--- /dev/null
+//
+// SOSCoder.c
+// sec
+//
+// Created by Richard Murphy on 2/6/13.
+//
+//
+#include <stdlib.h>
+
+#include <CoreFoundation/CFBase.h>
+#include <CoreFoundation/CFError.h>
+
+#include <Security/SecBasePriv.h>
+#include <Security/SecOTR.h>
+#include <Security/SecOTRSession.h>
+#include <SecureObjectSync/SOSInternal.h>
+#include <SecureObjectSync/SOSFullPeerInfo.h>
+#include <SecureObjectSync/SOSPeerInfo.h>
+#include <SecureObjectSync/SOSPeer.h>
+#include <SecureObjectSync/SOSCoder.h>
+
+#include <utilities/SecCFRelease.h>
+#include <utilities/SecCFWrappers.h>
+#include <utilities/SecIOFormat.h>
+#include <utilities/SecCFError.h>
+#include <utilities/debugging.h>
+
+#include <utilities/der_plist.h>
+#include <utilities/der_plist_internal.h>
+
+#include <corecrypto/ccder.h>
+#include <utilities/iCloudKeychainTrace.h>
+
+#include "AssertMacros.h"
+
+struct __OpaqueSOSCoder {
+ CFStringRef peer_id;
+ SecOTRSessionRef sessRef;
+ bool waitingForDataPacket;
+};
+
+static const char *SOSPeerCoderString(SOSPeerCoderStatus coderStatus) {
+ switch (coderStatus) {
+ case kSOSPeerCoderDataReturned: return "DataReturned";
+ case kSOSPeerCoderNegotiating: return "Negotiating";
+ case kSOSPeerCoderNegotiationCompleted: return "NegotiationCompleted";
+ case kSOSPeerCoderFailure: return "Failure";
+ case kSOSPeerCoderStaleEvent: return "StaleEvent";
+ default: return "StatusUnknown";
+ }
+}
+
+static size_t der_sizeof_bool(bool value) {
+ return ccder_sizeof(CCDER_BOOLEAN, 1);
+}
+
+static uint8_t* der_encode_bool(bool value, const uint8_t *der, uint8_t *der_end) {
+ uint8_t valueByte = value;
+ return ccder_encode_tl(CCDER_BOOLEAN, 1, der,
+ ccder_encode_body(1, &valueByte, der, der_end));
+}
+
+static const uint8_t* der_decode_bool(bool *value, const uint8_t *der, const uint8_t *der_end) {
+ size_t payload_size = 0;
+
+ der = ccder_decode_tl(CCDER_BOOLEAN, &payload_size, der, der_end);
+
+ if (payload_size != 1) {
+ der = NULL;
+ }
+
+ if (der != NULL) {
+ *value = (*der != 0);
+ der++;
+ }
+
+ return der;
+}
+
+static CFMutableDataRef sessSerialized(SOSCoderRef coder, CFErrorRef *error) {
+ CFMutableDataRef otr_state = NULL;
+
+ if(!coder || !coder->sessRef) {
+ SOSCreateErrorWithFormat(kSOSErrorUnexpectedType, NULL, error, 0, CFSTR("No session reference."));
+ return NULL;
+ }
+
+ if ((otr_state = CFDataCreateMutable(NULL, 0)) == NULL) {
+ SOSCreateErrorWithFormat(kSOSErrorAllocationFailure, NULL, error, 0, CFSTR("Mutable Data allocation failed."));
+ return NULL;
+ }
+
+ if (errSecSuccess != SecOTRSAppendSerialization(coder->sessRef, otr_state)) {
