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[apple/security.git] / sec / Security / SecOTRFullIdentity.c
diff --git a/sec/Security/SecOTRFullIdentity.c b/sec/Security/SecOTRFullIdentity.c
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+/*
+ *  SecOTRFullIdentity.c
+ *  libsecurity_libSecOTR
+ *
+ *  Created by Mitch Adler on 2/9/11.
+ *  Copyright 2011 Apple Inc. All rights reserved.
+ *
+ */
+
+#include "SecOTR.h"
+#include "SecOTRIdentityPriv.h"
+#include <utilities/array_size.h>
+#include <utilities/SecCFWrappers.h>
+
+#include <AssertMacros.h>
+
+#include <CoreFoundation/CFNumber.h>
+#include <CoreFoundation/CFString.h>
+#include <CoreFoundation/CFData.h>
+
+#include <Security/SecItem.h>
+#include <Security/SecKeyPriv.h>
+
+#include <Security/oidsalg.h>
+#include <Security/SecCertificatePriv.h>
+
+#include "SecOTRErrors.h"
+
+#include <TargetConditionals.h>
+
+//
+// Algorthim ID initialization
+//
+
+#define kMessageIdentityRSAKeyBits 1280
+#define kMessageIdentityECKeyBits 256
+
+void EnsureOTRAlgIDInited(void)
+{
+    static dispatch_once_t kSignatureAlgID_ONCE;
+    static SecAsn1AlgId kOTRECSignatureAlgID;
+
+    dispatch_once(&kSignatureAlgID_ONCE, ^{
+        kOTRECSignatureAlgID.algorithm = CSSMOID_ECDSA_WithSHA1;
+        kOTRSignatureAlgIDPtr = &kOTRECSignatureAlgID;
+    });
+}
+
+
+static CFStringRef sSigningKeyName = CFSTR("OTR Signing Key");
+
+//
+// SecOTRFullIdentity implementation
+//
+
+CFGiblisFor(SecOTRFullIdentity);
+
+static CF_RETURNS_RETAINED CFStringRef SecOTRFullIdentityCopyDescription(CFTypeRef cf) {
+    SecOTRFullIdentityRef requestor = (SecOTRFullIdentityRef)cf;
+    return CFStringCreateWithFormat(kCFAllocatorDefault,NULL,CFSTR("<SecOTRPublicIdentity: %p %02x%02x%02x%02x%02x%02x%02x%02x>"),
+                                    requestor,
+                                    requestor->publicIDHash[0], requestor->publicIDHash[1],
+                                    requestor->publicIDHash[2], requestor->publicIDHash[3],
+                                    requestor->publicIDHash[4], requestor->publicIDHash[5],
+                                    requestor->publicIDHash[6], requestor->publicIDHash[7]);
+}
+
+static void SecOTRFullIdentityDestroy(CFTypeRef cf) {
+    SecOTRFullIdentityRef requestor = (SecOTRFullIdentityRef)cf;
+
+    CFReleaseNull(requestor->privateSigningKey);
+    CFReleaseNull(requestor->publicSigningKey);
+}
+
+
+//
+// Shared statics
+//
+
+static OSStatus SecOTRFIPurgeFromKeychainByValue(SecKeyRef key, CFStringRef label)
+{
+    OSStatus status;
+    const void *keys[] =   { kSecClass,
+        kSecAttrLabel,
+        kSecValueRef,
+    };
+    const void *values[] = { kSecClassKey,
+        label,
+        key,
+    };
+    CFDictionaryRef dict = CFDictionaryCreate(NULL, keys, values, array_size(values), NULL, NULL);
+    status = SecItemDelete(dict);
+    CFReleaseSafe(dict);
+
+    return status;
+}
+
+static bool SecKeyDigestAndSignWithError(
+                                  SecKeyRef           key,            /* Private key */
+                                  const SecAsn1AlgId  *algId,         /* algorithm oid/params */
+                                  const uint8_t       *dataToDigest,   /* signature over this data */
+                                  size_t              dataToDigestLen,/* length of dataToDigest */
+                                  uint8_t             *sig,                    /* signature, RETURNED */
+                                  size_t              *sigLen,         /* IN/OUT */
+                                  CFErrorRef          *error) {
+
+    OSStatus status = SecKeyDigestAndSign(key, algId, dataToDigest, dataToDigestLen, sig, sigLen);
+    require_noerr(status, fail);
+    return true;
+fail:
+    SecOTRCreateError(secOTRErrorOSError, status, CFSTR("Error signing message. OSStatus in error code."), NULL, error);
+    return false;
+}
+
+//
+// SecOTRFullIdentity Functions
+//
+
+static bool SecOTRFICachePublicHash(SecOTRFullIdentityRef fullID, CFErrorRef *error)
+{
+    SecOTRPublicIdentityRef pubID = SecOTRPublicIdentityCopyFromPrivate(NULL, fullID, error);
+
+    require(pubID, fail);
+
+    SecOTRPICopyHash(pubID, fullID->publicIDHash);
+
+fail:
+    CFReleaseSafe(pubID);
+    return (pubID != NULL); // This is safe because we're not accessing the value after release, just checking if it ever had a value of some nature.
