--- /dev/null
+//
+// SecOTRSession.c
+// libsecurity_libSecOTR
+//
+// Created by Mitch Adler on 2/22/11.
+// Copyright 2011 Apple Inc. All rights reserved.
+//
+
+#include "SecOTRSession.h"
+
+#include "SecOTRMath.h"
+#include "SecOTRDHKey.h"
+#include "SecOTRSessionPriv.h"
+#include "SecOTRPackets.h"
+#include "SecOTRPacketData.h"
+
+#include <utilities/SecCFWrappers.h>
+
+#include <CoreFoundation/CFRuntime.h>
+#include <CoreFoundation/CFString.h>
+
+#include <Security/SecBasePriv.h>
+#include <Security/SecRandom.h>
+#include <Security/SecBase64.h>
+
+#include <AssertMacros.h>
+
+#ifdef USECOMMONCRYPTO
+#include <CommonCrypto/CommonHMAC.h>
+#endif
+
+#include <corecrypto/cchmac.h>
+#include <corecrypto/ccsha2.h>
+#include <corecrypto/ccsha1.h>
+
+#include <string.h>
+#include <stdlib.h>
+
+#include <syslog.h>
+
+#include "utilities/comparison.h"
+
+CFGiblisFor(SecOTRSession);
+
+static OTRMessageType SecOTRSGetMessageType(CFDataRef message)
+{
+ OTRMessageType type = kInvalidMessage;
+
+ CFMutableDataRef decodedBytes = CFDataCreateMutable(kCFAllocatorDefault, 0);
+ SecOTRGetIncomingBytes(message, decodedBytes);
+
+ const uint8_t *bytes = CFDataGetBytePtr(decodedBytes);
+ size_t size = CFDataGetLength(decodedBytes);
+
+ require_noerr(ReadHeader(&bytes, &size, &type), fail);
+
+fail:
+ CFReleaseNull(decodedBytes);
+
+ return type;
+}
+
+const char *SecOTRPacketTypeString(CFDataRef message)
+{
+ if (!message) return "NoMessage";
+ switch (SecOTRSGetMessageType(message)) {
+ case kDHMessage: return "DHMessage (0x02)";
+ case kDataMessage: return "DataMessage (0x03)";
+ case kDHKeyMessage: return "DHKeyMessage (0x0A)";
+ case kRevealSignatureMessage: return "RevealSignatureMessage (0x11)";
+ case kSignatureMessage: return "SignatureMessage (0x12)";
+ case kInvalidMessage: return "InvalidMessage (0xFF)";
+ default: return "UnknownMessage";
+ }
+}
+
+static const char *SecOTRAuthStateString(SecOTRAuthState authState)
+{
+ switch (authState) {
+ case kIdle: return "Idle";
+ case kAwaitingDHKey: return "AwaitingDHKey";
+ case kAwaitingRevealSignature: return "AwaitingRevealSignature";
+ case kAwaitingSignature: return "AwaitingSignature";
+ case kDone: return "Done";
+ default: return "InvalidState";
+ }
+}
+
+static CF_RETURNS_RETAINED CFStringRef SecOTRSessionCopyDescription(CFTypeRef cf) {
+ SecOTRSessionRef session = (SecOTRSessionRef)cf;
+ return CFStringCreateWithFormat(kCFAllocatorDefault,NULL,CFSTR("<%s %s%s%s%s %d:%d %s%s>"),
+ SecOTRAuthStateString(session->_state),
+ session->_me ? "F" : "-",
+ session->_them ? "P" : "-",
+ session->_receivedDHMessage ? "D" : "-",
+ session->_receivedDHKeyMessage ? "K" : "-",
+ session->_keyID,
+ session->_theirKeyID,
+ session->_theirPreviousKey ? "P" : "-",
+ session->_theirKey ? "T" : "-");
+}
+
+static void SecOTRSessionDestroy(CFTypeRef cf) {
+ SecOTRSessionRef session = (SecOTRSessionRef)cf;
+
+ CFReleaseNull(session->_receivedDHMessage);
+ CFReleaseNull(session->_receivedDHKeyMessage);
+
+ CFReleaseNull(session->_me);
+ CFReleaseNull(session->_myKey);
+ CFReleaseNull(session->_myNextKey);
+
+ CFReleaseNull(session->_them);
+ CFReleaseNull(session->_theirKey);
