_SHA256_CTX hash_ctx;
 322
 323     CC_SHA256_Init(&hash_ctx);
 324
 325     CC_SHA256_Update(&hash_ctx, &ctx->allowAnyRoot, sizeof(ctx->allowAnyRoot));
 326
 327 #if !TARGET_OS_IPHONE
 328     if(ctx->trustedLeafCerts) {
 329         CFArrayForEach(ctx->trustedLeafCerts, ^(const void *value) {
 330             SecCertificateRef cert = (SecCertificateRef) value;
 331             CC_SHA256_Update(&hash_ctx, SecCertificateGetBytePtr(cert), (CC_LONG)SecCertificateGetLength(cert));
 332         });
 333     }
 334 #endif
 335
 336     CC_SHA256_Update(&hash_ctx, &ctx->trustedCertsOnly, sizeof(ctx->trustedCertsOnly));
 337
 338
 339     if(ctx->trustedCerts) {
 340         CFArrayForEach(ctx->trustedCerts, ^(const void *value) {
 341             SecCertificateRef cert = (SecCertificateRef) value;
 342             CC_SHA256_Update(&hash_ctx, SecCertificateGetBytePtr(cert), (CC_LONG)SecCertificateGetLength(cert));
 343         });
 344     }
 345
 346     CC_SHA256_Final(md, &hash_ctx);
 347
 348     extended_peer_id->length = ctx->peerID.length + sizeof(md);
 349     extended_peer_id->data = sslMalloc(extended_peer_id->length);
 350     memcpy(extended_peer_id->data, ctx->peerID.data, ctx->peerID.length);
 351     memcpy(extended_peer_id->data+ctx->peerID.length, md, sizeof(md));
 352 }
 353
 354 /* Send the initial client hello */
 355 static OSStatus
 356 SSLHandshakeStart(SSLContext *ctx)
 357 {
 358     int err;
 359     tls_buffer extended_peer_id;
 360     get_extended_peer_id(ctx, &extended_peer_id);
 361     err = tls_handshake_negotiate(ctx->hdsk, &extended_peer_id);
 362     free(extended_peer_id.data);
 363     if(err)
 364         return err;
 365
 366     ctx->readCipher_ready = 0;
 367     ctx->writeCipher_ready = 0;
 368     SSLChangeHdskState(ctx, SSL_HdskStatePending);
 369
 370     return noErr;
 371 }
 372
 373 OSStatus
 374 SSLReHandshake(SSLContext *ctx)
 375 {
 376     if(ctx == NULL) {
 377         return errSecParam;
 378     }
 379
 380     switch (ctx->state) {
 381         case SSL_HdskStateGracefulClose:
 382             return errSSLClosedGraceful;
 383         case SSL_HdskStateErrorClose:
 384         case SSL_HdskStateOutOfBandError:
 385             return errSSLClosedAbort;
 386         case SSL_HdskStatePending:
 387             return errSecBadReq;
 388         default:
 389             break;
 390     }
 391
 392     /* If we are the client, we start the negotiation */
 393     if(ctx->protocolSide == kSSLClientSide) {
 394         return SSLHandshakeStart(ctx);
 395     } else {
 396         return tls_handshake_request_renegotiation(ctx->hdsk);
 397     }
 398 }
 399
 400 OSStatus
 401 SSLHandshake(SSLContext *ctx)
 402 {
 403         OSStatus  err;
 404
 405         if(ctx == NULL) {
 406                 return errSecParam;
 407         }
 408
 409     switch (ctx->state) {
 410         case SSL_HdskStateGracefulClose:
 411             return errSSLClosedGraceful;
 412         case SSL_HdskStateErrorClose:
 413             return errSSLClosedAbort;
 414         default:
 415             break;
 416     }
 417
 418     if(ctx->isDTLS && ctx->timeout_deadline) {
 419         CFAbsoluteTime current = CFAbsoluteTimeGetCurrent();
 420
 421         if (ctx->timeout_deadline<current) {
 422             sslDebugLog("%p, retransmition deadline expired\n", ctx);
 423             err = tls_handshake_retransmit_timer_expired(ctx->hdsk);
 424             if(err) {
 425                 return err;
 426             }
 427         }
 428     }
 429
 430     /* Initial Client Hello */
 431     if(ctx->state==SSL_HdskStateUninit) {
 432         /* If we are the client, we start the negotiation */
 433         if(ctx->protocolSide == kSSLClientSide) {
 434             err = SSLHandshakeStart(ctx);
 435             if(err) {
 436                 return err;
 437             }
 438         }
 439         SSLChangeHdskState(ctx, SSL_HdskStatePending);
 440     }
 441
 442     /* If an out-of-band error occurred, handle it here and then terminate
 443      the connection as needed. */
 444     if (ctx->state == SSL_HdskStateOutOfBandError) {
 445         bool shouldClose = true;
 446         switch (ctx->outOfBandError) {
 447             case errSecCertificateExpired:
 448                 SSLSendAlert(ctx, tls_handshake_alert_level_fatal, tls_handshake_alert_CertExpired);
 449                 break;
 450             case errSecCertificateRevoked:
 451                 SSLSendAlert(ctx, tls_handshake_alert_level_fatal, tls_handshake_alert_CertRevoked);
 452                 break;
 453             default:
 454                 shouldClose = false;
 455                 break;
 456         }
 457
 458         if (shouldClose) {
 459             return SSLClose(ctx);
 460         }
 461     }
 462
 463     do {
 464         err = SSLHandshakeProceed(ctx);
 465         if((err != 0) && (err != errSSLUnexpectedRecord))
 466             return err;
 467     } while (ctx->readCipher_ready == 0 || ctx->writeCipher_ready == 0);
