OSX/libsecurity_ssl/Security/SSLRecordInternal.c

   1 /*
   2  * Copyright (c) 2011-2014 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 /* THIS FILE CONTAINS KERNEL CODE */
  26
  27 #include "sslBuildFlags.h"
  28 #include "SSLRecordInternal.h"
  29 #include "sslDebug.h"
  30 #include "cipherSpecs.h"
  31 #include "sslUtils.h"
  32 #include "tls_record_internal.h"
  33
  34 #include <AssertMacros.h>
  35 #include <string.h>
  36
  37 #include <inttypes.h>
  38 #include <stddef.h>
  39
  40 /* Maximum encrypted record size, defined in TLS 1.2 RFC, section 6.2.3 */
  41 #define DEFAULT_BUFFER_SIZE (16384 + 2048)
  42
  43
  44 /*
  45  * Redirect SSLBuffer-based I/O call to user-supplied I/O.
  46  */
  47 static
  48 int sslIoRead(SSLBuffer                        buf,
  49               size_t                           *actualLength,
  50               struct SSLRecordInternalContext  *ctx)
  51 {
  52         int     ortn;
  53     SSLContextRef sslCtx = ctx->sslCtx;
  54
  55         *actualLength = buf.length;
  56
  57     ortn = sslCtx->ioCtx.read(sslCtx->ioCtx.ioRef, buf.data, actualLength);
  58
  59     /* We may need to translate error codes at this layer */
  60     if(ortn==errSSLWouldBlock) {
  61         ortn=errSSLRecordWouldBlock;
  62     }
  63
  64     sslLogRecordIo("sslIoRead: [%p] req %4lu actual %4lu status %d",
  65                    ctx, buf.length, *actualLength, (int)ortn);
  66
  67         return ortn;
  68 }
  69
  70 static
  71 int sslIoWrite(SSLBuffer                       buf,
  72                size_t                          *actualLength,
  73                struct SSLRecordInternalContext *ctx)
  74 {
  75         int     ortn;
  76     SSLContextRef sslCtx = ctx->sslCtx;
  77
  78         *actualLength = buf.length;
  79
  80     ortn = sslCtx->ioCtx.write(sslCtx->ioCtx.ioRef, buf.data, actualLength);
  81
  82     /* We may need to translate error codes at this layer */
  83     if(ortn==errSSLWouldBlock) {
  84         ortn=errSSLRecordWouldBlock;
  85     }
  86
  87     sslLogRecordIo("sslIoWrite: [%p] req %4lu actual %4lu status %d",
  88                    ctx, buf.length, *actualLength, (int)ortn);
  89
  90         return ortn;
  91 }
  92
  93 /* Entry points to Record Layer */
  94
  95 static int SSLRecordReadInternal(SSLRecordContextRef ref, SSLRecord *rec)
  96 {
  97     struct SSLRecordInternalContext *ctx = ref;
  98
  99     int     err;
 100     size_t  len, contentLen;
 101     SSLBuffer readData;
 102
 103     size_t head=tls_record_get_header_size(ctx->filter);
 104
 105     if (ctx->amountRead < head)
 106     {
 107         readData.length = head - ctx->amountRead;
 108         readData.data = ctx->partialReadBuffer.data + ctx->amountRead;
 109         len = readData.length;
 110         err = sslIoRead(readData, &len, ctx);
 111         if(err != 0)
 112         {
 113             switch(err) {
 114                 case errSSLRecordWouldBlock:
 115                     ctx->amountRead += len;
 116                     break;
 117                 default:
 118                     /* Any other error but errSSLWouldBlock is  translated to errSSLRecordClosedAbort */
 119                     err = errSSLRecordClosedAbort;
 120                     break;
 121             }
 122             return err;
 123         }
 124         ctx->amountRead += len;
 125
 126         check(ctx->amountRead == head);
 127     }
 128
 129
 130     tls_buffer header;
 131     header.data=ctx->partialReadBuffer.data;
 132     header.length=head;
 133
 134     uint8_t content_type;
 135
 136     tls_record_parse_header(ctx->filter, header, &contentLen, &content_type);
 137
 138     if(content_type&0x80) {
 139         // Looks like SSL2 record, reset expectations.
