Fix ZipFile local file entry parsing.

The file name length is given in both the central directory entry
and the local file entry, with no consistency check. ZipInputStream
and the VM's native code both use the local file entry's value but
ZipFile was using the value from the central directory.

This patch makes ZipFile behave like the other two. (Even though,
unlike the others, ZipFile actually has enough information to detect the
inconsistency and reject the file.)

Bug: 9950697
Change-Id: I1d58ac523ad2024baff1644d7bf822dae412495d
(cherry picked from commit 257d72c1b3a69e0af0abe44801b53966dbf7d214)
diff --git a/luni/src/main/java/java/util/zip/ b/luni/src/main/java/java/util/zip/
index 2f9e3b0..832235e 100644
--- a/luni/src/main/java/java/util/zip/
+++ b/luni/src/main/java/java/util/zip/
@@ -284,17 +284,20 @@
                 throw new ZipException("Invalid General Purpose Bit Flag: " + gpbf);
-            // At position 28 we find the length of the extra data. In some cases
-            // this length differs from the one coming in the central header.
-            is.skipBytes(20);
-            int localExtraLenOrWhatever = Short.reverseBytes(is.readShort()) & 0xffff;
+            // Offset 26 has the file name length, and offset 28 has the extra field length.
+            // These lengths can differ from the ones in the central header.
+            is.skipBytes(18);
+            int fileNameLength = Short.reverseBytes(is.readShort()) & 0xffff;
+            int extraFieldLength = Short.reverseBytes(is.readShort()) & 0xffff;
-            // Skip the name and this "extra" data or whatever it is:
-            rafStream.skip(entry.nameLength + localExtraLenOrWhatever);
+            // Skip the variable-size file name and extra field data.
+            rafStream.skip(fileNameLength + extraFieldLength);
+            // The compressed or stored file data follows immediately after.
             rafStream.length = rafStream.offset + entry.compressedSize;
             if (entry.compressionMethod == ZipEntry.DEFLATED) {
-                int bufSize = Math.max(1024, (int)Math.min(entry.getSize(), 65535L));
+                int bufSize = Math.max(1024, (int) Math.min(entry.getSize(), 65535L));
                 return new ZipInflaterInputStream(rafStream, new Inflater(true), bufSize, entry);
             } else {
                 return rafStream;