From 802d3cbf3043be5dce5317e140ccb1c17a6a2d39 Mon Sep 17 00:00:00 2001 From: Thomas Bernard Date: Tue, 29 Jan 2019 11:21:47 +0100 Subject: [PATCH] TIFFWriteDirectoryTagTransferfunction() : fix NULL dereferencing http://bugzilla.maptools.org/show_bug.cgi?id=2833 we must check the pointer is not NULL before memcmp() the memory --- libtiff/tif_dirwrite.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/libtiff/tif_dirwrite.c b/libtiff/tif_dirwrite.c index c15a28db..ef30c869 100644 --- a/libtiff/tif_dirwrite.c +++ b/libtiff/tif_dirwrite.c @@ -1893,12 +1893,14 @@ TIFFWriteDirectoryTagTransferfunction(TIFF* tif, uint32* ndir, TIFFDirEntry* dir n=3; if (n==3) { - if (!_TIFFmemcmp(tif->tif_dir.td_transferfunction[0],tif->tif_dir.td_transferfunction[2],m*sizeof(uint16))) + if (tif->tif_dir.td_transferfunction[2] == NULL || + !_TIFFmemcmp(tif->tif_dir.td_transferfunction[0],tif->tif_dir.td_transferfunction[2],m*sizeof(uint16))) n=2; } if (n==2) { - if (!_TIFFmemcmp(tif->tif_dir.td_transferfunction[0],tif->tif_dir.td_transferfunction[1],m*sizeof(uint16))) + if (tif->tif_dir.td_transferfunction[1] == NULL || + !_TIFFmemcmp(tif->tif_dir.td_transferfunction[0],tif->tif_dir.td_transferfunction[1],m*sizeof(uint16))) n=1; } if (n==0) -- 2.21.0