+ CFReleaseNull(session->_theirPreviousKey);
+
+ CFReleaseNull(session->_macKeysToExpose);
+
+ dispatch_release(session->_queue);
+}
+
+static void SecOTRSessionResetInternal(SecOTRSessionRef session)
+{
+ session->_state = kIdle;
+
+ CFReleaseNull(session->_receivedDHMessage);
+ CFReleaseNull(session->_receivedDHKeyMessage);
+
+ session->_keyID = 0;
+ CFReleaseNull(session->_myKey);
+ CFReleaseNull(session->_myNextKey);
+ //session->_myNextKey = SecOTRFullDHKCreate(kCFAllocatorDefault);
+ session->_theirKeyID = 0;
+ CFReleaseNull(session->_theirKey);
+ CFReleaseNull(session->_theirPreviousKey);
+ CFReleaseNull(session->_macKeysToExpose);
+ session->_macKeysToExpose = CFDataCreateMutable(kCFAllocatorDefault, 0);
+
+ bzero(session->_keyCache, sizeof(session->_keyCache));
+}
+
+void SecOTRSessionReset(SecOTRSessionRef session)
+{
+ dispatch_sync_f(session->_queue, session, (dispatch_function_t) SecOTRSessionResetInternal);
+}
+
+
+SecOTRSessionRef SecOTRSessionCreateFromID(CFAllocatorRef allocator,
+ SecOTRFullIdentityRef myID,
+ SecOTRPublicIdentityRef theirID)
+{
+ SecOTRSessionRef newID = CFTypeAllocate(SecOTRSession, struct _SecOTRSession, allocator);
+
+ newID->_queue = dispatch_queue_create("OTRSession", DISPATCH_QUEUE_SERIAL);
+
+ newID->_me = myID;
+ newID->_them = theirID;
+ newID->_receivedDHMessage = NULL;
+ newID->_receivedDHKeyMessage = NULL;
+ newID->_myKey = NULL;
+ newID->_myNextKey = NULL;
+ newID->_theirKey = NULL;
+ newID->_theirPreviousKey = NULL;
+ newID->_macKeysToExpose = NULL;
+ newID->_textOutput = false;
+
+ SecOTRSessionResetInternal(newID);
+
+ CFRetain(newID->_me);
+ CFRetain(newID->_them);
+
+ return newID;
+}
+
+SecOTRSessionRef SecOTRSessionCreateFromIDAndFlags(CFAllocatorRef allocator,
+ SecOTRFullIdentityRef myID,
+ SecOTRPublicIdentityRef theirID,
+ uint32_t flags)
+{
+ SecOTRSessionRef newID = SecOTRSessionCreateFromID(allocator, myID, theirID);
+ if (flags & kSecOTRSendTextMessages) {
+ newID->_textOutput = true;
+ }
+ return newID;
+}
+
+static uint64_t constant_zero = 0;
+
+static void SecOTRSFindKeysForMessage(SecOTRSessionRef session,
+ SecOTRFullDHKeyRef myKey,
+ SecOTRPublicDHKeyRef theirKey,
+ bool sending,
+ uint8_t** messageKey, uint8_t** macKey, uint64_t **counter)
+{
+ SecOTRCacheElement* emptyKeys = NULL;
+ SecOTRCacheElement* cachedKeys = NULL;
+
+ if ((NULL == myKey) || (NULL == theirKey)) {
+ if (messageKey)
+ *messageKey = NULL;
+ if (macKey)
+ *macKey = NULL;
+ if (counter)
+ *counter = &constant_zero;
+
+ return;
+ }
+
+ for(int i = 0; i < kOTRKeyCacheSize; ++i)
+ {
+ if (0 == constant_memcmp(session->_keyCache[i]._fullKeyHash, SecFDHKGetHash(myKey), CCSHA1_OUTPUT_SIZE)
+ && (0 == constant_memcmp(session->_keyCache[i]._publicKeyHash, SecPDHKGetHash(theirKey), CCSHA1_OUTPUT_SIZE))) {
+ cachedKeys = &session->_keyCache[i];
+ break;
+ }
+
+ if (emptyKeys == NULL
+ && session->_keyCache[i]._fullKey == NULL) {
+ emptyKeys = &session->_keyCache[i];
+ }
+ }
+
+ if (cachedKeys == NULL) {
+ if (emptyKeys == NULL) {
+ syslog(LOG_ERR, "SecOTRSession key cache was full. Should never happen, spooky.\n");
+ emptyKeys = &session->_keyCache[0];
+ }
+
+ // Fill in the entry.
