[PM-6428] Implement Legacy Secure Storage (#3027)

This commit is contained in:
Federico Maccaroni 2024-02-26 19:25:08 -03:00 committed by GitHub
parent d6c2ebe4c2
commit 04e7cfe06d
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
9 changed files with 555 additions and 9 deletions

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@ -5,7 +5,8 @@ namespace Bit.Core.Abstractions
{
public enum AwaiterPrecondition
{
EnvironmentUrlsInited
EnvironmentUrlsInited,
AndroidWindowCreated
}
public interface IConditionedAwaiterManager

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@ -12,12 +12,14 @@ namespace Bit.App.Pages
private readonly HomeViewModel _vm;
private readonly AppOptions _appOptions;
private IBroadcasterService _broadcasterService;
private IConditionedAwaiterManager _conditionedAwaiterManager;
readonly LazyResolve<ILogger> _logger = new LazyResolve<ILogger>();
public HomePage(AppOptions appOptions = null)
{
_broadcasterService = ServiceContainer.Resolve<IBroadcasterService>();
_conditionedAwaiterManager = ServiceContainer.Resolve<IConditionedAwaiterManager>();
_appOptions = appOptions;
InitializeComponent();
_vm = BindingContext as HomeViewModel;
@ -56,6 +58,8 @@ namespace Bit.App.Pages
PerformNavigationOnAccountChangedOnLoad = false;
accountsManager.NavigateOnAccountChangeAsync().FireAndForget();
}
_conditionedAwaiterManager.SetAsCompleted(AwaiterPrecondition.AndroidWindowCreated);
#endif
}

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@ -1,4 +1,5 @@
using Bit.App.Abstractions;
using Bit.Core.Abstractions;
using Bit.Core.Utilities;
namespace Bit.Core.Pages;
@ -6,15 +7,18 @@ namespace Bit.Core.Pages;
public partial class AndroidNavigationRedirectPage : ContentPage
{
private readonly IAccountsManager _accountsManager;
private readonly IConditionedAwaiterManager _conditionedAwaiterManager;
public AndroidNavigationRedirectPage()
{
_accountsManager = ServiceContainer.Resolve<IAccountsManager>("accountsManager");
_conditionedAwaiterManager = ServiceContainer.Resolve<IConditionedAwaiterManager>();
InitializeComponent();
}
private void AndroidNavigationRedirectPage_OnLoaded(object sender, EventArgs e)
{
_accountsManager.NavigateOnAccountChangeAsync().FireAndForget();
_conditionedAwaiterManager.SetAsCompleted(AwaiterPrecondition.AndroidWindowCreated);
}
}

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@ -10,7 +10,8 @@ namespace Bit.Core.Services
{
private readonly ConcurrentDictionary<AwaiterPrecondition, TaskCompletionSource<bool>> _preconditionsTasks = new ConcurrentDictionary<AwaiterPrecondition, TaskCompletionSource<bool>>
{
[AwaiterPrecondition.EnvironmentUrlsInited] = new TaskCompletionSource<bool>()
[AwaiterPrecondition.EnvironmentUrlsInited] = new TaskCompletionSource<bool>(),
[AwaiterPrecondition.AndroidWindowCreated] = new TaskCompletionSource<bool>()
};
public Task GetAwaiterForPrecondition(AwaiterPrecondition awaiterPrecondition)

