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[apple/security.git] / keychain / SecureObjectSync / SOSCircle.c
diff --git a/keychain/SecureObjectSync/SOSCircle.c b/keychain/SecureObjectSync/SOSCircle.c
new file mode 100644 (file)
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@@ -0,0 +1,1582 @@
+/*
+ * Copyright (c) 2012-2014 Apple Inc. All Rights Reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_LICENSE_HEADER_END@
+ */
+
+
+/*
+ * SOSCircle.c -  Implementation of the secure object syncing transport
+ */
+
+#include <AssertMacros.h>
+
+#include <CoreFoundation/CFArray.h>
+#include "keychain/SecureObjectSync/SOSTypes.h"
+#include "keychain/SecureObjectSync/SOSPeerInfo.h"
+#include "keychain/SecureObjectSync/SOSPeer.h"
+#include "keychain/SecureObjectSync/SOSCircle.h"
+#include "keychain/SecureObjectSync/SOSCloudCircle.h"
+#include "keychain/SecureObjectSync/SOSCloudCircleInternal.h"
+#include "keychain/SecureObjectSync/SOSInternal.h"
+#include "keychain/SecureObjectSync/SOSEnginePriv.h"
+#include "keychain/SecureObjectSync/SOSPeerInfoInternal.h"
+#include "keychain/SecureObjectSync/SOSGenCount.h"
+#include "keychain/SecureObjectSync/SOSPeerInfoCollections.h"
+#include <CoreFoundation/CoreFoundation.h>
+#include <Security/SecFramework.h>
+
+#include <Security/SecKey.h>
+#include <Security/SecKeyPriv.h>
+#include <utilities/SecBuffer.h>
+
+#include <utilities/SecCFWrappers.h>
+#include <utilities/SecCFError.h>
+
+#include "keychain/SecureObjectSync/SOSCirclePriv.h"
+
+//#include "ckdUtilities.h"
+
+#include <corecrypto/ccder.h>
+#include <corecrypto/ccdigest.h>
+#include <corecrypto/ccsha2.h>
+
+#include <stdlib.h>
+#include <assert.h>
+
+CFGiblisWithCompareFor(SOSCircle);
+
+SOSCircleRef SOSCircleCreate(CFAllocatorRef allocator, CFStringRef name, CFErrorRef *error) {
+    SOSCircleRef c = CFTypeAllocate(SOSCircle, struct __OpaqueSOSCircle, allocator);
+    assert(name);
+    
+    c->name = CFStringCreateCopy(allocator, name);
+    c->generation = SOSGenerationCreate();
+    c->peers = CFSetCreateMutableForSOSPeerInfosByID(allocator);
+    c->applicants = CFSetCreateMutableForSOSPeerInfosByID(allocator);
+    c->rejected_applicants = CFSetCreateMutableForSOSPeerInfosByID(allocator);
+    c->signatures = CFDictionaryCreateMutableForCFTypes(allocator);
+    return c;
+}
+
+static CFMutableSetRef CFSetOfPeerInfoDeepCopy(CFAllocatorRef allocator, CFSetRef peerInfoSet)
+{
+   __block CFMutableSetRef result = CFSetCreateMutableForSOSPeerInfosByID(allocator);
+    CFSetForEach(peerInfoSet, ^(const void *value) {
+        SOSPeerInfoRef pi = (SOSPeerInfoRef) value;
+        CFErrorRef localError = NULL;
+        SOSPeerInfoRef copiedPeer = SOSPeerInfoCreateCopy(allocator, pi, &localError);
+        if (copiedPeer) {
+            CFSetAddValue(result, copiedPeer);
+        } else {
+            secerror("Failed to copy peer: %@ (%@)", pi, localError);
+        }
+        CFReleaseSafe(copiedPeer);
+        CFReleaseSafe(localError);
+    });
+    return result;
+}
+
+SOSCircleRef SOSCircleCopyCircle(CFAllocatorRef allocator, SOSCircleRef otherCircle, CFErrorRef *error)
+{
+    SOSCircleRef c = CFTypeAllocate(SOSCircle, struct __OpaqueSOSCircle, allocator);
+
+    assert(otherCircle);
+    c->name = CFStringCreateCopy(allocator, otherCircle->name);
+    c->generation = SOSGenerationCopy(otherCircle->generation);
+
+    c->peers = CFSetOfPeerInfoDeepCopy(allocator, otherCircle->peers);
+    c->applicants = CFSetOfPeerInfoDeepCopy(allocator, otherCircle->applicants);
+    c->rejected_applicants = CFSetOfPeerInfoDeepCopy(allocator, otherCircle->rejected_applicants);
+
+    c->signatures = CFDictionaryCreateMutableCopy(allocator, 0, otherCircle->signatures);
+    
+    return c;
+}
+
+static Boolean SOSCircleCompare(CFTypeRef lhs, CFTypeRef rhs) {
+    if (CFGetTypeID(lhs) != SOSCircleGetTypeID()
+     || CFGetTypeID(rhs) != SOSCircleGetTypeID())
+        return false;
+
+    SOSCircleRef left = SOSCircleConvertAndAssertStable(lhs);
+    SOSCircleRef right = SOSCircleConvertAndAssertStable(rhs);
+
+    // TODO: we should be doing set equality for peers and applicants.
+    return NULL != left && NULL != right
+        && CFEqualSafe(left->generation, right->generation)
+        && SOSPeerInfoSetContainsIdenticalPeers(left->peers, right->peers)
+        && SOSPeerInfoSetContainsIdenticalPeers(left->applicants, right->applicants)
+        && SOSPeerInfoSetContainsIdenticalPeers(left->rejected_applicants, right->rejected_applicants)
+        && CFEqualSafe(left->signatures, right->signatures);
+}
+
+static CFMutableArrayRef CFSetCopyValuesCFArray(CFSetRef set)
+{
+    CFIndex count = CFSetGetCount(set);
+
+    CFMutableArrayRef result = CFArrayCreateMutableForCFTypes(kCFAllocatorDefault);
+    if (count > 0) {
+        const void * values[count];
+        CFSetGetValues(set, values);
+        for (int current = 0; current < count; ++current) {
+            CFArrayAppendValue(result, values[current]);
+        }
+    }
+    
+    return result;
+}
+
+static bool SOSCircleDigestArray(const struct ccdigest_info *di, CFMutableArrayRef array, void *hash_result, CFErrorRef *error)
+{
+    __block bool success = true;
+    ccdigest_di_decl(di, array_digest);
+    void * a_digest = (void * )array_digest;
+
+    ccdigest_init(di, array_digest);
+    CFArraySortValues(array, CFRangeMake(0, CFArrayGetCount(array)), SOSPeerInfoCompareByID, (void *)SOSPeerCmpPubKeyHash);
+    CFArrayForEach(array, ^(const void *peer) {
+        if (!SOSPeerInfoUpdateDigestWithPublicKeyBytes((SOSPeerInfoRef)peer, di, a_digest, error))
+            success = false;
+    });
+    ccdigest_final(di, array_digest, hash_result);
+
+    return success;
+}
+
+static bool SOSCircleDigestSet(const struct ccdigest_info *di, CFMutableSetRef set, void *hash_result, CFErrorRef *error)
+{
+    CFMutableArrayRef values = CFSetCopyValuesCFArray(set);
+    
+    bool result = SOSCircleDigestArray(di, values, hash_result, error);
+    
+    CFReleaseSafe(values);
+    
+    return result;
+}
+
+static bool SOSCircleHashGenAndPeers(const struct ccdigest_info *di, SOSGenCountRef gen, CFMutableSetRef peers, void*hash_result, CFErrorRef *error) {
+    ccdigest_di_decl(di, circle_digest);
+    ccdigest_init(di, circle_digest);
+    int64_t generation = SOSGetGenerationSint(gen);
+    ccdigest_update(di, circle_digest, sizeof(generation), &generation);
+
+    SOSCircleDigestSet(di, peers, hash_result, error);
+    ccdigest_update(di, circle_digest, di->output_size, hash_result);
+    ccdigest_final(di, circle_digest, hash_result);
+    return true;
+}
+
+static bool SOSCircleHash(const struct ccdigest_info *di, SOSCircleRef circle, void *hash_result, CFErrorRef *error) {
+    return SOSCircleHashGenAndPeers(di, SOSCircleGetGeneration(circle), circle->peers, hash_result, error);
+}
+
+static bool SOSCircleHashNextGenWithAdditionalPeer(const struct ccdigest_info *di, SOSCircleRef circle, SOSPeerInfoRef additionalPeer, void *hash_result, CFErrorRef *error) {
+    bool result = false;
+    CFMutableSetRef peers = CFSetCreateMutableCopy(NULL, 0, circle->peers);
+    CFSetAddValue(peers, additionalPeer);
+
+    SOSGenCountRef nextGen = SOSGenerationIncrementAndCreate(circle->generation);
+
+    result = SOSCircleHashGenAndPeers(di, nextGen, peers, hash_result, error);
+
+    CFReleaseNull(nextGen);
+    CFReleaseNull(peers);
+
+    return result;
+}
+
+bool SOSCircleSetSignature(SOSCircleRef circle, SecKeyRef pubkey, CFDataRef signature, CFErrorRef *error) {
+    bool result = false;
+    
+    CFStringRef pubKeyID = SOSCopyIDOfKey(pubkey, error);
+    require_quiet(pubKeyID, fail);
+    CFDictionarySetValue(circle->signatures, pubKeyID, signature);
+    result = true;
+
+fail:
+    CFReleaseSafe(pubKeyID);
+    return result;
+}
+
+static bool SOSCircleRemoveSignatures(SOSCircleRef circle, CFErrorRef *error) {
+    CFDictionaryRemoveAllValues(circle->signatures);
+    return true;
+}
+
+CFDataRef SOSCircleGetSignature(SOSCircleRef circle, SecKeyRef pubkey, CFErrorRef *error) {
