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 "sslCipherSpecs.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 "utilities/SecCFRelease.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", (int)ix+1, (int)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)))
 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 && !TARGET_OS_IPHONE
 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 (status || !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                                         (int)ix, (int)certCount-1, certLength, certBytes);
 143                         err = errSecParam; /* 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     err = sslAddSession(ctx->peerID, sessionID, ctx->sessionCacheTimeout);
 154     SSLFreeBuffer(&sessionID);
 155
 156         return err;
 157 }
 158
 159 /*
 160  * Retrieve resumable session data, from key ctx->peerID.
 161  */
 162 OSStatus
 163 SSLGetSessionData(SSLBuffer *sessionData, const SSLContext *ctx)
 164 {   OSStatus      err;
 165
 166     if (ctx->peerID.data == 0)
 167         return errSSLSessionNotFound;
 168
 169     sessionData->data = 0;
 170
 171     err = sslGetSession(ctx->peerID, sessionData);
 172     if (sessionData->data == 0)
 173         return errSSLSessionNotFound;
 174
 175     return err;
 176 }
 177
 178 OSStatus
 179 SSLDeleteSessionData(const SSLContext *ctx)
 180 {   OSStatus      err;
 181
 182     if (ctx->peerID.data == 0)
 183         return errSSLSessionNotFound;
 184
 185     err = sslDeleteSession(ctx->peerID);
 186     return err;
 187 }
 188
 189 /*
 190  * Given a sessionData blob, obtain the associated sessionID (NOT the key...).
 191  */
 192 OSStatus
 193 SSLRetrieveSessionID(
 194                 const SSLBuffer sessionData,
 195                 SSLBuffer *identifier,
 196                 const SSLContext *ctx)
 197 {   OSStatus            err;
 198     ResumableSession    *session;
 199
 200     session = (ResumableSession*) sessionData.data;
 201     if ((err = SSLAllocBuffer(identifier, session->sessionIDLen)))
 202         return err;
 203     memcpy(identifier->data, session->sessionID, session->sessionIDLen);
 204     return errSecSuccess;
 205 }
 206
 207 /*
 208  * Obtain the protocol version associated with a specified resumable session blob.
 209  */
 210 OSStatus
 211 SSLRetrieveSessionProtocolVersion(
 212                 const SSLBuffer sessionData,
 213                 SSLProtocolVersion *version,
 214                 const SSLContext *ctx)
 215 {   ResumableSession    *session;
 216
 217     session = (ResumableSession*) sessionData.data;
 218     *version = session->protocolVersion;
 219     return errSecSuccess;
 220 }
 221
 222 /*
 223  * Retrieve session state from specified sessionData blob, install into
 224  * ctx. Presumably, ctx->sessionID and
 225  * ctx->negProtocolVersion are already init'd (from the above two functions).
 226  */
 227
 228 /*
 229  * Netscape Enterprise Server is known to change cipherspecs upon session resumption.
 230  * For example, connecting to cdnow.com with all ciphersuites enabled results in
 231  * CipherSuite 4 (SSL_RSA_WITH_RC4_128_MD5) being selected on the first session,
 232  * and CipherSuite 10 (SSL_RSA_WITH_3DES_EDE_CBC_SHA) being selected on subsequent
 233  * sessions. This is contrary to the SSL3.0 spec, sesion 7.6.1.3, describing the
 234  * Server Hello message.
 235  *
 236  * This anomaly does not occur if only RC4 ciphers are enabled in the Client Hello
 237  * message. It also does not happen in SSL V2.
 238  */
 239 #define ALLOW_CIPHERSPEC_CHANGE         1
 240
 241 OSStatus
 242 SSLInstallSessionFromData(const SSLBuffer sessionData, SSLContext *ctx)
 243 {   OSStatus            err;
 244     ResumableSession    *session;
 245     uint8_t             *storedCertProgress;
 246 #ifdef USE_SSLCERTIFICATE
 247     SSLCertificate              *cert;
 248     SSLCertificate      *lastCert = NULL;
 249 #else
 250     SecCertificateRef   cert;
 251     CFMutableArrayRef   certChain = NULL;
 252 #endif
 253     size_t              certCount;
 254     size_t              certLen;
 255
 256     session = (ResumableSession*)sessionData.data;
 257
 258         /*
 259          * For SSLv3 and TLSv1, we know that selectedCipher has already been specified in
 260          * SSLProcessServerHello(). An SSLv2 server hello message with a session
 261          * ID hit contains no CipherKind field so we set it here.