+ SOSCreateErrorWithFormat(kSOSErrorEncodeFailure, NULL, error, 0, CFSTR("Append Serialization failed."));
+ CFReleaseSafe(otr_state);
+ return NULL;
+ }
+
+ return otr_state;
+
+}
+
+static size_t SOSCoderGetDEREncodedSize(SOSCoderRef coder, CFErrorRef *error) {
+ size_t encoded_size = 0;
+ CFMutableDataRef otr_state = sessSerialized(coder, error);
+
+ if (otr_state) {
+ size_t data_size = der_sizeof_data(otr_state, error);
+ size_t waiting_size = der_sizeof_bool(coder->waitingForDataPacket);
+
+ if ((data_size != 0) && (waiting_size != 0))
+ {
+ encoded_size = ccder_sizeof(CCDER_CONSTRUCTED_SEQUENCE, data_size + waiting_size);
+ }
+ CFReleaseSafe(otr_state);
+ }
+ return encoded_size;
+}
+
+static uint8_t* SOSCoderEncodeToDER(SOSCoderRef coder, CFErrorRef* error, const uint8_t* der, uint8_t* der_end) {
+ if(!der_end) return NULL;
+ uint8_t* result = NULL;
+ CFMutableDataRef otr_state = sessSerialized(coder, error);
+
+ if(otr_state) {
+ result = ccder_encode_constructed_tl(CCDER_CONSTRUCTED_SEQUENCE, der_end, der,
+ der_encode_data(otr_state, error, der,
+ der_encode_bool(coder->waitingForDataPacket, der, der_end)));
+ CFReleaseSafe(otr_state);
+ }
+ return result;
+}
+
+
+CFDataRef SOSCoderCopyDER(SOSCoderRef coder, CFErrorRef* error) {
+ CFMutableDataRef encoded = NULL;
+ size_t encoded_size = SOSCoderGetDEREncodedSize(coder, error);
+
+ if (encoded_size > 0) {
+ encoded = CFDataCreateMutable(NULL, encoded_size);
+ if (encoded) {
+ CFDataSetLength(encoded, encoded_size);
+ uint8_t * der = CFDataGetMutableBytePtr(encoded);
+ uint8_t * der_end = der + encoded_size;
+ if (!SOSCoderEncodeToDER(coder, error, der, der_end)) {
+ CFReleaseNull(encoded);
+ encoded = NULL;
+ }
+ }
+ }
+ return encoded;
+}
+
+SOSCoderRef SOSCoderCreateFromData(CFDataRef exportedData, CFErrorRef *error) {
+
+ SOSCoderRef p = calloc(1, sizeof(struct __OpaqueSOSCoder));
+
+ const uint8_t *der = CFDataGetBytePtr(exportedData);
+ const uint8_t *der_end = der + CFDataGetLength(exportedData);
+
+ CFDataRef otr_data = NULL;
+
+ ccder_tag tag;
+ require(ccder_decode_tag(&tag, der, der_end),fail);
+
+ switch (tag) {
+ case CCDER_OCTET_STRING:
+ {
+ der = der_decode_data(kCFAllocatorDefault, 0, &otr_data, error, der, der_end);
+ p->waitingForDataPacket = false;
+ }
+ break;
+
+ case CCDER_CONSTRUCTED_SEQUENCE:
+ {
+ const uint8_t *sequence_end = NULL;
+ der = ccder_decode_sequence_tl(&sequence_end, der, der_end);
+
+ require_action_quiet(sequence_end == der_end, fail, SecCFDERCreateError(kSOSErrorDecodeFailure, CFSTR("Extra data in SOS coder"), NULL, error));
+