+    CFStringRef pubKeyID = SOSCopyIDOfKey(pubkey, error);
+    CFDataRef result = NULL;
+    require_quiet(pubKeyID, fail);
+
+    CFTypeRef value = (CFDataRef)CFDictionaryGetValue(circle->signatures, pubKeyID);
+    
+    if (isData(value)) result = (CFDataRef) value;
+
+fail:
+    CFReleaseSafe(pubKeyID);
+    return result;
+}
+
+CFDictionaryRef SOSCircleCopyAllSignatures(SOSCircleRef circle) {
+    return CFDictionaryCreateCopy(kCFAllocatorDefault, circle->signatures);
+}
+
+#define circle_signature_di() ccsha256_di()
+
+static CFDataRef SecKeyCopyRawHashSignature(const struct ccdigest_info *di, const uint8_t* hashToSign, SecKeyRef privKey, CFErrorRef *error) {
+    CFDataRef result = NULL;
+
+    CFMutableDataRef signature = CFDataCreateMutableWithScratch(kCFAllocatorDefault, SecKeyGetSize(privKey, kSecKeySignatureSize));
+    size_t signatureSpace = CFDataGetLength(signature);
+
+    OSStatus status = SecKeyRawSign(privKey, kSecPaddingNone, hashToSign, di->output_size, CFDataGetMutableBytePtr(signature), &signatureSpace);
+    require_quiet(SecError(status, error, CFSTR("Signing failed: %d"), (int)status), fail);
+
+    if (signatureSpace < (size_t)CFDataGetLength(signature)) {
+        CFDataSetLength(signature, signatureSpace);
+    }
+
+    CFTransferRetained(result, signature);
+fail:
+    CFReleaseNull(signature);
+    return result;
+}
+
+bool SOSCircleSign(SOSCircleRef circle, SecKeyRef privKey, CFErrorRef *error) {
+    const struct ccdigest_info *di = circle_signature_di();
+
+    __block CFDataRef signature = NULL;
+    bool didSign = false;
+    require_quiet(privKey, fail);
+
+    PerformWithBuffer(di->output_size, ^(size_t size, uint8_t *hash_result) {
+        if (SOSCircleHash(di, circle, hash_result, error)) {
+            signature = SecKeyCopyRawHashSignature(di, hash_result, privKey, error);
+        }
+    });
+    require_quiet(signature, fail);
+    require_quiet(SOSCircleSetSignature(circle, privKey, signature, error), fail);
+
+    didSign = true;
+
+fail:
+    CFReleaseNull(signature);
+    return didSign;
+}
+
+CFDataRef SOSCircleCopyNextGenSignatureWithPeerAdded(SOSCircleRef circle, SOSPeerInfoRef peer, SecKeyRef privKey, CFErrorRef *error) {
+    const struct ccdigest_info *di = circle_signature_di();
+
+    __block CFDataRef signature = NULL;
+    require_quiet(privKey, fail);
+
+    PerformWithBuffer(di->output_size, ^(size_t size, uint8_t *hash_result) {
+        if (SOSCircleHashNextGenWithAdditionalPeer(di, circle, peer, hash_result, error)) {
+            signature = SecKeyCopyRawHashSignature(di, hash_result, privKey, error);
+        }
+    });
+
+fail:
+    return signature;
+}
+
+
+static bool SOSCircleConcordanceRingSign(SOSCircleRef circle, SecKeyRef privKey, CFErrorRef *error) {
+    secnotice("Development", "SOSCircleEnsureRingConsistency requires ring signing op", NULL);
+    return true;
+}
+
+
+bool SOSCircleVerifySignatureExists(SOSCircleRef circle, SecKeyRef pubKey, CFErrorRef *error) {
+    if(!pubKey) {
+        secerror("SOSCircleVerifySignatureExists no pubKey");
+        SOSCreateError(kSOSErrorBadFormat, CFSTR("SOSCircleVerifySignatureExists no pubKey"), (error != NULL) ? *error : NULL, error);
+        return false;
+    }
+    CFDataRef signature = SOSCircleGetSignature(circle, pubKey, error);
+    return NULL != signature;
+}
+
+CFStringRef SOSCircleCopyHashString(SOSCircleRef circle) {
+    const struct ccdigest_info *di = ccsha256_di();
+    uint8_t hash_result[di->output_size];
+    SOSCircleHash(di, circle, hash_result, NULL);
+    return SOSCopyHashBufAsString(hash_result, sizeof(hash_result));
+}
+
+bool SOSCircleVerify(SOSCircleRef circle, SecKeyRef pubKey, CFErrorRef *error) {
+    const struct ccdigest_info *di = ccsha256_di();
+    uint8_t hash_result[di->output_size];
+    
+    SOSCircleHash(di, circle, hash_result, error);
+
+    CFDataRef signature = SOSCircleGetSignature(circle, pubKey, error);
+    if(!signature) return false;
+
+    return SecError(SecKeyRawVerify(pubKey, kSecPaddingNone, hash_result, di->output_size,
+                                    CFDataGetBytePtr(signature), CFDataGetLength(signature)), error, CFSTR("Signature verification failed."));;
+}
+
+bool SOSCircleVerifyPeerSignatureExists(SOSCircleRef circle, SOSPeerInfoRef peer) {
+    bool result = false;
+    SecKeyRef pub_key = SOSPeerInfoCopyPubKey(peer, NULL);
+    require_quiet(pub_key, fail);
+    result = SOSCircleVerifySignatureExists(circle, pub_key, NULL);
+fail:
+    CFReleaseSafe(pub_key);
+    return result;
+}
+
+bool SOSCircleVerifyPeerSigned(SOSCircleRef circle, SOSPeerInfoRef peer, CFErrorRef *error) {
+    bool result = false;
+    SecKeyRef pub_key = SOSPeerInfoCopyPubKey(peer, error);
+    require_quiet(pub_key, fail);
+    
+    result = SOSCircleVerify(circle, pub_key, error);
+fail:
+    CFReleaseSafe(pub_key);
+    return result;
+}
+
+static void CFSetRemoveAllPassing(CFMutableSetRef set, bool (^test)(const void *) ){
+    CFMutableArrayRef toBeRemoved = CFArrayCreateMutable(kCFAllocatorDefault, 0, NULL);
+
+    CFSetForEach(set, ^(const void *value) {
+        if (test(value))
+            CFArrayAppendValue(toBeRemoved, value);
+    });
+    
+    CFArrayForEach(toBeRemoved, ^(const void *value) {
+        CFSetRemoveValue(set, value);
+    });
+    CFReleaseNull(toBeRemoved);
+}
+
+static void SOSCircleRejectNonValidApplicants(SOSCircleRef circle, SecKeyRef pubkey) {
+    CFMutableSetRef applicants = SOSCircleCopyApplicants(circle, NULL);
+    CFSetForEach(applicants, ^(const void *value) {
+        SOSPeerInfoRef pi = (SOSPeerInfoRef) value;
+        if(!SOSPeerInfoApplicationVerify(pi, pubkey, NULL)) {
+            CFSetTransferObject(pi, circle->applicants, circle->rejected_applicants);
+        }
+    });
+    CFReleaseNull(applicants);
+}
+
+static SOSPeerInfoRef SOSCircleCopyPeerInfo(SOSCircleRef circle, CFStringRef peer_id, CFErrorRef *error) {
+    __block SOSPeerInfoRef result = NULL;
+    
+    CFSetForEach(circle->peers, ^(const void *value) {
+        if (result == NULL) {
+            SOSPeerInfoRef tpi = (SOSPeerInfoRef)value;
+            if (CFEqual(SOSPeerInfoGetPeerID(tpi), peer_id))
+                result = tpi;
+        }
+    });
+    
+    CFRetainSafe(result);
+    return result;
+}
+
+static bool SOSCircleUpgradePeerInfo(SOSCircleRef circle, SecKeyRef user_approver, SOSFullPeerInfoRef peerinfo) {
+    bool retval = false;
+    SecKeyRef userPubKey = SecKeyCreatePublicFromPrivate(user_approver);
+    SOSPeerInfoRef fpi_pi = SOSFullPeerInfoGetPeerInfo(peerinfo);
+    SOSPeerInfoRef pi = SOSCircleCopyPeerInfo(circle, SOSPeerInfoGetPeerID(fpi_pi), NULL);
+    require_quiet(pi, out);
+    require_quiet(SOSPeerInfoApplicationVerify(pi, userPubKey, NULL), re_sign);
+    CFReleaseNull(userPubKey);
+    CFReleaseNull(pi);
+    return true;
+
+re_sign:
+    secnotice("circle", "SOSCircleGenerationSign: Upgraded peer's Application Signature");
+    SecKeyRef device_key = SOSFullPeerInfoCopyDeviceKey(peerinfo, NULL);
+    require_quiet(device_key, out);
+    SOSPeerInfoRef new_pi = SOSPeerInfoCopyAsApplication(pi, user_approver, device_key, NULL);
+    if(SOSCircleUpdatePeerInfo(circle, new_pi))
+        retval = true;
+    CFReleaseNull(new_pi);
+    CFReleaseNull(device_key);
+out:
+    CFReleaseNull(userPubKey);
+    CFReleaseNull(pi);
+    return retval;
+}
+
+static bool SOSCircleEnsureRingConsistency(SOSCircleRef circle, CFErrorRef *error) {
+    secnotice("Development", "SOSCircleEnsureRingConsistency requires ring membership and generation count consistency check", NULL);
+    return true;
+}
+
+bool SOSCircleSignOldStyleResetToOfferingCircle(SOSCircleRef circle, SOSFullPeerInfoRef peerinfo, SecKeyRef user_approver, CFErrorRef *error){
+    
+    SecKeyRef ourKey = SOSFullPeerInfoCopyDeviceKey(peerinfo, error);
+    SecKeyRef publicKey = NULL;
+    require_quiet(ourKey, fail);
+    
+    // Check if we're using an invalid peerinfo for this op.  There are cases where we might not be "upgraded".
