Add check for files which provide the app launcher

egregius313 · egregius313 · commit 500a6f3b8656 · 2022-08-30T12:54:26.000-04:00
Adds support for filtering which applications include the
`android.intent.action.MAIN` intent.
diff --git a/java/ql/lib/semmle/code/xml/AndroidManifest.qll b/java/ql/lib/semmle/code/xml/AndroidManifest.qll
@@ -98,6 +98,16 @@ class AndroidApplicationXmlElement extends XmlElement {
       attr.getValue() = "true"
     )
   }
+
+  predicate providesMainIntent() {
+    exists(AndroidActivityXmlElement activity |
+      activity = this.getAChild() and
+      exists(AndroidIntentFilterXmlElement intentFilter |
+        intentFilter = activity.getAChild() and
+        intentFilter.getAnActionElement().getActionName() = "android.intent.action.MAIN"
+      )
+    )
+  }
 }
 
 /**
diff --git a/java/ql/src/Security/CWE/CWE-312/AllowBackupAttributeEnabled.ql b/java/ql/src/Security/CWE/CWE-312/AllowBackupAttributeEnabled.ql
@@ -15,6 +15,11 @@ import semmle.code.xml.AndroidManifest
 
 from AndroidApplicationXmlElement androidAppElem
 where
-  androidAppElem.allowsBackup() and
-  androidAppElem.getFile().(AndroidManifestXmlFile).isInBuildDirectory()
+  not androidAppElem.getFile().(AndroidManifestXmlFile).isInBuildDirectory() and
+  (
+    androidAppElem.allowsBackupExplicitly()
+    or
+    androidAppElem.providesMainIntent() and
+    androidAppElem.allowsBackup()
+  )
 select androidAppElem, "The 'android:allowBackup' attribute is enabled."

Original file line number	Diff line number	Diff line change
`@@ -98,6 +98,16 @@ class AndroidApplicationXmlElement extends XmlElement {`
`98`	`98`	`attr.getValue() = "true"`
`99`	`99`	`)`
`100`	`100`	`}`
	`101`	`+`
	`102`	`+ predicate providesMainIntent() {`
	`103`	`+ exists(AndroidActivityXmlElement activity \|`
	`104`	`+ activity = this.getAChild() and`
	`105`	`+ exists(AndroidIntentFilterXmlElement intentFilter \|`
	`106`	`+ intentFilter = activity.getAChild() and`
	`107`	`+ intentFilter.getAnActionElement().getActionName() = "android.intent.action.MAIN"`
	`108`	`+ )`
	`109`	`+ )`
	`110`	`+ }`
`101`	`111`	`}`
`102`	`112`
`103`	`113`	`/**`