DO NOT MERGE: OMAParser: throw IOException when parsing a null XML string

This avoids a NullPointerException when parsing a null XML string.
OMAParser.parse is only used by PasspointManagementObjectManager for
adding/building/modifying a HomeSP from a XML string.

It is fine to use IOException since it is already being handled
gracefully by its upstream callers.

Bug: 31497435
Test: unit tests
Test: Verify system server crashes when executing the command below without the fix
      and doesn't crash with the fix:
              "adb shell service call wifi 8 i32 0"

Change-Id: If2ad13b8573d49ba0ccbea2427f3c63d841f866d
(cherry picked from commit 519056861a467ae64e142ff07d53891514ef9c70)

1 files changed, 3 insertions, 0 deletions

diff --git a/service/java/com/android/server/wifi/hotspot2/omadm/OMAParser.java b/service/java/com/android/server/wifi/hotspot2/omadm/OMAParser.java
index cbcd81d16..d39fa33a1 100644
--- a/service/java/com/android/server/wifi/hotspot2/omadm/OMAParser.java
+++ b/service/java/com/android/server/wifi/hotspot2/omadm/OMAParser.java
@@ -26,6 +26,9 @@ public class OMAParser extends DefaultHandler {
     }
 
     public MOTree parse(String text, String urn) throws IOException, SAXException {
+        if (text == null) {
+          throw new IOException("Missing text string");
+        }
         try {
             SAXParser parser = SAXParserFactory.newInstance().newSAXParser();
             parser.parse(new InputSource(new StringReader(text)), this);