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From 7a0aea5806d57e0e7c5187fbc9c2937a16e0bca1 Mon Sep 17 00:00:00 2001
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From: Eric Soroos <eric-github@soroos.net>
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Date: Thu, 17 Dec 2020 00:17:53 +0100
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Subject: [PATCH] Fix for CVE CVE-2020-35655 - Read Overflow in PCX Decoding.
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* Don't trust the image to specify a buffer size
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---
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src/PIL/PcxImagePlugin.py | 9 +++++++--
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1 file changed, 7 insertions(+), 2 deletions(-)
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diff --git a/src/PIL/PcxImagePlugin.py b/src/PIL/PcxImagePlugin.py
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index 564713a..17bbd18 100644
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--- a/src/PIL/PcxImagePlugin.py
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+++ b/src/PIL/PcxImagePlugin.py
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@@ -63,9 +63,9 @@ class PcxImageFile(ImageFile.ImageFile):
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version = i8(s[1])
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bits = i8(s[3])
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planes = i8(s[65])
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- stride = i16(s, 66)
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+ ignored_stride = i16(s, 66)
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logger.debug("PCX version %s, bits %s, planes %s, stride %s",
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- version, bits, planes, stride)
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+ version, bits, planes, ignored_stride)
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self.info["dpi"] = i16(s, 12), i16(s, 14)
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@@ -102,6 +102,11 @@ class PcxImageFile(ImageFile.ImageFile):
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self.mode = mode
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self.size = bbox[2]-bbox[0], bbox[3]-bbox[1]
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+ # don't trust the passed in stride. Calculate for ourselves.
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+ # CVE-2020-35653
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+ stride = (self.size[0] * bits + 7) // 8
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+ stride += stride % 2
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+
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bbox = (0, 0) + self.size
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logger.debug("size: %sx%s", *self.size)
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--
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2.29.2
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