AOSP/Email - Fixed - Security Vulnerability - Email App: Malicious app
is able to compose message with hidden attachments and bypass
attachments path checks attaching private files from
/data/data/com.android.email/*
+ Ported the following CLs. Code is different from gmail. Made the changes
to work with Email.
++ https://critique.corp.google.com/#review/136780360
+++ Add isExternal() to ComposeActivity.java and it always returns false.
Treat body and quoted text as plaintext if intent is external.
++ https://critique.corp.google.com/#review/137654162
+++ Don't let other apps use our EXTRA_MESSAGE.
Load EXTRA_MESSAGE only if action is LAUNCH_COMPOSE.
LAUNCH_COMPOSE action is an internal only action: b/32068883.
++ https://critique.corp.google.com/#review/142296051
+++ Don't let external Intent use EXTRA_MESSAGE
Bug: 32068883
Bug: 32502421
Bug: 32589229
Test: manual - Ran the following tests on Pixel phone. Tested the Email UI.
$ adb install -r out/target/product/marlin/system/app/Email/Email.apk
$ adb install -r app-debug.apk
Success
$ adb shell am start -n com.test.poc.poc32589229/.MainActivity -a android.intent.action.MAIN
Starting: Intent { act=android.intent.action.MAIN cmp=com.test.poc.poc32589229/.MainActivity }
Duplicated the steps in https://b.corp.google.com/issues/32589229#comment5
and didn't get the attachments after the fix (was getting attachments before the fix).
logcat output:
11-21 03:45:48.927 11705 11705 I poc-test: sending a hidden file attachment
11-21 03:45:48.929 11705 11705 I poc-test: Sending contentType: text/html, previewImage: null
11-21 03:45:48.935 914 4482 I ActivityManager: START u0 {act=com.android.mail.intent.action.LAUNCH_COMPOSE pkg=com.android.email cmp=com.android.email/.activity.ComposeActivityEmail (has extras)} from uid 10072
11-21 03:45:48.935 914 4482 W ActivityManager: Permission Denial: starting Intent { act=com.android.mail.intent.action.LAUNCH_COMPOSE pkg=com.android.email cmp=com.android.email/.activity.ComposeActivityEmail (has extras) } from ProcessRecord{6941817 11705:com.test.poc.poc32589229/u0a72} (pid=11705, uid=10072) not exported from uid 10062
11-21 03:45:48.937 11705 11705 D AndroidRuntime: Shutting down VM
--------- beginning of crash
11-21 03:45:48.940 11705 11705 E AndroidRuntime: FATAL EXCEPTION: main
11-21 03:45:48.940 11705 11705 E AndroidRuntime: Process: com.test.poc.poc32589229, PID: 11705
11-21 03:45:48.940 11705 11705 E AndroidRuntime: java.lang.IllegalStateException: Could not execute method for android:onClick
...
11-21 03:45:48.940 11705 11705 E AndroidRuntime: Caused by: java.lang.SecurityException: Permission Denial: starting Intent { act=com.android.mail.intent.action.LAUNCH_COMPOSE pkg=com.android.email cmp=com.android.email/.activity.ComposeActivityEmail (has extras) } from ProcessRecord{6941817 11705:com.test.poc.poc32589229/u0a72} (pid=11705, uid=10072) not exported from uid 10062
$ adb install -r out/target/product/marlin/testcases/EmailTests/EmailTests.apk
Performing Streamed Install
Success
$ adb shell am instrument -w com.android.email.tests
The number of failures are same as before (with or without this change).
Tests run: 158, Failures: 5
Change-Id: If6e2a2efa08b75675c980b72735cde8252e95760
(cherry picked from commit 3526a4ac552f93a83ea838ddae5de45e1e068af0)
diff --git a/src/com/android/mail/compose/ComposeActivity.java b/src/com/android/mail/compose/ComposeActivity.java
index 489f6d8..bfb8a1c 100644
--- a/src/com/android/mail/compose/ComposeActivity.java
+++ b/src/com/android/mail/compose/ComposeActivity.java
@@ -147,7 +147,8 @@
* An {@link Intent} action that launches {@link ComposeActivity}, but is handled as if the
* {@link Activity} were launched with no special action.
*/
- private static final String ACTION_LAUNCH_COMPOSE =
+ @VisibleForTesting
+ static final String ACTION_LAUNCH_COMPOSE =
"com.android.mail.intent.action.LAUNCH_COMPOSE";
// Identifiers for which type of composition this is
@@ -509,6 +510,11 @@
context.startActivity(intent);
}
+ /** Returns true if activity is started from an intent from an external application. */
+ public boolean isExternal() {
+ return false;
+ }
+
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
@@ -528,6 +534,16 @@
checkValidAccounts();
}
+ /** Used for escaping plaintext. If the input is null, then it will return an empty String. */
+ private static String escapeAndReplaceHtml(CharSequence text) {
+ if (text == null) {
+ return "";
+ }
+ String body = Html.escapeHtml(text);
+ // Replace \r\n and \n with <br> tags
+ return body.replaceAll("( | )", "<br>");
+ }
+
private void finishCreate() {
final Bundle savedState = mInnerSavedState;
findViews();
@@ -566,6 +582,9 @@
message = intent.getParcelableExtra(ORIGINAL_DRAFT_MESSAGE);
previews = intent.getParcelableArrayListExtra(EXTRA_ATTACHMENT_PREVIEWS);
mRefMessage = intent.getParcelableExtra(EXTRA_IN_REFERENCE_TO_MESSAGE);
+ if (isExternal() && mRefMessage != null && !TextUtils.isEmpty(mRefMessage.bodyHtml)) {
+ mRefMessage.bodyHtml = escapeAndReplaceHtml(mRefMessage.bodyHtml);
+ }
mRefMessageUri = intent.getParcelableExtra(EXTRA_IN_REFERENCE_TO_MESSAGE_URI);
quotedText = null;
@@ -1532,6 +1551,9 @@
}
String body = intent.getStringExtra(EXTRA_BODY);
if (body != null) {
+ if (isExternal()) {
+ body = escapeAndReplaceHtml(body);
+ }
setBody(body, false /* withSignature */);
}
}
@@ -1695,7 +1717,10 @@
} else if (EXTRA_BODY.equals(extra)) {
setBody(value, true /* with signature */);
} else if (EXTRA_QUOTED_TEXT.equals(extra)) {
- initQuotedText(value, true /* shouldQuoteText */);
+ if (isExternal()) {
+ value = escapeAndReplaceHtml(value);
+ }
+ initQuotedText(value, true /* shouldQuoteText */);
}
}
}