 468
 469         /* one more flush at completion of successful handshake */
 470     if ((err = SSLServiceWriteQueue(ctx)) != 0) {
 471                 return err;
 472         }
 473
 474     return errSecSuccess;
 475 }
 476
 477 #if (TARGET_OS_IPHONE && !TARGET_IPHONE_SIMULATOR)
 478
 479 #include "SecADWrapper.h"
 480
 481 static void ad_log_SecureTransport_early_fail(long signature)
 482 {
 483     CFStringRef key = CFStringCreateWithFormat(kCFAllocatorDefault, NULL, CFSTR("com.apple.SecureTransport.early_fail.%ld"), signature);
 484
 485     if (key) {
 486         SecADAddValueForScalarKey(key, 1);
 487         CFRelease(key);
 488     }
 489 }
 490
 491 #endif
 492
 493
 494 #if (!TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
 495
 496 #include <msgtracer_client.h>
 497
 498 static void mt_log_SecureTransport_early_fail(long signature)
 499 {
 500     char signature_string[16];
 501
 502     snprintf(signature_string, sizeof(signature_string), "%ld", signature);
 503
 504     msgtracer_log_with_keys("com.apple.SecureTransport.early_fail", ASL_LEVEL_NOTICE,
 505                             "com.apple.message.signature", signature_string,
 506                             "com.apple.message.summarize", "YES",
 507                             NULL);
 508 }
 509
 510 #endif
 511
 512
 513 static void log_SecureTransport_early_fail(long signature)
 514 {
 515 #if (!TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
 516     mt_log_SecureTransport_early_fail(signature);
 517 #endif
 518
 519 #if (TARGET_OS_IPHONE && !TARGET_OS_SIMULATOR)
 520     ad_log_SecureTransport_early_fail(signature);
 521 #endif
 522 }
 523
 524
 525 static OSStatus
 526 SSLHandshakeProceed(SSLContext *ctx)
 527 {
 528     OSStatus  err;
 529
 530     if ((err = tls_handshake_continue(ctx->hdsk)) != 0)
 531         return err;
 532
 533     if ((err = SSLServiceWriteQueue(ctx)) != 0)
 534         return err;
 535
 536     SSLRecord rec;
 537
 538     err = SSLReadRecord(&rec, ctx);
 539
 540     if(!err) {
 541         sslDebugLog("%p going to process a record (rec.len=%zd, ct=%d)\n", ctx, rec.contents.length, rec.contentType);
 542         err = tls_handshake_process(ctx->hdsk, rec.contents, rec.contentType);
 543         sslDebugLog("%p processed a record (rec.len=%zd, ct=%d, err=%d)\n", ctx, rec.contents.length, rec.contentType, (int)err);
 544         SSLFreeRecord(rec, ctx);
 545     } else if(err!=errSSLWouldBlock) {
 546         sslDebugLog("%p Read error err=%d\n\n", ctx, (int)err);
 547     }
 548
 549     if(ctx->protocolSide == kSSLClientSide &&
 550        ctx->dheEnabled == false &&
 551        !ctx->serverHelloReceived &&
 552        err && err != errSSLWouldBlock)
 553     {
 554         log_SecureTransport_early_fail(err);
 555     }
 556
 557     return err;
 558 }
 559
 560 static OSStatus
 561 SSLProcessProtocolMessage(SSLRecord *rec, SSLContext *ctx)
 562 {
 563     return tls_handshake_process(ctx->hdsk, rec->contents, rec->contentType);
 564 }
 565
 566 OSStatus
 567 SSLClose(SSLContext *ctx)
 568 {
 569         OSStatus      err = errSecSuccess;
 570
 571         sslHdskStateDebug("SSLClose");
 572         if(ctx == NULL) {
 573                 return errSecParam;
 574         }
 575
 576     err = tls_handshake_close(ctx->hdsk);
 577
 578     if (err == 0)
 579         err = SSLServiceWriteQueue(ctx);
 580
 581     SSLChangeHdskState(ctx, SSL_HdskStateGracefulClose);
 582     if (err == errSecIO)
 583         err = errSecSuccess;     /* Ignore errors related to closed streams */
 584     return err;
 585 }
 586
 587 static OSStatus
 588 SSLSendAlert(SSLContext *ctx, tls_alert_level_t alertLevel, tls_alert_t alert)
 589 {
 590     sslHdskStateDebug("SSLSendAlert");
 591     if (ctx == NULL) {
 592         return errSecParam;
 593     }
 594
 595     return tls_handshake_send_alert(ctx->hdsk, alertLevel, alert);
 596 }
 597
 598 OSStatus
 599 SSLSetError(SSLContext *ctx, OSStatus error)
 600 {
 601     ctx->state = SSL_HdskStateOutOfBandError;
 602     ctx->outOfBandError = error;
 603     return errSecSuccess;
 604 }
 605
 606 /*
 607  * Determine how much data the client can be guaranteed to
 608  * obtain via SSLRead() without blocking or causing any low-level
 609  * read operations to occur.
 610  *
 611  * Implemented here because the relevant info in SSLContext (receivedDataBuffer
 612  * and receivedDataPos) are only used in this file.
 613  */
 614 OSStatus
 615 SSLGetBufferedReadSize(SSLContextRef ctx,
 616         size_t *bufSize)                        /* RETURNED */
 617 {
 618         if(ctx == NULL) {
 619                 return errSecParam;
 620         }
 621         if(ctx->receivedDataBuffer.data == NULL) {
 622                 *bufSize = 0;
 623         }
 624         else {
 625                 assert(ctx->receivedDataBuffer.length >= ctx->receivedDataPos);
 626                 *bufSize = ctx->receivedDataBuffer.length - ctx->receivedDataPos;
 627         }
 628         return errSecSuccess;
 629 }