Merge pull request #1572 from AzureAD/ameyapat/msid-jwe-decryptor

Shifted decryptor logic from broker to common-core. Use Big Endian fo…

Author: ameyapat

IdentityCore/IdentityCore.xcodeproj/project.pbxproj

@@ -0,0 +1,37 @@
+//
+// Copyright (c) Microsoft Corporation.
+// All rights reserved.
+//
+// This code is licensed under the MIT License.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.  
+
+
+import Foundation
+import CryptoKit
+
+public class MSIDAesGcmDecryptor: NSObject {
+    
+    @objc public func decryptWithAES256GCMHandler(message ciphertext: Data, iv nonce: Data, key keyData: Data, tag: Data, aad: Data) throws -> Data
+    {
+        let sealedBox = try AES.GCM.SealedBox(nonce: AES.GCM.Nonce(data: nonce), ciphertext: ciphertext, tag: tag)
+        let key = SymmetricKey(data: keyData)
+        return try AES.GCM.open(sealedBox, using: key, authenticating: aad)
+    }
+}

IdentityCore/src/JWEResponse/MSIDAesGcmDecryptor.swift

@@ -0,0 +1,44 @@
+//
+// Copyright (c) Microsoft Corporation.
+// All rights reserved.
+//
+// This code is licensed under the MIT License.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.  
+
+#import <Foundation/Foundation.h>
+#import "MSIDJweResponse.h"
+#import "MSIDRequestContext.h"
+#import "MSIDJWECrypto.h"
+#import "MSIDJsonSerializable.h"
+
+typedef NSString *const MSIDJWECryptoKeyExchangeAlgorithm NS_TYPED_ENUM;
+typedef NSString *const MSIDJWECryptoKeyResponseEncryptionAlgorithm NS_TYPED_ENUM;
+
+extern MSIDJWECryptoKeyExchangeAlgorithm const _Nonnull MSID_KEY_EXCHANGE_ALGORITHM_ECDH_ES;
+extern MSIDJWECryptoKeyResponseEncryptionAlgorithm const _Nonnull MSID_RESPONSE_ENCRYPTION_ALGORITHM_A256GCM;
+
+NS_ASSUME_NONNULL_BEGIN
+@interface MSIDJweResponse (EcdhAesGcm)
+- (BOOL)IsJweResponseAlgorithmSupported:(NSError * _Nullable __autoreleasing * _Nullable)error;
+- (nullable NSDictionary *)decryptJweResponseWithPrivateStk:(SecKeyRef)privateStk
+                                                  jweCrypto:(MSIDJWECrypto *)jweCrypto
+                                                      error:(NSError * _Nullable __autoreleasing * _Nullable)error;
+@end
+NS_ASSUME_NONNULL_END

