//

 //  MYPrivateKey.m

 //  MYCrypto

 //

 //  Created by Jens Alfke on 4/7/09.

 //  Copyright 2009 Jens Alfke. All rights reserved.

 //

 #import "MYPrivateKey.h"

 #import "MYCrypto_Private.h"

 #import "MYDigest.h"

 #import <CommonCrypto/CommonDigest.h>

 #if !TARGET_OS_IPHONE

 #import "MYCertGen.h"

 #endif

 @implementation MYPrivateKey

 - (id) initWithKeyRef: (SecKeyRef)privateKey

 {

     self = [super initWithKeyRef: privateKey];

     if (self) {

         // No public key given, so look it up:

         MYSHA1Digest *digest = self._keyDigest;

         if (digest)

             _publicKey = [[self.keychain publicKeyWithDigest: digest] retain];

         if (!_publicKey) {

             // The matching public key won't turn up if it's embedded in a certificate;

             // I'd have to search for certs if I wanted to look that up. Skip it for now.

             Log(@"MYPrivateKey(%p): Couldn't find matching public key for private key! digest=%@",

                 self, digest);

             [self release];

             return nil;

         }

     }

     return self;

 }

 - (id) _initWithKeyRef: (SecKeyRef)privateKey

              publicKey: (MYPublicKey*)publicKey 

 {

     Assert(publicKey);

     self = [super initWithKeyRef: privateKey];

     if (self) {

         _publicKey = [publicKey retain];

     }

     return self;

 }

 - (id) initWithKeyRef: (SecKeyRef)privateKey

          publicKeyRef: (SecKeyRef)publicKeyRef

 {

     MYPublicKey *publicKey = [[MYPublicKey alloc] initWithKeyRef: publicKeyRef];

     self = [self _initWithKeyRef: privateKey publicKey: publicKey];

     [publicKey release];

     return self;

 }

 - (id) _initWithKeyRef: (SecKeyRef)privateKey 

          publicKeyData: (NSData*)pubKeyData

            forKeychain: (SecKeychainRef)keychain 

 {

     if (!privateKey) {

         [self release];

         return nil;

     }

     MYPublicKey *pubKey = [[MYPublicKey alloc] _initWithKeyData: pubKeyData forKeychain: keychain];

     if (!pubKey) {

         [self release];

         return nil;

     }

     self = [super initWithKeyRef: privateKey];

     if (self) {

         _publicKey = pubKey;

     } else {

         [pubKey removeFromKeychain];

         [pubKey release];

     }

     return self;

 }

 #if !TARGET_OS_IPHONE

 // The public API for this is in MYKeychain.

 - (id) _initWithKeyData: (NSData*)privKeyData 

           publicKeyData: (NSData*)pubKeyData

             forKeychain: (SecKeychainRef)keychain 

              alertTitle: (NSString*)title

             alertPrompt: (NSString*)prompt

 {

     // Try to import the private key first, since the user might cancel the passphrase alert.

     SecKeyImportExportParameters params = {

         .flags = kSecKeySecurePassphrase,

         .alertTitle = (CFStringRef) title,

         .alertPrompt = (CFStringRef) prompt

     };

     SecKeyRef privateKey = importKey(privKeyData,kSecItemTypePrivateKey,keychain,&params);

     return [self _initWithKeyRef: privateKey publicKeyData: pubKeyData forKeychain: keychain];

 }

 // This method is for testing, so unit-tests don't require user intervention.

 // It's deliberately not made public, to discourage clients from trying to manage the passphrases

 // themselves (this is less secure than letting the Security agent do it.)

 - (id) _initWithKeyData: (NSData*)privKeyData 

           publicKeyData: (NSData*)pubKeyData

             forKeychain: (SecKeychainRef)keychain 

              passphrase: (NSString*)passphrase

 {

     SecKeyImportExportParameters params = {

         .passphrase = (CFStringRef) passphrase,

     };

     SecKeyRef privateKey = importKey(privKeyData,kSecItemTypePrivateKey,keychain,&params);

     return [self _initWithKeyRef: privateKey publicKeyData: pubKeyData forKeychain: keychain];

 }

 #endif

 - (void) dealloc

 {

     [_publicKey release];

     [super dealloc];

 }

 + (MYPrivateKey*) _generateRSAKeyPairOfSize: (unsigned)keySize

                                  inKeychain: (MYKeychain*)keychain 

 {

     Assert( keySize == 512 || keySize == 1024 || keySize == 2048, @"Unsupported key size %u", keySize );

     SecKeyRef pubKey=NULL, privKey=NULL;

     OSStatus err;

 #if MYCRYPTO_USE_IPHONE_API

     NSDictionary *pubKeyAttrs = $dict({(id)kSecAttrIsPermanent, $true});

     NSDictionary *privKeyAttrs = $dict({(id)kSecAttrIsPermanent, $true});

