From 7abe129ac48ed85fd8e2b849076f06a66a50fc05 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Wed, 7 Aug 2019 17:08:18 +0100
Subject: [PATCH] don't invert signed ints in tiffload

---
 ...e-minimized-thumbnail_fuzzer-5718717719117824 | Bin 0 -> 1050 bytes
 libvips/foreign/tiff2vips.c                      |   7 ++++++-
 2 files changed, 6 insertions(+), 1 deletion(-)
 create mode 100644 fuzz/thumbnail_fuzzer_corpus/clusterfuzz-testcase-minimized-thumbnail_fuzzer-5718717719117824

diff --git a/fuzz/thumbnail_fuzzer_corpus/clusterfuzz-testcase-minimized-thumbnail_fuzzer-5718717719117824 b/fuzz/thumbnail_fuzzer_corpus/clusterfuzz-testcase-minimized-thumbnail_fuzzer-5718717719117824
new file mode 100644
index 0000000000000000000000000000000000000000..5f4ecac4d4644f5c25ba389aea38efb3b807b265
GIT binary patch
literal 1050
zcmebD)M8k`z`&qDckur|UMv5Dfr1y+T*ko2%)kirX&}%<MkpKP0wx$6D9#3D6B{0a
zj4WU?Iq-y_ILu5IkZm{s#JBiE1cz4a!axT#V3!#crFRGr7p-E@bn>5pIQIoZ)iV*P
Jo;XtxssNSbiP!)D

literal 0
HcmV?d00001

diff --git a/libvips/foreign/tiff2vips.c b/libvips/foreign/tiff2vips.c
index 03a4e31b..8d909722 100644
--- a/libvips/foreign/tiff2vips.c
+++ b/libvips/foreign/tiff2vips.c
@@ -938,7 +938,12 @@ rtiff_greyscale_line( Rtiff *rtiff,
 	int photometric_interpretation = 
 		rtiff->header.photometric_interpretation;
 	VipsBandFormat format = rtiff_guess_format( rtiff ); 
-	gboolean invert = photometric_interpretation == PHOTOMETRIC_MINISWHITE;
+
+	/* Swapping black and white doesn't work for the signed formats.
+	 */
+	gboolean invert = 
+		photometric_interpretation == PHOTOMETRIC_MINISWHITE &&
+		vips_band_format_isuint( format );
 
 	int x, i;