+ emptyKeys->_fullKey = myKey;
+ memcpy(emptyKeys->_fullKeyHash, SecFDHKGetHash(myKey), CCSHA1_OUTPUT_SIZE);
+ emptyKeys->_publicKey = theirKey;
+ memcpy(emptyKeys->_publicKeyHash, SecPDHKGetHash(theirKey), CCSHA1_OUTPUT_SIZE);
+
+ emptyKeys->_counter = 0;
+ emptyKeys->_theirCounter = 0;
+
+ SecOTRDHKGenerateOTRKeys(emptyKeys->_fullKey, emptyKeys->_publicKey,
+ emptyKeys->_sendEncryptionKey, emptyKeys->_sendMacKey,
+ emptyKeys->_receiveEncryptionKey, emptyKeys->_receiveMacKey);
+
+ cachedKeys = emptyKeys;
+ }
+
+ if (messageKey)
+ *messageKey = sending ? cachedKeys->_sendEncryptionKey : cachedKeys->_receiveEncryptionKey;
+ if (macKey)
+ *macKey = sending ? cachedKeys->_sendMacKey : cachedKeys->_receiveMacKey;
+ if (counter)
+ *counter = sending ? &cachedKeys->_counter : &cachedKeys->_theirCounter;
+}
+
+SecOTRSessionRef SecOTRSessionCreateFromData(CFAllocatorRef allocator, CFDataRef data)
+{
+ if (data == NULL)
+ return NULL;
+
+ SecOTRSessionRef result = NULL;
+ SecOTRSessionRef session = CFTypeAllocate(SecOTRSession, struct _SecOTRSession, allocator);
+
+ const uint8_t *bytes = CFDataGetBytePtr(data);
+ size_t size = (size_t)CFDataGetLength(data);
+
+ session->_queue = dispatch_queue_create("OTRSession", DISPATCH_QUEUE_SERIAL);
+
+ session->_me = NULL;
+ session->_them = NULL;
+ session->_myKey = NULL;
+ session->_myNextKey = NULL;
+ session->_theirKey = NULL;
+ session->_theirPreviousKey = NULL;
+ session->_receivedDHMessage = NULL;
+ session->_receivedDHKeyMessage = NULL;
+ bzero(session->_keyCache, sizeof(session->_keyCache));
+
+ uint8_t version;
+ require_noerr(ReadByte(&bytes, &size, &version), fail);
+ require(version <= 3, fail);
+
+ require_noerr(ReadLong(&bytes, &size, &session->_state), fail);
+ session->_me = SecOTRFullIdentityCreateFromBytes(kCFAllocatorDefault, &bytes, &size, NULL);
+ require(session->_me != NULL, fail);
+ session->_them = SecOTRPublicIdentityCreateFromBytes(kCFAllocatorDefault, &bytes, &size, NULL);
+ require(session->_them != NULL, fail);
+
+ require(size > sizeof(session->_r), fail);
+ memcpy(session->_r, bytes, sizeof(session->_r));
+ bytes += sizeof(session->_r);
+ size -= sizeof(session->_r);
+
+ {
+ uint8_t hasMessage = false;
+ ReadByte(&bytes, &size, &hasMessage);
+ if (hasMessage) {
+ session->_receivedDHMessage = CFDataCreateMutableFromOTRDATA(kCFAllocatorDefault, &bytes, &size);
+ }
+ }
+
+ if (version >= 2) {
+ uint8_t hasMessage = false;
+ ReadByte(&bytes, &size, &hasMessage);
+ if (hasMessage) {
+ session->_receivedDHKeyMessage = CFDataCreateMutableFromOTRDATA(kCFAllocatorDefault, &bytes, &size);
+ }
+ }
+
+ if (version < 3) {
+ uint8_t ready;
+ require_noerr(ReadByte(&bytes, &size, &ready), fail);
+ if (ready && session->_state == kIdle)
+ session->_state = kDone;
+ }
+
+ require_noerr(ReadLong(&bytes, &size, &session->_keyID), fail);
+ if (session->_keyID > 0) {
+ session->_myKey = SecOTRFullDHKCreateFromBytes(kCFAllocatorDefault, &bytes, &size);