+    require_quiet(SOSCircleUpgradePeerInfo(circle, user_approver, peerinfo), fail);
+    SOSCircleRemoveRetired(circle, error); // Prune off retirees since we're signing this one
+    CFSetRemoveAllValues(circle->rejected_applicants); // Dump rejects so we clean them up sometime.
+    publicKey = SecKeyCreatePublicFromPrivate(user_approver);
+    SOSCircleRejectNonValidApplicants(circle, publicKey);
+    require_quiet(SOSCircleEnsureRingConsistency(circle, error), fail);
+    require_quiet(SOSCircleRemoveSignatures(circle, error), fail);
+    require_quiet(SOSCircleSign(circle, user_approver, error), fail);
+    require_quiet(SOSCircleSign(circle, ourKey, error), fail);
+    
+    CFReleaseNull(ourKey);
+    CFReleaseNull(publicKey);
+    return true;
+    
+fail:
+    CFReleaseNull(ourKey);
+    CFReleaseNull(publicKey);
+    return false;
+}
+
+bool SOSCirclePreGenerationSign(SOSCircleRef circle, SecKeyRef userPubKey, CFErrorRef *error) {
+    bool retval = false;
+    
+    SOSCircleRemoveRetired(circle, error); // Prune off retirees since we're signing this one
+    CFSetRemoveAllValues(circle->rejected_applicants); // Dump rejects so we clean them up sometime.
+    SOSCircleRejectNonValidApplicants(circle, userPubKey);
+
+    require_quiet(SOSCircleRemoveSignatures(circle, error), errOut);
+    
+    retval = true;
+
+errOut:
+    return retval;
+    
+}
+
+static bool SOSCircleGenerationSign_Internal(SOSCircleRef circle, SecKeyRef userKey, SOSFullPeerInfoRef fpi, CFErrorRef *error) {
+    // require_quiet(SOSCircleEnsureRingConsistency(circle, error), fail); Placeholder - this was never implemented
+    bool retval = false;
+    SecKeyRef ourKey = NULL;
+    if (SOSCircleCountPeers(circle) != 0) {
+        ourKey = SOSFullPeerInfoCopyDeviceKey(fpi, error);
+        require_quiet(ourKey, errOut);
+        
+        // Check if we're using an invalid peerinfo for this op.  There are cases where we might not be "upgraded".
+        require_quiet(SOSCircleUpgradePeerInfo(circle, userKey, fpi), errOut);
+        
+        require_quiet(SOSCircleSign(circle, userKey, error), errOut);
+        require_quiet(SOSCircleSign(circle, ourKey, error), errOut);
+        CFReleaseNull(ourKey);
+    }
+    retval = true;
+    
+errOut:
+    CFReleaseNull(ourKey);
+    return retval;
+}
+
+bool SOSCircleGenerationSign(SOSCircleRef circle, SecKeyRef userKey, SOSFullPeerInfoRef fpi, CFErrorRef *error) {
+    bool retval = false;
+    SecKeyRef publicKey = NULL;
+    publicKey = SecKeyCreatePublicFromPrivate(userKey);
+
+    require_quiet(SOSCirclePreGenerationSign(circle, publicKey, error), errOut);
+    SOSCircleGenerationIncrement(circle);
+    require_quiet(SOSCircleGenerationSign_Internal(circle, userKey, fpi, error), errOut);
+    retval = true;
+    
+errOut:
+    CFReleaseNull(publicKey);
+    return retval;
+}
+
+
+static bool SOSCircleGenerationSignWithGenCount(SOSCircleRef circle, SecKeyRef userKey, SOSFullPeerInfoRef fpi, SOSGenCountRef gencount, CFErrorRef *error) {
+    bool retval = false;
+    SOSGenCountRef currentGen = SOSCircleGetGeneration(circle);
+    require_action_quiet(SOSGenerationIsOlder(currentGen, gencount), errOut, SOSCreateError(kSOSErrorReplay, CFSTR("Generation Count for new circle is too old"), NULL, error));
+    require_quiet(SOSCirclePreGenerationSign(circle, userKey, error), errOut);
+    SOSCircleSetGeneration(circle, gencount);
+    require_quiet(SOSCircleGenerationSign_Internal(circle, userKey, fpi, error), errOut);
+    retval = true;
+    
+errOut:
+    return retval;
+}
+
+
+bool SOSCircleConcordanceSign(SOSCircleRef circle, SOSFullPeerInfoRef peerinfo, CFErrorRef *error) {
+    bool success = false;
+    SecKeyRef ourKey = SOSFullPeerInfoCopyDeviceKey(peerinfo, error);
+    require_quiet(ourKey, exit);
+    
+    success = SOSCircleSign(circle, ourKey, error);
+    SOSCircleConcordanceRingSign(circle, ourKey, error);
+
+exit:
+    CFReleaseNull(ourKey);
+    return success;
+}
+
+static inline SOSConcordanceStatus CheckPeerStatus(SOSCircleRef circle, SOSPeerInfoRef peer, SecKeyRef user_public_key, CFErrorRef *error) {
+    SOSConcordanceStatus result = kSOSConcordanceNoPeer;
+    SecKeyRef pubKey = SOSPeerInfoCopyPubKey(peer, error);
+    require_quiet(pubKey, exit);
+
+    require_action_quiet(SOSCircleHasActiveValidPeer(circle, peer, user_public_key, error), exit, result = kSOSConcordanceNoPeer);
+    require_action_quiet(SOSCircleVerifySignatureExists(circle, pubKey, error), exit, result = kSOSConcordanceNoPeerSig);
+    require_action_quiet(SOSCircleVerify(circle, pubKey, error), exit, result = kSOSConcordanceBadPeerSig);
+
+    result = kSOSConcordanceTrusted;
+    
+exit:
+    CFReleaseNull(pubKey);
+    return result;
+}
+
+static inline SOSConcordanceStatus CombineStatus(SOSConcordanceStatus status1, SOSConcordanceStatus status2)
+{
+    if (status1 == kSOSConcordanceTrusted || status2 == kSOSConcordanceTrusted)
+        return kSOSConcordanceTrusted;
+    
+    if (status1 == kSOSConcordanceBadPeerSig || status2 == kSOSConcordanceBadPeerSig)
+        return kSOSConcordanceBadPeerSig;
+    
+    if (status1 == kSOSConcordanceNoPeerSig || status2 == kSOSConcordanceNoPeerSig)
+        return kSOSConcordanceNoPeerSig;
+
+    return status1;
+}
+
+static inline bool SOSCircleIsEmpty(SOSCircleRef circle) {
+    return SOSCircleCountPeers(circle) == 0;
+}
+
+static inline bool SOSCircleHasDegenerateGeneration(SOSCircleRef deGenCircle){
+    CFIndex testPtr;
+    CFNumberRef genCountTest = SOSCircleGetGeneration(deGenCircle);
+    CFNumberGetValue(genCountTest, kCFNumberCFIndexType, &testPtr);
+    return (testPtr== 0);
+}
+
+
+static inline bool SOSCircleIsDegenerateReset(SOSCircleRef deGenCircle){
+    return SOSCircleHasDegenerateGeneration(deGenCircle) && SOSCircleIsEmpty(deGenCircle);
+}
+
+
+__unused static inline bool SOSCircleIsResignOffering(SOSCircleRef circle, SecKeyRef pubkey) {
+    return SOSCircleCountActiveValidPeers(circle, pubkey) == 1;
+}
+
+static inline SOSConcordanceStatus GetSignersStatus(SOSCircleRef signers_circle, SOSCircleRef status_circle,
+                                                    SecKeyRef user_pubKey, SOSPeerInfoRef exclude, CFErrorRef *error) {
+    CFStringRef excluded_id = exclude ? SOSPeerInfoGetPeerID(exclude) : NULL;
+
+    __block SOSConcordanceStatus status = kSOSConcordanceNoPeer;
+    SOSCircleForEachActivePeer(signers_circle, ^(SOSPeerInfoRef peer) {
+        SOSConcordanceStatus peerStatus = CheckPeerStatus(status_circle, peer, user_pubKey, error);
+
+        if (peerStatus == kSOSConcordanceNoPeerSig &&
+            (CFEqualSafe(SOSPeerInfoGetPeerID(peer), excluded_id) || SOSPeerInfoIsCloudIdentity(peer)))
+            peerStatus = kSOSConcordanceNoPeer;
+
+        status = CombineStatus(status, peerStatus); // TODO: Use multiple error gathering.