+}
+
+#if !TARGET_OS_IPHONE && !TARGET_IPHONE_SIMULATOR
+#define SEC_CONST_DECL(k,v) CFTypeRef k = (CFTypeRef)(CFSTR(v));
+SEC_CONST_DECL (kSecAttrAccessible, "pdmn");
+SEC_CONST_DECL (kSecAttrAccessibleAlwaysThisDeviceOnly, "dku");
+#endif
+
+SecOTRFullIdentityRef SecOTRFullIdentityCreate(CFAllocatorRef allocator, CFErrorRef *error)
+{
+    CFDictionaryRef keygen_parameters = NULL;
+    SecOTRFullIdentityRef newID = CFTypeAllocate(SecOTRFullIdentity, struct _SecOTRFullIdentity, allocator);
+    SecKeyRef tempSigningKey = NULL;
+
+    newID->publicSigningKey = NULL;
+    newID->privateSigningKey = NULL;
+
+    require(newID, out);
+
+    EnsureOTRAlgIDInited();
+
+    const int signing_keySizeLocal = kMessageIdentityECKeyBits;
+    CFNumberRef signing_bitsize = CFNumberCreate(kCFAllocatorDefault, kCFNumberIntType, &signing_keySizeLocal);
+
+    const void *signing_keygen_keys[] = { kSecAttrKeyType,
+                                          kSecAttrKeySizeInBits,
+                                          kSecAttrIsPermanent,
+                                          kSecAttrAccessible,
+                                          kSecAttrLabel,
+                                        };
+
+    const void *signing_keygen_vals[] = { kSecAttrKeyTypeEC,
+                                          signing_bitsize,
+                                          kCFBooleanTrue,
+                                          kSecAttrAccessibleAlwaysThisDeviceOnly,
+                                          sSigningKeyName
+                                        };
+    keygen_parameters = CFDictionaryCreate(kCFAllocatorDefault,
+                                           signing_keygen_keys, signing_keygen_vals, array_size(signing_keygen_vals),
+                                           &kCFTypeDictionaryKeyCallBacks, &kCFTypeDictionaryValueCallBacks );
+    CFReleaseNull(signing_bitsize);
+    require_noerr(SecKeyGeneratePair(keygen_parameters, &tempSigningKey, &newID->privateSigningKey), out);
+    CFReleaseNull(keygen_parameters);
+
+    newID->publicSigningKey = SecKeyCreatePublicFromPrivate(tempSigningKey);
+
+    (void) SecOTRFIPurgeFromKeychainByValue(tempSigningKey, sSigningKeyName);
+    CFReleaseNull(tempSigningKey);
+
+    require(SecOTRFICachePublicHash(newID, error), out);
+
+    return newID;
+
+out:
+    if (NULL != newID) {
+        SecOTRFIPurgeFromKeychain(newID, NULL);
+    }
+    CFReleaseSafe(keygen_parameters);
+    CFReleaseSafe(newID);
+    CFReleaseSafe(tempSigningKey);
+    return NULL;
+}
+
+
+static
+OSStatus SecOTRFICreatePrivateKeyReadPersistentRef(const uint8_t **bytes, size_t *size, SecKeyRef* privateKey)
+{
+    OSStatus status = errSecParam;
+    uint16_t dataSize;
+    CFDataRef persistentRef = NULL;
+
+    require_noerr_quiet(readSize(bytes, size, &dataSize), fail);
+    require_quiet(dataSize <= *size, fail);
+
+    SecKeyRef lookedUpKey = NULL;
+    persistentRef = CFDataCreateWithBytesNoCopy(kCFAllocatorDefault, *bytes, dataSize, kCFAllocatorNull);
+    require_quiet(persistentRef, fail);
+