 140         head = 2;
 141         err=tls_record_parse_ssl2_header(ctx->filter, header, &contentLen, &content_type);
 142         if(err!=0) return errSSLRecordUnexpectedRecord;
 143     }
 144
 145     check(ctx->partialReadBuffer.length>=head+contentLen);
 146
 147     if(head+contentLen>ctx->partialReadBuffer.length)
 148         return errSSLRecordRecordOverflow;
 149
 150     if (ctx->amountRead < head + contentLen)
 151     {   readData.length = head + contentLen - ctx->amountRead;
 152         readData.data = ctx->partialReadBuffer.data + ctx->amountRead;
 153         len = readData.length;
 154         err = sslIoRead(readData, &len, ctx);
 155         if(err != 0)
 156         {   if (err == errSSLRecordWouldBlock)
 157             ctx->amountRead += len;
 158             return err;
 159         }
 160         ctx->amountRead += len;
 161     }
 162
 163     check(ctx->amountRead == head + contentLen);
 164
 165     tls_buffer record;
 166     record.data = ctx->partialReadBuffer.data;
 167     record.length = ctx->amountRead;
 168
 169     rec->contentType = content_type;
 170
 171     ctx->amountRead = 0;        /* We've used all the data in the cache */
 172
 173     if(content_type==tls_record_type_SSL2) {
 174         /* Just copy the SSL2 record, dont decrypt since this is only for SSL2 Client Hello */
 175         return SSLCopyBuffer(&record, &rec->contents);
 176     } else {
 177         size_t sz = tls_record_decrypted_size(ctx->filter, record.length);
 178
 179         /* There was an underflow - For TLS, we return errSSLRecordClosedAbort for historical reason - see ssl-44-crashes test */
 180         if(sz==0) {
 181             sslErrorLog("underflow in SSLReadRecordInternal");
 182             if(ctx->dtls) {
 183                 // For DTLS, we should just drop it.
 184                 return errSSLRecordUnexpectedRecord;
 185             } else {
 186                 // For TLS, we are going to close the connection.
 187                 return errSSLRecordClosedAbort;
 188             }
 189         }
 190
 191         /* Allocate a buffer for the plaintext */
 192         if ((err = SSLAllocBuffer(&rec->contents, sz)))
 193         {
 194             return err;
 195         }
 196
 197         return tls_record_decrypt(ctx->filter, record, &rec->contents, NULL);
 198     }
 199 }
 200
 201 static int SSLRecordWriteInternal(SSLRecordContextRef ref, SSLRecord rec)
 202 {
 203     int err;
 204     struct SSLRecordInternalContext *ctx = ref;
 205     WaitingRecord *queue, *out;
 206     tls_buffer data;
 207     tls_buffer content;
 208     size_t len;
 209
 210     err = errSSLRecordInternal; /* FIXME: allocation error */
 211     len=tls_record_encrypted_size(ctx->filter, rec.contentType, rec.contents.length);
 212
 213     require((out = (WaitingRecord *)sslMalloc(offsetof(WaitingRecord, data) + len)), fail);
 214     out->next = NULL;
 215         out->sent = 0;
 216         out->length = len;
 217
 218     data.data=&out->data[0];
 219     data.length=out->length;
 220
 221     content.data = rec.contents.data;
 222     content.length = rec.contents.length;
 223
 224     require_noerr((err=tls_record_encrypt(ctx->filter, content, rec.contentType, &data)), fail);
 225
 226     out->length = data.length; // This should not be needed if tls_record_encrypted_size works properly.
 227
 228     /* Enqueue the record to be written from the idle loop */
 229     if (ctx->recordWriteQueue == 0)
 230         ctx->recordWriteQueue = out;
 231     else
 232     {   queue = ctx->recordWriteQueue;
 233         while (queue->next != 0)
 234             queue = queue->next;
 235         queue->next = out;
 236     }
 237
 238     return 0;
 239 fail:
 240     if(out)
 241         sslFree(out);
 242     return err;
 243 }
 244
 245 /* Record Layer Entry Points */
 246
 247 static int
 248 SSLRollbackInternalRecordLayerWriteCipher(SSLRecordContextRef ref)
 249 {
 250     struct SSLRecordInternalContext *ctx = ref;
 251     return tls_record_rollback_write_cipher(ctx->filter);
 252 }
 253
 254 static int
 255 SSLAdvanceInternalRecordLayerWriteCipher(SSLRecordContextRef ref)
 256 {
 257     struct SSLRecordInternalContext *ctx = ref;
 258     return tls_record_advance_write_cipher(ctx->filter);
 259 }
 260
 261 static int