+ der = der_decode_data(kCFAllocatorDefault, 0, &otr_data, error, der, der_end);
+ der = der_decode_bool(&p->waitingForDataPacket, der, sequence_end);
+ }
+ break;
+
+ default:
+ SecCFDERCreateError(kSOSErrorDecodeFailure, CFSTR("Unsupported SOS Coder DER"), NULL, error);
+ goto fail;
+ }
+
+ require(der, fail);
+
+ p->sessRef = SecOTRSessionCreateFromData(NULL, otr_data);
+ require(p->sessRef, fail);
+
+ CFReleaseSafe(otr_data);
+ return p;
+
+fail:
+ SOSCoderDispose(p);
+ CFReleaseSafe(otr_data);
+ return NULL;
+}
+
+
+SOSCoderRef SOSCoderCreate(SOSPeerInfoRef peerInfo, SOSFullPeerInfoRef myPeerInfo, CFErrorRef *error) {
+ CFAllocatorRef allocator = CFGetAllocator(peerInfo);
+
+ SOSCoderRef p = calloc(1, sizeof(struct __OpaqueSOSCoder));
+
+ SecOTRFullIdentityRef myRef = NULL;
+ SecOTRPublicIdentityRef peerRef = NULL;
+ SecKeyRef privateKey = NULL;
+ SecKeyRef publicKey = NULL;
+
+ if (myPeerInfo && peerInfo) {
+ privateKey = SOSFullPeerInfoCopyDeviceKey(myPeerInfo, error);
+ require_quiet(privateKey, errOut);
+
+ myRef = SecOTRFullIdentityCreateFromSecKeyRef(allocator, privateKey, error);
+ require_quiet(myRef, errOut);
+
+ CFReleaseNull(privateKey);
+
+ publicKey = SOSPeerInfoCopyPubKey(peerInfo);
+
+ peerRef = SecOTRPublicIdentityCreateFromSecKeyRef(allocator, publicKey, error);
+ require_quiet(peerRef, errOut);
+
+ p->sessRef = SecOTRSessionCreateFromID(allocator, myRef, peerRef);
+
+ require(p->sessRef, errOut);
+
+ p->waitingForDataPacket = false;
+
+ CFReleaseNull(publicKey);
+ CFReleaseNull(privateKey);
+ CFReleaseNull(myRef);
+ CFReleaseNull(peerRef);
+ } else {
+ secnotice("coder", "NULL Coder requested, no transport security");
+ }
+
+ return p;
+
+errOut:
+ secerror("Coder create failed: %@\n", *error);
+ CFReleaseNull(myRef);
+ CFReleaseNull(peerRef);
+ CFReleaseNull(publicKey);
+ CFReleaseNull(privateKey);
+
+ free(p);
+ return NULL;
+}
+
+void SOSCoderDispose(SOSCoderRef coder)
+{
+ CFReleaseNull(coder->sessRef);
+
+ free(coder);
+}
+
+void SOSCoderReset(SOSCoderRef coder)
+{
+ SecOTRSessionReset(coder->sessRef);
+ coder->waitingForDataPacket = false;
+}
+
+static bool SOSOTRSAppendStartPacket(SecOTRSessionRef session, CFMutableDataRef appendPacket, CFErrorRef *error) {
+ OSStatus otrStatus = SecOTRSAppendStartPacket(session, appendPacket);
+ if (otrStatus != errSecSuccess) {
+ SOSCreateErrorWithFormat(kSOSErrorEncodeFailure, (error != NULL) ? *error : NULL, error, NULL, CFSTR("append start packet returned: %" PRIdOSStatus), otrStatus);
+ }
+ return otrStatus == errSecSuccess;
+}
+
+// Start OTR negotiation if we haven't already done so.
