From 13f2c5ae14901c89c38f898496102afd9daeaf6d Mon Sep 17 00:00:00 2001 From: Eric Soroos Date: Fri, 28 Oct 2022 14:11:25 +0200 Subject: [PATCH 1/5] Prevent DOS with large SAMPLESPERPIXEL in Tiff IFD A large value in the SAMPLESPERPIXEL tag could lead to a memory and runtime DOS in TiffImagePlugin.py when setting up the context for image decoding. diff --git a/src/PIL/TiffImagePlugin.py b/src/PIL/TiffImagePlugin.py index 04a63bd2b44..46166fc6335 100644 --- a/src/PIL/TiffImagePlugin.py +++ b/src/PIL/TiffImagePlugin.py @@ -257,6 +257,8 @@ (MM, 8, (1,), 1, (8, 8, 8), ()): ("LAB", "LAB"), } +MAX_SAMPLESPERPIXEL = max(len(key_tp[4]) for key_tp in OPEN_INFO.keys()) + PREFIXES = [ b"MM\x00\x2A", # Valid TIFF header with big-endian byte order b"II\x2A\x00", # Valid TIFF header with little-endian byte order @@ -1396,6 +1398,12 @@ def _setup(self): SAMPLESPERPIXEL, 3 if self._compression == "tiff_jpeg" and photo in (2, 6) else 1, ) + + if samples_per_pixel > MAX_SAMPLESPERPIXEL: + # DOS check, samples_per_pixel can be a Long, and we extend the tuple below + logger.error("More samples per pixel than can be decoded: %s", samples_per_pixel) + raise SyntaxError("Invalid value for samples per pixel") + if samples_per_pixel < bps_actual_count: # If a file has more values in bps_tuple than expected, # remove the excess.