libsecurity_ssl/lib/sslSession.c

   1 /*
   2  * Copyright (c) 2000-2001,2005-2008,2010-2012 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 #include "ssl.h"
  25 #include "sslContext.h"
  26 #include "sslSession.h"
  27 #include "sslMemory.h"
  28 #include "sslUtils.h"
  29 #include "sslDebug.h"
  30 #include "cipherSpecs.h"
  31 #include "appleSession.h"
  32
  33 #include <assert.h>
  34 #include <string.h>
  35 #include <stddef.h>
  36 #include <Security/SecCertificate.h>
  37 #include <Security/SecCertificatePriv.h>
  38 #include <Security/SecInternal.h>
  39
  40 typedef struct
  41 {   size_t              sessionIDLen;
  42     UInt8               sessionID[32];
  43     SSLProtocolVersion  protocolVersion;
  44     UInt16              cipherSuite;
  45         UInt16                          padding;        /* so remainder is word aligned */
  46     UInt8               masterSecret[48];
  47     size_t              certCount;
  48     UInt8               certs[1];   /* Actually, variable length */
  49 } ResumableSession;
  50
  51 /*
  52  * Cook up a (private) resumable session blob, based on the
  53  * specified ctx, store it with ctx->peerID as the key.
  54  * NOTE: This is contrary to the SSL v3 spec, which claims that
  55  * servers store resumable sessions using ctx->sessionID as the key.
  56  * I don' think this is an issue...is it?
  57  */
  58 OSStatus
  59 SSLAddSessionData(const SSLContext *ctx)
  60 {   OSStatus            err;
  61         size_t              sessionIDLen;
  62         SSLBuffer           sessionID;
  63         ResumableSession    *session;
  64         size_t              certCount;
  65 #ifdef USE_SSLCERTIFICATE
  66         SSLCertificate      *cert;
  67 #else
  68         CFArrayRef                      certChain;
  69         size_t                          ix;
  70 #endif
  71         uint8_t             *certDest;
  72
  73         /* If we don't know who the peer is, we can't store a session */
  74         if (ctx->peerID.data == 0)
  75                 return errSSLSessionNotFound;
  76
  77         sessionIDLen = offsetof(ResumableSession, certs);
  78 #ifdef USE_SSLCERTIFICATE
  79         cert = ctx->peerCert;
  80         certCount = 0;
  81         while (cert)
  82         {   ++certCount;
  83                 sessionIDLen += 4 + cert->derCert.length;
  84                 cert = cert->next;
  85         }
  86 #else
  87         certChain = ctx->peerCert;
  88         certCount = certChain ? CFArrayGetCount(certChain) : 0;
  89         for (ix = 0; ix < certCount; ++ix) {
  90                 SecCertificateRef cert = (SecCertificateRef)CFArrayGetValueAtIndex(certChain, ix);
  91                 #if SSL_DEBUG
  92                 sslDebugLog("SSLAddSessionData: got cert %d of %d\n", ix+1, certCount);
  93                 if (!cert || CFGetTypeID(cert) != SecCertificateGetTypeID()) {
  94                         sslErrorLog("SSLAddSessionData: non-cert in peerCert array!\n");
  95                 }
  96                 #endif
  97                 sessionIDLen += 4 + (size_t)SecCertificateGetLength(cert);
  98         }
  99 #endif
 100
 101         if ((err = SSLAllocBuffer(&sessionID, sessionIDLen, ctx)) != 0)
 102                 return err;
 103
 104         session = (ResumableSession*)sessionID.data;
 105
 106         session->sessionIDLen = ctx->sessionID.length;
 107         memcpy(session->sessionID, ctx->sessionID.data, session->sessionIDLen);
 108         session->protocolVersion = ctx->negProtocolVersion;
 109         session->cipherSuite = ctx->selectedCipher;
 110         memcpy(session->masterSecret, ctx->masterSecret, 48);
 111         session->certCount = certCount;
 112         session->padding = 0;
 113
 114         certDest = session->certs;
 115
 116 #ifdef USE_SSLCERTIFICATE
 117         cert = ctx->peerCert;
 118         while (cert)
 119         {   certDest = SSLEncodeInt(certDest, cert->derCert.length, 4);
 120                 memcpy(certDest, cert->derCert.data, cert->derCert.length);
 121                 certDest += cert->derCert.length;
 122                 cert = cert->next;
 123         }
 124 #else
 125         for (ix = 0; ix < certCount; ++ix) {
 126                 SecCertificateRef certRef = (SecCertificateRef)CFArrayGetValueAtIndex(certChain, ix);
