From cab352e249ed3372dd9355c85e837613fff98fa2 Mon Sep 17 00:00:00 2001
From: Hugo Lefeuvre <hle@debian.org>
Date: Wed, 7 Nov 2018 18:48:29 +0100
Subject: [PATCH] jp2: convert: fix null pointer dereference

Tile components in a JP2 image might have null data pointer by defining a
zero component size (for example using large horizontal or vertical
sampling periods). This null data pointer leads to null image component
data pointer, causing crash when dereferenced without != null check in
imagetopnm.

Add != null check.

This commit addresses #1152 (CVE-2018-18088).
---
 src/bin/jp2/convert.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/bin/jp2/convert.c b/src/bin/jp2/convert.c
index fa02e31c5..e670cd82f 100644
--- a/src/bin/jp2/convert.c
+++ b/src/bin/jp2/convert.c
@@ -2233,6 +2233,11 @@ int imagetopnm(opj_image_t * image, const char *outfile, int force_split)
                 opj_version(), wr, hr, max);
 
         red = image->comps[compno].data;
+        if (!red) {
+            fclose(fdest);
+            continue;
+        }
+
         adjustR =
             (image->comps[compno].sgnd ? 1 << (image->comps[compno].prec - 1) : 0);