diff options
Diffstat (limited to 'app/src/main/java/dev/msfjarvis/aps/util/autofill/AutofillMatcher.kt')
| -rw-r--r-- | app/src/main/java/dev/msfjarvis/aps/util/autofill/AutofillMatcher.kt | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/app/src/main/java/dev/msfjarvis/aps/util/autofill/AutofillMatcher.kt b/app/src/main/java/dev/msfjarvis/aps/util/autofill/AutofillMatcher.kt new file mode 100644 index 00000000..52f74087 --- /dev/null +++ b/app/src/main/java/dev/msfjarvis/aps/util/autofill/AutofillMatcher.kt @@ -0,0 +1,193 @@ +/* + * Copyright © 2014-2020 The Android Password Store Authors. All Rights Reserved. + * SPDX-License-Identifier: GPL-3.0-only + */ +package dev.msfjarvis.aps.util.autofill + +import android.content.Context +import android.content.SharedPreferences +import android.widget.Toast +import androidx.core.content.edit +import com.github.ajalt.timberkt.Timber.e +import com.github.ajalt.timberkt.d +import com.github.ajalt.timberkt.w +import com.github.michaelbull.result.Err +import com.github.michaelbull.result.Ok +import com.github.michaelbull.result.Result +import com.github.androidpasswordstore.autofillparser.FormOrigin +import com.github.androidpasswordstore.autofillparser.computeCertificatesHash +import dev.msfjarvis.aps.R +import java.io.File + +private const val PREFERENCES_AUTOFILL_APP_MATCHES = "oreo_autofill_app_matches" +private val Context.autofillAppMatches + get() = getSharedPreferences(PREFERENCES_AUTOFILL_APP_MATCHES, Context.MODE_PRIVATE) + +private const val PREFERENCES_AUTOFILL_WEB_MATCHES = "oreo_autofill_web_matches" +private val Context.autofillWebMatches + get() = getSharedPreferences(PREFERENCES_AUTOFILL_WEB_MATCHES, Context.MODE_PRIVATE) + +private fun Context.matchPreferences(formOrigin: FormOrigin): SharedPreferences { + return when (formOrigin) { + is FormOrigin.App -> autofillAppMatches + is FormOrigin.Web -> autofillWebMatches + } +} + +class AutofillPublisherChangedException(val formOrigin: FormOrigin) : + Exception("The publisher of '${formOrigin.identifier}' changed since an entry was first matched with this app") { + + init { + require(formOrigin is FormOrigin.App) + } +} + +/** + * Manages "matches", i.e., associations between apps or websites and Password Store entries. + */ +class AutofillMatcher { + + companion object { + + private const val MAX_NUM_MATCHES = 10 + + private const val PREFERENCE_PREFIX_TOKEN = "token;" + private fun tokenKey(formOrigin: FormOrigin.App) = + "$PREFERENCE_PREFIX_TOKEN${formOrigin.identifier}" + + private const val PREFERENCE_PREFIX_MATCHES = "matches;" + private fun matchesKey(formOrigin: FormOrigin) = + "$PREFERENCE_PREFIX_MATCHES${formOrigin.identifier}" + + private fun hasFormOriginHashChanged(context: Context, formOrigin: FormOrigin): Boolean { + return when (formOrigin) { + is FormOrigin.Web -> false + is FormOrigin.App -> { + val packageName = formOrigin.identifier + val certificatesHash = computeCertificatesHash(context, packageName) + val storedCertificatesHash = + context.autofillAppMatches.getString(tokenKey(formOrigin), null) + ?: return false + val hashHasChanged = certificatesHash != storedCertificatesHash + if (hashHasChanged) { + e { "$packageName: stored=$storedCertificatesHash, new=$certificatesHash" } + true + } else { + false + } + } + } + } + + private fun storeFormOriginHash(context: Context, formOrigin: FormOrigin) { + if (formOrigin is FormOrigin.App) { + val packageName = formOrigin.identifier + val certificatesHash = computeCertificatesHash(context, packageName) + context.autofillAppMatches.edit { + putString(tokenKey(formOrigin), certificatesHash) + } + } + // We don't need to store a hash for FormOrigin.Web since it can only originate from + // browsers we trust to verify the origin. + } + + /** + * Get all Password Store entries that have