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@ -0,0 +1,295 @@
#if ANDROID
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Security;
using Android.Security.Keystore;
using Java.Security;
using Javax.Crypto;
using Javax.Crypto.Spec;
using System.Text;
namespace Bit.Core.Services;
class AndroidKeyStore
{
const string androidKeyStore = "AndroidKeyStore"; // this is an Android const value
const string aesAlgorithm = "AES";
const string cipherTransformationAsymmetric = "RSA/ECB/PKCS1Padding";
const string cipherTransformationSymmetric = "AES/GCM/NoPadding";
const string prefsMasterKey = "SecureStorageKey";
const int initializationVectorLen = 12; // Android supports an IV of 12 for AES/GCM
internal AndroidKeyStore(Context context, string keystoreAlias, bool alwaysUseAsymmetricKeyStorage)
{
alwaysUseAsymmetricKey = alwaysUseAsymmetricKeyStorage;
appContext = context;
alias = keystoreAlias;
keyStore = KeyStore.GetInstance(androidKeyStore);
keyStore.Load(null);
}
readonly Context appContext;
readonly string alias;
readonly bool alwaysUseAsymmetricKey;
readonly string useSymmetricPreferenceKey = "essentials_use_symmetric";
KeyStore keyStore;
bool useSymmetric = false;
ISecretKey GetKey()
{
// check to see if we need to get our key from past-versions or newer versions.
// we want to use symmetric if we are >= 23 or we didn't set it previously.
var hasApiLevel = Build.VERSION.SdkInt >= BuildVersionCodes.M;
useSymmetric = Preferences.Get(useSymmetricPreferenceKey, hasApiLevel, alias);
// If >= API 23 we can use the KeyStore's symmetric key
if (useSymmetric && !alwaysUseAsymmetricKey)
return GetSymmetricKey();
// NOTE: KeyStore in < API 23 can only store asymmetric keys
// specifically, only RSA/ECB/PKCS1Padding
// So we will wrap our symmetric AES key we just generated
// with this and save the encrypted/wrapped key out to
// preferences for future use.
// ECB should be fine in this case as the AES key should be
// contained in one block.
// Get the asymmetric key pair
var keyPair = GetAsymmetricKeyPair();
var existingKeyStr = Preferences.Get(prefsMasterKey, null, alias);
if (!string.IsNullOrEmpty(existingKeyStr))
{
try
{
var wrappedKey = Convert.FromBase64String(existingKeyStr);
var unwrappedKey = UnwrapKey(wrappedKey, keyPair.Private);
var kp = unwrappedKey.JavaCast<ISecretKey>();
return kp;
}
catch (InvalidKeyException ikEx)
{
System.Diagnostics.Debug.WriteLine(
$"Unable to unwrap key: Invalid Key. This may be caused by system backup or upgrades. All secure storage items will now be removed. {ikEx.Message}");
}
catch (IllegalBlockSizeException ibsEx)
{
System.Diagnostics.Debug.WriteLine(
$"Unable to unwrap key: Illegal Block Size. This may be caused by system backup or upgrades. All secure storage items will now be removed. {ibsEx.Message}");
}
catch (BadPaddingException paddingEx)
{
System.Diagnostics.Debug.WriteLine(
$"Unable to unwrap key: Bad Padding. This may be caused by system backup or upgrades. All secure storage items will now be removed. {paddingEx.Message}");
}
LegacySecureStorage.RemoveAll();
}
var keyGenerator = KeyGenerator.GetInstance(aesAlgorithm);
var defSymmetricKey = keyGenerator.GenerateKey();
var newWrappedKey = WrapKey(defSymmetricKey, keyPair.Public);
Preferences.Set(prefsMasterKey, Convert.ToBase64String(newWrappedKey), alias);
return defSymmetricKey;
}
// API 23+ Only
#pragma warning disable CA1416
ISecretKey GetSymmetricKey()
{
Preferences.Set(useSymmetricPreferenceKey, true, alias);
var existingKey = keyStore.GetKey(alias, null);
if (existingKey != null)
{
var existingSecretKey = existingKey.JavaCast<ISecretKey>();
return existingSecretKey;
}
var keyGenerator = KeyGenerator.GetInstance(KeyProperties.KeyAlgorithmAes, androidKeyStore);
var builder = new KeyGenParameterSpec.Builder(alias, KeyStorePurpose.Encrypt | KeyStorePurpose.Decrypt)
.SetBlockModes(KeyProperties.BlockModeGcm)
.SetEncryptionPaddings(KeyProperties.EncryptionPaddingNone)
.SetRandomizedEncryptionRequired(false);
keyGenerator.Init(builder.Build());
return keyGenerator.GenerateKey();
}
#pragma warning restore CA1416
KeyPair GetAsymmetricKeyPair()
{
// set that we generated keys on pre-m device.
Preferences.Set(useSymmetricPreferenceKey, false, alias);
var asymmetricAlias = $"{alias}.asymmetric";
var privateKey = keyStore.GetKey(asymmetricAlias, null)?.JavaCast<IPrivateKey>();
var publicKey = keyStore.GetCertificate(asymmetricAlias)?.PublicKey;
// Return the existing key if found
if (privateKey != null && publicKey != null)
return new KeyPair(publicKey, privateKey);
var originalLocale = Java.Util.Locale.Default;
try
{
// Force to english for known bug in date parsing:
// https://issuetracker.google.com/issues/37095309
SetLocale(Java.Util.Locale.English);
// Otherwise we create a new key
#pragma warning disable CA1416
var generator = KeyPairGenerator.GetInstance(KeyProperties.KeyAlgorithmRsa, androidKeyStore);
#pragma warning restore CA1416
var end = DateTime.UtcNow.AddYears(20);
var startDate = new Java.Util.Date();
#pragma warning disable CS0618 // Type or member is obsolete
var endDate = new Java.Util.Date(end.Year, end.Month, end.Day);
#pragma warning restore CS0618 // Type or member is obsolete
#pragma warning disable CS0618
var builder = new KeyPairGeneratorSpec.Builder(Platform.AppContext)
.SetAlias(asymmetricAlias)
.SetSerialNumber(Java.Math.BigInteger.One)
.SetSubject(new Javax.Security.Auth.X500.X500Principal($"CN={asymmetricAlias} CA Certificate"))
.SetStartDate(startDate)
.SetEndDate(endDate);
generator.Initialize(builder.Build());
#pragma warning restore CS0618
return generator.GenerateKeyPair();
}
finally
{
SetLocale(originalLocale);
}
}
byte[] WrapKey(IKey keyToWrap, IKey withKey)
{
var cipher = Cipher.GetInstance(cipherTransformationAsymmetric);
cipher.Init(CipherMode.WrapMode, withKey);
return cipher.Wrap(keyToWrap);
}
#pragma warning disable CA1416
IKey UnwrapKey(byte[] wrappedData, IKey withKey)
{
var cipher = Cipher.GetInstance(cipherTransformationAsymmetric);
cipher.Init(CipherMode.UnwrapMode, withKey);
var unwrapped = cipher.Unwrap(wrappedData, KeyProperties.KeyAlgorithmAes, KeyType.SecretKey);
return unwrapped;
}
#pragma warning restore CA1416
internal byte[] Encrypt(string data)
{
var key = GetKey();
// Generate initialization vector
var iv = new byte[initializationVectorLen];
var sr = new SecureRandom();
sr.NextBytes(iv);
Cipher cipher;
// Attempt to use GCMParameterSpec by default
try
{
cipher = Cipher.GetInstance(cipherTransformationSymmetric);
cipher.Init(CipherMode.EncryptMode, key, new GCMParameterSpec(128, iv));
}
catch (InvalidAlgorithmParameterException)
{
// If we encounter this error, it's likely an old bouncycastle provider version
// is being used which does not recognize GCMParameterSpec, but should work
// with IvParameterSpec, however we only do this as a last effort since other
// implementations will error if you use IvParameterSpec when GCMParameterSpec
// is recognized and expected.
cipher = Cipher.GetInstance(cipherTransformationSymmetric);
cipher.Init(CipherMode.EncryptMode, key, new IvParameterSpec(iv));
}
var decryptedData = Encoding.UTF8.GetBytes(data);
var encryptedBytes = cipher.DoFinal(decryptedData);
// Combine the IV and the encrypted data into one array
var r = new byte[iv.Length + encryptedBytes.Length];
Buffer.BlockCopy(iv, 0, r, 0, iv.Length);
Buffer.BlockCopy(encryptedBytes, 0, r, iv.Length, encryptedBytes.Length);
return r;
}
internal string Decrypt(byte[] data)
{
if (data.Length < initializationVectorLen)
return null;
var key = GetKey();
// IV will be the first 16 bytes of the encrypted data
var iv = new byte[initializationVectorLen];
Buffer.BlockCopy(data, 0, iv, 0, initializationVectorLen);
Cipher cipher;
// Attempt to use GCMParameterSpec by default
try
{
cipher = Cipher.GetInstance(cipherTransformationSymmetric);
cipher.Init(CipherMode.DecryptMode, key, new GCMParameterSpec(128, iv));
}
catch (InvalidAlgorithmParameterException)
{
// If we encounter this error, it's likely an old bouncycastle provider version
// is being used which does not recognize GCMParameterSpec, but should work
// with IvParameterSpec, however we only do this as a last effort since other
// implementations will error if you use IvParameterSpec when GCMParameterSpec
// is recognized and expected.
cipher = Cipher.GetInstance(cipherTransformationSymmetric);
cipher.Init(CipherMode.DecryptMode, key, new IvParameterSpec(iv));
}
// Decrypt starting after the first 16 bytes from the IV
var decryptedData = cipher.DoFinal(data, initializationVectorLen, data.Length - initializationVectorLen);
return Encoding.UTF8.GetString(decryptedData);
}
internal void SetLocale(Java.Util.Locale locale)
{
Java.Util.Locale.Default = locale;
var resources = appContext.Resources;
var config = resources.Configuration;
if (Build.VERSION.SdkInt >= BuildVersionCodes.N)
config.SetLocale(locale);
else
#pragma warning disable CS0618 // Type or member is obsolete
config.Locale = locale;
#pragma warning restore CS0618 // Type or member is obsolete
#pragma warning disable CS0618 // Type or member is obsolete
resources.UpdateConfiguration(config, resources.DisplayMetrics);
#pragma warning restore CS0618 // Type or member is obsolete
}
}
#endif