+    });
+
+    return status;
+}
+
+// Is current older than proposed?
+bool SOSCircleIsOlderGeneration(SOSCircleRef older, SOSCircleRef newer) {
+    return SOSGenerationIsOlder(older->generation, newer->generation);
+}
+
+static inline bool SOSCircleIsValidReset(SOSCircleRef current, SOSCircleRef proposed) {
+    bool retval = false;
+    retval = SOSCircleIsEmpty(proposed);
+    require_quiet(retval, errOut);
+    retval = SOSCircleIsOlderGeneration(current, proposed);
+errOut:
+    return retval;
+}
+
+
+bool SOSCircleSharedTrustedPeers(SOSCircleRef current, SOSCircleRef proposed, SOSPeerInfoRef me) {
+    __block bool retval = false;
+    SOSCircleForEachPeer(current, ^(SOSPeerInfoRef peer) {
+        if(!CFEqual(me, peer) && SOSCircleHasPeer(proposed, peer, NULL)) retval = true;
+    });
+    return retval;
+}
+
+static SOSConcordanceStatus GetOfferingStatus(SOSCircleRef circle, SecKeyRef user_pubKey, CFErrorRef *error) {
+    __block SOSConcordanceStatus status = kSOSConcordanceNoPeer;
+    SOSCircleForEachPeer(circle, ^(SOSPeerInfoRef peer) {
+        status = CheckPeerStatus(circle, peer, user_pubKey, error);
+        if(status != kSOSConcordanceTrusted) status = kSOSConcordanceNoPeer;
+    });
+    return status;
+}
+
+
+SOSConcordanceStatus SOSCircleConcordanceTrust(SOSCircleRef known_circle, SOSCircleRef proposed_circle,
+                                               SecKeyRef known_pubkey, SecKeyRef user_pubkey,
+                                               SOSPeerInfoRef me, CFErrorRef *error) {
+    if(user_pubkey == NULL) {
+        SOSCreateError(kSOSErrorPublicKeyAbsent, CFSTR("Concordance with no user public key"), NULL, error);
+        return kSOSConcordanceNoUserKey;
+    }
+    
+    if(SOSCircleIsDegenerateReset(proposed_circle)) {
+        return kSOSConcordanceTrusted;
+    }
+
+    if (SOSCircleIsValidReset(known_circle, proposed_circle)) {
+        return kSOSConcordanceTrusted;
+    }
+    
+    if(!SOSCircleVerifySignatureExists(proposed_circle, user_pubkey, error)) {
+        SOSCreateError(kSOSErrorBadSignature, CFSTR("No public signature to match current user key"), (error != NULL) ? *error : NULL, error);
+        return kSOSConcordanceNoUserSig;
+    }
+    
+    if(!SOSCircleVerify(proposed_circle, user_pubkey, error)) {
+        SOSCreateError(kSOSErrorBadSignature, CFSTR("Bad user public signature"), (error != NULL) ? *error : NULL, error);
+        debugDumpCircle(CFSTR("proposed_circle"), proposed_circle);
+        return kSOSConcordanceBadUserSig;
+    }
+
+    if (SOSCircleIsEmpty(known_circle)) {
+        return GetSignersStatus(proposed_circle, proposed_circle, user_pubkey, NULL, error);
+    }
+    
+    if(SOSCircleHasDegenerateGeneration(proposed_circle) && SOSCircleIsOffering(proposed_circle)){
+        return GetSignersStatus(proposed_circle, proposed_circle, user_pubkey, NULL, error);
+    }
+    
+    if(SOSCircleIsOlderGeneration(proposed_circle, known_circle)) {
+        SOSCreateError(kSOSErrorReplay, CFSTR("Bad generation - proposed circle gencount is older than known circle gencount"), NULL, error);
+        debugDumpCircle(CFSTR("isOlderGeneration known_circle"), known_circle);
+        debugDumpCircle(CFSTR("isOlderGeneration proposed_circle"), proposed_circle);
+        return kSOSConcordanceGenOld;
+    }
+    
+    if(SOSCircleIsOffering(proposed_circle)){
+        return GetOfferingStatus(proposed_circle, user_pubkey, error);
+    }
+
+    return GetSignersStatus(known_circle, proposed_circle, user_pubkey, me, error);
+}
+
+
+static void SOSCircleDestroy(CFTypeRef aObj) {
+    SOSCircleRef c = (SOSCircleRef) aObj;
+
+    CFReleaseNull(c->name);
+    CFReleaseNull(c->generation);
+    CFReleaseNull(c->peers);
+    CFReleaseNull(c->applicants);
+    CFReleaseNull(c->rejected_applicants);
+    CFReleaseNull(c->signatures);
+}
+
+static CFMutableStringRef defaultDescriptionCreate(CFTypeRef aObj){
+    SOSCircleRef c = (SOSCircleRef) aObj;
+    CFStringRef initPeerSep = CFSTR("\n");
+    CFStringRef peerSep = CFSTR("\n");
+
+    CFMutableStringRef description = CFStringCreateMutable(kCFAllocatorDefault, 0);
+
+    SOSGenerationCountWithDescription(c->generation, ^(CFStringRef genDescription) {
+        CFStringAppendFormat(description, NULL, CFSTR("<SOSCircle@%p: '%@' %@ P:["), c, c->name, genDescription);
+    });
+
+    __block CFStringRef separator = initPeerSep;
+    SOSCircleForEachActivePeer(c, ^(SOSPeerInfoRef peer) {
+        CFStringRef sig = NULL;
+        if (SOSCircleVerifyPeerSigned(c, peer, NULL)) {
+            sig = CFSTR("√");
+        } else {
+            SecKeyRef pub_key = SOSPeerInfoCopyPubKey(peer, NULL);
+            CFDataRef signature = pub_key ? SOSCircleGetSignature(c, pub_key, NULL) : NULL;
+            sig = (signature == NULL) ? CFSTR("-") : CFSTR("?");
+            CFReleaseNull(pub_key);
+        }
+        
+        CFStringAppendFormat(description, NULL, CFSTR("%@%@ %@"), separator, peer, sig);
+        separator = peerSep;
+    });
+    
+    //applicants
+    CFStringAppend(description, CFSTR("], A:["));
+    separator = initPeerSep;
+    if(CFSetGetCount(c->applicants) == 0 )
+        CFStringAppendFormat(description, NULL, CFSTR("-"));
+    else{
+        
+        SOSCircleForEachApplicant(c, ^(SOSPeerInfoRef peer) {
+            CFStringAppendFormat(description, NULL, CFSTR("%@%@"), separator, peer);
+            separator = peerSep;
+        });
+    }
+    
+    //rejected
+    CFStringAppend(description, CFSTR("], R:["));
+    separator = initPeerSep;
+    if(CFSetGetCount(c->rejected_applicants) == 0)
+        CFStringAppendFormat(description, NULL, CFSTR("-"));
+    else{
+        CFSetForEach(c->rejected_applicants, ^(const void *value) {
+            SOSPeerInfoRef peer = (SOSPeerInfoRef) value;
+            CFStringAppendFormat(description, NULL, CFSTR("%@%@"), separator, peer);
+            separator = peerSep;
+        });
+    }
+    CFStringAppend(description, CFSTR("]>"));
+    return description;
+    
+}
+static CFMutableStringRef descriptionCreateWithFormatOptions(CFTypeRef aObj, CFDictionaryRef formatOptions){
+    SOSCircleRef c = (SOSCircleRef) aObj;
+
+    CFMutableStringRef description = CFStringCreateMutable(kCFAllocatorDefault, 0);
+
+    if(CFDictionaryContainsKey(formatOptions, CFSTR("SyncD"))) {
+        CFStringRef generationDescription = SOSGenerationCountCopyDescription(c->generation);
+        CFStringAppendFormat(description, NULL, CFSTR("<C: gen:'%@' %@>\n"), generationDescription, c->name);
+        CFReleaseNull(generationDescription);
+        __block CFStringRef separator = CFSTR("\t\t");
+        SOSCircleForEachActivePeer(c, ^(SOSPeerInfoRef peer) {
+            CFStringRef sig = NULL;
+            if (SOSCircleVerifyPeerSigned(c, peer, NULL)) {
+                sig = CFSTR("√");
+            } else {
+                SecKeyRef pub_key = SOSPeerInfoCopyPubKey(peer, NULL);
+                CFDataRef signature = pub_key ? SOSCircleGetSignature(c, pub_key, NULL) : NULL;
+                sig = (signature == NULL) ? CFSTR("-") : CFSTR("?");
+                CFReleaseNull(pub_key);
+            }
+            
+            CFStringAppendFormat(description, formatOptions, CFSTR("%@%@ %@"), separator, peer, sig);
+            separator = CFSTR("\n\t\t");
+        });
