PDFBOX-5645: clone UTC TZ before using, as suggested by Daniel Gredler

git-svn-id: https://svn.apache.org/repos/asf/pdfbox/trunk@1911610 13f79535-47bb-0310-9956-ffa450edef68
apache · Aug 12, 2023 · 62bba0e · 62bba0e
1 parent b8fbb1d
commit 62bba0e
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Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/fontbox/src/main/java/org/apache/fontbox/ttf/TTFDataStream.java b/fontbox/src/main/java/org/apache/fontbox/ttf/TTFDataStream.java
@@ -32,7 +32,7 @@
  */
 abstract class TTFDataStream implements Closeable
 {
-    private static final TimeZone TIMEZONE_UTC = TimeZone.getTimeZone("UTC");
+    private static final TimeZone TIMEZONE_UTC = TimeZone.getTimeZone("UTC"); // clone before using
 
     TTFDataStream()
     {
@@ -210,7 +210,7 @@ public short readSignedShort() throws IOException
     public Calendar readInternationalDate() throws IOException
     {
         long secondsSince1904 = readLong();
-        Calendar cal = Calendar.getInstance(TIMEZONE_UTC);
+        Calendar cal = Calendar.getInstance((TimeZone) TIMEZONE_UTC.clone());
         cal.set(1904, 0, 1, 0, 0, 0);
         cal.set(Calendar.MILLISECOND, 0);
         long millisFor1904 = cal.getTimeInMillis();

diff --git a/fontbox/src/main/java/org/apache/fontbox/ttf/TTFSubsetter.java b/fontbox/src/main/java/org/apache/fontbox/ttf/TTFSubsetter.java
@@ -54,7 +54,7 @@ public final class TTFSubsetter
 
     private static final byte[] PAD_BUF = new byte[] { 0, 0, 0 };
 
-    private static final TimeZone TIMEZONE_UTC = TimeZone.getTimeZone("UTC");
+    private static final TimeZone TIMEZONE_UTC = TimeZone.getTimeZone("UTC"); // clone before using
 
     private final TrueTypeFont ttf;
     private final CmapLookup unicodeCmap;
@@ -1086,7 +1086,7 @@ private void writeUint8(DataOutputStream out, int i) throws IOException
     private void writeLongDateTime(DataOutputStream out, Calendar calendar) throws IOException
     {
         // inverse operation of TTFDataStream.readInternationalDate()
-        Calendar cal = Calendar.getInstance(TIMEZONE_UTC);
+        Calendar cal = Calendar.getInstance((TimeZone) TIMEZONE_UTC.clone());
         cal.set(1904, 0, 1, 0, 0, 0);
         cal.set(Calendar.MILLISECOND, 0);
         long millisFor1904 = cal.getTimeInMillis();