     NSDictionary *keyAttrs = $dict( {(id)kSecAttrKeyType, (id)kSecAttrKeyTypeRSA},

                                     {(id)kSecAttrKeySizeInBits, $object(keySize)},

                                     {(id)kSecPublicKeyAttrs, pubKeyAttrs},

                                     {(id)kSecPrivateKeyAttrs, privKeyAttrs} );

     err = SecKeyGeneratePair((CFDictionaryRef)keyAttrs,&pubKey,&privKey);

 #else

     err = SecKeyCreatePair(keychain.keychainRefOrDefault,

                            CSSM_ALGID_RSA, 

                            keySize,

                            0LL,

                            CSSM_KEYUSE_ENCRYPT | CSSM_KEYUSE_VERIFY | CSSM_KEYUSE_WRAP,        // public key

                            CSSM_KEYATTR_EXTRACTABLE | CSSM_KEYATTR_PERMANENT,

                            CSSM_KEYUSE_ANY,                                 // private key

                            CSSM_KEYATTR_EXTRACTABLE | CSSM_KEYATTR_PERMANENT | CSSM_KEYATTR_SENSITIVE,

                            NULL,                                            // SecAccessRef

                            &pubKey, &privKey);

 #endif

     if (!check(err, @"SecKeyCreatePair")) {

         return nil;

     } else

         return [[[self alloc] initWithKeyRef: privKey publicKeyRef: pubKey] autorelease];

 }

 #pragma mark -

 #pragma mark ACCESSORS:

 - (NSString*) description {

     return $sprintf(@"%@[%@ %@ /%p]", [self class], 

                     self.publicKeyDigest.abbreviatedHexString,

                     (self.name ?:@""),

                     self.keychainItemRef);

 }

 @synthesize publicKey=_publicKey;

 - (MYSHA1Digest*) _keyDigest {

     if (_publicKey)

         return _publicKey.publicKeyDigest;

     else {

         NSData *digestData;

 #if MYCRYPTO_USE_IPHONE_API

         digestData = [self _attribute: kSecAttrApplicationLabel];

 #else

         digestData = [[self class] _getAttribute: kSecKeyLabel 

                                           ofItem: (SecKeychainItemRef)self.keyRef]; 

 #endif

         return [MYSHA1Digest digestFromDigestData: digestData];

     }

 }

 - (MYSHA1Digest*) publicKeyDigest {

     return self._keyDigest;

 }

 - (SecExternalItemType) keyClass {

 #if MYCRYPTO_USE_IPHONE_API

     return kSecAttrKeyClassPublic;

 #else

     return kSecItemTypePrivateKey;

 #endif

 }

 #if MYCRYPTO_USE_IPHONE_API

 - (SecExternalItemType) keyType {

     return kSecAttrKeyTypeRSA;

 }

 #endif

 - (NSData *) keyData {

     [NSException raise: NSGenericException format: @"Can't access keyData of a PrivateKey"];

     return nil;

 }

 - (BOOL) setValue: (NSString*)valueStr ofAttribute: (SecKeychainAttrType)attr {

     return [super setValue: valueStr ofAttribute: attr]

         && [_publicKey setValue: valueStr ofAttribute: attr];

 }

 #pragma mark -

 #pragma mark OPERATIONS:

 - (BOOL) removeFromKeychain {

     return [super removeFromKeychain]

         && [_publicKey removeFromKeychain];

 }

 - (NSData*) rawDecryptData: (NSData*)data {

     return [self _crypt: data operation: NO];

 }

 - (NSData*) signData: (NSData*)data {

     Assert(data);

 #if MYCRYPTO_USE_IPHONE_API

     uint8_t digest[CC_SHA1_DIGEST_LENGTH];

     CC_SHA1(data.bytes,data.length, digest);

     size_t sigLen = 1024;

     uint8_t sigBuf[sigLen];

     OSStatus err = SecKeyRawSign(self.keyRef, kSecPaddingPKCS1SHA1,

                                  digest,sizeof(digest), //data.bytes, data.length,

                                  sigBuf, &sigLen);

     if(err) {

         Warn(@"SecKeyRawSign failed: %i",err);

         return nil;

     } else

         return [NSData dataWithBytes: sigBuf length: sigLen];

 #else

     NSData *signature = nil;

     CSSM_CC_HANDLE ccHandle = [self _createSignatureContext: CSSM_ALGID_SHA1WithRSA];

     if (!ccHandle) return nil;

     CSSM_DATA original = {data.length, (void*)data.bytes};

     CSSM_DATA result = {0,NULL};

     if (checkcssm(CSSM_SignData(ccHandle, &original, 1, CSSM_ALGID_NONE, &result), @"CSSM_SignData"))

         signature = [NSData dataWithBytesNoCopy: result.Data length: result.Length

                                    freeWhenDone: YES];

     CSSM_DeleteContext(ccHandle);

     return signature;

 #endif

 }

 #if !TARGET_OS_IPHONE

 - (NSData*) exportKeyInFormat: (SecExternalFormat)format 

                       withPEM: (BOOL)withPEM

                    alertTitle: (NSString*)title

                   alertPrompt: (NSString*)prompt

 {

     SecKeyImportExportParameters params = {

         .version = SEC_KEY_IMPORT_EXPORT_PARAMS_VERSION,

         .flags = kSecKeySecurePassphrase,

         .alertTitle = (CFStringRef)title,

         .alertPrompt = (CFStringRef)prompt

     };

