2 files changed, 6 insertions, 1 deletions
diff --git a/deflate.c b/deflate.c
index ecae0d0..a04f86d 100644
--- a/deflate.c
+++ b/deflate.c
@@ -2441,8 +2441,12 @@ int deflate_decompress_data(deflate_decompress_ctx *dctx,
 	     */
 	    if (dctx->nbits < 16)
 		goto finished;
-	    nlen = dctx->bits & 0xFFFF;
+	    nlen = 0xFFFF & ~dctx->bits;
 	    EATBITS(16);
+	    if (dctx->uncomplen != (nlen ^ 0xFFFF)) {
+                error = DEFLATE_ERR_UNCOMP_HDR;
+                goto finished;
+            }
 	    if (dctx->uncomplen == 0)
 		dctx->state = OUTSIDEBLK;	/* block is empty */
 	    else
diff --git a/deflate.h b/deflate.h
index 80837f9..6f51407 100644
--- a/deflate.h
+++ b/deflate.h
@@ -150,6 +150,7 @@ int deflate_decompress_data(deflate_decompress_ctx *ctx,
     A(DEFLATE_ERR_GZIP_FHCRC, "gzip header specifies disputed FHCRC flag"), \
     A(DEFLATE_ERR_SMALL_HUFTABLE, "under-committed Huffman code space"), \
     A(DEFLATE_ERR_LARGE_HUFTABLE, "over-committed Huffman code space"), \
+    A(DEFLATE_ERR_UNCOMP_HDR, "wrongly formatted header in uncompressed block"), \
     A(DEFLATE_ERR_CHECKSUM, "incorrect data checksum"), \
     A(DEFLATE_ERR_INLEN, "incorrect data length"), \
     A(DEFLATE_ERR_UNEXPECTED_EOF, "unexpected end of data")