+ require(session->_myKey != NULL, fail);
+ session->_myNextKey = SecOTRFullDHKCreateFromBytes(kCFAllocatorDefault, &bytes, &size);
+ require(session->_myNextKey != NULL, fail);
+ }
+
+ require_noerr(ReadLong(&bytes, &size, &session->_theirKeyID), fail);
+ if (session->_theirKeyID > 0) {
+ if (session->_theirKeyID > 1) {
+ session->_theirPreviousKey = SecOTRPublicDHKCreateFromSerialization(kCFAllocatorDefault, &bytes, &size);
+ require(session->_theirPreviousKey != NULL, fail);
+ }
+ session->_theirKey = SecOTRPublicDHKCreateFromSerialization(kCFAllocatorDefault, &bytes, &size);
+ require(session->_theirKey != NULL, fail);
+ }
+
+ uint64_t *counter;
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirKey, false, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirKey, true, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirPreviousKey, false, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirPreviousKey, true, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirKey, false, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirKey, true, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirPreviousKey, false, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirPreviousKey, true, NULL, NULL, &counter);
+ require_noerr(ReadLongLong(&bytes, &size, counter), fail);
+
+ session->_macKeysToExpose = CFDataCreateMutableFromOTRDATA(kCFAllocatorDefault, &bytes, &size);
+ require(session->_macKeysToExpose != NULL, fail);
+
+ uint8_t textMode;
+ require_noerr(ReadByte(&bytes, &size, &textMode), fail);
+ session->_textOutput = (textMode != 0);
+
+ result = session;
+ session = NULL;
+
+fail:
+ CFReleaseNull(session);
+ return result;
+}
+
+
+OSStatus SecOTRSAppendSerialization(SecOTRSessionRef session, CFMutableDataRef serializeInto)
+{
+ __block OSStatus result = errSecParam;
+
+ require(session, abort);
+ require(serializeInto, abort);
+
+ CFIndex start = CFDataGetLength(serializeInto);
+
+ dispatch_sync(session->_queue, ^{
+ const uint8_t version = 3;
+
+ CFDataAppendBytes(serializeInto, &version, sizeof(version));
+
+ AppendLong(serializeInto, session->_state);
+
+ result = (SecOTRFIAppendSerialization(session->_me, serializeInto, NULL)) ? errSecSuccess : errSecParam;
+
+ if (result == errSecSuccess) {
+ result = (SecOTRPIAppendSerialization(session->_them, serializeInto, NULL)) ? errSecSuccess : errSecParam;
+ }
+
+ if (result == errSecSuccess) {
+ CFDataAppendBytes(serializeInto, session->_r, sizeof(session->_r));
+
+ if (session->_receivedDHMessage == NULL) {
+ AppendByte(serializeInto, 0);
+ } else {
+ AppendByte(serializeInto, 1);
+ AppendCFDataAsDATA(serializeInto, session->_receivedDHMessage);
+ }
+
+ if (session->_receivedDHKeyMessage == NULL) {
+ AppendByte(serializeInto, 0);
+ } else {
+ AppendByte(serializeInto, 1);
+ AppendCFDataAsDATA(serializeInto, session->_receivedDHKeyMessage);
+ }
+
+ AppendLong(serializeInto, session->_keyID);