+        CFStringAppend(description, CFSTR("\n\t\t<A:["));
+        separator = CFSTR("");
+        
+        //applicants list
+        if(CFSetGetCount(c->applicants) == 0 )
+            CFStringAppendFormat(description, NULL, CFSTR("-"));
+        else{
+            
+            SOSCircleForEachApplicant(c, ^(SOSPeerInfoRef peer) {
+                CFStringAppendFormat(description, formatOptions, CFSTR("%@A: %@"), separator, peer);
+                separator = CFSTR("\n\t\t\t");
+            });
+        }
+        //rejected list
+        CFStringAppend(description, CFSTR("]> \n\t\t<R:["));
+        separator = CFSTR("");
+        if(CFSetGetCount(c->rejected_applicants) == 0)
+            CFStringAppendFormat(description, NULL, CFSTR("-"));
+        else{
+            CFSetForEach(c->rejected_applicants, ^(const void *value) {
+                SOSPeerInfoRef peer = (SOSPeerInfoRef) value;
+                CFStringAppendFormat(description, formatOptions, CFSTR("%@R: %@"), separator, peer);
+                separator = CFSTR("\n\t\t");
+            });
+        }
+        CFStringAppend(description, CFSTR("]>"));
+    }
+
+    else{
+        CFReleaseNull(description);
+        description = defaultDescriptionCreate(aObj);
+    }
+    
+    return description;
+    
+}
+
+
+static CFStringRef SOSCircleCopyFormatDescription(CFTypeRef aObj, CFDictionaryRef formatOptions) {
+    SOSCircleRef c = (SOSCircleRef) aObj;
+    SOSCircleAssertStable(c);
+    CFMutableStringRef description = NULL;
+    
+    if(formatOptions != NULL){
+        description = descriptionCreateWithFormatOptions(aObj, formatOptions);
+    }
+    else{
+        description = defaultDescriptionCreate(aObj);
+    }
+    return description;
+}
+
+CFStringRef SOSCircleGetName(SOSCircleRef circle) {
+    assert(circle);
+    assert(circle->name);
+    return circle->name;
+}
+
+const char *SOSCircleGetNameC(SOSCircleRef circle) {
+    CFStringRef name = SOSCircleGetName(circle);
+    if (!name)
+        return strdup("");
+    return CFStringToCString(name);
+}
+
+SOSGenCountRef SOSCircleGetGeneration(SOSCircleRef circle) {
+    assert(circle);
+    assert(circle->generation);
+    return circle->generation;
+}
+
+void SOSCircleSetGeneration(SOSCircleRef circle, SOSGenCountRef gencount) {
+    assert(circle);
+    CFReleaseNull(circle->generation);
+    circle->generation = CFRetainSafe(gencount);
+}
+
+int64_t SOSCircleGetGenerationSint(SOSCircleRef circle) {
+    SOSGenCountRef gen = SOSCircleGetGeneration(circle);
+    return SOSGetGenerationSint(gen);
+}
+
+void SOSCircleGenerationSetValue(SOSCircleRef circle, int64_t value) {
+    CFAssignRetained(circle->generation, SOSGenerationCreateWithValue(value));
+}
+
+void SOSCircleGenerationIncrement(SOSCircleRef circle) {
+    SOSGenCountRef old = circle->generation;
+    circle->generation = SOSGenerationIncrementAndCreate(old);
+    CFReleaseNull(old);
+}
+
+int SOSCircleCountPeers(SOSCircleRef circle) {
+    SOSCircleAssertStable(circle);
+    __block int count = 0;
+    SOSCircleForEachPeer(circle, ^(SOSPeerInfoRef peer) {
+        ++count;
+    });
+    return count;
+}
+
+int SOSCircleCountActivePeers(SOSCircleRef circle) {
+    SOSCircleAssertStable(circle);
+    __block int count = 0;
+    SOSCircleForEachActivePeer(circle, ^(SOSPeerInfoRef peer) {
+        ++count;
+    });
+    return count;
+}
+
+int SOSCircleCountActiveValidPeers(SOSCircleRef circle, SecKeyRef pubkey) {
+    SOSCircleAssertStable(circle);
+    __block int count = 0;
+    SOSCircleForEachActiveValidPeer(circle, pubkey, ^(SOSPeerInfoRef peer) {
+        ++count;
+    });
+    return count;
+}
+
+int SOSCircleCountValidSyncingPeers(SOSCircleRef circle, SecKeyRef pubkey) {
+    SOSCircleAssertStable(circle);
+    __block int count = 0;
+    SOSCircleForEachValidSyncingPeer(circle, pubkey, ^(SOSPeerInfoRef peer) {
+        ++count;
+    });
+    return count;
+
+}
+
+int SOSCircleCountRetiredPeers(SOSCircleRef circle) {
+    SOSCircleAssertStable(circle);
+    __block int count = 0;
+    SOSCircleForEachRetiredPeer(circle, ^(SOSPeerInfoRef peer) {
+        ++count;
+    });
+    return count;
+}
+
+int SOSCircleCountApplicants(SOSCircleRef circle) {
+    SOSCircleAssertStable(circle);
+    
+    return (int)CFSetGetCount(circle->applicants);
+}
+
+bool SOSCircleHasApplicant(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    
+    return CFSetContainsValue(circle->applicants, peerInfo);
+}
+
+CFMutableSetRef SOSCircleCopyApplicants(SOSCircleRef circle, CFAllocatorRef allocator) {
+    SOSCircleAssertStable(circle);
+    
+    return CFSetCreateMutableCopy(allocator, 0, circle->applicants);
+}
+
+int SOSCircleCountRejectedApplicants(SOSCircleRef circle) {
+    SOSCircleAssertStable(circle);
+    
+    return (int)CFSetGetCount(circle->rejected_applicants);
+}
+
+bool SOSCircleHasRejectedApplicant(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    return CFSetContainsValue(circle->rejected_applicants, peerInfo);
+}
+
+SOSPeerInfoRef SOSCircleCopyRejectedApplicant(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    return CFRetainSafe((SOSPeerInfoRef)CFSetGetValue(circle->rejected_applicants, peerInfo));
+}
+
+CFMutableArrayRef SOSCircleCopyRejectedApplicants(SOSCircleRef circle, CFAllocatorRef allocator) {
+    SOSCircleAssertStable(circle);
+    
+    return CFSetCopyValuesCFArray(circle->rejected_applicants);
+}
+
+bool SOSCircleResetToEmpty(SOSCircleRef circle, CFErrorRef *error) {
+    CFSetRemoveAllValues(circle->applicants);
+    CFSetRemoveAllValues(circle->rejected_applicants);
+    CFSetRemoveAllValues(circle->peers);
+    CFDictionaryRemoveAllValues(circle->signatures);
+    SOSGenCountRef oldGen = SOSCircleGetGeneration(circle);
+    SOSGenCountRef newGen = SOSGenerationCreateWithBaseline(oldGen);
+    SOSCircleSetGeneration(circle, newGen);
+    CFReleaseSafe(newGen);
+    return true;
+}
+
+bool SOSCircleResetToEmptyWithSameGeneration(SOSCircleRef circle, CFErrorRef *error) {
+    SOSGenCountRef gen = SOSGenerationCopy(SOSCircleGetGeneration(circle));
+    SOSCircleResetToEmpty(circle, error);
+    SOSCircleSetGeneration(circle, gen);
+    CFReleaseNull(gen);
+    return true;
+}
+
+bool SOSCircleResetToOffering(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef requestor, CFErrorRef *error){
+
+    return SOSCircleResetToEmpty(circle, error)
+        && SOSCircleRequestAdmission(circle, user_privkey, requestor, error)
+        && SOSCircleAcceptRequest(circle, user_privkey, requestor, SOSFullPeerInfoGetPeerInfo(requestor), error);
+}
+
+bool SOSCircleRemoveRetired(SOSCircleRef circle, CFErrorRef *error) {
+    CFSetRemoveAllPassing(circle->peers,  ^ bool (const void *element) {
+        SOSPeerInfoRef peer = (SOSPeerInfoRef) element;
+        
+        return SOSPeerInfoIsRetirementTicket(peer);
+    });
+    
+    return true;
+}
+
+static bool SOSCircleRecordAdmissionRequest(SOSCircleRef circle, SecKeyRef user_pubkey, SOSPeerInfoRef requestorPeerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    
+    bool isPeer = SOSCircleHasPeer(circle, requestorPeerInfo, error);
+    
+    require_action_quiet(!isPeer, fail, SOSCreateError(kSOSErrorAlreadyPeer, CFSTR("Cannot request admission when already a peer"), NULL, error));
+    
+    // This adds to applicants and will take off rejected if it's there.
