Throw exceptions when headers contain unrecognized flags

ehrmann · Jun 4, 2017 · 41369e3 · 41369e3
1 parent dc0b552
commit 41369e3
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diff --git a/core/src/main/java/com/davidehrmann/vcdiff/engine/VCDiffHeaderParser.java b/core/src/main/java/com/davidehrmann/vcdiff/engine/VCDiffHeaderParser.java
@@ -197,6 +197,11 @@ public DeltaWindowHeader parseWinIndicatorAndSourceSegment(
             return null;
         }
 
+        int unrecognized_flags = win_indicator & 0xff & ~(VCD_SOURCE | VCD_TARGET);
+        if (unrecognized_flags != 0) {
+            LOGGER.warn(String.format("Unrecognized win_indicator flags: 0x%02x", unrecognized_flags));
+        }
+
         int source_target_flags = win_indicator & (VCD_SOURCE | VCD_TARGET);
         switch (source_target_flags) {
             case VCD_SOURCE:

diff --git a/core/src/main/java/com/davidehrmann/vcdiff/engine/VCDiffStreamingDecoderImpl.java b/core/src/main/java/com/davidehrmann/vcdiff/engine/VCDiffStreamingDecoderImpl.java
@@ -462,17 +462,25 @@ private int readDeltaFileHeader(ByteBuffer data) throws IOException {
             }
             if (data_size < DeltaFileHeader.SERIALIZED_SIZE) return RESULT_END_OF_DATA;
         }
+
+        int unrecognizedFlags = header.hdr_indicator & 0xff & ~(VCD_DECOMPRESS | VCD_CODETABLE);
+        if (unrecognizedFlags != 0) {
+            throw new IOException(String.format("Unrecognized hdr_indicator flags: %02x", unrecognizedFlags));
+        }
+
         // Secondary compressor not supported.
         if ((header.hdr_indicator & VCD_DECOMPRESS) != 0) {
             throw new IOException("Secondary compression is not supported");
         }
+
         if ((header.hdr_indicator & VCD_CODETABLE) != 0) {
             int bytes_parsed = InitCustomCodeTable(data.array(), data.arrayOffset() + data.position() + DeltaFileHeader.SERIALIZED_SIZE,
                         data.remaining() - DeltaFileHeader.SERIALIZED_SIZE);
             if (bytes_parsed == RESULT_END_OF_DATA) {
                 return RESULT_END_OF_DATA;
             }
             data.position(data.position() + DeltaFileHeader.SERIALIZED_SIZE + bytes_parsed);
+            // TODO unknown flags on hdr_indicator
         } else {
             addrCache = new VCDiffAddressCacheImpl();
             // addrCache->init() will be called