+ if (session->_keyID > 0) {
+ SecFDHKAppendSerialization(session->_myKey, serializeInto);
+ SecFDHKAppendSerialization(session->_myNextKey, serializeInto);
+ }
+
+ AppendLong(serializeInto, session->_theirKeyID);
+ if (session->_theirKeyID > 0) {
+ if (session->_theirKeyID > 1) {
+ SecPDHKAppendSerialization(session->_theirPreviousKey, serializeInto);
+ }
+ SecPDHKAppendSerialization(session->_theirKey, serializeInto);
+ }
+
+ uint64_t *counter;
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirKey, false, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirKey, true, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirPreviousKey, false, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirPreviousKey, true, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirKey, false, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirKey, true, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirPreviousKey, false, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+ SecOTRSFindKeysForMessage(session, session->_myNextKey, session->_theirPreviousKey, true, NULL, NULL, &counter);
+ AppendLongLong(serializeInto, *counter);
+
+ AppendCFDataAsDATA(serializeInto, session->_macKeysToExpose);
+
+ AppendByte(serializeInto, session->_textOutput ? 1 : 0);
+ }
+ });
+
+ if (result != errSecSuccess)
+ CFDataSetLength(serializeInto, start);
+
+abort:
+ return result;
+}
+
+
+bool SecOTRSGetIsReadyForMessages(SecOTRSessionRef session)
+{
+ __block bool result;
+
+ dispatch_sync(session->_queue, ^{ result = session->_state == kDone; });
+
+ return result;
+}
+
+bool SecOTRSGetIsIdle(SecOTRSessionRef session)
+{
+ __block bool result;
+
+ dispatch_sync(session->_queue, ^{ result = session->_state == kIdle; });
+
+ return result;
+}
+
+static void SecOTRSExpireCachedKeysForFullKey(SecOTRSessionRef session, SecOTRFullDHKeyRef myKey)
+{
+ for(int i = 0; i < kOTRKeyCacheSize; ++i)
+ {
+ if (0 == constant_memcmp(session->_keyCache[i]._fullKeyHash, SecFDHKGetHash(myKey), CCSHA1_OUTPUT_SIZE)) {
+ CFDataAppendBytes(session->_macKeysToExpose, session->_keyCache[i]._receiveMacKey, sizeof(session->_keyCache[i]._receiveMacKey));
+
+ bzero(&session->_keyCache[i], sizeof(session->_keyCache[i]));
+ }
+ }
+}
+
+static void SecOTRSExpireCachedKeysForPublicKey(SecOTRSessionRef session, SecOTRPublicDHKeyRef theirKey)
+{
+ for(int i = 0; i < kOTRKeyCacheSize; ++i)
+ {
+ if (0 == constant_memcmp(session->_keyCache[i]._publicKeyHash, SecPDHKGetHash(theirKey), CCSHA1_OUTPUT_SIZE)) {
+ CFDataAppendBytes(session->_macKeysToExpose, session->_keyCache[i]._receiveMacKey, sizeof(session->_keyCache[i]._receiveMacKey));
+
+ bzero(&session->_keyCache[i], sizeof(session->_keyCache[i]));
+ }
+ }
+}
+
+static void SecOTRSPrecalculateForPair(SecOTRSessionRef session,
+ SecOTRFullDHKeyRef myKey,
+ SecOTRPublicDHKeyRef theirKey)
+{
+ if (myKey == NULL || theirKey == NULL)
+ return;
+
