Restrict SipProfiles to profiles directory

We now check SIP profile names to ensure that they do not attempt file
traversal when being saved. They are now restricted to be children of
the profiles/ directory.

BUG: 31530456
Change-Id: I9c9bce59d852e8a1cf500be6ca59b5e303877180

2 files changed, 27 insertions, 4 deletions

diff --git a/sip/src/com/android/services/telephony/sip/SipEditor.java b/sip/src/com/android/services/telephony/sip/SipEditor.java
index 6304220ce..8512fe303 100644
--- a/sip/src/com/android/services/telephony/sip/SipEditor.java
+++ b/sip/src/com/android/services/telephony/sip/SipEditor.java
@@ -259,7 +259,7 @@ public class SipEditor extends PreferenceActivity
      *
      * @param p The {@link SipProfile} to delete.
      */
-    private void deleteAndUnregisterProfile(SipProfile p) {
+    private void deleteAndUnregisterProfile(SipProfile p) throws IOException {
         if (p == null) return;
         mProfileDb.deleteProfile(p);
         mSipAccountRegistry.stopSipService(this, p.getProfileName());
diff --git a/sip/src/com/android/services/telephony/sip/SipProfileDb.java b/sip/src/com/android/services/telephony/sip/SipProfileDb.java
index 578c68311..5ead30b43 100644
--- a/sip/src/com/android/services/telephony/sip/SipProfileDb.java
+++ b/sip/src/com/android/services/telephony/sip/SipProfileDb.java
@@ -21,6 +21,7 @@ import com.android.internal.os.AtomicFile;
 import android.content.Context;
 import android.net.sip.SipProfile;
 import android.text.TextUtils;
+import android.util.EventLog;
 import android.util.Log;
 
 import java.io.File;
@@ -54,9 +55,13 @@ class SipProfileDb {
         mSipSharedPreferences = new SipSharedPreferences(context);
     }
 
-    public void deleteProfile(SipProfile p) {
+    public void deleteProfile(SipProfile p) throws IOException {
         synchronized(SipProfileDb.class) {
-            deleteProfile(new File(mProfilesDirectory + p.getProfileName()));
+            File profileFile = new File(mProfilesDirectory, p.getProfileName());
+            if (!isChild(new File(mProfilesDirectory), profileFile)) {
+                throw new IOException("Invalid Profile Credentials!");
+            }
+            deleteProfile(profileFile);
             if (mProfilesCount < 0) retrieveSipProfileListInternal();
             mSipSharedPreferences.setProfilesCount(--mProfilesCount);
         }
@@ -72,7 +77,10 @@ class SipProfileDb {
     public void saveProfile(SipProfile p) throws IOException {
         synchronized(SipProfileDb.class) {
             if (mProfilesCount < 0) retrieveSipProfileListInternal();
-            File f = new File(mProfilesDirectory + p.getProfileName());
+            File f = new File(mProfilesDirectory, p.getProfileName());
+            if (!isChild(new File(mProfilesDirectory), f)) {
+                throw new IOException("Invalid Profile Credentials!");
+            }
             if (!f.exists()) f.mkdirs();
             AtomicFile atomicFile = new AtomicFile(new File(f, PROFILE_OBJ_FILE));
             FileOutputStream fos = null;
@@ -158,4 +166,19 @@ class SipProfileDb {
     private static void log(String msg) {
         Log.d(SipUtil.LOG_TAG, PREFIX + msg);
     }
+
+    /**
+     * Verifies that the file is a direct child of the base directory.
+     */
+    private boolean isChild(File base, File file) {
+        if (base == null || file == null) {
+            return false;
+        }
+        if (!base.equals(file.getAbsoluteFile().getParentFile())) {
+            Log.w(SipUtil.LOG_TAG, "isChild, file is not a child of the base dir.");
+            EventLog.writeEvent(0x534e4554, "31530456", -1, "");
+            return false;
+        }
+        return true;
+    }
 }