already been associated with [formOrigin] by the + * user. + * + * If [formOrigin] represents an app and that app's certificates have changed since the + * first time the user associated an entry with it, an [AutofillPublisherChangedException] + * will be thrown. + */ + fun getMatchesFor(context: Context, formOrigin: FormOrigin): Result<List<File>, AutofillPublisherChangedException> { + if (hasFormOriginHashChanged(context, formOrigin)) { + return Err(AutofillPublisherChangedException(formOrigin)) + } + val matchPreferences = context.matchPreferences(formOrigin) + val matchedFiles = + matchPreferences.getStringSet(matchesKey(formOrigin), emptySet())!!.map { File(it) } + return Ok(matchedFiles.filter { it.exists() }.also { validFiles -> + matchPreferences.edit { + putStringSet(matchesKey(formOrigin), validFiles.map { it.absolutePath }.toSet()) + } + }) + } + + fun clearMatchesFor(context: Context, formOrigin: FormOrigin) { + context.matchPreferences(formOrigin).edit { + remove(matchesKey(formOrigin)) + if (formOrigin is FormOrigin.App) remove(tokenKey(formOrigin)) + } + } + + /** + * Associates the store entry [file] with [formOrigin], such that future Autofill responses + * to requests from this app or website offer this entry as a dataset. + * + * The maximum number of matches is limited by [MAX_NUM_MATCHES] since older versions of + * Android may crash when too many datasets are offered. + */ + fun addMatchFor(context: Context, formOrigin: FormOrigin, file: File) { + if (!file.exists()) return + if (hasFormOriginHashChanged(context, formOrigin)) { + // This should never happen since we already verified the publisher in + // getMatchesFor. + e { "App publisher changed between getMatchesFor and addMatchFor" } + throw AutofillPublisherChangedException(formOrigin) + } + val matchPreferences = context.matchPreferences(formOrigin) + val matchedFiles = + matchPreferences.getStringSet(matchesKey(formOrigin), emptySet())!!.map { File(it) } + val newFiles = setOf(file.absoluteFile).union(matchedFiles) + if (newFiles.size > MAX_NUM_MATCHES) { + Toast.makeText( + context, + context.getString(R.string.oreo_autofill_max_matches_reached, MAX_NUM_MATCHES), + Toast.LENGTH_LONG + ).show() + return + } + matchPreferences.edit { + putStringSet(matchesKey(formOrigin), newFiles.map { it.absolutePath }.toSet()) + } + storeFormOriginHash(context, formOrigin) + d { "Stored match for $formOrigin" } + } + + /** + * Goes through all existing matches and updates their associated entries by using + * [moveFromTo] as a lookup table and deleting the matches for files in [delete]. + */ + fun updateMatches(context: Context, moveFromTo: Map<File, File> = emptyMap(), delete: Collection<File> = emptyList()) { + val deletePathList = delete.map { it.absolutePath } + val oldNewPathMap = moveFromTo.mapValues { it.value.absolutePath } + .mapKeys { it.key.absolutePath } + for (prefs in listOf(context.autofillAppMatches, context.autofillWebMatches)) { + for ((key, value) in prefs.all) { + if (!key.startsWith(PREFERENCE_PREFIX_MATCHES)) continue + // We know that preferences starting with `PREFERENCE_PREFIX_MATCHES` were + // created with `putStringSet`. + @Suppress("UNCHECKED_CAST") + val oldMatches = value as? Set<String> + if (oldMatches == null) { + w { "Failed to read matches for $key" } + continue + } + // Delete all matches for file locations that are going to be overwritten, then + // transfer matches over to the files at their new locations. + val newMatches = + oldMatches.asSequence() + .minus(deletePathList) + .minus(oldNewPathMap.values) + .map { match -> + val newPath = oldNewPathMap[match] ?: return@map match + d { "Updating match for $key: $match --> $newPath" } + newPath + }.toSet() + if (newMatches != oldMatches) + prefs.edit { putStringSet(key, newMatches) } + } + } + } + } +} |