From: simon <simon@cda61777-01e9-0310-a592-d414129be87e>
Date: Thu, 3 May 2012 17:38:08 +0000 (+0000)
Subject: Add an error check for correct formatting in Deflate uncompressed
X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/halibut/commitdiff_plain/8f664e7e91c918cd13248f6b684580c4dd2cdb31

Add an error check for correct formatting in Deflate uncompressed
block headers. (Ubuntu 12.04's gcc spotted that nlen was unused, which
it shouldn't have been.)


git-svn-id: svn://svn.tartarus.org/sgt/halibut@9475 cda61777-01e9-0310-a592-d414129be87e
---

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")