+ SecOTRSFindKeysForMessage(session, myKey, theirKey, true, NULL, NULL, NULL);
+ SecOTRSFindKeysForMessage(session, myKey, theirKey, false, NULL, NULL, NULL);
+}
+
+static void SecOTRSPrecalculateKeysInternal(SecOTRSessionRef session)
+{
+ SecOTRSPrecalculateForPair(session, session->_myKey, session->_theirKey);
+ SecOTRSPrecalculateForPair(session, session->_myNextKey, session->_theirKey);
+ SecOTRSPrecalculateForPair(session, session->_myKey, session->_theirPreviousKey);
+ SecOTRSPrecalculateForPair(session, session->_myNextKey, session->_theirPreviousKey);
+}
+
+void SecOTRSPrecalculateKeys(SecOTRSessionRef session)
+{
+ dispatch_sync_f(session->_queue, session, (dispatch_function_t) SecOTRSPrecalculateKeysInternal);
+}
+
+enum SecOTRSMessageKind SecOTRSGetMessageKind(SecOTRSessionRef session, CFDataRef message)
+{
+ enum SecOTRSMessageKind kind = kOTRUnknownPacket;
+
+ CFMutableDataRef decodedBytes = CFDataCreateMutable(kCFAllocatorDefault, 0);
+ SecOTRGetIncomingBytes(message, decodedBytes);
+
+ const uint8_t *bytes = CFDataGetBytePtr(decodedBytes);
+ size_t size = CFDataGetLength(decodedBytes);
+
+ OTRMessageType type;
+ require_noerr(ReadHeader(&bytes, &size, &type), fail);
+
+ kind = (type == kDataMessage) ? kOTRDataPacket : kOTRNegotiationPacket;
+
+fail:
+ CFReleaseNull(decodedBytes);
+
+ return kind;
+}
+
+OSStatus SecOTRSSignAndProtectMessage(SecOTRSessionRef session,
+ CFDataRef sourceMessage,
+ CFMutableDataRef protectedMessage)
+{
+ __block OSStatus result = errSecParam;
+
+ require(session, abort);
+ require(sourceMessage, abort);
+ require(protectedMessage, abort);
+
+ dispatch_sync(session->_queue, ^{
+ if (session->_myKey == NULL ||
+ session->_theirKey == NULL) {
+ return;
+ }
+
+ CFMutableDataRef destinationMessage;
+ if (session->_textOutput) {
+ destinationMessage = CFDataCreateMutable(kCFAllocatorDefault, 0);
+ } else {
+ destinationMessage = protectedMessage;
+ }
+
+ uint8_t *messageKey;
+ uint8_t *macKey;
+ uint64_t *counter;
+
+ CFIndex start = CFDataGetLength(destinationMessage);
+
+ SecOTRSFindKeysForMessage(session, session->_myKey, session->_theirKey,
+ true,
+ &messageKey, &macKey, &counter);
+
+ AppendHeader(destinationMessage, kDataMessage);
+ AppendByte(destinationMessage, 0); // Flags, all zero
+
+ AppendLong(destinationMessage, session->_keyID);
+ AppendLong(destinationMessage, session->_theirKeyID);
+ SecFDHKAppendPublicSerialization(session->_myNextKey, destinationMessage);
+ AppendLongLong(destinationMessage, ++*counter);
+
+ CFIndex sourceSize = CFDataGetLength(sourceMessage);
+ assert(((unsigned long)sourceSize)<=UINT32_MAX); /* this is correct as long as CFIndex is a signed long */
+ AppendLong(destinationMessage, (uint32_t)sourceSize);
+ uint8_t* encryptedDataPointer = CFDataIncreaseLengthAndGetMutableBytes(destinationMessage, sourceSize);
+ AES_CTR_HighHalf_Transform(kOTRMessageKeyBytes, messageKey,
+ *counter,
+ (size_t)sourceSize, CFDataGetBytePtr(sourceMessage),