+SOSPeerCoderStatus
+SOSCoderStart(SOSCoderRef coder, SOSPeerSendBlock sendBlock, CFStringRef clientId, CFErrorRef *error) {
+ CFMutableStringRef action = CFStringCreateMutable(kCFAllocatorDefault, 0);
+ CFStringRef beginState = NULL;
+ SOSPeerCoderStatus result = kSOSPeerCoderFailure;
+ CFMutableDataRef startPacket = NULL;
+
+ require_action_quiet(coder->sessRef, coderFailure, CFStringAppend(action, CFSTR("*** no otr session ***")));
+ beginState = CFCopyDescription(coder->sessRef);
+ require_action_quiet(!coder->waitingForDataPacket, negotiatingOut, CFStringAppend(action, CFSTR("waiting for peer to send first data packet")));
+ require_action_quiet(!SecOTRSGetIsReadyForMessages(coder->sessRef), coderFailure, CFStringAppend(action, CFSTR("otr session ready"));
+ result = kSOSPeerCoderDataReturned);
+ require_action_quiet(SecOTRSGetIsIdle(coder->sessRef), negotiatingOut, CFStringAppend(action, CFSTR("otr negotiating already")));
+ require_action_quiet(startPacket = CFDataCreateMutable(kCFAllocatorDefault, 0), coderFailure, SOSCreateError(kSOSErrorAllocationFailure, CFSTR("alloc failed"), NULL, error));
+ require_quiet(SOSOTRSAppendStartPacket(coder->sessRef, startPacket, error), coderFailure);
+ require_quiet(sendBlock(startPacket, error), coderFailure);
+
+negotiatingOut:
+ result = kSOSPeerCoderNegotiating;
+coderFailure:
+ // Uber state log
+ if (result == kSOSPeerCoderFailure && error && *error)
+ CFStringAppendFormat(action, NULL, CFSTR(" %@"), *error);
+ secnotice("coder", "%@ %@ %s %@ %@ returned %s", clientId, beginState,
+ SecOTRPacketTypeString(startPacket), action, coder->sessRef, SOSPeerCoderString(result));
+ CFReleaseNull(startPacket);
+ CFReleaseSafe(beginState);
+ CFRelease(action);
+
+ return result;
+
+}
+
+SOSPeerCoderStatus
+SOSCoderResendDH(SOSCoderRef coder, SOSPeerSendBlock sendBlock, CFErrorRef *error) {
+ if(coder->sessRef == NULL) return kSOSPeerCoderDataReturned;
+
+ CFMutableDataRef startPacket = CFDataCreateMutable(kCFAllocatorDefault, 0);
+ if (SecOTRSAppendRestartPacket(coder->sessRef, startPacket)) {
+ return kSOSPeerCoderFailure;
+ }
+
+ secnotice("coder", "Resending OTR Start %@", startPacket);
+ SOSPeerCoderStatus result = sendBlock(startPacket, error) ? kSOSPeerCoderNegotiating : kSOSPeerCoderFailure;
+ CFReleaseNull(startPacket);
+ return result;
+}
+
+
+static SOSPeerCoderStatus nullCoder(CFDataRef from, CFMutableDataRef *to) {
+ *to = CFDataCreateMutableCopy(NULL, CFDataGetLength(from), from);
+ return kSOSPeerCoderDataReturned;
+}
+
+SOSPeerCoderStatus SOSCoderUnwrap(SOSCoderRef coder, SOSPeerSendBlock send_block,
+ CFDataRef codedMessage, CFMutableDataRef *message,
+ CFStringRef clientId,
+ CFErrorRef *error) {
+ if(codedMessage == NULL) return kSOSPeerCoderDataReturned;
+ if(coder->sessRef == NULL) return nullCoder(codedMessage, message);
+ CFMutableStringRef action = CFStringCreateMutable(kCFAllocatorDefault, 0);
+ /* This should be the "normal" case. We just use OTR to unwrap the received message. */
+ SOSPeerCoderStatus result = kSOSPeerCoderFailure;
+
+ CFStringRef beginState = CFCopyDescription(coder->sessRef);
+ enum SecOTRSMessageKind kind = SecOTRSGetMessageKind(coder->sessRef, codedMessage);
+
+ switch (kind) {
+ case kOTRNegotiationPacket: {
+ if(send_block) {
+ /* If we're in here we haven't completed negotiating a session. Use SecOTRSProcessPacket() to go through
+ the negotiation steps and immediately send a reply back if necessary using the sendBlock. This
+ assumes the sendBlock is still available.