IdentityCore/src/JWEResponse/MSIDJweResponse+EcdhAesGcm.h

@@ -0,0 +1,264 @@
+//
+// Copyright (c) Microsoft Corporation.
+// All rights reserved.
+//
+// This code is licensed under the MIT License.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files(the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions :
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.  
+
+
+#import <Foundation/Foundation.h>
+#import "MSIDJweResponse+EcdhAesGcm.h"
+#import "MSIDJWECrypto.h"
+#import "MSIDJweResponse.h"
+#import "NSData+MSIDExtensions.h"
+#import "NSData+MSIDEccSecKeyRef.h"
+#import "MSIDEcdhApv.h"
+#import "MSIDJsonSerializer.h"
+#import "IdentityCore-Swift.h"
+#import "MSIDFlightManager.h"
+#import "MSIDConstants.h"
+
+MSIDJWECryptoKeyExchangeAlgorithm const MSID_KEY_EXCHANGE_ALGORITHM_ECDH_ES = @"ECDH-ES";
+MSIDJWECryptoKeyResponseEncryptionAlgorithm const MSID_RESPONSE_ENCRYPTION_ALGORITHM_A256GCM = @"A256GCM";
+
+@implementation MSIDJweResponse (EcdhAesGcm)
+
+- (nullable NSDictionary *)decryptJweResponseWithPrivateStk:(nonnull SecKeyRef)privateStkRef
+                                                  jweCrypto:(nonnull MSIDJWECrypto *)jweCrypto
+                                                      error:(NSError * _Nullable __autoreleasing * _Nullable)error
+{
+    MSID_LOG_WITH_CTX(MSIDLogLevelInfo, nil, @"Starting to decrypt JWE response using ECDH-AESGCM using jwe_crypto : %@", jweCrypto.urlEncodedJweCrypto);
+    
+    // 1. Check for necessary request parameters
+    NSData *apv = [NSData msidDataFromBase64UrlEncodedString:jweCrypto.apv.APV];
+    
+    if (!apv.length)
+    {
+        if (error)
+        {
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, @"Unexpected input parameters, no apv present in request JWE Crypto", nil, nil, nil, nil, nil, NO);
+        }
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Unexpected input parameters, no apv present in request JWE Crypto");
+        return nil;
+    }
+    
+    // 2. Check for necessary response parameters, epk, enc, apu
+    NSDictionary *epk = self.jweHeader[@"epk"];
+    
+    if (![epk count]
+        || ![epk isKindOfClass:[NSDictionary class]])
+    {
+        if (error)
+        {
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, @"Unexpected server response, no epk present in JWE header", nil, nil, nil, nil, nil, YES);
+        }
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Unexpected server response, no epk present in JWE header, epk %@", epk);
+        return nil;
+    }
+    
+    NSString *encHeader = self.jweHeader[@"enc"];
+    NSString *apuHeader = self.jweHeader[@"apu"];
+    
+    if ([NSString msidIsStringNilOrBlank:encHeader]
+        || [NSString msidIsStringNilOrBlank:apuHeader])
+    {
+        if (error)
+        {
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, @"Unexpected server response, no enc or apu present JWE header", nil, nil, nil, nil, nil, NO);
+        }
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Unexpected server response, no enc or apu present JWE header, enc %@, apu %@", encHeader, apuHeader);
+        return nil;
+    }
+    
+    if (![self IsJweResponseAlgorithmSupported:error])
+    {
+        return nil;
+    }
+    
+    // 3. Create key from server response
+    SecKeyRef serverKeyRef = [NSData createKeyFromEccJsonWebKey:epk error:error];
+    
+    if (!serverKeyRef)
+    {
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Could not get EC public key from server JWE response payload.");
+        return nil;
+    }
+    
+    // 4. Calculate shared key through a key exchange
+    // It performs a Diffie-Hellman key exchange (kSecKeyAlgorithmECDHKeyExchangeStandard) using the Device Encryption public key and the Ephemeral private key.
+    NSData *sharedSecret = [self calculateSharedSecretUsingEcdhWithOtherPartyPublicEcKey:serverKeyRef
+                                                                              privateStk:privateStkRef
+                                                                                   error:error];
+    
+    if (!sharedSecret)
+    {
+        CFRelease(serverKeyRef);
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Failed to calculate shared secret using ECDH");
+        return nil;
+    }
+    
+    // 5. Calculate derived key using ConcatKDF
+    // ConcatKDF is performed using the key exchange result, algorithm, PartyUInfo, and PartyVInfo.
+    NSData *algorithmId = [encHeader dataUsingEncoding:NSASCIIStringEncoding];
+    NSData *apu = [NSData msidDataFromBase64UrlEncodedString:apuHeader];
+    
+    NSData *derivedKey = [self calculateDerivedKeyWithSharedKey:sharedSecret
+                                                    algorithmId:algorithmId
+                                                            apu:apu
+                                                            apv:apv
+                                                          error:error];
+    
+    if (!derivedKey)
+    {
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Failed to calculate derived key from shared secret using ConcatKDF");
+        return nil;
+    }
+    
+    // 6. Decrypt JWE using derived key as the AES GCM decryption key
+    // The key from ConcatKDF is used along with the Initialization Vector, and the Additional Authentication Data (AAD) to encrypt the plain text using AESGCM.
+    return [self decryptJweResponseUsingSymmetricKey:derivedKey error:error];
+}
+
+- (NSData *)calculateSharedSecretUsingEcdhWithOtherPartyPublicEcKey:(SecKeyRef)serverKeyRef
+                                                         privateStk:(SecKeyRef)privateStkRef
+                                                              error:(NSError * _Nullable __autoreleasing * _Nullable)error
+{
+    SecKeyAlgorithm algorithm = kSecKeyAlgorithmECDHKeyExchangeStandard;
+    NSDictionary *attributes = @{(id)kSecKeyKeyExchangeParameterRequestedSize:@32};
+    
+    CFErrorRef cfError = NULL;
+    NSData *sharedKey = (NSData *)CFBridgingRelease(SecKeyCopyKeyExchangeResult(privateStkRef, algorithm, serverKeyRef, (__bridge CFDictionaryRef)attributes, &cfError));
+    
+    if (!sharedKey)
+    {
+        NSError *nsError = CFBridgingRelease(cfError);
+        
+        if (error)
+        {
+            *error = nsError;
+        }
+        
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Failed to do key exchange with error %@", nsError);
+        return nil;
+    }
+    
+    return sharedKey;
+}
+
+- (NSData *)calculateDerivedKeyWithSharedKey:(NSData *)sharedSecret
+                                 algorithmId:(NSData *)algorithmId
+                                         apu:(NSData *)apu
+                                         apv:(NSData *)apv
+                                       error:(NSError * _Nullable __autoreleasing * _Nullable)error
+{
+    NSError *concatKDFError = nil;
+    MSIDConcatKdfProvider *concatKDFProvider = [MSIDConcatKdfProvider new];
+    NSData *derivedKey = [concatKDFProvider concatKDFWithSHA256WithSharedSecret:sharedSecret
+                                                           outputKeyLen:32
+                                                            algorithmId:algorithmId
+                                                             partyUInfo:apu
+                                                             partyVInfo:apv
+                                                                  error:&concatKDFError];
+    // Deallocating sharedSecret as it is no longer needed
+    sharedSecret = nil;
+    if (!derivedKey)
+    {
+        if (error)
+        {
+            *error = concatKDFError;
+        }
+        
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Failed to calculate ConcatKDF with error %@", concatKDFError);
+        return nil;
+    }
+    
+    return derivedKey;
+}
+
+- (NSDictionary *)decryptJweResponseUsingSymmetricKey:(NSData *)symmetricKey
+                                                error:(NSError * _Nullable __autoreleasing * _Nullable)error
+{
+    if (!symmetricKey)
+    {
+        if (error)
+        {
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, @"Symmetric key is nil", nil, nil, nil, nil, nil, YES);
+        }
+        return nil;
+    }
+    
+    if (![self IsJweResponseAlgorithmSupported:error])
+    {
+        return nil;
+    }
+    
+    // Since only A256GCM is supported, we can decrypt jwe message using AES256GCM.
+    MSIDAesGcmDecryptor *decryptor = [MSIDAesGcmDecryptor new];
+    NSData *decryptedData = [decryptor decryptWithAES256GCMHandlerWithMessage:self.payload iv:self.iv key:symmetricKey tag:self.tag aad:self.aad error:error];
+    // Deallocate symmetricKey as it is no longer needed
+    symmetricKey = nil;
+    if (!decryptedData)
+    {
+        if (error)
+        {
+            NSError *subError = *error ? *error : nil;
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, @"Unexpected server response, failed to decrypt JWE", nil, [subError description], subError, nil, nil, YES);
+        }
+        MSID_LOG_WITH_CTX(MSIDLogLevelError, nil, @"Unexpected server response, failed to decrypt JWE");
+        return nil;
+    }
+    
+    MSIDJsonSerializer *serializer = [MSIDJsonSerializer new];
+    
+    NSDictionary *jsonResult = [serializer deserializeJSON:decryptedData error:error];
+    if (!jsonResult)
+    {
+        if (error)
+        {
+            NSError *subError = *error ? *error : nil;
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, @"Failed to serialize decrypted data to JSON", nil, [subError description], subError, nil, nil, YES);
+        }
+    }
+    return jsonResult;
+}
+
+- (BOOL)IsJweResponseAlgorithmSupported:(NSError * _Nullable __autoreleasing * _Nullable)error
+{
+    if (self.headerAlgorithm && ![self.headerAlgorithm isEqualToString:MSID_KEY_EXCHANGE_ALGORITHM_ECDH_ES])
+    {
+        if (error)
+        {
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, [NSString stringWithFormat:@"Unsupported JWE algorithm : %@", self.headerAlgorithm], nil, nil, nil, nil, nil, YES);
+        }
+        return NO;
+    }
+    
+    if (![self.headerEncryptionAlgorithm isEqualToString:MSID_RESPONSE_ENCRYPTION_ALGORITHM_A256GCM])
+    {
+        if (error)
+        {
+            *error = MSIDCreateError(MSIDErrorDomain, MSIDErrorInternal, [NSString stringWithFormat:@"Unsupported JWE encryption algorithm : %@", self.jweHeader[@"enc"]], nil, nil, nil, nil, nil, YES);
+        }
+        return NO;
+    }
+    
+    return YES;
+}
+@end

