diff options
Diffstat (limited to 'app/src/main/java/dev/msfjarvis/aps/util/git/sshj')
6 files changed, 1129 insertions, 0 deletions
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/ContinuationContainerActivity.kt b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/ContinuationContainerActivity.kt new file mode 100644 index 00000000..8bcdad05 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/ContinuationContainerActivity.kt @@ -0,0 +1,37 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.git.sshj + +import android.content.Intent +import androidx.activity.result.contract.ActivityResultContracts +import androidx.annotation.LayoutRes +import androidx.appcompat.app.AppCompatActivity +import kotlin.coroutines.Continuation +import kotlin.coroutines.resume +import kotlin.coroutines.resumeWithException +import net.schmizz.sshj.common.DisconnectReason +import net.schmizz.sshj.userauth.UserAuthException + +/** + * Workaround for https://msfjarvis.dev/aps/issue/1164 + */ +open class ContinuationContainerActivity : AppCompatActivity { + + constructor() : super() + constructor(@LayoutRes layoutRes: Int) : super(layoutRes) + + var stashedCont: Continuation<Intent>? = null + + val continueAfterUserInteraction = registerForActivityResult(ActivityResultContracts.StartIntentSenderForResult()) { result -> + stashedCont?.let { cont -> + stashedCont = null + val data = result.data + if (data != null) + cont.resume(data) + else + cont.resumeWithException(UserAuthException(DisconnectReason.AUTH_CANCELLED_BY_USER)) + } + } +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/OpenKeychainKeyProvider.kt b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/OpenKeychainKeyProvider.kt new file mode 100644 index 00000000..3b0b2549 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/OpenKeychainKeyProvider.kt @@ -0,0 +1,191 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.git.sshj + +import android.app.PendingIntent +import android.content.Intent +import androidx.activity.result.IntentSenderRequest +import androidx.core.content.edit +import com.github.ajalt.timberkt.d +import dev.msfjarvis.aps.util.extensions.OPENPGP_PROVIDER +import dev.msfjarvis.aps.util.settings.PreferenceKeys +import dev.msfjarvis.aps.util.extensions.sharedPrefs +import java.io.Closeable +import java.security.PublicKey +import kotlin.coroutines.resume +import kotlin.coroutines.suspendCoroutine +import kotlinx.coroutines.Dispatchers +import kotlinx.coroutines.withContext +import net.schmizz.sshj.common.DisconnectReason +import net.schmizz.sshj.common.KeyType +import net.schmizz.sshj.userauth.UserAuthException +import net.schmizz.sshj.userauth.keyprovider.KeyProvider +import org.openintents.ssh.authentication.ISshAuthenticationService +import org.openintents.ssh.authentication.SshAuthenticationApi +import org.openintents.ssh.authentication.SshAuthenticationApiError +import org.openintents.ssh.authentication.SshAuthenticationConnection +import org.openintents.ssh.authentication.request.KeySelectionRequest +import org.openintents.ssh.authentication.request.Request +import org.openintents.ssh.authentication.request.SigningRequest +import org.openintents.ssh.authentication.request.SshPublicKeyRequest +import org.openintents.ssh.authentication.response.KeySelectionResponse +import org.openintents.ssh.authentication.response.Response +import org.openintents.ssh.authentication.response.SigningResponse +import org.openintents.ssh.authentication.response.SshPublicKeyResponse + +class OpenKeychainKeyProvider private constructor(val activity: ContinuationContainerActivity) : KeyProvider, Closeable { + + companion object { + + suspend fun prepareAndUse(activity: ContinuationContainerActivity, block: (provider: OpenKeychainKeyProvider) -> Unit) { + withContext(Dispatchers.Main) { + OpenKeychainKeyProvider(activity) + }.prepareAndUse(block) + } + } + + private sealed class ApiResponse { + data class Success(val response: Response) : ApiResponse() + data class GeneralError(val exception: Exception) : ApiResponse() + data class NoSuchKey(val exception: Exception) : ApiResponse() + } + + private val context = activity.applicationContext + private val sshServiceConnection = SshAuthenticationConnection(context, OPENPGP_PROVIDER) + private val preferences = context.sharedPrefs + private lateinit var sshServiceApi: SshAuthenticationApi + + private var keyId + get() = preferences.getString(PreferenceKeys.SSH_OPENKEYSTORE_KEYID, null) + set(value) { + preferences.edit { + putString(PreferenceKeys.SSH_OPENKEYSTORE_KEYID, value) + } + } + private var publicKey: PublicKey? = null + private var privateKey: OpenKeychainPrivateKey? = null + + private suspend fun prepareAndUse(block: (provider: OpenKeychainKeyProvider) -> Unit) { + prepare() + use(block) + } + + private suspend fun prepare() { + sshServiceApi = suspendCoroutine { cont -> + sshServiceConnection.connect(object : SshAuthenticationConnection.OnBound { + override fun onBound(sshAgent: ISshAuthenticationService) { + d { "Bound to SshAuthenticationApi: $OPENPGP_PROVIDER" } + cont.resume(SshAuthenticationApi(context, sshAgent)) + } + + override fun onError() { + throw UserAuthException(DisconnectReason.UNKNOWN, "OpenKeychain service unavailable") + } + }) + } + + if (keyId == null) { + selectKey() + } + check(keyId != null) + fetchPublicKey() + makePrivateKey() + } + + private suspend fun fetchPublicKey(isRetry: Boolean = false) { + when (val sshPublicKeyResponse = executeApiRequest(SshPublicKeyRequest(keyId))) { + is ApiResponse.Success -> { + val response = sshPublicKeyResponse.response as SshPublicKeyResponse + val sshPublicKey = response.sshPublicKey!! + publicKey = parseSshPublicKey(sshPublicKey) + ?: throw IllegalStateException("OpenKeychain API returned invalid SSH key") + } + is ApiResponse.NoSuchKey -> if (isRetry) { + throw sshPublicKeyResponse.exception + } else { + // Allow the user to reselect an authentication key and retry + selectKey() + fetchPublicKey(true) + } + is ApiResponse.GeneralError -> throw sshPublicKeyResponse.exception + } + } + + private suspend fun selectKey() { + when (val keySelectionResponse = executeApiRequest(KeySelectionRequest())) { + is ApiResponse.Success -> keyId = (keySelectionResponse.response as KeySelectionResponse).keyId + is ApiResponse.GeneralError -> throw keySelectionResponse.exception + is ApiResponse.NoSuchKey -> throw keySelectionResponse.exception + } + } + + private suspend fun executeApiRequest(request: Request, resultOfUserInteraction: Intent? = null): ApiResponse { + d { "executeRequest($request) called" } + val result = withContext(Dispatchers.Main) { + // If the request required user interaction, the data returned from the PendingIntent + // is used as the real request. + sshServiceApi.executeApi(resultOfUserInteraction ?: request.toIntent())!! + } + return parseResult(request, result).also { + d { "executeRequest($request): $it" } + } + } + + private suspend fun parseResult(request: Request, result: Intent): ApiResponse { + return when (result.getIntExtra(SshAuthenticationApi.EXTRA_RESULT_CODE, SshAuthenticationApi.RESULT_CODE_ERROR)) { + SshAuthenticationApi.RESULT_CODE_SUCCESS -> { + ApiResponse.Success(when (request) { + is KeySelectionRequest -> KeySelectionResponse(result) + is SshPublicKeyRequest -> SshPublicKeyResponse(result) + is SigningRequest -> SigningResponse(result) + else -> throw IllegalArgumentException("Unsupported OpenKeychain request type") + }) + } + SshAuthenticationApi.RESULT_CODE_USER_INTERACTION_REQUIRED -> { + val pendingIntent: PendingIntent = result.getParcelableExtra(SshAuthenticationApi.EXTRA_PENDING_INTENT)!! + val resultOfUserInteraction: Intent = withContext(Dispatchers.Main) { + suspendCoroutine { cont -> + activity.stashedCont = cont + activity.continueAfterUserInteraction.launch(IntentSenderRequest.Builder(pendingIntent).build()) + } + } + executeApiRequest(request, resultOfUserInteraction) + } + else -> { + val error = result.getParcelableExtra<SshAuthenticationApiError>(SshAuthenticationApi.EXTRA_ERROR) + val exception = UserAuthException(DisconnectReason.UNKNOWN, "Request ${request::class.simpleName} failed: ${error?.message}") + when (error?.error) { + SshAuthenticationApiError.NO_AUTH_KEY, SshAuthenticationApiError.NO_SUCH_KEY -> ApiResponse.NoSuchKey(exception) + else -> ApiResponse.GeneralError(exception) + } + } + } + } + + private fun makePrivateKey() { + check(keyId != null && publicKey != null) + privateKey = object : OpenKeychainPrivateKey { + override suspend fun sign(challenge: ByteArray, hashAlgorithm: Int) = + when (val signingResponse = executeApiRequest(SigningRequest(challenge, keyId, hashAlgorithm))) { + is ApiResponse.Success -> (signingResponse.response as SigningResponse).signature + is ApiResponse.GeneralError -> throw signingResponse.exception + is ApiResponse.NoSuchKey -> throw signingResponse.exception + } + + override fun getAlgorithm() = publicKey!!.algorithm + } + } + + override fun close() { + activity.continueAfterUserInteraction.unregister() + sshServiceConnection.disconnect() + } + + override fun getPrivate() = privateKey + + override fun getPublic() = publicKey + + override fun getType() = KeyType.fromKey(publicKey) +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/OpenKeychainWrappedKeyAlgorithmFactory.kt b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/OpenKeychainWrappedKeyAlgorithmFactory.kt new file mode 100644 index 00000000..272a04dd --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/OpenKeychainWrappedKeyAlgorithmFactory.kt @@ -0,0 +1,93 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.git.sshj + +import com.hierynomus.sshj.key.KeyAlgorithm +import java.io.ByteArrayOutputStream +import java.security.PrivateKey +import kotlinx.coroutines.runBlocking +import net.schmizz.sshj.common.Buffer +import net.schmizz.sshj.common.Factory +import net.schmizz.sshj.signature.Signature +import org.openintents.ssh.authentication.SshAuthenticationApi + +interface OpenKeychainPrivateKey : PrivateKey { + + suspend fun sign(challenge: ByteArray, hashAlgorithm: Int): ByteArray + + override fun getFormat() = null + override fun getEncoded() = null +} + +class OpenKeychainWrappedKeyAlgorithmFactory(private val factory: Factory.Named<KeyAlgorithm>) : Factory.Named<KeyAlgorithm> by factory { + + override fun create() = OpenKeychainWrappedKeyAlgorithm(factory.create()) +} + +class OpenKeychainWrappedKeyAlgorithm(private val keyAlgorithm: KeyAlgorithm) : KeyAlgorithm by keyAlgorithm { + + private val hashAlgorithm = when (keyAlgorithm.keyAlgorithm) { + "rsa-sha2-512" -> SshAuthenticationApi.SHA512 + "rsa-sha2-256" -> SshAuthenticationApi.SHA256 + "ssh-rsa", "ssh-rsa-cert-v01@openssh.com" -> SshAuthenticationApi.SHA1 + // Other algorithms don't use this value, but it has to be valid. + else -> SshAuthenticationApi.SHA512 + } + + override fun newSignature() = OpenKeychainWrappedSignature(keyAlgorithm.newSignature(), hashAlgorithm) +} + +class OpenKeychainWrappedSignature(private val wrappedSignature: Signature, private val hashAlgorithm: Int) : Signature by wrappedSignature { + + private val data = ByteArrayOutputStream() + + private var bridgedPrivateKey: OpenKeychainPrivateKey? = null + + override fun initSign(prvkey: PrivateKey?) { + if (prvkey is OpenKeychainPrivateKey) { + bridgedPrivateKey = prvkey + } else { + wrappedSignature.initSign(prvkey) + } + } + + override fun update(H: ByteArray?) { + if (bridgedPrivateKey != null) { + data.write(H!!) + } else { + wrappedSignature.update(H) + } + } + + override fun update(H: ByteArray?, off: Int, len: Int) { + if (bridgedPrivateKey != null) { + data.write(H!!, off, len) + } else { + wrappedSignature.update(H, off, len) + } + } + + override fun sign(): ByteArray? = if (bridgedPrivateKey != null) { + runBlocking { + bridgedPrivateKey!!.sign(data.toByteArray(), hashAlgorithm) + } + } else { + wrappedSignature.sign() + } + + override fun encode(signature: ByteArray?): ByteArray? = if (bridgedPrivateKey != null) { + require(signature != null) { "OpenKeychain signature must not be null" } + val encodedSignature = Buffer.PlainBuffer(signature) + // We need to drop the algorithm name and extract the raw signature since SSHJ adds the name + // later. + encodedSignature.readString() + encodedSignature.readBytes().also { + bridgedPrivateKey = null + data.reset() + } + } else { + wrappedSignature.encode(signature) + } +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshKey.kt b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshKey.kt new file mode 100644 index 00000000..352465e0 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshKey.kt @@ -0,0 +1,336 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.git.sshj + +import android.content.Context +import android.content.pm.PackageManager +import android.net.Uri +import android.os.Build +import android.provider.OpenableColumns +import android.security.keystore.KeyGenParameterSpec +import android.security.keystore.KeyInfo +import android.security.keystore.KeyProperties +import android.util.Base64 +import androidx.core.content.edit +import androidx.security.crypto.EncryptedFile +import androidx.security.crypto.MasterKey +import com.github.ajalt.timberkt.d +import com.github.ajalt.timberkt.e +import com.github.michaelbull.result.getOrElse +import com.github.michaelbull.result.runCatching +import dev.msfjarvis.aps.Application +import dev.msfjarvis.aps.R +import dev.msfjarvis.aps.util.settings.PreferenceKeys +import dev.msfjarvis.aps.util.extensions.getEncryptedGitPrefs +import dev.msfjarvis.aps.util.extensions.getString +import dev.msfjarvis.aps.util.extensions.sharedPrefs +import java.io.File +import java.io.IOException +import java.security.KeyFactory +import java.security.KeyPairGenerator +import java.security.KeyStore +import java.security.PrivateKey +import java.security.PublicKey +import javax.crypto.SecretKey +import javax.crypto.SecretKeyFactory +import kotlinx.coroutines.Dispatchers +import kotlinx.coroutines.runBlocking +import kotlinx.coroutines.withContext +import net.i2p.crypto.eddsa.EdDSAPrivateKey +import net.i2p.crypto.eddsa.spec.EdDSANamedCurveTable +import net.i2p.crypto.eddsa.spec.EdDSAPrivateKeySpec +import net.schmizz.sshj.SSHClient +import net.schmizz.sshj.common.Buffer +import net.schmizz.sshj.common.KeyType +import net.schmizz.sshj.userauth.keyprovider.KeyProvider + +private const val PROVIDER_ANDROID_KEY_STORE = "AndroidKeyStore" +private const val KEYSTORE_ALIAS = "sshkey" +private const val ANDROIDX_SECURITY_KEYSET_PREF_NAME = "androidx_sshkey_keyset_prefs" + +private val androidKeystore: KeyStore by lazy(LazyThreadSafetyMode.NONE) { + KeyStore.getInstance(PROVIDER_ANDROID_KEY_STORE).apply { load(null) } +} + +private val KeyStore.sshPrivateKey + get() = getKey(KEYSTORE_ALIAS, null) as? PrivateKey + +private val KeyStore.sshPublicKey + get() = getCertificate(KEYSTORE_ALIAS)?.publicKey + +fun parseSshPublicKey(sshPublicKey: String): PublicKey? { + val sshKeyParts = sshPublicKey.split("""\s+""".toRegex()) + if (sshKeyParts.size < 2) + return null + return Buffer.PlainBuffer(Base64.decode(sshKeyParts[1], Base64.NO_WRAP)).readPublicKey() +} + +fun toSshPublicKey(publicKey: PublicKey): String { + val rawPublicKey = Buffer.PlainBuffer().putPublicKey(publicKey).compactData + val keyType = KeyType.fromKey(publicKey) + return "$keyType ${Base64.encodeToString(rawPublicKey, Base64.NO_WRAP)}" +} + +object SshKey { + + val sshPublicKey + get() = if (publicKeyFile.exists()) publicKeyFile.readText() else null + val canShowSshPublicKey + get() = type in listOf(Type.LegacyGenerated, Type.KeystoreNative, Type.KeystoreWrappedEd25519) + val exists + get() = type != null + val mustAuthenticate: Boolean + get() { + return runCatching { + if (type !in listOf(Type.KeystoreNative, Type.KeystoreWrappedEd25519)) + return false + when (val key = androidKeystore.getKey(KEYSTORE_ALIAS, null)) { + is PrivateKey -> { + val factory = KeyFactory.getInstance(key.algorithm, PROVIDER_ANDROID_KEY_STORE) + return