+ */
+ CFMutableDataRef response = CFDataCreateMutable(kCFAllocatorDefault, 0);
+ OSStatus ppstatus = errSecSuccess;
+ if (response) {
+ switch (ppstatus = SecOTRSProcessPacket(coder->sessRef, codedMessage, response)) {
+ case errSecSuccess:
+ if (CFDataGetLength(response) > 1) {
+ CFStringAppendFormat(action, NULL, CFSTR("Sending OTR Response %s"), SecOTRPacketTypeString(response));
+ if (send_block(response, error)) {
+ result = kSOSPeerCoderNegotiating;
+ if (SecOTRSGetIsReadyForMessages(coder->sessRef)) {
+ CFStringAppend(action, CFSTR(" begin waiting for data packet"));
+ coder->waitingForDataPacket = true;
+ }
+ } else {
+ secerror("%@ Coder send Error %@", clientId, (CFTypeRef)error);
+ result = kSOSPeerCoderFailure;
+ }
+ } else if(!SecOTRSGetIsReadyForMessages(coder->sessRef)) {
+ CFStringAppend(action, CFSTR("stuck?"));
+ result = kSOSPeerCoderNegotiating;
+ } else {
+ CFStringAppend(action, CFSTR("completed negotiation"));
+ result = kSOSPeerCoderNegotiationCompleted;
+ coder->waitingForDataPacket = false;
+ }
+ break;
+ case errSecDecode:
+ CFStringAppend(action, CFSTR("resending dh"));
+ result = SOSCoderResendDH(coder, send_block, error);
+ break;
+ default:
+ SOSCreateErrorWithFormat(kSOSErrorEncodeFailure, (error != NULL) ? *error : NULL, error, NULL, CFSTR("%@ Cannot negotiate session (%ld)"), clientId, (long)ppstatus);
+ result = kSOSPeerCoderFailure;
+ break;
+ };
+ } else {
+ SOSCreateErrorWithFormat(kSOSErrorAllocationFailure, (error != NULL) ? *error : NULL, error, NULL, CFSTR("%@ Cannot allocate CFData"), clientId);
+ result = kSOSPeerCoderFailure;
+ }
+
+ CFReleaseNull(response);
+ } else {
+ secerror("%@ Can't send, no send_block!!", clientId);
+ SOSCreateErrorWithFormat(kSOSErrorEncodeFailure, (error != NULL) ? *error : NULL, error, NULL, CFSTR("%@ Cannot negotiate session"), clientId);
+ result = kSOSPeerCoderFailure;
+ }
+
+ break;
+ }
+
+ case kOTRDataPacket:
+ if(!SecOTRSGetIsReadyForMessages(coder->sessRef)) {
+ CFStringAppend(action, CFSTR("not ready, resending DH packet"));
+ SetCloudKeychainTraceValueForKey(kCloudKeychainNumberOfTimesSyncFailed, 1);
+ CFStringAppend(action, CFSTR("not ready for data; resending dh"));
+ result = SOSCoderResendDH(coder, send_block, error);
+ } else {
+ if (coder->waitingForDataPacket) {
+ CFStringAppend(action, CFSTR("got data packet we were waiting for "));
+ coder->waitingForDataPacket = false;
+ }
+ CFMutableDataRef exposed = CFDataCreateMutable(0, 0);
+ OSStatus otrResult = SecOTRSVerifyAndExposeMessage(coder->sessRef, codedMessage, exposed);
+ CFStringAppend(action, CFSTR("verify and expose message"));
+ if (otrResult) {
+ if (otrResult == errSecOTRTooOld) {
+ CFStringAppend(action, CFSTR(" too old"));
+ result = kSOSPeerCoderStaleEvent;
+ } else {
+ SecError(otrResult, error, CFSTR("%@ Cannot expose message: %" PRIdOSStatus), clientId, otrResult);
+ secerror("%@ Decode OTR Protected Packet: %@", clientId, error ? *error : NULL);