+    CFSetTransferObject(requestorPeerInfo, circle->rejected_applicants, circle->applicants);
+    
+    return true;
+    
+fail:
+    return false;
+    
+}
+
+bool SOSCircleRequestReadmission(SOSCircleRef circle, SecKeyRef user_pubkey, SOSPeerInfoRef peer, CFErrorRef *error) {
+    bool success = false;
+    
+    require_quiet(SOSPeerInfoApplicationVerify(peer, user_pubkey, error), fail);
+    success = SOSCircleRecordAdmissionRequest(circle, user_pubkey, peer, error);
+fail:
+    return success;
+}
+
+bool SOSCircleRequestAdmission(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef requestor, CFErrorRef *error) {
+    bool success = false;
+    
+    SecKeyRef user_pubkey = SecKeyCreatePublicFromPrivate(user_privkey);
+    require_action_quiet(user_pubkey, fail, SOSCreateError(kSOSErrorBadKey, CFSTR("No public key for key"), NULL, error));
+
+    require(SOSFullPeerInfoPromoteToApplication(requestor, user_privkey, error), fail);
+    
+    success = SOSCircleRecordAdmissionRequest(circle, user_pubkey, SOSFullPeerInfoGetPeerInfo(requestor), error);
+fail:
+    CFReleaseNull(user_pubkey);
+    return success;
+}
+
+static bool sosCircleUpdatePeerInfoSet(CFMutableSetRef theSet, SOSPeerInfoRef replacement_peer_info) {
+    CFTypeRef old = NULL;
+    if(!replacement_peer_info) return false;
+    if(!(old = CFSetGetValue(theSet, replacement_peer_info))) return false;
+    if(CFEqualSafe(old, replacement_peer_info)) return false;
+    CFSetReplaceValue(theSet, replacement_peer_info);
+    return true;
+}
+
+bool SOSCircleUpdatePeerInfo(SOSCircleRef circle, SOSPeerInfoRef replacement_peer_info) {
+    if(sosCircleUpdatePeerInfoSet(circle->peers, replacement_peer_info)) return true;
+    if(sosCircleUpdatePeerInfoSet(circle->applicants, replacement_peer_info)) return true;
+    if(sosCircleUpdatePeerInfoSet(circle->rejected_applicants, replacement_peer_info)) return true;
+    return false;
+}
+
+static bool SOSCircleRemovePeerInternal(SOSCircleRef circle, SOSFullPeerInfoRef requestor, SOSPeerInfoRef peer_to_remove, CFErrorRef *error) {
+    SOSPeerInfoRef requestor_peer_info = SOSFullPeerInfoGetPeerInfo(requestor);
+
+    if (SOSCircleHasPeer(circle, peer_to_remove, NULL)) {
+        if (!SOSCircleHasPeer(circle, requestor_peer_info, error)) {
+            SOSCreateError(kSOSErrorAlreadyPeer, CFSTR("Must be peer to remove peer"), NULL, error);
+            return false;
+        }
+        CFSetRemoveValue(circle->peers, peer_to_remove);
+    }
+
+    if (SOSCircleHasApplicant(circle, peer_to_remove, error)) {
+        return SOSCircleRejectRequest(circle, requestor, peer_to_remove, error);
+    }
+
+    return true;
+}
+
+bool SOSCircleRemovePeers(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef requestor, CFSetRef peersToRemove, CFErrorRef *error) {
+
+    bool success = false;
+
+    __block bool removed_all = true;
+    CFSetForEach(peersToRemove, ^(const void *value) {
+        SOSPeerInfoRef peerInfo = asSOSPeerInfo(value);
+        if (peerInfo) {
+            removed_all &= SOSCircleRemovePeerInternal(circle, requestor, peerInfo, error);
+        }
+    });
+
+    require_quiet(removed_all, exit);
+
+    require_quiet(SOSCircleGenerationSign(circle, user_privkey, requestor, error), exit);
+
+    success = true;
+
+exit:
+    return success;
+}
+
+
+bool SOSCircleRemovePeersByID(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef requestor, CFSetRef peersToRemove, CFErrorRef *error) {
+    
+    bool success = false;
+    
+    __block bool removed_all = true;
+    CFSetForEach(peersToRemove, ^(const void *value) {
+        CFStringRef peerID = asString(value, NULL);
+        if(peerID) {
+            SOSPeerInfoRef peerInfo = SOSCircleCopyPeerInfo(circle, peerID, NULL);
+            if (peerInfo) {
+                removed_all &= SOSCircleRemovePeerInternal(circle, requestor, peerInfo, error);
+                CFReleaseNull(peerInfo);
+            }
+        }
+    });
+    
+    require_quiet(removed_all, exit);
+    
+    require_quiet(SOSCircleGenerationSign(circle, user_privkey, requestor, error), exit);
+    
+    success = true;
+    
+exit:
+    return success;
+}
+
+static bool SOSCircleRemovePeerUnsigned(SOSCircleRef circle, SOSPeerInfoRef peer_to_remove) {
+    bool retval = false;
+    if (SOSCircleHasPeer(circle, peer_to_remove, NULL)) {
+        CFSetRemoveValue(circle->peers, peer_to_remove);
+        retval = true;
+    }
+    return retval;
+}
+
+bool SOSCircleRemovePeersByIDUnsigned(SOSCircleRef circle, CFSetRef peersToRemove) {
+    __block bool removed_all = true;
+    CFSetForEach(peersToRemove, ^(const void *value) {
+        CFStringRef peerID = asString(value, NULL);
+        SOSPeerInfoRef peerInfo = SOSCircleCopyPeerInfo(circle, peerID, NULL);
+        removed_all &= SOSCircleRemovePeerUnsigned(circle, peerInfo);
+        CFReleaseNull(peerInfo);
+    });
+    return removed_all;
+}
+
+bool SOSCircleRemovePeer(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef requestor, SOSPeerInfoRef peer_to_remove, CFErrorRef *error) {
+    bool success = false;
+
+    require_quiet(SOSCircleRemovePeerInternal(circle, requestor, peer_to_remove, error), exit);
+
+    require_quiet(SOSCircleGenerationSign(circle, user_privkey, requestor, error), exit);
+
+    success = true;
+exit:
+    return success;
+}
+
+bool SOSCircleAcceptRequest(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef device_approver, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+
+    SecKeyRef publicKey = NULL;
+    bool result = false;
+
+    require_action_quiet(CFSetContainsValue(circle->applicants, peerInfo), fail,
+                         SOSCreateError(kSOSErrorNotApplicant, CFSTR("Cannot accept non-applicant"), NULL, error));
+    
+    publicKey = SecKeyCreatePublicFromPrivate(user_privkey);
+    require_quiet(SOSPeerInfoApplicationVerify(peerInfo, publicKey, error), fail);
+
+    CFSetTransferObject(peerInfo, circle->applicants, circle->peers);
+    
+    result = SOSCircleGenerationSign(circle, user_privkey, device_approver, error);
+
+fail:
+    CFReleaseNull(publicKey);
+    return result;
+}
+
+bool SOSCircleWithdrawRequest(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+
+    CFSetRemoveValue(circle->applicants, peerInfo);
+
+    return true;
+}
+
+bool SOSCircleRemoveRejectedPeer(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    
+    CFSetRemoveValue(circle->rejected_applicants, peerInfo);
+    
+    return true;
+}
+
+
+bool SOSCircleRejectRequest(SOSCircleRef circle, SOSFullPeerInfoRef device_rejector,
+                            SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+
+    if (CFEqual(SOSPeerInfoGetPeerID(peerInfo), SOSPeerInfoGetPeerID(SOSFullPeerInfoGetPeerInfo(device_rejector))))
+        return SOSCircleWithdrawRequest(circle, peerInfo, error);
+
+    if (!CFSetContainsValue(circle->applicants, peerInfo)) {
+        SOSCreateError(kSOSErrorNotApplicant, CFSTR("Cannot reject non-applicant"), NULL, error);
+        return false;
+    }
+    
+    CFSetTransferObject(peerInfo, circle->applicants, circle->rejected_applicants);
+    
+    // TODO: Maybe we sign the rejection with device_rejector.
