* libtiff/tif_pixarlog.c: fix potential buffer write overrun in

PixarLogDecode() on corrupted/unexpected images (reported by Mathias Svensson)
vadz · Jun 28, 2016 · 391e77f · 391e77f
1 parent c421b99
commit 391e77f
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diff --git a/ChangeLog b/ChangeLog
@@ -1,3 +1,8 @@
+2016-06-28  Even Rouault <even.rouault at spatialys.com>
+
+	* libtiff/tif_pixarlog.c: fix potential buffer write overrun in
+	PixarLogDecode() on corrupted/unexpected images (reported by Mathias Svensson)
+
 2016-06-15  Bob Friesenhahn  <bfriesen@simple.dallas.tx.us>
 
 	* libtiff/libtiff.def: Added _TIFFMultiply32 and _TIFFMultiply64

diff --git a/libtiff/tif_pixarlog.c b/libtiff/tif_pixarlog.c
@@ -459,6 +459,7 @@ horizontalAccumulate8abgr(uint16 *wp, int n, int stride, unsigned char *op,
 typedef	struct {
 	TIFFPredictorState	predict;
 	z_stream		stream;
+	tmsize_t		tbuf_size; /* only set/used on reading for now */
 	uint16			*tbuf; 
 	uint16			stride;
 	int			state;
@@ -694,6 +695,7 @@ PixarLogSetupDecode(TIFF* tif)
 	sp->tbuf = (uint16 *) _TIFFmalloc(tbuf_size);
 	if (sp->tbuf == NULL)
 		return (0);
+	sp->tbuf_size = tbuf_size;
 	if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN)
 		sp->user_datafmt = PixarLogGuessDataFmt(td);
 	if (sp->user_datafmt == PIXARLOGDATAFMT_UNKNOWN) {
@@ -783,6 +785,12 @@ PixarLogDecode(TIFF* tif, uint8* op, tmsize_t occ, uint16 s)
 		TIFFErrorExt(tif->tif_clientdata, module, "ZLib cannot deal with buffers this size");
 		return (0);
 	}
+	/* Check that we will not fill more than what was allocated */
+	if (sp->stream.avail_out > sp->tbuf_size)
+	{
+		TIFFErrorExt(tif->tif_clientdata, module, "sp->stream.avail_out > sp->tbuf_size");
+		return (0);
+	}
 	do {
 		int state = inflate(&sp->stream, Z_PARTIAL_FLUSH);
 		if (state == Z_STREAM_END) {