+ result = kSOSPeerCoderFailure;
+ }
+ } else {
+ CFStringAppend(action, CFSTR("decoded OTR protected packet"));
+ *message = exposed;
+ exposed = NULL;
+ result = kSOSPeerCoderDataReturned;
+ }
+ CFReleaseNull(exposed);
+ }
+ break;
+
+ default:
+ secerror("%@ Unknown packet type: %@", clientId, codedMessage);
+ SOSCreateError(kSOSErrorDecodeFailure, CFSTR("Unknown packet type"), (error != NULL) ? *error : NULL, error);
+ result = kSOSPeerCoderFailure;
+ break;
+ };
+
+ // Uber state log
+ if (result == kSOSPeerCoderFailure && error && *error)
+ CFStringAppendFormat(action, NULL, CFSTR(" %@"), *error);
+ secnotice("coder", "%@ %@ %s %@ %@ returned %s", clientId, beginState,
+ SecOTRPacketTypeString(codedMessage), action, coder->sessRef, SOSPeerCoderString(result));
+ CFReleaseSafe(beginState);
+ CFRelease(action);
+
+ return result;
+}
+
+
+SOSPeerCoderStatus SOSCoderWrap(SOSCoderRef coder, CFDataRef message, CFMutableDataRef *codedMessage, CFStringRef clientId, CFErrorRef *error) {
+ CFMutableStringRef action = CFStringCreateMutable(kCFAllocatorDefault, 0);
+ SOSPeerCoderStatus result = kSOSPeerCoderDataReturned;
+ CFStringRef beginState = NULL;
+ CFMutableDataRef encoded = NULL;
+ OSStatus otrStatus = 0;
+
+ require_action_quiet(coder->sessRef, errOut,
+ CFStringAppend(action, CFSTR("*** using null coder ***"));
+ result = nullCoder(message, codedMessage));
+ beginState = CFCopyDescription(coder->sessRef);
+ require_action_quiet(SecOTRSGetIsReadyForMessages(coder->sessRef), errOut,
+ CFStringAppend(action, CFSTR("not ready"));
+ result = kSOSPeerCoderNegotiating);
+ require_action_quiet(!coder->waitingForDataPacket, errOut,
+ CFStringAppend(action, CFSTR("waiting for peer to send data packet first"));
+ result = kSOSPeerCoderNegotiating);
+ require_action_quiet(encoded = CFDataCreateMutable(kCFAllocatorDefault, 0), errOut,
+ SOSCreateErrorWithFormat(kSOSErrorAllocationFailure, NULL, error, NULL, CFSTR("%@ alloc failed"), clientId);
+ result = kSOSPeerCoderFailure);
+ require_noerr_action_quiet(otrStatus = SecOTRSSignAndProtectMessage(coder->sessRef, message, encoded), errOut,
+ SOSCreateErrorWithFormat(kSOSErrorEncodeFailure, (error != NULL) ? *error : NULL, error, NULL, CFSTR("%@ cannot protect message: %" PRIdOSStatus), clientId, otrStatus);
+ CFReleaseNull(encoded);
+ result = kSOSPeerCoderFailure);
+ *codedMessage = encoded;
+
+errOut:
+ // Uber state log
+ if (result == kSOSPeerCoderFailure && error && *error)
+ CFStringAppendFormat(action, NULL, CFSTR(" %@"), *error);
+ secnotice("coder", "%@ %@ %s %@ %@ returned %s", clientId, beginState,
+ SecOTRPacketTypeString(encoded), action, coder->sessRef, SOSPeerCoderString(result));
+ CFReleaseSafe(beginState);
+ CFRelease(action);
+
+ return result;
+}
+
+bool SOSCoderCanWrap(SOSCoderRef coder) {
+ return coder->sessRef && SecOTRSGetIsReadyForMessages(coder->sessRef) && !coder->waitingForDataPacket;
+}
projects / apple / security.git / blobdiff