 127                 size_t certLength = (size_t)SecCertificateGetLength(certRef);
 128                 const uint8_t *certBytes = SecCertificateGetBytePtr(certRef);
 129
 130                 #if SSL_DEBUG
 131                 /* print cert name when debugging; leave disabled otherwise */
 132                 CFStringRef certName = NULL;
 133                 OSStatus status = SecCertificateInferLabel(certRef, &certName);
 134                 char buf[1024];
 135                 if (!certName || !CFStringGetCString(certName, buf, 1024-1, kCFStringEncodingUTF8)) { buf[0]=0; }
 136                 sslDebugLog("SSLAddSessionData: flattening \"%s\" (%ld bytes)\n", buf, certLength);
 137                 CFReleaseSafe(certName);
 138                 #endif
 139
 140                 if (!certBytes || !certLength) {
 141                         sslErrorLog("SSLAddSessionData: invalid certificate at index %d of %d (length=%ld, data=%p)\n",
 142                                         ix, certCount-1, certLength, (const uintptr_t)certBytes);
 143                         err = paramErr; /* if we have a bad cert, don't add session to cache */
 144                 }
 145                 else {
 146                         certDest = SSLEncodeSize(certDest, certLength, 4);
 147                         memcpy(certDest, certBytes, certLength);
 148                         certDest += certLength;
 149                 }
 150         }
 151 #endif
 152
 153         if (!err) {
 154                 err = sslAddSession(ctx->peerID, sessionID, ctx->sessionCacheTimeout);
 155         }
 156         SSLFreeBuffer(&sessionID, ctx);
 157
 158         return err;
 159 }
 160
 161 /*
 162  * Retrieve resumable session data, from key ctx->peerID.
 163  */
 164 OSStatus
 165 SSLGetSessionData(SSLBuffer *sessionData, const SSLContext *ctx)
 166 {   OSStatus      err;
 167
 168     if (ctx->peerID.data == 0)
 169         return errSSLSessionNotFound;
 170
 171     sessionData->data = 0;
 172
 173     err = sslGetSession(ctx->peerID, sessionData);
 174     if (sessionData->data == 0)
 175         return errSSLSessionNotFound;
 176
 177     return err;
 178 }
 179
 180 OSStatus
 181 SSLDeleteSessionData(const SSLContext *ctx)
 182 {   OSStatus      err;
 183
 184     if (ctx->peerID.data == 0)
 185         return errSSLSessionNotFound;
 186
 187     err = sslDeleteSession(ctx->peerID);
 188     return err;
 189 }
 190
 191 /*
 192  * Given a sessionData blob, obtain the associated sessionID (NOT the key...).
 193  */
 194 OSStatus
 195 SSLRetrieveSessionID(
 196                 const SSLBuffer sessionData,
 197                 SSLBuffer *identifier,
 198                 const SSLContext *ctx)
 199 {   OSStatus            err;
 200     ResumableSession    *session;
 201
 202     session = (ResumableSession*) sessionData.data;
 203     if ((err = SSLAllocBuffer(identifier, session->sessionIDLen, ctx)) != 0)
 204         return err;
 205     memcpy(identifier->data, session->sessionID, session->sessionIDLen);
 206     return noErr;
 207 }
 208
 209 /*
 210  * Obtain the protocol version associated with a specified resumable session blob.
 211  */
 212 OSStatus
 213 SSLRetrieveSessionProtocolVersion(
 214                 const SSLBuffer sessionData,
 215                 SSLProtocolVersion *version,
 216                 const SSLContext *ctx)
 217 {   ResumableSession    *session;
 218
 219     session = (ResumableSession*) sessionData.data;
 220     *version = session->protocolVersion;
 221     return noErr;
 222 }
 223
 224 /*
 225  * Retrieve session state from specified sessionData blob, install into
 226  * ctx. Presumably, ctx->sessionID and
 227  * ctx->negProtocolVersion are already init'd (from the above two functions).
 228  */
 229
 230 /*
 231  * Netscape Enterprise Server is known to change cipherspecs upon session resumption.
 232  * For example, connecting to cdnow.com with all ciphersuites enabled results in
 233  * CipherSuite 4 (SSL_RSA_WITH_RC4_128_MD5) being selected on the first session,
 234  * and CipherSuite 10 (SSL_RSA_WITH_3DES_EDE_CBC_SHA) being selected on subsequent
 235  * sessions. This is contrary to the SSL3.0 spec, sesion 7.6.1.3, describing the
 236  * Server Hello message.
 237  *
 238  * This anomaly does not occur if only RC4 ciphers are enabled in the Client Hello
 239  * message. It also does not happen in SSL V2.