factory.getKeySpec(key, KeyInfo::class.java).isUserAuthenticationRequired + } + is SecretKey -> { + val factory = SecretKeyFactory.getInstance(key.algorithm, PROVIDER_ANDROID_KEY_STORE) + (factory.getKeySpec(key, KeyInfo::class.java) as KeyInfo).isUserAuthenticationRequired + } + else -> throw IllegalStateException("SSH key does not exist in Keystore") + } + }.getOrElse { error -> + // It is fine to swallow the exception here since it will reappear when the key is + // used for SSH authentication and can then be shown in the UI. + d(error) + false + } + } + + private val context: Context + get() = Application.instance.applicationContext + + private val privateKeyFile + get() = File(context.filesDir, ".ssh_key") + private val publicKeyFile + get() = File(context.filesDir, ".ssh_key.pub") + + private var type: Type? + get() = Type.fromValue(context.sharedPrefs.getString(PreferenceKeys.GIT_REMOTE_KEY_TYPE)) + set(value) = context.sharedPrefs.edit { + putString(PreferenceKeys.GIT_REMOTE_KEY_TYPE, value?.value) + } + + private val isStrongBoxSupported by lazy(LazyThreadSafetyMode.NONE) { + if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) + context.packageManager.hasSystemFeature(PackageManager.FEATURE_STRONGBOX_KEYSTORE) + else + false + } + + private enum class Type(val value: String) { + Imported("imported"), + KeystoreNative("keystore_native"), + KeystoreWrappedEd25519("keystore_wrapped_ed25519"), + + // Behaves like `Imported`, but allows to view the public key. + LegacyGenerated("legacy_generated"), + ; + + companion object { + + fun fromValue(value: String?): Type? = values().associateBy { it.value }[value] + } + } + + enum class Algorithm(val algorithm: String, val applyToSpec: KeyGenParameterSpec.Builder.() -> Unit) { + Rsa(KeyProperties.KEY_ALGORITHM_RSA, { + setKeySize(3072) + setSignaturePaddings(KeyProperties.SIGNATURE_PADDING_RSA_PKCS1) + setDigests(KeyProperties.DIGEST_SHA1, KeyProperties.DIGEST_SHA256, KeyProperties.DIGEST_SHA512) + }), + Ecdsa(KeyProperties.KEY_ALGORITHM_EC, { + setKeySize(256) + setAlgorithmParameterSpec(java.security.spec.ECGenParameterSpec("secp256r1")) + setDigests(KeyProperties.DIGEST_SHA256) + if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) { + setIsStrongBoxBacked(isStrongBoxSupported) + } + }), + } + + private fun delete() { + androidKeystore.deleteEntry(KEYSTORE_ALIAS) + // Remove Tink key set used by AndroidX's EncryptedFile. + context.getSharedPreferences(ANDROIDX_SECURITY_KEYSET_PREF_NAME, Context.MODE_PRIVATE).edit { + clear() + } + if (privateKeyFile.isFile) { + privateKeyFile.delete() + } + if (publicKeyFile.isFile) { + publicKeyFile.delete() + } + context.getEncryptedGitPrefs().edit { + remove(PreferenceKeys.SSH_KEY_LOCAL_PASSPHRASE) + } + type = null + } + + fun import(uri: Uri) { + // First check whether the content at uri is likely an SSH private key. + val fileSize = context.contentResolver.query(uri, arrayOf(OpenableColumns.SIZE), null, null, null) + ?.use { cursor -> + // Cursor returns only a single row. + cursor.moveToFirst() + cursor.getInt(0) + } ?: throw IOException(context.getString(R.string.ssh_key_does_not_exist)) + + // We assume that an SSH key's ideal size is > 0 bytes && < 100 kilobytes. + if (fileSize > 100_000 || fileSize == 0) + throw IllegalArgumentException(context.getString(R.string.ssh_key_import_error_not_an_ssh_key_message)) + + val sshKeyInputStream = context.contentResolver.openInputStream(uri) + ?: throw IOException(context.getString(R.string.ssh_key_does_not_exist)) + val lines = sshKeyInputStream.bufferedReader().readLines() + + // The file must have more than 2 lines, and the first and last line must have private key + // markers. + if (lines.size < 2 || + !Regex("BEGIN .* PRIVATE KEY").containsMatchIn(lines.first()) || + !Regex("END .* PRIVATE KEY").containsMatchIn(lines.last()) + ) + throw IllegalArgumentException(context.getString(R.string.ssh_key_import_error_not_an_ssh_key_message)) + + // At this point, we are reasonably confident that we have actually been provided a private + // key and delete the old key. + delete() + // Canonicalize line endings to '\n'. + privateKeyFile.writeText(lines.joinToString("\n")) + + type = Type.Imported + } + + @Deprecated("To be used only in Migrations.kt") + fun useLegacyKey(isGenerated: Boolean) { + type = if (isGenerated) Type.LegacyGenerated else Type.Imported + } + + @Suppress("BlockingMethodInNonBlockingContext") + private suspend fun getOrCreateWrappingMasterKey(requireAuthentication: Boolean) = withContext(Dispatchers.IO) { + MasterKey.Builder(context, KEYSTORE_ALIAS).run { + setKeyScheme(MasterKey.KeyScheme.AES256_GCM) + setRequestStrongBoxBacked(true) + setUserAuthenticationRequired(requireAuthentication, 15) + build() + } + } + + @Suppress("BlockingMethodInNonBlockingContext") + private suspend fun getOrCreateWrappedPrivateKeyFile(requireAuthentication: Boolean) = withContext(Dispatchers.IO) { + EncryptedFile.Builder(context, + privateKeyFile, + getOrCreateWrappingMasterKey(requireAuthentication), + EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB).run { + setKeysetPrefName(ANDROIDX_SECURITY_KEYSET_PREF_NAME) + build() + } + } + + @Suppress("BlockingMethodInNonBlockingContext") + suspend fun generateKeystoreWrappedEd25519Key(requireAuthentication: Boolean) = withContext(Dispatchers.IO) { + delete() + + val