+    
+    return true;
+}
+
+bool SOSCircleAcceptRequests(SOSCircleRef circle, SecKeyRef user_privkey, SOSFullPeerInfoRef device_approver,
+                             CFErrorRef *error) {
+    // Returns true if we accepted someone and therefore have to post the circle back to KVS
+    __block bool result = false;
+    
+    SOSCircleForEachApplicant(circle, ^(SOSPeerInfoRef peer) {
+        if (!SOSCircleAcceptRequest(circle, user_privkey, device_approver, peer, error)) {
+            secnotice("circle", "error in SOSCircleAcceptRequest\n");
+        } else {
+            secnotice("circle", "Accepted peer: %@", peer);
+            result = true;
+        }
+    });
+    
+    if (result) {
+        SOSCircleGenerationSign(circle, user_privkey, device_approver, error);
+        secnotice("circle", "Countersigned accepted requests");
+    }
+
+    return result;
+}
+
+bool SOSCirclePeerSigUpdate(SOSCircleRef circle, SecKeyRef userPrivKey, SOSFullPeerInfoRef fpi,
+                             CFErrorRef *error) {
+    // Returns true if we accepted someone and therefore have to post the circle back to KVS
+    __block bool result = false;
+    SecKeyRef userPubKey = SecKeyCreatePublicFromPrivate(userPrivKey);
+
+    // We're going to remove any applicants using a mismatched user key.
+    SOSCircleForEachApplicant(circle, ^(SOSPeerInfoRef peer) {
+        if(!SOSPeerInfoApplicationVerify(peer, userPubKey, NULL)) {
+            if(!SOSCircleRejectRequest(circle, fpi, peer, NULL)) {
+                // do we care?
+            }
+        }
+    });
+    
+    result = SOSCircleUpdatePeerInfo(circle, SOSFullPeerInfoGetPeerInfo(fpi));
+    
+    if (result) {
+        SOSCircleGenerationSign(circle, userPrivKey, fpi, error);
+        secnotice("circle", "Generation signed updated signatures on peerinfo");
+    }
+    
+    return result;
+}
+
+//
+// Peer iteration and membership
+//
+
+static inline void SOSCircleForEachPeerMatching(SOSCircleRef circle,
+                                                void (^action)(SOSPeerInfoRef peer),
+                                                bool (^condition)(SOSPeerInfoRef peer)) {
+    CFSetForEach(circle->peers, ^(const void *value) {
+        SOSPeerInfoRef peer = (SOSPeerInfoRef) value;
+        if (condition(peer))
+            action(peer);
+    });
+}
+
+static inline bool isHiddenPeer(SOSPeerInfoRef peer) {
+    return SOSPeerInfoIsRetirementTicket(peer) || SOSPeerInfoIsCloudIdentity(peer);
+}
+
+void SOSCircleForEachPeer(SOSCircleRef circle, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return !isHiddenPeer(peer);
+    });
+}
+
+void SOSCircleForEachRetiredPeer(SOSCircleRef circle, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return SOSPeerInfoIsRetirementTicket(peer);
+    });
+}
+
+void SOSCircleForEachiCloudIdentityPeer(SOSCircleRef circle, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return SOSPeerInfoIsCloudIdentity(peer);
+    });
+} 
+
+
+void SOSCircleForEachActivePeer(SOSCircleRef circle, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return true;
+    });
+}
+
+void SOSCircleForEachActiveValidPeer(SOSCircleRef circle, SecKeyRef user_public_key, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return SOSPeerInfoApplicationVerify(peer, user_public_key, NULL);
+    });
+}
+
+void SOSCircleForEachValidPeer(SOSCircleRef circle, SecKeyRef user_public_key, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return !isHiddenPeer(peer) && SOSPeerInfoApplicationVerify(peer, user_public_key, NULL);
+    });
+}
+
+void SOSCircleForEachValidSyncingPeer(SOSCircleRef circle, SecKeyRef user_public_key, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachValidPeer(circle, user_public_key, action);
+}
+
+void SOSCircleForEachBackupCapablePeerForView(SOSCircleRef circle, SecKeyRef user_public_key, CFStringRef viewName, void (^action)(SOSPeerInfoRef peer)) {
+    SOSCircleForEachPeerMatching(circle, action, ^bool(SOSPeerInfoRef peer) {
+        return (!isHiddenPeer(peer) && SOSPeerInfoIsEnabledView(peer, viewName) && SOSPeerInfoHasBackupKey(peer) && SOSPeerInfoApplicationVerify(peer, user_public_key, NULL));
+    });
+}
+
+void SOSCircleForEachApplicant(SOSCircleRef circle, void (^action)(SOSPeerInfoRef peer)) {
+    CFSetForEach(circle->applicants, ^(const void*value) { action((SOSPeerInfoRef) value); } );
+}
+
+
+bool SOSCircleHasPeerWithID(SOSCircleRef circle, CFStringRef peerid, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+
+    SOSPeerInfoRef found = asSOSPeerInfo(CFSetGetValue(circle->peers, peerid));
+    return found && !isHiddenPeer(found);
+}
+
+SOSPeerInfoRef SOSCircleCopyPeerWithID(SOSCircleRef circle, CFStringRef peerid, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+
+    SOSPeerInfoRef found = asSOSPeerInfo(CFSetGetValue(circle->peers, peerid));
+    return found ? SOSPeerInfoCreateCopy(kCFAllocatorDefault, found, NULL) : NULL;
+}
+
+bool SOSCircleHasPeer(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    if(!peerInfo) return false;
+    return SOSCircleHasPeerWithID(circle, SOSPeerInfoGetPeerID(peerInfo), error);
+}
+
+bool SOSCircleHasActivePeerWithID(SOSCircleRef circle, CFStringRef peerid, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    SOSPeerInfoRef found = asSOSPeerInfo(CFSetGetValue(circle->peers, peerid));
+    return found;
+}
+
+bool SOSCircleHasActivePeer(SOSCircleRef circle, SOSPeerInfoRef peerInfo, CFErrorRef *error) {
+    if(!peerInfo) return false;
+    return SOSCircleHasActivePeerWithID(circle, SOSPeerInfoGetPeerID(peerInfo), error);
+}
+
+bool SOSCircleHasActiveValidPeerWithID(SOSCircleRef circle, CFStringRef peerid, SecKeyRef user_public_key, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    SOSPeerInfoRef found = asSOSPeerInfo(CFSetGetValue(circle->peers, peerid));
+    return found && SOSPeerInfoApplicationVerify(found, user_public_key, NULL);
+}
+
+bool SOSCircleHasValidSyncingPeer(SOSCircleRef circle, SOSPeerInfoRef peerInfo, SecKeyRef user_public_key, CFErrorRef *error) {
+    SOSCircleAssertStable(circle);
+    SOSPeerInfoRef found = asSOSPeerInfo(CFSetGetValue(circle->peers, peerInfo));
+    return found && !isHiddenPeer(found) && SOSPeerInfoApplicationVerify(found, user_public_key, NULL);
+}
+
+bool SOSCircleHasActiveValidPeer(SOSCircleRef circle, SOSPeerInfoRef peerInfo, SecKeyRef user_public_key, CFErrorRef *error) {
+    if(!peerInfo) return false;
+    return SOSCircleHasActiveValidPeerWithID(circle, SOSPeerInfoGetPeerID(peerInfo), user_public_key, error);
+}
+
+
+CFMutableSetRef SOSCircleCopyPeers(SOSCircleRef circle, CFAllocatorRef allocator) {
+    SOSCircleAssertStable(circle);
+    
+    CFMutableSetRef result = CFSetCreateMutableForSOSPeerInfosByID(allocator);
+    
+    SOSCircleForEachPeer(circle, ^(SOSPeerInfoRef peer) {
+        CFSetAddValue(result, peer);
+    });
+
+    return result;
+}
+
+
+CFMutableSetRef SOSCircleCopyBackupCapablePeersForView(SOSCircleRef circle, CFAllocatorRef allocator, SecKeyRef userPubKey, CFStringRef viewName) {
+    SOSCircleAssertStable(circle);
+
+    CFMutableSetRef result = CFSetCreateMutableForSOSPeerInfosByID(allocator);
+
+    SOSCircleForEachBackupCapablePeerForView(circle, userPubKey, viewName, ^(SOSPeerInfoRef peer) {
+        CFSetAddValue(result, peer);
+    });
+
+    return result;
+}
+
+bool SOSCircleAppendConcurringPeers(SOSCircleRef circle, CFMutableArrayRef appendHere, CFErrorRef *error) {
+    SOSCircleForEachActivePeer(circle, ^(SOSPeerInfoRef peer) {
+        CFErrorRef localError = NULL;
+        if (SOSCircleVerifyPeerSigned(circle, peer, &localError)) {
+            SOSPeerInfoRef peerInfo = SOSPeerInfoCreateCopy(kCFAllocatorDefault, peer, error);
+            CFArrayAppendValue(appendHere, peerInfo);
+            CFRelease(peerInfo);
+        } else if (error != NULL) {
+            secerror("Error checking concurrence: %@", localError);
+        }
+        CFReleaseNull(localError);
+    });
+
+    return true;
+}
+
+CFMutableArrayRef SOSCircleCopyConcurringPeers(SOSCircleRef circle, CFErrorRef* error) {
+    SOSCircleAssertStable(circle);
+
+    CFMutableArrayRef concurringPeers = CFArrayCreateMutableForCFTypes(kCFAllocatorDefault);
+
+    if (!SOSCircleAppendConcurringPeers(circle, concurringPeers, error))
+        CFReleaseNull(concurringPeers);
+
+    return concurringPeers;
+}
+
+SOSFullPeerInfoRef SOSCircleCopyiCloudFullPeerInfoRef(SOSCircleRef circle, CFErrorRef *error) {
+    __block SOSFullPeerInfoRef cloud_full_peer = NULL;
+    __block CFErrorRef searchError = NULL;
+    SOSCircleForEachActivePeer(circle, ^(SOSPeerInfoRef peer) {
+        if (SOSPeerInfoIsCloudIdentity(peer)) {
+            if (cloud_full_peer == NULL) {
+                if (searchError) {
+                    secerror("More than one cloud identity found, first had error, trying new one.");
+                }
+                CFReleaseNull(searchError);
+                cloud_full_peer = SOSFullPeerInfoCreateCloudIdentity(kCFAllocatorDefault, peer, &searchError);
+                if (!cloud_full_peer) {
+                    secnotice("icloud-identity", "Failed to make FullPeer for iCloud Identity: %@ (%@)", cloud_full_peer, searchError);
+                }
+            } else {
+                secerror("Additional cloud identity found in circle after successful creation: %@", circle);
+            }
+        }
+    });
+    // If we didn't find one at all, report the error.