+    require_noerr_quiet(SecKeyFindWithPersistentRef(persistentRef, &lookedUpKey), fail);
+
+    *privateKey = lookedUpKey;
+
+    *bytes += dataSize;
+    *size -= dataSize;
+
+    status = errSecSuccess;
+
+fail:
+    CFReleaseSafe(persistentRef);
+
+    return status;
+}
+
+static
+OSStatus SecOTRFICreateKeysFromReadPersistentRef(const uint8_t **bytes, size_t *size, SecKeyRef *publicKey, SecKeyRef* privateKey)
+{
+    SecKeyRef foundKey = NULL;
+
+    OSStatus status = SecOTRFICreatePrivateKeyReadPersistentRef(bytes, size, &foundKey);
+    require_noerr_quiet(status, fail);
+    require_quiet(foundKey, fail);
+
+    *publicKey = SecKeyCreatePublicFromPrivate(*privateKey);
+    require_action_quiet(*publicKey, fail, status = errSecParam);
+
+    *privateKey = foundKey;
+    foundKey = NULL;
+
+    status = errSecSuccess;
+
+fail:
+    CFReleaseSafe(foundKey);
+    return status;
+}
+
+typedef SecKeyRef (*SecOTRPublicKeyCreateFunction)(CFAllocatorRef allocator, const uint8_t** data, size_t* limit);
+
+static
+OSStatus SecOTRFICreateKeysFromReadPersistentRefAndPublicKey(const uint8_t **bytes, size_t *size, SecKeyRef *publicKey, SecKeyRef* privateKey, SecOTRPublicKeyCreateFunction createPublic)
+{
+    SecKeyRef foundKey = NULL;
+
+    OSStatus status = SecOTRFICreatePrivateKeyReadPersistentRef(bytes, size, &foundKey);
+    require_noerr_quiet(status, fail);
+    require_quiet(foundKey, fail);
+
+    *publicKey = (*createPublic)(NULL, bytes, size);
+    require_action_quiet(*publicKey, fail, status = errSecParam);
+
+    *privateKey = foundKey;
+
+fail:
+    return status;
+}
+
+static
+OSStatus SecOTRFIInitFromV1Bytes(SecOTRFullIdentityRef newID, CFAllocatorRef allocator,
+                                const uint8_t **bytes,size_t *size) {
+    require(**bytes == 1, fail);
+    ++*bytes;
+    --*size;
+
+    require_noerr_quiet(SecOTRFICreateKeysFromReadPersistentRef(bytes, size, &newID->publicSigningKey, &newID->privateSigningKey), fail);
+
+    return errSecSuccess;
+
+fail:
+    CFReleaseNull(newID->publicSigningKey);
+    CFReleaseNull(newID->privateSigningKey);
+
+    return errSecParam;
+}
+
+static
+OSStatus SecOTRFIInitFromV2Bytes(SecOTRFullIdentityRef newID, CFAllocatorRef allocator,
+                                const uint8_t **bytes,size_t *size) {
+    require(**bytes == 2, fail);
+    ++*bytes;
+    --*size;
+
+    require_noerr_quiet(SecOTRFICreateKeysFromReadPersistentRefAndPublicKey(bytes, size, &newID->publicSigningKey, &newID->privateSigningKey, &CreateECPublicKeyFrom), fail);
+
+    return errSecSuccess;
+
+fail:
+    CFReleaseNull(newID->publicSigningKey);
+    CFReleaseNull(newID->privateSigningKey);
+
+    return errSecParam;
+}
+
+SecOTRFullIdentityRef SecOTRFullIdentityCreateFromSecKeyRef(CFAllocatorRef allocator, SecKeyRef privateKey,
+                                                            CFErrorRef *error) {
+    // TODO - make sure this is an appropriate key type
+    SecOTRFullIdentityRef newID = CFTypeAllocate(SecOTRFullIdentity, struct _SecOTRFullIdentity, allocator);
+    newID->privateSigningKey = privateKey;
+    CFRetain(newID->privateSigningKey);
