--- /dev/null
+From 6173a57d39e04d68b139f8c1aa499a24dbe74ba1 Mon Sep 17 00:00:00 2001
+From: Even Rouault <even.rouault@spatialys.com>
+Date: Fri, 30 Jun 2017 17:29:44 +0000
+Subject: [PATCH] * libtiff/tif_dirwrite.c: in
+ TIFFWriteDirectoryTagCheckedXXXX() functions associated with LONG8/SLONG8
+ data type, replace assertion that the file is BigTIFF, by a non-fatal error.
+ Fixes http://bugzilla.maptools.org/show_bug.cgi?id=2712 Reported by team
+ OWL337
+
+[Peter: drop ChangeLog modification]
+Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
+---
+ libtiff/tif_dirwrite.c | 20 ++++++++++++++++----
+ 1 file changed, 23 insertions(+), 4 deletions(-)
+
+diff --git a/libtiff/tif_dirwrite.c b/libtiff/tif_dirwrite.c
+index 2967da58..8d6686ba 100644
+--- a/libtiff/tif_dirwrite.c
++++ b/libtiff/tif_dirwrite.c
+@@ -2111,7 +2111,10 @@ TIFFWriteDirectoryTagCheckedLong8(TIFF* tif, uint32* ndir, TIFFDirEntry* dir, ui
+ {
+ uint64 m;
+ assert(sizeof(uint64)==8);
+- assert(tif->tif_flags&TIFF_BIGTIFF);
++ if( !(tif->tif_flags&TIFF_BIGTIFF) ) {
++ TIFFErrorExt(tif->tif_clientdata,"TIFFWriteDirectoryTagCheckedLong8","LONG8 not allowed for ClassicTIFF");
++ return(0);
++ }
+ m=value;
+ if (tif->tif_flags&TIFF_SWAB)
+ TIFFSwabLong8(&m);
+@@ -2124,7 +2127,10 @@ TIFFWriteDirectoryTagCheckedLong8Array(TIFF* tif, uint32* ndir, TIFFDirEntry* di
+ {
+ assert(count<0x20000000);
+ assert(sizeof(uint64)==8);
+- assert(tif->tif_flags&TIFF_BIGTIFF);
++ if( !(tif->tif_flags&TIFF_BIGTIFF) ) {
++ TIFFErrorExt(tif->tif_clientdata,"TIFFWriteDirectoryTagCheckedLong8","LONG8 not allowed for ClassicTIFF");
++ return(0);
++ }
+ if (tif->tif_flags&TIFF_SWAB)
+ TIFFSwabArrayOfLong8(value,count);
+ return(TIFFWriteDirectoryTagData(tif,ndir,dir,tag,TIFF_LONG8,count,count*8,value));
+@@ -2136,7 +2142,10 @@ TIFFWriteDirectoryTagCheckedSlong8(TIFF* tif, uint32* ndir, TIFFDirEntry* dir, u
+ {
+ int64 m;
+ assert(sizeof(int64)==8);
+- assert(tif->tif_flags&TIFF_BIGTIFF);
++ if( !(tif->tif_flags&TIFF_BIGTIFF) ) {
++ TIFFErrorExt(tif->tif_clientdata,"TIFFWriteDirectoryTagCheckedLong8","SLONG8 not allowed for ClassicTIFF");
++ return(0);
++ }
+ m=value;
+ if (tif->tif_flags&TIFF_SWAB)
+ TIFFSwabLong8((uint64*)(&m));
+@@ -2149,7 +2158,10 @@ TIFFWriteDirectoryTagCheckedSlong8Array(TIFF* tif, uint32* ndir, TIFFDirEntry* d
+ {
+ assert(count<0x20000000);
+ assert(sizeof(int64)==8);
+- assert(tif->tif_flags&TIFF_BIGTIFF);
++ if( !(tif->tif_flags&TIFF_BIGTIFF) ) {
++ TIFFErrorExt(tif->tif_clientdata,"TIFFWriteDirectoryTagCheckedLong8","SLONG8 not allowed for ClassicTIFF");
++ return(0);
++ }
+ if (tif->tif_flags&TIFF_SWAB)
+ TIFFSwabArrayOfLong8((uint64*)value,count);
+ return(TIFFWriteDirectoryTagData(tif,ndir,dir,tag,TIFF_SLONG8,count,count*8,value));
+--
+2.11.0
+