+ encryptedDataPointer);
+
+ CFIndex macedContentsSize = CFDataGetLength(destinationMessage) - start;
+ CFIndex macSize = CCSHA1_OUTPUT_SIZE;
+ uint8_t* macDataPointer = CFDataIncreaseLengthAndGetMutableBytes(destinationMessage, macSize);
+
+#ifdef USECOMMONCRYPTO
+ CCHmac(kCCHmacAlgSHA1,
+ macKey, kOTRMessageMacKeyBytes,
+ CFDataGetBytePtr(destinationMessage) + start, (size_t)macedContentsSize,
+ macDataPointer);
+#else
+ cchmac(ccsha1_di(),
+ kOTRMessageMacKeyBytes, macKey,
+ macedContentsSize, CFDataGetBytePtr(destinationMessage) + start,
+ macDataPointer);
+#endif
+
+ CFDataAppend(destinationMessage, session->_macKeysToExpose);
+
+ CFDataSetLength(session->_macKeysToExpose, 0);
+
+ if (session->_textOutput) {
+ SecOTRPrepareOutgoingBytes(destinationMessage, protectedMessage);
+ CFReleaseSafe(destinationMessage);
+ }
+
+ result = errSecSuccess;
+ });
+
+abort:
+ return result;
+}
+
+OSStatus SecOTRSVerifyAndExposeMessage(SecOTRSessionRef session,
+ CFDataRef incomingMessage,
+ CFMutableDataRef exposedMessageContents)
+{
+ __block SecOTRPublicDHKeyRef newKey = NULL;
+ __block OSStatus result = errSecParam;
+
+
+ require(session, abort);
+ require(incomingMessage, abort);
+ require(exposedMessageContents, abort);
+
+ dispatch_sync(session->_queue, ^{
+ const uint8_t* bytes;
+ size_t size;
+ CFMutableDataRef decodedBytes = CFDataCreateMutable(kCFAllocatorDefault, 0);
+ SecOTRGetIncomingBytes(incomingMessage, decodedBytes);
+
+ bytes = CFDataGetBytePtr(decodedBytes);
+ size = CFDataGetLength(decodedBytes);
+
+ const uint8_t* macDataStart = bytes;
+
+ uint32_t theirID;
+ uint32_t myID;
+
+ if ((result = ReadAndVerifyHeader(&bytes, &size, kDataMessage))){
+ CFReleaseSafe(decodedBytes);
+ return;
+ }
+
+ if (size <= 0) { result = errSecDecode; CFReleaseSafe(decodedBytes); return; }
+
+ if ((result = ReadAndVerifyByte(&bytes, &size, 0))) { CFReleaseSafe(decodedBytes); return;} // No flags
+
+ if ((result = ReadLong(&bytes, &size, &theirID))){ CFReleaseSafe(decodedBytes); return; }
+
+ if (theirID != session->_theirKeyID &&
+ (session->_theirPreviousKey == NULL || theirID != (session->_theirKeyID - 1)))
+ {
+ result = ((theirID + 1) < session->_theirKeyID) ? errSecOTRTooOld : errSecOTRIDTooNew;
+ CFReleaseSafe(decodedBytes);
+ return;
+ };
+
+ if ((result = ReadLong(&bytes, &size, &myID))){ CFReleaseSafe(decodedBytes); return; }
+ if (myID != session->_keyID && myID != (session->_keyID + 1))
+ {
+ result = (myID < session->_keyID) ? errSecOTRTooOld : errSecOTRIDTooNew;
+ CFReleaseSafe(decodedBytes);
+ return;
+ };
+
+
+ // Choose appripriate keys for message:
+ {
+ uint8_t *messageKey;
+ uint8_t *macKey;
+ uint64_t *theirCounter;
+
+ SecOTRFullDHKeyRef myKeyForMessage = (myID == session->_keyID) ? session->_myKey : session->_myNextKey;
+ SecOTRPublicDHKeyRef theirKeyForMessage = (theirID == session->_theirKeyID) ? session->_theirKey : session->_theirPreviousKey;