 262 SSLAdvanceInternalRecordLayerReadCipher(SSLRecordContextRef ref)
 263 {
 264     struct SSLRecordInternalContext *ctx = ref;
 265     return tls_record_advance_read_cipher(ctx->filter);
 266 }
 267
 268 static int
 269 SSLInitInternalRecordLayerPendingCiphers(SSLRecordContextRef ref, uint16_t selectedCipher, bool isServer, SSLBuffer key)
 270 {
 271     struct SSLRecordInternalContext *ctx = ref;
 272     return tls_record_init_pending_ciphers(ctx->filter, selectedCipher, isServer, key);
 273 }
 274
 275 static int
 276 SSLSetInternalRecordLayerProtocolVersion(SSLRecordContextRef ref, SSLProtocolVersion negVersion)
 277 {
 278     struct SSLRecordInternalContext *ctx = ref;
 279     return tls_record_set_protocol_version(ctx->filter, negVersion);
 280 }
 281
 282 static int
 283 SSLRecordFreeInternal(SSLRecordContextRef ref, SSLRecord rec)
 284 {
 285     return SSLFreeBuffer(&rec.contents);
 286 }
 287
 288 static int
 289 SSLRecordServiceWriteQueueInternal(SSLRecordContextRef ref)
 290 {
 291     int             werr = 0;
 292     size_t          written = 0;
 293     SSLBuffer       buf;
 294     WaitingRecord   *rec;
 295     struct SSLRecordInternalContext *ctx= ref;
 296
 297     while (!werr && ((rec = ctx->recordWriteQueue) != 0))
 298     {   buf.data = rec->data + rec->sent;
 299         buf.length = rec->length - rec->sent;
 300         werr = sslIoWrite(buf, &written, ctx);
 301         rec->sent += written;
 302         if (rec->sent >= rec->length)
 303         {
 304             check(rec->sent == rec->length);
 305             ctx->recordWriteQueue = rec->next;
 306                         sslFree(rec);
 307         }
 308     }
 309
 310     return werr;
 311 }
 312
 313 static int
 314 SSLRecordSetOption(SSLRecordContextRef ref, SSLRecordOption option, bool value)
 315 {
 316     struct SSLRecordInternalContext *ctx = (struct SSLRecordInternalContext *)ref;
 317     switch (option) {
 318         case kSSLRecordOptionSendOneByteRecord:
 319             return tls_record_set_record_splitting(ctx->filter, value);
 320             break;
 321         default:
 322             return 0;
 323             break;
 324     }
 325 }
 326
 327 /***** Internal Record Layer APIs *****/
 328
 329 #include <CommonCrypto/CommonRandomSPI.h>
 330 #define CCRNGSTATE ccDRBGGetRngState()
 331
 332 SSLRecordContextRef
 333 SSLCreateInternalRecordLayer(SSLContextRef sslCtx)
 334 {
 335     struct SSLRecordInternalContext *ctx;
 336
 337     ctx = sslMalloc(sizeof(struct SSLRecordInternalContext));
 338     if(ctx==NULL)
 339         return NULL;
 340
 341     memset(ctx, 0, sizeof(struct SSLRecordInternalContext));
 342
 343     require((ctx->filter=tls_record_create(sslCtx->isDTLS, CCRNGSTATE)), fail);
 344     require_noerr(SSLAllocBuffer(&ctx->partialReadBuffer,
 345                                  DEFAULT_BUFFER_SIZE), fail);
 346
 347     ctx->sslCtx = sslCtx;
 348     return ctx;
 349
 350 fail:
 351     if(ctx->filter)
 352         tls_record_destroy(ctx->filter);
 353     sslFree(ctx);
 354     return NULL;
 355 }
 356
 357 void
 358 SSLDestroyInternalRecordLayer(SSLRecordContextRef ref)
 359 {
 360     struct SSLRecordInternalContext *ctx = ref;
 361         WaitingRecord   *waitRecord, *next;
 362
 363     /* RecordContext cleanup : */
 364     SSLFreeBuffer(&ctx->partialReadBuffer);
 365     waitRecord = ctx->recordWriteQueue;
 366     while (waitRecord)
 367     {   next = waitRecord->next;
 368         sslFree(waitRecord);
 369         waitRecord = next;
 370     }
 371
 372     if(ctx->filter)
 373         tls_record_destroy(ctx->filter);
 374
 375     sslFree(ctx);
 376
 377 }
 378
 379 struct SSLRecordFuncs SSLRecordLayerInternal =
 380 {
 381     .read  = SSLRecordReadInternal,
 382     .write = SSLRecordWriteInternal,
 383     .initPendingCiphers = SSLInitInternalRecordLayerPendingCiphers,
 384     .advanceWriteCipher = SSLAdvanceInternalRecordLayerWriteCipher,
 385     .advanceReadCipher = SSLAdvanceInternalRecordLayerReadCipher,
 386     .rollbackWriteCipher = SSLRollbackInternalRecordLayerWriteCipher,
 387     .setProtocolVersion = SSLSetInternalRecordLayerProtocolVersion,
 388     .free = SSLRecordFreeInternal,
 389     .serviceWriteQueue = SSLRecordServiceWriteQueueInternal,
 390     .setOption = SSLRecordSetOption,
 391 };
 392