GsmSST: Disregard any invalid verbose values for timezones in NITZ requests

And assume anything resulting in "GMT" is invalid, since that's the
default value returned by libcore

Change-Id: I361650400e71976d8327ee3929947ca26a9eff57
(cherry picked from commit f440bcd71fe735872b7e4c7ecd557503a79df756)

1 files changed, 9 insertions, 0 deletions

diff --git a/src/java/com/android/internal/telephony/gsm/GsmServiceStateTracker.java b/src/java/com/android/internal/telephony/gsm/GsmServiceStateTracker.java
index 21d6c5d7d..3014838b5 100644
--- a/src/java/com/android/internal/telephony/gsm/GsmServiceStateTracker.java
+++ b/src/java/com/android/internal/telephony/gsm/GsmServiceStateTracker.java
@@ -1542,8 +1542,17 @@ final class GsmServiceStateTracker extends ServiceStateTracker {
             if (nitzSubs.length >= 9) {
                 String  tzname = nitzSubs[8].replace('!','/');
                 zone = TimeZone.getTimeZone( tzname );
+                // From luni's getTimeZone() "We never return null; on failure we return the
+                // equivalent of "GMT"." This is bad, since it'll force all invalid strings
+                // to "GMT"... and all the null-zone checks below will fail, making tzOffset
+                // irrelevant and GMT the active TZ. So tzOffset will take precedence if this
+                // results in "GMT"
+                if (TimeZone.getTimeZone("GMT").equals(zone) && tzOffset != 0) {
+                    zone = null;
+                }
             }
 
+
             String iso = SystemProperties.get(TelephonyProperties.PROPERTY_OPERATOR_ISO_COUNTRY);
 
             if (zone == null) {