+
+ SecOTRSFindKeysForMessage(session, myKeyForMessage, theirKeyForMessage, false,
+ &messageKey, &macKey, &theirCounter);
+
+ size_t nextKeyMPISize;
+ const uint8_t* nextKeyMPIBytes;
+ if ((result = SizeAndSkipMPI(&bytes, &size, &nextKeyMPIBytes, &nextKeyMPISize))){ CFReleaseSafe(decodedBytes); return;}
+
+ uint64_t counter;
+ if ((result = ReadLongLong(&bytes, &size, &counter))) { CFReleaseSafe(decodedBytes); return; }
+
+ if (counter <= *theirCounter) { result = errSecOTRTooOld; CFReleaseSafe(decodedBytes); return; };
+
+ size_t messageSize;
+ const uint8_t* messageStart;
+ if ((result = SizeAndSkipDATA(&bytes, &size, &messageStart, &messageSize))) { CFReleaseSafe(decodedBytes); return; }
+
+ size_t macDataSize = (bytes - macDataStart) ? (size_t)(bytes - macDataStart) : 0;
+ uint8_t mac[CCSHA1_OUTPUT_SIZE];
+ if (sizeof(mac) > size) { result = errSecDecode; CFReleaseSafe(decodedBytes); return; }
+
+#ifdef USECOMMONCRYPTO
+ CCHmac(kCCHmacAlgSHA1,
+ macKey, kOTRMessageMacKeyBytes,
+ macDataStart, macDataSize,
+ mac);
+#else
+ cchmac(ccsha1_di(),
+ kOTRMessageMacKeyBytes, macKey,
+ macDataSize, macDataStart,
+ mac);
+#endif
+
+ if (0 != constant_memcmp(mac, bytes, sizeof(mac))) { result = errSecAuthFailed; CFReleaseSafe(decodedBytes); return; }
+ //if (messageSize > 65535) { result = errSecDataTooLarge; CFReleaseSafe(decodedBytes); return; }
+ uint8_t* dataSpace = CFDataIncreaseLengthAndGetMutableBytes(exposedMessageContents, (CFIndex)messageSize);
+
+
+ AES_CTR_HighHalf_Transform(kOTRMessageKeyBytes, messageKey,
+ counter,
+ messageSize, messageStart,
+ dataSpace);
+
+ // Everything is good, accept the meta data.
+ *theirCounter = counter;
+
+ newKey = SecOTRPublicDHKCreateFromBytes(kCFAllocatorDefault, &nextKeyMPIBytes, &nextKeyMPISize);
+ }
+
+ SecOTRSPrecalculateKeysInternal(session);
+
+ bool acceptTheirNewKey = newKey != NULL && theirID == session->_theirKeyID;
+
+ if (acceptTheirNewKey) {
+ if (session->_theirPreviousKey) {
+ SecOTRSExpireCachedKeysForPublicKey(session, session->_theirPreviousKey);
+ }
+
+ CFReleaseNull(session->_theirPreviousKey);
+ session->_theirPreviousKey = session->_theirKey;
+ session->_theirKey = newKey;
+
+ session->_theirKeyID += 1;
+
+ newKey = NULL;
+ }
+
+ if (myID == (session->_keyID + 1)) {
+ SecOTRSExpireCachedKeysForFullKey(session, session->_myKey);
+
+ // Swap the keys so we know the current key.
+ {
+ SecOTRFullDHKeyRef oldKey = session->_myKey;
+ session->_myKey = session->_myNextKey;
+ session->_myNextKey = oldKey;
+ }
+
+ // Derive a new next key by regenerating over the old key.
+ SecFDHKNewKey(session->_myNextKey);
+
+ session->_keyID = myID;
+ }
+ CFReleaseSafe(decodedBytes);
+ });
+
+abort:
+ CFReleaseNull(newKey);
+ return result;
+}
+
+
+OSStatus SecOTRSEndSession(SecOTRSessionRef session,
+ CFMutableDataRef messageToSend)
+{
+ return errSecUnimplemented;
+}
projects / apple / security.git / blobdiff