     CFDataRef data = NULL;

     if (check(SecKeychainItemExport(self.keyRef,

                                     format, (withPEM ?kSecItemPemArmour :0), 

                                     &params, &data),

               @"SecKeychainItemExport"))

         return [(id)CFMakeCollectable(data) autorelease];

     else

         return nil;

 }

 - (NSData*) exportKey {

     return [self exportKeyInFormat: kSecFormatWrappedOpenSSL withPEM: YES

                         alertTitle: @"Export Private Key"

                        alertPrompt: @"Enter a passphrase to protect the private-key file.\n"

             "You will need to re-enter the passphrase later when importing the key from this file, "

             "so keep it in a safe place."];

     //FIX: Should make these messages localizable.

 }

 - (NSData*) _exportKeyInFormat: (SecExternalFormat)format

                        withPEM: (BOOL)withPEM

                     passphrase: (NSString*)passphrase

 {

     SecKeyImportExportParameters params = {

         .version = SEC_KEY_IMPORT_EXPORT_PARAMS_VERSION,

         .passphrase = (CFStringRef)passphrase

     };

     CFDataRef data = NULL;

     if (check(SecKeychainItemExport(self.keyRef,

                                     format, (withPEM ?kSecItemPemArmour :0), 

                                     &params, &data),

               @"SecKeychainItemExport"))

         return [(id)CFMakeCollectable(data) autorelease];

     else

         return nil;

 }

 - (MYSymmetricKey*) unwrapSessionKey: (NSData*)wrappedData

                        withAlgorithm: (CCAlgorithm)algorithm

                           sizeInBits: (unsigned)sizeInBits

 {

     // First create a wrapped-key structure from the data:

     CSSM_WRAP_KEY wrappedKey = {

         .KeyHeader = {

             .BlobType = CSSM_KEYBLOB_WRAPPED,

             .Format = CSSM_KEYBLOB_RAW_FORMAT_PKCS3,

             .AlgorithmId = CSSMFromCCAlgorithm(algorithm),

             .KeyClass = CSSM_KEYCLASS_SESSION_KEY,

             .LogicalKeySizeInBits = sizeInBits,

             .KeyAttr = CSSM_KEYATTR_EXTRACTABLE,

             .KeyUsage = CSSM_KEYUSE_ANY,

             .WrapAlgorithmId = self.cssmAlgorithm,

         },

         .KeyData = {

             .Data = (void*)wrappedData.bytes,

             .Length = wrappedData.length

         }

     };

     const CSSM_ACCESS_CREDENTIALS* credentials;

     credentials = [self cssmCredentialsForOperation: CSSM_ACL_AUTHORIZATION_IMPORT_WRAPPED

                                                type: kSecCredentialTypeDefault error: nil];

     CSSM_CSP_HANDLE cspHandle = self.cssmCSPHandle;

     CSSM_CC_HANDLE ctx;

     if (!checkcssm(CSSM_CSP_CreateAsymmetricContext(cspHandle,

                                                     self.cssmAlgorithm,

                                                     credentials, 

                                                     self.cssmKey,

                                                     CSSM_PADDING_PKCS1,

                                                     &ctx), 

                    @"CSSM_CSP_CreateAsymmetricContext"))

         return nil;

     // Now unwrap the key:

     MYSymmetricKey *result = nil;

     CSSM_KEY *unwrappedKey = calloc(1,sizeof(CSSM_KEY));

     CSSM_DATA label = {.Data=(void*)"Imported key", .Length=strlen("Imported key")};

     CSSM_DATA descriptiveData = {};

     if (checkcssm(CSSM_UnwrapKey(ctx, 

                                  self.cssmKey,

                                  &wrappedKey,

                                  wrappedKey.KeyHeader.KeyUsage,

                                  wrappedKey.KeyHeader.KeyAttr,

                                  &label,

                                  NULL,

                                  unwrappedKey,

                                  &descriptiveData),

                   @"CSSM_UnwrapKey")) {

         result = [[[MYSymmetricKey alloc] _initWithCSSMKey: unwrappedKey] autorelease];

     }

     // Finally, delete the context

     if (!result)

         free(unwrappedKey);

     CSSM_DeleteContext(ctx);

     return result;

 }

 #endif !TARGET_OS_IPHONE

 @end

 /*

  Copyright (c) 2009, Jens Alfke <jens@mooseyard.com>. All rights reserved.

  Redistribution and use in source and binary forms, with or without modification, are permitted

  provided that the following conditions are met:

  * Redistributions of source code must retain the above copyright notice, this list of conditions

  and the following disclaimer.

  * Redistributions in binary form must reproduce the above copyright notice, this list of conditions

  and the following disclaimer in the documentation and/or other materials provided with the

  distribution.

  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR

  IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND 

  FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRI-

  BUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 

   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 

  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 

  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  */