+    newID->publicSigningKey = SecKeyCreatePublicFromPrivate(privateKey);
+    require(SecOTRFICachePublicHash(newID, error), fail);
+    return newID;
+fail:
+    CFRelease(newID->privateSigningKey);
+    CFRelease(newID->publicSigningKey);
+    CFReleaseSafe(newID);
+    return NULL;
+}
+
+SecOTRFullIdentityRef SecOTRFullIdentityCreateFromBytes(CFAllocatorRef allocator, const uint8_t**bytes, size_t *size, CFErrorRef *error)
+{
+    SecOTRFullIdentityRef newID = CFTypeAllocate(SecOTRFullIdentity, struct _SecOTRFullIdentity, allocator);
+    EnsureOTRAlgIDInited();
+
+    require(*size > 0, fail);
+
+    switch (**bytes) {
+        case 1:
+            require_noerr_quiet(SecOTRFIInitFromV1Bytes(newID, allocator, bytes, size), fail);
+            break;
+        case 2:
+            require_noerr_quiet(SecOTRFIInitFromV2Bytes(newID, allocator, bytes, size), fail);
+            break;
+        case 0: // Version 0 was used in seeds of 5.0, transition from those seeds unsupported - keys were in exported data.
+        default:
+            require(false, fail);
+            break;
+    }
+
+    require(SecOTRFICachePublicHash(newID, error), fail);
+
+    return newID;
+
+fail:
+    if (NULL != newID) {
+        SecOTRFIPurgeFromKeychain(newID, NULL);
+    }
+    CFReleaseSafe(newID);
+    return NULL;
+}
+
+SecOTRFullIdentityRef SecOTRFullIdentityCreateFromData(CFAllocatorRef allocator, CFDataRef data, CFErrorRef *error)
+{
+    if (data == NULL)
+        return NULL;
+
+    size_t size = (size_t)CFDataGetLength(data);
+    const uint8_t* bytes = CFDataGetBytePtr(data);
+
+    return SecOTRFullIdentityCreateFromBytes(allocator, &bytes, &size, error);
+}
+
+bool SecOTRFIPurgeFromKeychain(SecOTRFullIdentityRef thisID, CFErrorRef *error)
+{
+    OSStatus result = SecOTRFIPurgeFromKeychainByValue(thisID->privateSigningKey, sSigningKeyName);
+    if (errSecSuccess == result) {
+        return true;
+    } else {
+        SecOTRCreateError(secOTRErrorOSError, result, CFSTR("OSStatus returned in error code"), NULL, error);
+        return false;
+    }
+}
+
+
+static OSStatus SecOTRFIPurgeAllFromKeychainByLabel(CFStringRef label)
+{
+    OSStatus status;
+    const void *keys[] =   { kSecClass,
+        kSecAttrKeyClass,
+        kSecAttrLabel,
+    };
+    const void *values[] = { kSecClassKey,
+        kSecAttrKeyClassPrivate,
+        label,
+    };
+    CFDictionaryRef dict = CFDictionaryCreate(NULL, keys, values, array_size(values), NULL, NULL);
+    bool deleteAtLeastOne = false;
+    int loopLimiter = 500;
+    do {
+        status = SecItemDelete(dict);
+        if (status == errSecSuccess) {
+            deleteAtLeastOne = true;
+        }
+        loopLimiter--;
+    } while ((status == errSecSuccess) && (loopLimiter > 0));
+    if ((status == errSecItemNotFound) && (deleteAtLeastOne)) {
+        // We've looped until we can't delete any more keys.
+        // Since this will produce an expected 'itemNotFound', but we don't want to break the contract above
+        // (and also we want to make sense)
+        // we muffle the non-error to a success case, which it is.