 240  */
 241 #define ALLOW_CIPHERSPEC_CHANGE         1
 242
 243 OSStatus
 244 SSLInstallSessionFromData(const SSLBuffer sessionData, SSLContext *ctx)
 245 {   OSStatus            err;
 246     ResumableSession    *session;
 247     uint8_t             *storedCertProgress;
 248 #ifdef USE_SSLCERTIFICATE
 249     SSLCertificate              *cert;
 250     SSLCertificate      *lastCert = NULL;
 251 #else
 252     SecCertificateRef   cert;
 253     CFMutableArrayRef   certChain = NULL;
 254 #endif
 255     size_t              certCount;
 256     size_t              certLen;
 257
 258     session = (ResumableSession*)sessionData.data;
 259
 260         /*
 261          * For SSLv3 and TLSv1, we know that selectedCipher has already been specified in
 262          * SSLProcessServerHello(). An SSLv2 server hello message with a session
 263          * ID hit contains no CipherKind field so we set it here.
 264          */
 265         if(ctx->negProtocolVersion == SSL_Version_2_0) {
 266                 if(ctx->protocolSide == kSSLClientSide) {
 267                         assert(ctx->selectedCipher == 0);
 268                         ctx->selectedCipher = session->cipherSuite;
 269                 }
 270                 else {
 271                         /*
 272                          * Else...what if they don't match? Could never happen, right?
 273                          * Wouldn't that mean the client is trying to switch ciphers on us?
 274                          */
 275                         if(ctx->selectedCipher != session->cipherSuite) {
 276                                 sslErrorLog("+++SSL2: CipherSpec change from %d to %d on session "
 277                                         "resume\n",
 278                                 session->cipherSuite, ctx->selectedCipher);
 279                                 return errSSLProtocol;
 280                         }
 281                 }
 282         }
 283         else {
 284                 assert(ctx->selectedCipher != 0);
 285                 if(ctx->selectedCipher != session->cipherSuite) {
 286                         #if             ALLOW_CIPHERSPEC_CHANGE
 287                         sslErrorLog("+++WARNING: CipherSpec change from %d to %d "
 288                                         "on session resume\n",
 289                                 session->cipherSuite, ctx->selectedCipher);
 290                         #else
 291                         sslErrorLog("+++SSL: CipherSpec change from %d to %d on session resume\n",
 292                                 session->cipherSuite, ctx->selectedCipher);
 293                         return errSSLProtocol;
 294                         #endif
 295                 }
 296     }
 297     if ((err = FindCipherSpec(ctx)) != 0) {
 298         return err;
 299     }
 300     memcpy(ctx->masterSecret, session->masterSecret, 48);
 301
 302     storedCertProgress = session->certs;
 303     certCount = session->certCount;
 304
 305     while (certCount--)
 306     {
 307 #ifdef USE_SSLCERTIFICATE
 308                 cert = (SSLCertificate *)sslMalloc(sizeof(SSLCertificate));
 309                 if(cert == NULL) {
 310                         return memFullErr;
 311                 }
 312         cert->next = 0;
 313         certLen = SSLDecodeInt(storedCertProgress, 4);
 314         storedCertProgress += 4;
 315         if ((err = SSLAllocBuffer(&cert->derCert, certLen, ctx)) != 0)
 316         {
 317                         sslFree(cert);
 318             return err;
 319         }
 320         memcpy(cert->derCert.data, storedCertProgress, certLen);
 321         storedCertProgress += certLen;
 322         if (lastCert == 0)
 323             ctx->peerCert = cert;
 324         else
 325             lastCert->next = cert;
 326         lastCert = cert;
 327 #else
 328         certLen = SSLDecodeInt(storedCertProgress, 4);
 329         storedCertProgress += 4;
 330                 cert = SecCertificateCreateWithBytes(NULL, storedCertProgress, certLen);
 331                 #if SSL_DEBUG
 332                 sslDebugLog("SSLInstallSessionFromData: creating cert with bytes=%p len=%lu\n",
 333                         (uintptr_t)storedCertProgress, certLen);
 334                 if (!cert || CFGetTypeID(cert) != SecCertificateGetTypeID()) {
 335                         sslErrorLog("SSLInstallSessionFromData: SecCertificateCreateWithBytes failed\n");
 336                 }
 337                 #endif
 338                 if(cert == NULL) {
 339                         return memFullErr;
 340                 }
 341         storedCertProgress += certLen;
 342                 /* @@@ This is almost the same code as in sslCert.c: SSLProcessCertificate() */
 343                 if (!certChain) {
 344                         certChain = CFArrayCreateMutable(kCFAllocatorDefault,
 345                                 session->certCount, &kCFTypeArrayCallBacks);
 346             if (!certChain) {
 347                                 CFRelease(cert);
 348                                 return memFullErr;
 349                         }
 350                         ctx->peerCert = certChain;
 351                 }
 352
 353                 CFArrayAppendValue(certChain, cert);
 354                 CFRelease(cert);
 355 #endif
 356     }
 357
 358     return noErr;
 359 }