encryptedPrivateKeyFile = getOrCreateWrappedPrivateKeyFile(requireAuthentication) + // Generate the ed25519 key pair and encrypt the private key. + val keyPair = net.i2p.crypto.eddsa.KeyPairGenerator().generateKeyPair() + encryptedPrivateKeyFile.openFileOutput().use { os -> + os.write((keyPair.private as EdDSAPrivateKey).seed) + } + + // Write public key in SSH format to .ssh_key.pub. + publicKeyFile.writeText(toSshPublicKey(keyPair.public)) + + type = Type.KeystoreWrappedEd25519 + } + + fun generateKeystoreNativeKey(algorithm: Algorithm, requireAuthentication: Boolean) { + delete() + + // Generate Keystore-backed private key. + val parameterSpec = KeyGenParameterSpec.Builder( + KEYSTORE_ALIAS, KeyProperties.PURPOSE_SIGN + ).run { + apply(algorithm.applyToSpec) + if (requireAuthentication) { + setUserAuthenticationRequired(true) + if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) { + setUserAuthenticationParameters(30, KeyProperties.AUTH_DEVICE_CREDENTIAL) + } else { + @Suppress("DEPRECATION") + setUserAuthenticationValidityDurationSeconds(30) + } + } + build() + } + val keyPair = KeyPairGenerator.getInstance(algorithm.algorithm, PROVIDER_ANDROID_KEY_STORE).run { + initialize(parameterSpec) + generateKeyPair() + } + + // Write public key in SSH format to .ssh_key.pub. + publicKeyFile.writeText(toSshPublicKey(keyPair.public)) + + type = Type.KeystoreNative + } + + fun provide(client: SSHClient, passphraseFinder: InteractivePasswordFinder): KeyProvider? = when (type) { + Type.LegacyGenerated, Type.Imported -> client.loadKeys(privateKeyFile.absolutePath, passphraseFinder) + Type.KeystoreNative -> KeystoreNativeKeyProvider + Type.KeystoreWrappedEd25519 -> KeystoreWrappedEd25519KeyProvider + null -> null + } + + private object KeystoreNativeKeyProvider : KeyProvider { + + override fun getPublic(): PublicKey = runCatching { + androidKeystore.sshPublicKey!! + }.getOrElse { error -> + e(error) + throw IOException("Failed to get public key '$KEYSTORE_ALIAS' from Android Keystore", error) + } + + override fun getPrivate(): PrivateKey = runCatching { + androidKeystore.sshPrivateKey!! + }.getOrElse { error -> + e(error) + throw IOException("Failed to access private key '$KEYSTORE_ALIAS' from Android Keystore", error) + } + + override fun getType(): KeyType = KeyType.fromKey(public) + } + + private object KeystoreWrappedEd25519KeyProvider : KeyProvider { + + override fun getPublic(): PublicKey = runCatching { + parseSshPublicKey(sshPublicKey!!)!! + }.getOrElse { error -> + e(error) + throw IOException("Failed to get the public key for wrapped ed25519 key", error) + } + + override fun getPrivate(): PrivateKey = runCatching { + // The current MasterKey API does not allow getting a reference to an existing one + // without specifying the KeySpec for a new one. However, the value for passed here + // for `requireAuthentication` is not used as the key already exists at this point. + val encryptedPrivateKeyFile = runBlocking { + getOrCreateWrappedPrivateKeyFile(false) + } + val rawPrivateKey = encryptedPrivateKeyFile.openFileInput().use { it.readBytes() } + EdDSAPrivateKey(EdDSAPrivateKeySpec(rawPrivateKey, EdDSANamedCurveTable.ED_25519_CURVE_SPEC)) + }.getOrElse { error -> + e(error) + throw IOException("Failed to unwrap wrapped ed25519 key", error) + } + + override fun getType(): KeyType = KeyType.fromKey(public) + } +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshjConfig.kt b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshjConfig.kt new file mode 100644 index 00000000..8402d232 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshjConfig.kt @@ -0,0 +1,275 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.git.sshj + +import com.github.ajalt.timberkt.Timber +import com.github.ajalt.timberkt.d +import com.github.michaelbull.result.runCatching +import com.hierynomus.sshj.key.KeyAlgorithms +import com.hierynomus.sshj.transport.cipher.BlockCiphers +import com.hierynomus.sshj.transport.kex.ExtInfoClientFactory +import com.hierynomus.sshj.transport.mac.Macs +import com.hierynomus.sshj.userauth.keyprovider.OpenSSHKeyV1KeyFile +import java.security.Security +import net.schmizz.keepalive.KeepAliveProvider +import net.schmizz.sshj.ConfigImpl +import net.schmizz.sshj.common.LoggerFactory +import net.schmizz.sshj.common.SecurityUtils +import net.schmizz.sshj.transport.compression.NoneCompression +import net.schmizz.sshj.transport.kex.Curve25519SHA256 +import net.schmizz.sshj.transport.kex.Curve25519SHA256.FactoryLibSsh +import net.schmizz.sshj.transport.kex.DHGexSHA256 +import net.schmizz.sshj.transport.random.JCERandom +import net.schmizz.sshj.transport.random.SingletonRandomFactory +import net.schmizz.sshj.userauth.keyprovider.OpenSSHKeyFile +import net.schmizz.sshj.userauth.keyprovider.PKCS5KeyFile +import net.schmizz.sshj.userauth.keyprovider.PKCS8KeyFile +import net.schmizz.sshj.userauth.keyprovider.PuTTYKeyFile +import org.bouncycastle.jce.provider.BouncyCastleProvider +import org.slf4j.Logger +import org.slf4j.Marker + + +fun setUpBouncyCastleForSshj() { + // Replace the Android BC provider with the Java BouncyCastle provider since the former does + // not include all the required algorithms. + // Note: This may affect crypto operations in other parts of the application. + val bcIndex = Security.getProviders().indexOfFirst { + it.name == BouncyCastleProvider.PROVIDER_NAME + } + if (bcIndex == -1) { + // No Android BC found, install Java BC at lowest priority. + Security.addProvider(BouncyCastleProvider()) + } else { + // Replace Android BC with Java BC, inserted at the same position. + Security.removeProvider(BouncyCastleProvider.PROVIDER_NAME) + // May be needed on Android Pie+ as per https://stackoverflow.com/a/57897224/297261 + runCatching { Class.forName("sun.security.jca.Providers") } + Security.insertProviderAt(BouncyCastleProvider(), bcIndex + 1) + } + d { "JCE providers: ${Security.getProviders().joinToString { "${it.name} (${it.version})" }}" } + // Prevent sshj from forwarding all cryptographic operations to BC. + SecurityUtils.setRegisterBouncyCastle(false) + SecurityUtils.setSecurityProvider(null) +} + +private abstract class AbstractLogger(private val name: String) : Logger { + + abstract fun t(message: String, t: Throwable? = null, vararg args: Any?) + abstract fun d(message: String, t: Throwable? = null, vararg args: Any?) + abstract fun i(message: String, t: Throwable? = null, vararg args: Any?) + abstract fun w(message: String, t: Throwable? = null, vararg args: Any?) + abstract fun e(message: String, t: Throwable? = null, vararg args: Any?) + + override fun getName() = name + + override fun isTraceEnabled(marker: Marker?): Boolean = isTraceEnabled + override fun isDebugEnabled(marker: Marker?): Boolean = isDebugEnabled + override fun isInfoEnabled(marker: Marker?): Boolean = isInfoEnabled + override fun isWarnEnabled(marker: Marker?): Boolean = isWarnEnabled + override fun isErrorEnabled(marker: Marker?): Boolean = isErrorEnabled + + override fun trace(msg: String) = t(msg) + override fun trace(format: String, arg: Any?) = t(format, null, arg) + override fun trace(format: String, arg1: Any?, arg2: Any?) = t(format, null, arg1, arg2) + override fun trace(format: String, vararg arguments: Any?) = t(format, null, *arguments) + override fun trace(msg: String, t: Throwable?) = t(msg, t) + override fun trace(marker: Marker, msg: String) = trace(msg) + override fun trace(marker: Marker?, format: String, arg: Any?) = trace(format, arg) + override fun trace(marker: Marker?, format: String, arg1: Any?, arg2: Any?) = + trace(format, arg1, arg2) + + override fun trace(marker: Marker?, format: String, vararg arguments: Any?) = + trace(format, *arguments) + + override fun trace(marker: Marker?, msg: String, t: Throwable?) = trace(msg, t) + + override fun debug(msg: String) = d(msg) + override fun debug(format: String, arg: Any?) = d(format, null, arg) + override fun debug(format: String, arg1: Any?, arg2: Any?) = d(format, null, arg1, arg2) + override fun debug(format: String, vararg arguments: Any?) = d(format, null, *arguments) + override fun debug(msg: String, t: Throwable?) = d(msg, t) + override fun debug(marker: Marker, msg: String) = debug(msg) + override fun debug(marker: Marker?, format: String, arg: Any?) = debug(format, arg) + override fun debug(marker: Marker?, format: String, arg1: Any?, arg2: Any?) = + debug(format, arg1, arg2) + + override fun debug(marker: Marker?, format: String, vararg arguments: Any?) = + debug(format, *arguments) + + override fun debug(marker: Marker?, msg: String, t: Throwable?) = debug(msg, t) + + override fun info(msg: String) = i(msg) + override fun info(format: String, arg: Any?) = i(format, null, arg) + override fun info(format: String, arg1: Any?, arg2: Any?) = i(format, null, arg1, arg2) + override fun info(format: String, vararg arguments: Any?) = i(format, null, *arguments) + override fun info(msg: String, t: Throwable?) = i(msg, t) + override fun info(marker: Marker, msg: String) = info(msg) + override fun info(marker: Marker?, format: String, arg: Any?) = info(format, arg) + override fun info(marker: Marker?, format: String, arg1: Any?, arg2: Any?) = + info(format, arg1, arg2) + + override fun info(marker: Marker?, format: String, vararg arguments: Any?) = + info(format, *arguments) + + override fun info(marker: Marker?, msg: String, t: Throwable?) = info(msg, t) + + override fun warn(msg: String) = w(msg) + override fun warn(format: String, arg: Any?) = w(format, null, arg) + override fun warn(format: String, arg1: Any?, arg2: Any?) = w(format, null, arg1, arg2) + override fun warn(format: String, vararg arguments: Any?) = w(format, null, *arguments) + override fun warn(msg: String, t: Throwable?) = w(msg, t) + override fun warn(marker: Marker, msg: String) = warn(msg) + override fun warn(marker: Marker?, format: String, arg: Any?) = warn(format, arg) + override fun warn(marker: Marker?, format: String, arg1: Any?, arg2: Any?) = + warn(format, arg1, arg2) + + override fun warn(marker: Marker?, format: String, vararg arguments: Any?) = + warn(format, *arguments) + + override fun warn(marker: Marker?, msg: String, t: Throwable?) = warn(msg, t) + + override fun error(msg: String) = e(msg) + override fun error(format: String, arg: Any?) = e(format, null, arg) + override fun error(format: String, arg1: Any?, arg2: Any?) = e(format, null, arg1, arg2) + override fun error(format: String, vararg arguments: Any?) = e(format, null, *arguments) + override fun error(msg: String, t: Throwable?) = e(msg, t) + override fun error(marker: Marker, msg: String) = error(msg) + override fun error(marker: Marker?, format: String, arg: Any?) = error(format, arg) + override fun error(marker: Marker?, format: String, arg1: Any?, arg2: Any?) = + error(format, arg1, arg2) + + override fun error(marker: Marker?, format: String, vararg arguments: Any?) = + error(format, *arguments) + + override fun error(marker: Marker?, msg: String, t: Throwable?) = error(msg, t) +} + +object TimberLoggerFactory : LoggerFactory { + private class TimberLogger(name: String) : AbstractLogger(name) { + + // We defer the log level checks to Timber. + override fun isTraceEnabled() = true + override fun isDebugEnabled() = true + override fun isInfoEnabled() = true + override fun isWarnEnabled() = true + override fun isErrorEnabled() = true + + // Replace slf4j's "{}" format string style with standard Java's "%s". + // The supposedly redundant escape on the } is not redundant. + @Suppress("RegExpRedundantEscape") + private fun String.fix() = replace("""(?!<\\)\{\}""".toRegex(), "%s") + + override fun t(message: String, t: Throwable?, vararg args: Any?) { + Timber.tag(name).v(t, message.fix(), *args) + } + + override fun d(message: String, t: Throwable?, vararg args: Any?) { + Timber.tag(name).d(t, message.fix(), *args) + } + + override fun i(message: String, t: Throwable?, vararg args: Any?) { + Timber.tag(name).i(t, message.fix(), *args) + } + + override fun w(message: String, t: Throwable?, vararg args: Any?) { + Timber.tag(name).w(t, message.fix(), *args) + } + + override fun e(message: String, t: Throwable?, vararg args: Any?) { + Timber.tag(name).e(t, message.fix(), *args) + } + } + + override fun getLogger(name: String): Logger { + return TimberLogger(name) + } + + override fun getLogger(clazz: Class<*>): Logger { + return TimberLogger(clazz.name) + } + +} + +class SshjConfig : ConfigImpl() { + + init { + loggerFactory = TimberLoggerFactory + keepAliveProvider = KeepAliveProvider.HEARTBEAT + version = "OpenSSH_8.2p1 Ubuntu-4ubuntu0.1" + + initKeyExchangeFactories() + initKeyAlgorithms() + initRandomFactory() + initFileKeyProviderFactories() + initCipherFactories() + initCompressionFactories() + initMACFactories() + } + + private fun initKeyExchangeFactories() { + keyExchangeFactories = listOf( + Curve25519SHA256.Factory(), + FactoryLibSsh(), + DHGexSHA256.Factory(), + // Sends "ext-info-c" with the list of key exchange algorithms. This is needed to get + // rsa-sha2-* key types to work with some servers (e.g. GitHub). + ExtInfoClientFactory(), + ) + } + + private fun initKeyAlgorithms() { + keyAlgorithms = listOf( + KeyAlgorithms.SSHRSACertV01(), + KeyAlgorithms.EdDSA25519(), + KeyAlgorithms.RSASHA512(), + KeyAlgorithms.RSASHA256(), + KeyAlgorithms.SSHRSA(), + KeyAlgorithms.ECDSASHANistp521(), + KeyAlgorithms.ECDSASHANistp384(), + KeyAlgorithms.ECDSASHANistp256(), + ).map { + OpenKeychainWrappedKeyAlgorithmFactory(it) + } + } + + private fun initRandomFactory() { + randomFactory = SingletonRandomFactory(JCERandom.Factory()) + } + + private fun initFileKeyProviderFactories() { + fileKeyProviderFactories = listOf( + OpenSSHKeyV1KeyFile.Factory(), + PKCS8KeyFile.Factory(), + PKCS5KeyFile.Factory(), + OpenSSHKeyFile.Factory(), + PuTTYKeyFile.Factory(), + ) + } + + + private fun initCipherFactories() { + cipherFactories = listOf( + BlockCiphers.AES256CTR(), + BlockCiphers.AES192CTR(), + BlockCiphers.AES128CTR(), + ) + } + + private fun initMACFactories() { + macFactories = listOf( + Macs.HMACSHA2512Etm(), + Macs.HMACSHA2256Etm(), + Macs.HMACSHA2512(), + Macs.HMACSHA2256(), + ) + } + + private fun initCompressionFactories() { + compressionFactories = listOf( + NoneCompression.Factory(), + ) + } +} diff --git a/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshjSessionFactory.kt b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshjSessionFactory.kt new file mode 100644 index 00000000..7cd39653 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/git/sshj/SshjSessionFactory.kt @@ -0,0 +1,197 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.git.sshj + +import android.util.Base64 +import com.github.ajalt.timberkt.d +import com.github.ajalt.timberkt.w +import com.github.michaelbull.result.getOrElse +import com.github.michaelbull.result.runCatching +import dev.msfjarvis.aps.util.settings.AuthMode +import dev.msfjarvis.aps.util.git.operation.CredentialFinder +import java.io.File +import java.io.IOException +import java.io.InputStream +import java.io.OutputStream +import java.util.concurrent.TimeUnit +import kotlin.coroutines.Continuation +import kotlin.coroutines.suspendCoroutine +import kotlinx.coroutines.Dispatchers +import kotlinx.coroutines.runBlocking +import net.schmizz.sshj.SSHClient +import net.schmizz.sshj.common.Buffer.PlainBuffer +import net.schmizz.sshj.common.DisconnectReason +import net.schmizz.sshj.common.SSHException +import net.schmizz.sshj.common.SSHRuntimeException +import net.schmizz.sshj.common.SecurityUtils +import net.schmizz.sshj.connection.channel.direct.Session +import net.schmizz.sshj.transport.verification.FingerprintVerifier +import net.schmizz.sshj.transport.verification.HostKeyVerifier +import net.schmizz.sshj.userauth.method.AuthPassword +import net.schmizz.sshj.userauth.method.AuthPublickey +import net.schmizz.sshj.userauth.password.PasswordFinder +import net.schmizz.sshj.userauth.password.Resource +import org.eclipse.jgit.transport.CredentialsProvider +import org.eclipse.jgit.transport.RemoteSession +import org.eclipse.jgit.transport.SshSessionFactory +import org.eclipse.jgit.transport.URIish +import org.eclipse.jgit.util.FS + +sealed class SshAuthMethod(val activity: ContinuationContainerActivity) { + class Password(activity: ContinuationContainerActivity) : SshAuthMethod(activity) + class SshKey(activity: ContinuationContainerActivity) : SshAuthMethod(activity) + class OpenKeychain(activity: ContinuationContainerActivity) : SshAuthMethod(activity) +} + +abstract class InteractivePasswordFinder : PasswordFinder { + + private var isRetry = false + + abstract fun askForPassword(cont: Continuation<String?