From 61fc692d6675a6b2f35c7ff53ea8fa88728a1e39 Mon Sep 17 00:00:00 2001 From: Yo Chiang Date: Fri, 6 Dec 2019 15:10:59 +0800 Subject: DSU to support GSI key revocation list DSU installation service fetches a key revocation list (key blacklist). Revocation list is a https URL specified in a resource string. Fetched result is cached in HttpResponseCache to save bandwidth, and the cached result is always forced validated with server to ensure freshness. In other words, fetching a revocation list is done via a "conditional GET", such http GET returns a brief (304 NOT MODIFIED) response if ours cache is still valid, else the server sends a (200 OK) response with new data. TODO: Compare the installed DSU image's public key with the revocation list and boot-ramdisk. If the public key is revoked then abort installation. Bug: 128892201 Test: atest DynamicSystemInstallationServiceTests Test: adb shell am start-activity \ -n com.android.dynsystem/com.android.dynsystem.VerificationActivity \ -a android.os.image.action.START_INSTALL \ --el KEY_USERDATA_SIZE 8589934592 \ -d file:///storage/emulated/0/Download/aosp_arm64-dsu_test.zip \ --es KEY_PUBKEY key1 Change-Id: I29ae088acb1bd23336ec09654f38b4fc464316d8 --- .../DynamicSystemInstallationService.java | 19 +++ .../android/dynsystem/InstallationAsyncTask.java | 30 ++++- .../com/android/dynsystem/KeyRevocationList.java | 148 +++++++++++++++++++++ 3 files changed, 195 insertions(+), 2 deletions(-) create mode 100644 packages/DynamicSystemInstallationService/src/com/android/dynsystem/KeyRevocationList.java (limited to 'packages/DynamicSystemInstallationService/src') diff --git a/packages/DynamicSystemInstallationService/src/com/android/dynsystem/DynamicSystemInstallationService.java b/packages/DynamicSystemInstallationService/src/com/android/dynsystem/DynamicSystemInstallationService.java index beb3affa5c9d..3fb827df403f 100644 --- a/packages/DynamicSystemInstallationService/src/com/android/dynsystem/DynamicSystemInstallationService.java +++ b/packages/DynamicSystemInstallationService/src/com/android/dynsystem/DynamicSystemInstallationService.java @@ -46,6 +46,7 @@ import android.app.PendingIntent; import android.app.Service; import android.content.Context; import android.content.Intent; +import android.net.http.HttpResponseCache; import android.os.Bundle; import android.os.Handler; import android.os.IBinder; @@ -60,6 +61,8 @@ import android.text.TextUtils; import android.util.Log; import android.widget.Toast; +import java.io.File; +import java.io.IOException; import java.lang.ref.WeakReference; import java.util.ArrayList; @@ -146,10 +149,26 @@ public class DynamicSystemInstallationService extends Service prepareNotification(); mDynSystem = (DynamicSystemManager) getSystemService(Context.DYNAMIC_SYSTEM_SERVICE); + + // Install an HttpResponseCache in the application cache directory so we can cache + // gsi key revocation list. The http(s) protocol handler uses this cache transparently. + // The cache size is chosen heuristically. Since we don't have too much traffic right now, + // a moderate size of 1MiB should be enough. + try { + File httpCacheDir = new File(getCacheDir(), "httpCache"); + long httpCacheSize = 1 * 1024 * 1024; // 1 MiB + HttpResponseCache.install(httpCacheDir, httpCacheSize); + } catch (IOException e) { + Log.d(TAG, "HttpResponseCache.install() failed: " + e); + } } @Override public void onDestroy() { + HttpResponseCache cache = HttpResponseCache.getInstalled(); + if (cache != null) { + cache.flush(); + } // Cancel the persistent notification. mNM.cancel(NOTIFICATION_ID); } diff --git a/packages/DynamicSystemInstallationService/src/com/android/dynsystem/InstallationAsyncTask.java b/packages/DynamicSystemInstallationService/src/com/android/dynsystem/InstallationAsyncTask.java index 9aea0e713179..438c435ef0e4 100644 --- a/packages/DynamicSystemInstallationService/src/com/android/dynsystem/InstallationAsyncTask.java +++ b/packages/DynamicSystemInstallationService/src/com/android/dynsystem/InstallationAsyncTask.java @@ -25,6 +25,8 @@ import android.os.image.DynamicSystemManager; import android.util.Log; import android.webkit.URLUtil; +import org.json.JSONException; + import java.io.BufferedInputStream; import java.io.File; import java.io.IOException; @@ -100,7 +102,9 @@ class InstallationAsyncTask extends AsyncTask mEntries; + + static class RevocationStatus { + final String mStatus; + final String mReason; + + RevocationStatus(String status, String reason) { + mStatus = status; + mReason = reason; + } + } + + KeyRevocationList() { + mEntries = new HashMap(); + } + + /** + * Returns the revocation status of a public key. + * + * @return a RevocationStatus for |publicKey|, null if |publicKey| doesn't exist. + */ + RevocationStatus getRevocationStatusForKey(String publicKey) { + return mEntries.get(publicKey); + } + + /** Test if a public key is revoked or not. */ + boolean isRevoked(String publicKey) { + RevocationStatus entry = getRevocationStatusForKey(publicKey); + return entry != null && TextUtils.equals(entry.mStatus, STATUS_REVOKED); + } + + @VisibleForTesting + void addEntry(String publicKey, String status, String reason) { + mEntries.put(publicKey, new RevocationStatus(status, reason)); + } + + /** + * Creates a KeyRevocationList from a JSON String. + * + * @param jsonString the revocation list, for example: + * 
{@code
+     *      {
+     *        "entries": [
+     *          {
+     *            "public_key": "00fa2c6637c399afa893fe83d85f3569998707d5",
+     *            "status": "REVOKED",
+     *            "reason": "Revocation Reason"
+     *          }
+     *        ]
+     *      }
+     *     }
+ * + * @throws JSONException if |jsonString| is malformed. + */ + static KeyRevocationList fromJsonString(String jsonString) throws JSONException { + JSONObject jsonObject = new JSONObject(jsonString); + KeyRevocationList list = new KeyRevocationList(); + Log.d(TAG, "Begin of revocation list"); + if (jsonObject.has(JSON_ENTRIES)) { + JSONArray entries = jsonObject.getJSONArray(JSON_ENTRIES); + for (int i = 0; i < entries.length(); ++i) { + JSONObject entry = entries.getJSONObject(i); + String publicKey = entry.getString(JSON_PUBLIC_KEY); + String status = entry.getString(JSON_STATUS); + String reason = entry.has(JSON_REASON) ? entry.getString(JSON_REASON) : ""; + list.addEntry(publicKey, status, reason); + Log.d(TAG, "Revocation entry: " + entry.toString()); + } + } + Log.d(TAG, "End of revocation list"); + return list; + } + + /** + * Creates a KeyRevocationList from a URL. + * + * @throws IOException if |url| is inaccessible. + * @throws JSONException if fetched content is malformed. + */ + static KeyRevocationList fromUrl(URL url) throws IOException, JSONException { + Log.d(TAG, "Fetch from URL: " + url.toString()); + // Force "conditional GET" + // Force validate the cached result with server each time, and use the cached result + // only if it is validated by server, else fetch new data from server. + // Ref: https://developer.android.com/reference/android/net/http/HttpResponseCache#force-a-network-response + URLConnection connection = url.openConnection(); + connection.setUseCaches(true); + connection.addRequestProperty("Cache-Control", "max-age=0"); + try (InputStream stream = connection.getInputStream()) { + return fromJsonString(readFully(stream)); + } + } + + private static String readFully(InputStream in) throws IOException { + int n; + byte[] buffer = new byte[4096]; + StringBuilder builder = new StringBuilder(); + while ((n = in.read(buffer, 0, 4096)) > -1) { + builder.append(new String(buffer, 0, n)); + } + return builder.toString(); + } +} -- cgit v1.2.3