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@ -0,0 +1,128 @@
#if IOS
using System.Diagnostics;
using Foundation;
using Security;
namespace Bit.Core.Services;
internal class KeyChain
{
SecAccessible accessible;
internal KeyChain(SecAccessible accessible) =>
this.accessible = accessible;
SecRecord ExistingRecordForKey(string key, string service)
{
return new SecRecord(SecKind.GenericPassword)
{
Account = key,
Service = service
};
}
internal string ValueForKey(string key, string service)
{
using (var record = ExistingRecordForKey(key, service))
using (var match = SecKeyChain.QueryAsRecord(record, out var resultCode))
{
if (resultCode == SecStatusCode.Success)
return NSString.FromData(match.ValueData, NSStringEncoding.UTF8);
else
return null;
}
}
internal void SetValueForKey(string value, string key, string service)
{
using (var record = ExistingRecordForKey(key, service))
{
if (string.IsNullOrEmpty(value))
{
if (!string.IsNullOrEmpty(ValueForKey(key, service)))
RemoveRecord(record);
return;
}
// if the key already exists, remove it
if (!string.IsNullOrEmpty(ValueForKey(key, service)))
RemoveRecord(record);
}
using (var newRecord = CreateRecordForNewKeyValue(key, value, service))
{
var result = SecKeyChain.Add(newRecord);
switch (result)
{
case SecStatusCode.DuplicateItem:
{
Debug.WriteLine("Duplicate item found. Attempting to remove and add again.");
// try to remove and add again
if (Remove(key, service))
{
result = SecKeyChain.Add(newRecord);
if (result != SecStatusCode.Success)
throw new Exception($"Error adding record: {result}");
}
else
{
Debug.WriteLine("Unable to remove key.");
}
}
break;
case SecStatusCode.Success:
return;
default:
throw new Exception($"Error adding record: {result}");
}
}
}
internal bool Remove(string key, string service)
{
using (var record = ExistingRecordForKey(key, service))
using (var match = SecKeyChain.QueryAsRecord(record, out var resultCode))
{
if (resultCode == SecStatusCode.Success)
{
RemoveRecord(record);
return true;
}
}
return false;
}
internal void RemoveAll(string service)
{
using (var query = new SecRecord(SecKind.GenericPassword) { Service = service })
{
SecKeyChain.Remove(query);
}
}
SecRecord CreateRecordForNewKeyValue(string key, string value, string service)
{
return new SecRecord(SecKind.GenericPassword)
{
Account = key,
Service = service,
Label = key,
Accessible = accessible,
ValueData = NSData.FromString(value, NSStringEncoding.UTF8),
};
}
bool RemoveRecord(SecRecord record)
{
var result = SecKeyChain.Remove(record);
if (result != SecStatusCode.Success && result != SecStatusCode.ItemNotFound)
throw new Exception($"Error removing record: {result}");
return true;
}
}
#endif

