Fix #413. Ignore trailing bytes where a property cannot fit

msgparser/pom.xml

@@ -36,5 +36,11 @@
             <version>6.0.2</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.jimfs</groupId>
+            <artifactId>jimfs</artifactId>
+            <version>1.3.1</version>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 </project>

msgparser/src/main/java/com/auxilii/msgparser/MsgParser.java

@@ -69,7 +69,7 @@ private static Message parseMsg(DirectoryEntry dir) throws IOException {
                 DirectoryEntry entry = (DirectoryEntry) dir.getEntry(String.format("__attach_version1.0_#%08X", index));
                 msg.addAttachment(parseAttachment(entry));
             }
-            while (propertyStream.available() > 0) {
+            while (propertyStream.available() >= 8) {
                 msg.setProperty(new Property(propertyStream, dir));
             }
             return msg;
@@ -113,7 +113,7 @@ private static Attachment parseAttachment(DirectoryEntry dir) throws IOException
         if (dir.hasEntry(Ptyp.SUBSTORAGE_PREFIX + "3701000D")) {
             return parseEmbeddedMessage(dir);
         }
-        return ParseFileAttachment(dir);
+        return parseFileAttachment(dir);
     }
 
     private static MsgAttachment parseEmbeddedMessage(DirectoryEntry dir) throws IOException {
@@ -122,7 +122,7 @@ private static MsgAttachment parseEmbeddedMessage(DirectoryEntry dir) throws IOE
         return new MsgAttachment(parseMsg(entry));
     }
 
-    private static FileAttachment ParseFileAttachment(DirectoryEntry dir) throws IOException {
+    private static FileAttachment parseFileAttachment(DirectoryEntry dir) throws IOException {
         DocumentEntry propertyEntry = (DocumentEntry) dir.getEntry(PROPERTIES_ENTRY);
         try (DocumentInputStream propertyStream = new DocumentInputStream(propertyEntry)) {
             propertyStream.skip(8);

msgparser/src/test/java/com/auxilii/msgparser/MsgParserTest.java

@@ -0,0 +1,37 @@
+package com.auxilii.msgparser;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+import com.google.common.jimfs.Jimfs;
+import java.io.*;
+import java.nio.file.*;
+import org.apache.poi.poifs.filesystem.*;
+import org.junit.jupiter.api.Test;
+
+class MsgParserTest {
+    @Test
+    void should_ignore_trailing_bytes() throws IOException {
+        try (FileSystem fileSystem = Jimfs.newFileSystem()) {
+            Path messagePath = fileSystem.getPath("message.msg");
+            writeMessageWithTrailingBytes(messagePath);
+            MsgParser parser = new MsgParser(messagePath);
+            assertDoesNotThrow(parser::parseMsg);
+        }
+    }
+
+    private static void writeMessageWithTrailingBytes(Path target) throws IOException {
+        try (POIFSFileSystem fs = new POIFSFileSystem()) {
+            byte[] content = {
+                0,0,0,0,0,0,0,0, // reserved
+                0,0,0,0, // nextRecipientId
+                0,0,0,0, // nextAttachmentId
+                0,0,0,0, // recipientCount
+                0,0,0,0, // attachmentCount
+                0,0,0,0,0,0,0,0, // reserved for top level message
+                1,2,3,4 // trailing garbage
+            };
+            fs.getRoot().createDocument("__properties_version1.0", new ByteArrayInputStream(content));
+            fs.writeFilesystem(Files.newOutputStream(target));
+        }
+    }
+}