+        status = errSecSuccess;
+    }
+    CFReleaseSafe(dict);
+
+    return status;
+}
+
+bool SecOTRFIPurgeAllFromKeychain(CFErrorRef *error)
+{
+    OSStatus result = SecOTRFIPurgeAllFromKeychainByLabel(sSigningKeyName);
+    if (errSecSuccess == result) {
+        return true;
+    } else {
+        SecOTRCreateError(secOTRErrorOSError, result, CFSTR("OSStatus returned in error code"), NULL, error);
+        return false;
+    }
+}
+
+static OSStatus appendPersistentRefData(SecKeyRef theKey, CFMutableDataRef serializeInto, CFStringRef name)
+{
+    OSStatus status;
+    CFDataRef persistent_ref = NULL;
+    require_noerr(status = SecKeyCopyPersistentRef(theKey, &persistent_ref), fail);
+
+    status = appendSizeAndData(persistent_ref, serializeInto);
+
+fail:
+    CFReleaseSafe(persistent_ref);
+
+    return status;
+}
+
+static OSStatus SecOTRFIAppendV2Serialization(SecOTRFullIdentityRef fullID, CFMutableDataRef serializeInto)
+{
+    const uint8_t version = 2;
+    CFIndex start = CFDataGetLength(serializeInto);
+
+    CFDataAppendBytes(serializeInto, &version, sizeof(version));
+
+    require(errSecSuccess == appendPersistentRefData(fullID->privateSigningKey, serializeInto, sSigningKeyName), fail);
+    require(errSecSuccess == appendPublicOctetsAndSize(fullID->publicSigningKey, serializeInto), fail);
+    return errSecSuccess;
+
+fail:
+    CFDataSetLength(serializeInto, start);
+
+    return errSecParam;
+}
+
+
+bool SecOTRFIAppendSerialization(SecOTRFullIdentityRef fullID, CFMutableDataRef serializeInto, CFErrorRef *error)
+{
+    OSStatus status = SecOTRFIAppendV2Serialization(fullID, serializeInto);
+    if (errSecSuccess == status) {
+        return true;
+    } else {
+        SecOTRCreateError(secOTRErrorOSError, status, CFSTR("OSStatus returned in error code"), NULL, error);
+        return false;
+    }
+}
+
+size_t SecOTRFISignatureSize(SecOTRFullIdentityRef fullID)
+{
+    return SecKeyGetSize(fullID->publicSigningKey, kSecKeySignatureSize);
+}
+
+bool SecOTRFIAppendSignature(SecOTRFullIdentityRef fullID,
+                                CFDataRef dataToHash,
+                                CFMutableDataRef appendTo,
+                                CFErrorRef *error)
+{
+    const size_t signatureSize = SecOTRFISignatureSize(fullID);
+    const CFIndex sourceLength = CFDataGetLength(dataToHash);
+    const uint8_t* sourceData = CFDataGetBytePtr(dataToHash);
+
+    CFIndex start = CFDataGetLength(appendTo);
+
+    require(((CFIndex)signatureSize) >= 0, fail);
+
+    CFDataIncreaseLength(appendTo, (CFIndex)signatureSize + 1);
+
+    uint8_t *size = CFDataGetMutableBytePtr(appendTo) + start;
+    uint8_t* signatureStart = size + 1;
+    size_t signatureUsed = signatureSize;
+
+   require(SecKeyDigestAndSignWithError(fullID->privateSigningKey, kOTRSignatureAlgIDPtr,
+                                    sourceData, (size_t)sourceLength,
+                                    signatureStart, &signatureUsed, error), fail);
+
+    require(signatureUsed < 256, fail);
+    require(((CFIndex)signatureUsed) >= 0, fail);
+    *size = signatureUsed;
+
+    CFDataSetLength(appendTo, start + (CFIndex)signatureUsed + 1);
+
+    return true;
+
+fail:
+    CFDataSetLength(appendTo, start);
+
+    return false;
+}
+
+void SecOTRFIAppendPublicHash(SecOTRFullIdentityRef fullID, CFMutableDataRef appendTo)
+{
+    CFDataAppendBytes(appendTo, fullID->publicIDHash, sizeof(fullID->publicIDHash));
+}
+
+bool SecOTRFIComparePublicHash(SecOTRFullIdentityRef fullID, const uint8_t hash[kMPIDHashSize])
+{
+    return 0 == memcmp(hash, fullID->publicIDHash, kMPIDHashSize);
+}