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@ -0,0 +1,108 @@
#nullable enable
#if IOS
using Security;
#endif
#if ANDROID
using Javax.Crypto;
#endif
namespace Bit.Core.Services;
public class LegacySecureStorage
{
internal static readonly string Alias = $"{AppInfo.PackageName}.xamarinessentials";
#if IOS
private static SecAccessible DefaultAccessible { get; set; } = SecAccessible.AfterFirstUnlock;
#endif
public static Task<string?> GetAsync(string key)
{
if (string.IsNullOrWhiteSpace(key))
throw new ArgumentNullException(nameof(key));
#if ANDROID
return Task.Run(() =>
{
object locker = new object();
string? encVal = Preferences.Get(key, null, Alias);
if (!string.IsNullOrEmpty(encVal))
{
try
{
byte[] encData = Convert.FromBase64String(encVal);
lock (locker)
{
AndroidKeyStore keyStore = new AndroidKeyStore(Platform.AppContext, Alias, false);
return keyStore.Decrypt(encData);
}
}
catch (AEADBadTagException)
{
System.Diagnostics.Debug.WriteLine($"Unable to decrypt key, {key}, which is likely due to an app uninstall. Removing old key and returning null.");
Remove(key);
}
}
return null;
});
#elif IOS
var keyChain = new KeyChain(DefaultAccessible);
return Task.FromResult<string?>(keyChain.ValueForKey(key, Alias));
#else
return Task.FromResult((string?)null);
#endif
}
public static Task SetAsync(string key, string value)
{
#if ANDROID
return Task.Run(() =>
{
var context = Platform.AppContext;
byte[] encryptedData = null;
object locker = new object();
lock (locker)
{
AndroidKeyStore keyStore = new AndroidKeyStore(Platform.AppContext, Alias, false);
encryptedData = keyStore.Encrypt(value);
}
var encStr = Convert.ToBase64String(encryptedData);
Preferences.Set(key, encStr, Alias);
});
#elif IOS
KeyChain keyChain = new KeyChain(DefaultAccessible);
keyChain.SetValueForKey(value, key, Alias);
#endif
return Task.CompletedTask;
}
public static bool Remove(string key)
{
#if ANDROID
Preferences.Remove(key, Alias);
return true;
#elif IOS
var keyChain = new KeyChain(DefaultAccessible);
return keyChain.Remove(key, Alias);
#else
return false;
#endif
}
public static void RemoveAll()
{
#if ANDROID
Preferences.Clear(Alias);
#elif IOS
var keyChain = new KeyChain(DefaultAccessible);
keyChain.RemoveAll(Alias);
#endif
}
}

