diff --git a/leveldb/journal/journal.go b/leveldb/journal/journal.go
index 891098b..d094c3d 100644
--- a/leveldb/journal/journal.go
+++ b/leveldb/journal/journal.go
@@ -180,34 +180,37 @@
 			checksum := binary.LittleEndian.Uint32(r.buf[r.j+0 : r.j+4])
 			length := binary.LittleEndian.Uint16(r.buf[r.j+4 : r.j+6])
 			chunkType := r.buf[r.j+6]
-
+			unprocBlock := r.n - r.j
 			if checksum == 0 && length == 0 && chunkType == 0 {
 				// Drop entire block.
-				m := r.n - r.j
 				r.i = r.n
 				r.j = r.n
-				return r.corrupt(m, "zero header", false)
-			} else {
-				m := r.n - r.j
-				r.i = r.j + headerSize
-				r.j = r.j + headerSize + int(length)
-				if r.j > r.n {
-					// Drop entire block.
-					r.i = r.n
-					r.j = r.n
-					return r.corrupt(m, "chunk length overflows block", false)
-				} else if r.checksum && checksum != util.NewCRC(r.buf[r.i-1:r.j]).Value() {
-					// Drop entire block.
-					r.i = r.n
-					r.j = r.n
-					return r.corrupt(m, "checksum mismatch", false)
-				}
+				return r.corrupt(unprocBlock, "zero header", false)
+			}
+			if chunkType < fullChunkType || chunkType > lastChunkType {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, fmt.Sprintf("invalid chunk type %#x", chunkType), false)
+			}
+			r.i = r.j + headerSize
+			r.j = r.j + headerSize + int(length)
+			if r.j > r.n {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, "chunk length overflows block", false)
+			} else if r.checksum && checksum != util.NewCRC(r.buf[r.i-1:r.j]).Value() {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, "checksum mismatch", false)
 			}
 			if first && chunkType != fullChunkType && chunkType != firstChunkType {
-				m := r.j - r.i
+				chunkLength := (r.j - r.i) + headerSize
 				r.i = r.j
 				// Report the error, but skip it.
-				return r.corrupt(m+headerSize, "orphan chunk", true)
+				return r.corrupt(chunkLength, "orphan chunk", true)
 			}
 			r.last = chunkType == fullChunkType || chunkType == lastChunkType
 			return nil