IdentityCore/src/JWEResponse/MSIDJweResponse+EcdhAesGcm.m

@@ -232,9 +232,13 @@ extern NSString * _Nonnull const MSID_FLIGHT_IGNORE_COOKIES_IN_DUNA_RESUME;
  */
 extern NSString * _Nonnull const MSID_FLIGHT_DISABLE_REMOVE_ACCOUNT_ARTIFACTS;
 
-extern NSString * _Nonnull const MSID_FLIGHT_ENABLE_QUERYING_STK;
+/// Flight to enable support for bound app RT
+/// Owner: amepatil
+/// ECS configuration id: /1678824
 extern NSString * _Nonnull const MSID_FLIGHT_IS_BART_SUPPORTED;
 
+extern NSString * _Nonnull const MSID_FLIGHT_ENABLE_QUERYING_STK;
+
 extern NSString * _Nonnull const MSID_DOMAIN_HINT_KEY;
 
 #define METHODANDLINE   [NSString stringWithFormat:@"%s [Line %d]", __PRETTY_FUNCTION__, __LINE__]

IdentityCore/src/MSIDConstants.h

@@ -98,9 +98,10 @@
 NSString *const MSID_FLIGHT_DISABLE_REMOVE_ACCOUNT_ARTIFACTS = @"disable_rm_metadata";
 
 NSString *const MSID_FLIGHT_ENABLE_QUERYING_STK = @"enable_querying_stk";
-NSString *const MSID_FLIGHT_IS_BART_SUPPORTED = @"is_msal_bart_supported";
-
 NSString *const MSID_DOMAIN_HINT_KEY  = @"domain_hint";
 
 
+NSString *const MSID_FLIGHT_IS_BART_SUPPORTED = @"is_bound_app_rt_supported";
+
+
 #define METHODANDLINE   [NSString stringWithFormat:@"%s [Line %d]", __PRETTY_FUNCTION__, __LINE__]