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@ -1,5 +1,5 @@
using System.Threading.Tasks;
using Bit.Core.Abstractions;
using Bit.Core.Abstractions;
using Bit.Core.Services;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
@ -16,7 +16,7 @@ namespace Bit.App.Services
public async Task<T> GetAsync<T>(string key)
{
var formattedKey = string.Format(_keyFormat, key);
var val = await Microsoft.Maui.Storage.SecureStorage.GetAsync(formattedKey);
var val = await LegacySecureStorage.GetAsync(formattedKey);
if (typeof(T) == typeof(string))
{
return (T)(object)val;
@ -37,11 +37,11 @@ namespace Bit.App.Services
var formattedKey = string.Format(_keyFormat, key);
if (typeof(T) == typeof(string))
{
await Microsoft.Maui.Storage.SecureStorage.SetAsync(formattedKey, obj as string);
await LegacySecureStorage.SetAsync(formattedKey, obj as string);
}
else
{
await Microsoft.Maui.Storage.SecureStorage.SetAsync(formattedKey,
await LegacySecureStorage.SetAsync(formattedKey,
JsonConvert.SerializeObject(obj, _jsonSettings));
}
}
@ -49,7 +49,7 @@ namespace Bit.App.Services
public Task RemoveAsync(string key)
{
var formattedKey = string.Format(_keyFormat, key);
Microsoft.Maui.Storage.SecureStorage.Remove(formattedKey);
LegacySecureStorage.Remove(formattedKey);
return Task.FromResult(0);
}
}

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@ -60,7 +60,9 @@ namespace Bit.App.Utilities.AccountManagement
public async Task StartDefaultNavigationFlowAsync(Action<AppOptions> appOptionsAction)
{
await _conditionedAwaiterManager.GetAwaiterForPrecondition(AwaiterPrecondition.EnvironmentUrlsInited);
#if ANDROID
await _conditionedAwaiterManager.GetAwaiterForPrecondition(AwaiterPrecondition.AndroidWindowCreated);
#endif
appOptionsAction(Options);
await NavigateOnAccountChangeAsync();
@ -69,6 +71,9 @@ namespace Bit.App.Utilities.AccountManagement
public async Task NavigateOnAccountChangeAsync(bool? isAuthed = null)
{
await _conditionedAwaiterManager.GetAwaiterForPrecondition(AwaiterPrecondition.EnvironmentUrlsInited);
#if ANDROID
await _conditionedAwaiterManager.GetAwaiterForPrecondition(AwaiterPrecondition.AndroidWindowCreated);
#endif
// TODO: this could be improved by doing chain of responsability pattern
// but for now it may be an overkill, if logic gets more complex consider refactoring it