From 43bc256d8ae44b92d2734a3c5bc73957a4d7c1ec Mon Sep 17 00:00:00 2001
From: erouault <erouault>
Date: Sat, 3 Dec 2016 11:15:18 +0000
Subject: [PATCH] * libtiff/tif_ojpeg.c: make OJPEGDecode() early exit in case
 of failure in OJPEGPreDecode(). This will avoid a divide by zero, and
 potential other issues. Reported by Agostino Sarubbo. Fixes
 http://bugzilla.maptools.org/show_bug.cgi?id=2611

---
 libtiff/tif_ojpeg.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libtiff/tif_ojpeg.c b/libtiff/tif_ojpeg.c
index 1ccc3f9..f19e8fd 100644
--- a/libtiff/tif_ojpeg.c
+++ b/libtiff/tif_ojpeg.c
@@ -244,6 +244,7 @@ typedef enum {
 
 typedef struct {
 	TIFF* tif;
+        int decoder_ok;
 	#ifndef LIBJPEG_ENCAP_EXTERNAL
 	JMP_BUF exit_jmpbuf;
 	#endif
@@ -722,6 +723,7 @@ OJPEGPreDecode(TIFF* tif, uint16 s)
 		}
 		sp->write_curstrile++;
 	}
+	sp->decoder_ok = 1;
 	return(1);
 }
 
@@ -784,8 +786,14 @@ OJPEGPreDecodeSkipScanlines(TIFF* tif)
 static int
 OJPEGDecode(TIFF* tif, uint8* buf, tmsize_t cc, uint16 s)
 {
+        static const char module[]="OJPEGDecode";
 	OJPEGState* sp=(OJPEGState*)tif->tif_data;
 	(void)s;
+        if( !sp->decoder_ok )
+        {
+            TIFFErrorExt(tif->tif_clientdata,module,"Cannot decode: decoder not correctly initialized");
+            return 0;
+        }
 	if (sp->libjpeg_jpeg_query_style==0)
 	{
 		if (OJPEGDecodeRaw(tif,buf,cc)==0)
-- 
2.7.4