+    if (cloud_full_peer == NULL && searchError == NULL) {
+        SOSErrorCreate(kSOSErrorNoiCloudPeer, &searchError, NULL, CFSTR("No iCloud identity PeerInfo found in circle"));
+        secnotice("icloud-identity", "No iCloud identity PeerInfo found in circle");
+    }
+    if (error) {
+        CFTransferRetained(*error, searchError);
+    }
+    CFReleaseNull(searchError);
+    return cloud_full_peer;
+}
+
+SOSFullPeerInfoRef SOSCircleCopyiCloudFullPeerInfoVerifier(SOSCircleRef circle, CFErrorRef *error) {
+    __block CFErrorRef searchError = NULL;
+    __block SOSFullPeerInfoRef cloud_full_peer = NULL;
+    SOSCircleForEachActivePeer(circle, ^(SOSPeerInfoRef peer) {
+        // There should only ever be one signing iCloud identity.  If there are more we'll take the first one.
+        if (!cloud_full_peer && SOSPeerInfoIsCloudIdentity(peer) && SOSCircleVerifyPeerSignatureExists(circle, peer)) {
+            cloud_full_peer = SOSFullPeerInfoCreateCloudIdentity(kCFAllocatorDefault, peer, &searchError);
+        }
+    });
+    // If we didn't find one at all, report the error.
+    if (cloud_full_peer == NULL && searchError == NULL) {
+        SOSErrorCreate(kSOSErrorNoiCloudPeer, &searchError, NULL, CFSTR("No iCloud identity PeerInfo found in circle"));
+        secnotice("icloud-identity", "No iCloud identity PeerInfo found in circle");
+    }
+    if (error) {
+        CFTransferRetained(*error, searchError);
+    }
+    CFReleaseNull(searchError);
+    return cloud_full_peer;
+}
+
+void debugDumpCircle(CFStringRef message, SOSCircleRef circle) {
+    CFErrorRef error;
+
+    secinfo("circledebug", "%@: %@", message, circle);
+    if (!circle)
+        return;
+
+    CFDataRef derdata = SOSCircleCopyEncodedData(circle, kCFAllocatorDefault, &error);
+    if (derdata) {
+        CFStringRef hex = CFDataCopyHexString(derdata);
+        secinfo("circledebug", "Full contents: %@", hex);
+        if (hex) CFRelease(hex);
+        CFRelease(derdata);
+    }
+}
+
+bool SOSCircleAcceptPeerFromHSA2(SOSCircleRef circle, SecKeyRef userKey, SOSGenCountRef gencount, SecKeyRef pPubKey, CFDataRef signature, SOSFullPeerInfoRef fpi, CFErrorRef *error) {
+    SOSPeerInfoRef peerInfo = SOSFullPeerInfoGetPeerInfo(fpi);
+    bool res;
+
+    CFSetAddValue(circle->peers, peerInfo);
+
+    // Gen sign first, then add signature from our approver - remember gensign removes all existing sigs.
+    res = SOSCircleGenerationSignWithGenCount(circle, userKey, fpi, gencount, error);
+    if (!res) {
+        secnotice("circleOps", "Failed to regenerate circle with new gen count: %@", error ? *error : NULL);
+        return res;
+    }
+    res = SOSCircleSetSignature(circle, pPubKey, signature, error);
+    if (!res) {
+        secnotice("circleOps", "Failed to set signature: %@", error ? *error : NULL);
+        return res;
+    }
+    res = SOSCircleVerify(circle, pPubKey, error);
+    if (!res) {
+        secnotice("circleOps", "Circle failed to validate after peer signature: %@", error ? *error : NULL);
+        return res;
+    }
+    secnotice("circleOps", "Circle accepted successfully");
+
+    return true;
+}
+
+
+/*
+ ccstatus: Not in Circle (1)
+ Account user public is trusted
+ Generation Count: [2016-05-19 15:53 4]
+
+ */
+
+static inline void logPeerInfo(char *category, SOSCircleRef circle, SecKeyRef pubKey, CFStringRef myPID, SOSPeerInfoRef peer) {
+    char sigchr = 'v';
+    if (SOSCircleVerifyPeerSignatureExists(circle, peer)) {
+        sigchr = 'V';
+    }
+    SOSPeerInfoLogState(category, peer, pubKey, myPID, sigchr);
+}
+
+void SOSCircleLogState(char *category, SOSCircleRef circle, SecKeyRef pubKey, CFStringRef myPID) {
+    if(!circle) return;
+    CFStringRef genString = SOSGenerationCountCopyDescription(SOSCircleGetGeneration(circle));
+    char sigchr = 'v';
+    if(pubKey && SOSCircleVerifySignatureExists(circle, pubKey, NULL)) {
+        sigchr = 'V';
+    }
+    secnotice(category, "CIRCLE:    [%20@] UserSigned: %c", genString, sigchr);
+    if(CFSetGetCount(circle->peers) == 0 )
+        secnotice(category, "Peers In Circle: None");
+    else{
+        secnotice(category, "Peers In Circle:");
+        SOSCircleForEachPeer(circle, ^(SOSPeerInfoRef peer) {
+            logPeerInfo(category, circle, pubKey, myPID, peer);
+        });
+        SOSCircleForEachRetiredPeer(circle, ^(SOSPeerInfoRef peer) {
+            logPeerInfo(category, circle, pubKey, myPID, peer);
+        });
+        SOSCircleForEachiCloudIdentityPeer(circle, ^(SOSPeerInfoRef peer) {
+            logPeerInfo(category, circle, pubKey, myPID, peer);
+        });
+    }
+
+    //applicants
+    if(CFSetGetCount(circle->applicants) == 0 )
+        secnotice(category, "Applicants To Circle: None");
+    else{
+        secnotice(category, "Applicants To Circle:");
+
+        SOSCircleForEachApplicant(circle, ^(SOSPeerInfoRef peer) {
+            SOSPeerInfoLogState(category, peer, pubKey, myPID, 'v');
+        });
+    }
+    
+    //rejected
+    if(CFSetGetCount(circle->rejected_applicants) == 0)
+        secnotice(category, "Rejected Applicants To Circle: None");
+    else{
+        secnotice(category, "Rejected Applicants To Circle:");
+        CFSetForEach(circle->rejected_applicants, ^(const void *value) {
+            SOSPeerInfoRef peer = (SOSPeerInfoRef) value;
+            SOSPeerInfoLogState(category, peer, pubKey, myPID, 'v');
+        });
+    }
+    CFReleaseNull(genString);
+}
+