>, isRetry: Boolean) + + final override fun reqPassword(resource: Resource<*>?): CharArray { + val password = runBlocking(Dispatchers.Main) { + suspendCoroutine<String?> { cont -> + askForPassword(cont, isRetry) + } + } + isRetry = true + return password?.toCharArray() + ?: throw SSHException(DisconnectReason.AUTH_CANCELLED_BY_USER) + } + + final override fun shouldRetry(resource: Resource<*>?) = true +} + +class SshjSessionFactory(private val authMethod: SshAuthMethod, private val hostKeyFile: File) : SshSessionFactory() { + + private var currentSession: SshjSession? = null + + override fun getSession(uri: URIish, credentialsProvider: CredentialsProvider?, fs: FS?, tms: Int): RemoteSession { + return currentSession + ?: SshjSession(uri, uri.user, authMethod, hostKeyFile).connect().also { + d { "New SSH connection created" } + currentSession = it + } + } + + fun close() { + currentSession?.close() + } +} + +private fun makeTofuHostKeyVerifier(hostKeyFile: File): HostKeyVerifier { + if (!hostKeyFile.exists()) { + return HostKeyVerifier { _, _, key -> + val digest = runCatching { + SecurityUtils.getMessageDigest("SHA-256") + }.getOrElse { e -> + throw SSHRuntimeException(e) + } + digest.update(PlainBuffer().putPublicKey(key).compactData) + val digestData = digest.digest() + val hostKeyEntry = "SHA256:${Base64.encodeToString(digestData, Base64.NO_WRAP)}" + d { "Trusting host key on first use: $hostKeyEntry" } + hostKeyFile.writeText(hostKeyEntry) + true + } + } else { + val hostKeyEntry = hostKeyFile.readText() + d { "Pinned host key: $hostKeyEntry" } + return FingerprintVerifier.getInstance(hostKeyEntry) + } +} + +private class SshjSession(uri: URIish, private val username: String, private val authMethod: SshAuthMethod, private val hostKeyFile: File) : RemoteSession { + + private lateinit var ssh: SSHClient + private var currentCommand: Session? = null + + private val uri = if (uri.host.contains('@')) { + // URIish's String constructor cannot handle '@' in the user part of the URI and the URL + // constructor can't be used since Java's URL does not recognize the ssh scheme. We thus + // need to patch everything up ourselves. + d { "Before fixup: user=${uri.user}, host=${uri.host}" } + val userPlusHost = "${uri.user}@${uri.host}" + val realUser = userPlusHost.substringBeforeLast('@') + val realHost = userPlusHost.substringAfterLast('@') + uri.setUser(realUser).setHost(realHost).also { d { "After fixup: user=${it.user}, host=${it.host}" } } + } else { + uri + } + + fun connect(): SshjSession { + ssh = SSHClient(SshjConfig()) + ssh.addHostKeyVerifier(makeTofuHostKeyVerifier(hostKeyFile)) + ssh.connect(uri.host, uri.port.takeUnless { it == -1 } ?: 22) + if (!ssh.isConnected) + throw IOException() + val passwordAuth = AuthPassword(CredentialFinder(authMethod.activity, AuthMode.Password)) + when (authMethod) { + is SshAuthMethod.Password -> { + ssh.auth(username, passwordAuth) + } + is SshAuthMethod.SshKey -> { + val pubkeyAuth = AuthPublickey(SshKey.provide(ssh, CredentialFinder(authMethod.activity, AuthMode.SshKey))) + ssh.auth(username, pubkeyAuth, passwordAuth) + } + is SshAuthMethod.OpenKeychain -> { + runBlocking { + OpenKeychainKeyProvider.prepareAndUse(authMethod.activity) { provider -> + val openKeychainAuth = AuthPublickey(provider) + ssh.auth(username, openKeychainAuth, passwordAuth) + } + } + } + } + return this + } + + override fun exec(commandName: String?, timeout: Int): Process { + if (currentCommand != null) { + w { "Killing old command" } + disconnect() + } + val session = ssh.startSession() + currentCommand = session + return SshjProcess(session.exec(commandName), timeout.toLong()) + } + + /** + * Kills the current command if one is running and returns the session into a state where `exec` + * can be called. + * + * Note that this does *not* disconnect the session. Unfortunately, the function has to be + * called `disconnect` to override the corresponding abstract function in `RemoteSession`. + */ + override fun disconnect() { + currentCommand?.close() + currentCommand = null + } + + fun close() { + disconnect() + ssh.close() + } +} + +private class SshjProcess(private val command: Session.Command, private val timeout: Long) : Process() { + + override fun waitFor(): Int { + command.join(timeout, TimeUnit.SECONDS) + command.close() + return exitValue() + } + + override fun destroy() = command.close() + + override fun getOutputStream(): OutputStream = command.outputStream + + override fun getErrorStream(): InputStream = command.errorStream + + override fun exitValue(): Int = command.exitStatus + + override fun getInputStream(): InputStream = command.inputStream +} |