Only enforce the encrypted bit in the GPBF, and ignore other unsupported bits.

(cherry-pick of 7a302a49a7c8b99e2f34fff660e199fb7c776bc1.)

Bug: 8617715
Change-Id: Ibfe919d67fd17cee050d23811faa5aa64116dfb4

3 files changed, 15 insertions, 5 deletions

diff --git a/luni/src/main/java/java/util/zip/ZipEntry.java b/luni/src/main/java/java/util/zip/ZipEntry.java
index 6dd9839..fbd477d 100644
--- a/luni/src/main/java/java/util/zip/ZipEntry.java
+++ b/luni/src/main/java/java/util/zip/ZipEntry.java
@@ -368,7 +368,7 @@ public class ZipEntry implements ZipConstants, Cloneable {
         it.seek(8);
         int gpbf = it.readShort();
 
-        if ((gpbf & ~ZipFile.GPBF_SUPPORTED_MASK) != 0) {
+        if ((gpbf & ZipFile.GPBF_UNSUPPORTED_MASK) != 0) {
             throw new ZipException("Invalid General Purpose Bit Flag: " + gpbf);
         }
 
diff --git a/luni/src/main/java/java/util/zip/ZipFile.java b/luni/src/main/java/java/util/zip/ZipFile.java
index 1a77e6c..5182f88 100644
--- a/luni/src/main/java/java/util/zip/ZipFile.java
+++ b/luni/src/main/java/java/util/zip/ZipFile.java
@@ -48,6 +48,12 @@ import libcore.io.Streams;
  */
 public class ZipFile implements ZipConstants {
     /**
+     * General Purpose Bit Flags, Bit 0.
+     * If set, indicates that the file is encrypted.
+     */
+    static final int GPBF_ENCRYPTED_FLAG = 1 << 0;
+
+    /**
      * General Purpose Bit Flags, Bit 3.
      * If this bit is set, the fields crc-32, compressed
      * size and uncompressed size are set to zero in the
@@ -70,9 +76,13 @@ public class ZipFile implements ZipConstants {
 
     /**
      * Supported General Purpose Bit Flags Mask.
-     * Bit mask of supported GPBF bits.
+     * Bit mask of bits not supported.
+     * Note: The only bit that we will enforce at this time
+     * is the encrypted bit. Although other bits are not supported,
+     * we must not enforce them as this could break some legitimate
+     * use cases (See http://b/8617715).
      */
-    static final int GPBF_SUPPORTED_MASK = GPBF_DATA_DESCRIPTOR_FLAG | GPBF_UTF8_FLAG;
+    static final int GPBF_UNSUPPORTED_MASK = GPBF_ENCRYPTED_FLAG;
 
     /**
      * Open zip file for reading.
@@ -255,7 +265,7 @@ public class ZipFile implements ZipConstants {
             RAFStream rafStream= new RAFStream(raf, entry.mLocalHeaderRelOffset + 6);
             DataInputStream is = new DataInputStream(rafStream);
             int gpbf = Short.reverseBytes(is.readShort());
-            if ((gpbf & ~ZipFile.GPBF_SUPPORTED_MASK) != 0) {
+            if ((gpbf & ZipFile.GPBF_UNSUPPORTED_MASK) != 0) {
                 throw new ZipException("Invalid General Purpose Bit Flag: " + gpbf);
             }
 
diff --git a/luni/src/main/java/java/util/zip/ZipInputStream.java b/luni/src/main/java/java/util/zip/ZipInputStream.java
index 319a0fa..9a9ecec 100644
--- a/luni/src/main/java/java/util/zip/ZipInputStream.java
+++ b/luni/src/main/java/java/util/zip/ZipInputStream.java
@@ -240,7 +240,7 @@ public class ZipInputStream extends InflaterInputStream implements ZipConstants
             throw new ZipException("Cannot read local header version " + version);
         }
         int flags = peekShort(LOCFLG - LOCVER);
-        if ((flags & ~ZipFile.GPBF_SUPPORTED_MASK) != 0) {
+        if ((flags & ZipFile.GPBF_UNSUPPORTED_MASK) != 0) {
             throw new ZipException("Invalid General Purpose Bit Flag: " + flags);
         }