 262          */
 263         if(ctx->negProtocolVersion == SSL_Version_2_0) {
 264                 if(ctx->protocolSide == kSSLClientSide) {
 265                         assert(ctx->selectedCipher == 0);
 266                         ctx->selectedCipher = session->cipherSuite;
 267                 }
 268                 else {
 269                         /*
 270                          * Else...what if they don't match? Could never happen, right?
 271                          * Wouldn't that mean the client is trying to switch ciphers on us?
 272                          */
 273                         if(ctx->selectedCipher != session->cipherSuite) {
 274                                 sslErrorLog("+++SSL2: CipherSpec change from %d to %d on session "
 275                                         "resume\n",
 276                                 session->cipherSuite, ctx->selectedCipher);
 277                                 return errSSLProtocol;
 278                         }
 279                 }
 280         }
 281         else {
 282                 assert(ctx->selectedCipher != 0);
 283                 if(ctx->selectedCipher != session->cipherSuite) {
 284                         #if             ALLOW_CIPHERSPEC_CHANGE
 285                         sslErrorLog("+++WARNING: CipherSpec change from %d to %d "
 286                                         "on session resume\n",
 287                                 session->cipherSuite, ctx->selectedCipher);
 288                         #else
 289                         sslErrorLog("+++SSL: CipherSpec change from %d to %d on session resume\n",
 290                                 session->cipherSuite, ctx->selectedCipher);
 291                         return errSSLProtocol;
 292                         #endif
 293                 }
 294     }
 295     if ((err = FindCipherSpec(ctx)) != 0) {
 296         return err;
 297     }
 298     memcpy(ctx->masterSecret, session->masterSecret, 48);
 299
 300     storedCertProgress = session->certs;
 301     certCount = session->certCount;
 302
 303     while (certCount--)
 304     {
 305 #ifdef USE_SSLCERTIFICATE
 306                 cert = (SSLCertificate *)sslMalloc(sizeof(SSLCertificate));
 307                 if(cert == NULL) {
 308                         return errSecAllocate;
 309                 }
 310         cert->next = 0;
 311         certLen = SSLDecodeInt(storedCertProgress, 4);
 312         storedCertProgress += 4;
 313         if ((err = SSLAllocBuffer(&cert->derCert, certLen)
 314         {
 315                         sslFree(cert);
 316             return err;
 317         }
 318         memcpy(cert->derCert.data, storedCertProgress, certLen);
 319         storedCertProgress += certLen;
 320         if (lastCert == 0)
 321             ctx->peerCert = cert;
 322         else
 323             lastCert->next = cert;
 324         lastCert = cert;
 325 #else
 326         certLen = SSLDecodeInt(storedCertProgress, 4);
 327         storedCertProgress += 4;
 328                 cert = SecCertificateCreateWithBytes(NULL, storedCertProgress, certLen);
 329                 #if SSL_DEBUG
 330                 sslDebugLog("SSLInstallSessionFromData: creating cert with bytes=%p len=%lu\n",
 331                         storedCertProgress, certLen);
 332                 if (!cert || CFGetTypeID(cert) != SecCertificateGetTypeID()) {
 333                         sslErrorLog("SSLInstallSessionFromData: SecCertificateCreateWithBytes failed\n");
 334                 }
 335                 #endif
 336                 if(cert == NULL) {
 337                         return errSecAllocate;
 338                 }
 339         storedCertProgress += certLen;
 340                 /* @@@ This is almost the same code as in sslCert.c: SSLProcessCertificate() */
 341                 if (!certChain) {
 342                         certChain = CFArrayCreateMutable(kCFAllocatorDefault,
 343                                 session->certCount, &kCFTypeArrayCallBacks);
 344             if (!certChain) {
 345                                 CFRelease(cert);
 346                                 return errSecAllocate;
 347                         }
 348             if (ctx->peerCert) {
 349                                 sslDebugLog("SSLInstallSessionFromData: releasing existing cert chain\n");
 350                                 CFRelease(ctx->peerCert);
 351                         }
 352                         ctx->peerCert = certChain;
 353                 }
 354
 355                 CFArrayAppendValue(certChain, cert);
 356                 CFRelease(cert);
 357 #endif
 358     }
 359
 360     return errSecSuccess;
 361 }