gentoo-overlay/media-gfx/exiv2/files/exiv2-0.26_p20180319-CVE-2018-4868.patch

From ce4f575e106697c0e513091e95a7cd12ed6a488b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dan=20=C4=8Cerm=C3=A1k?= <dan.cermak@cgc-instruments.com>
Date: Tue, 9 Jan 2018 21:18:36 +0100
Subject: [PATCH 1/8] Add check for DataBuf.size_ in Jp2Image::readMetadata()

When parsing a subBox that is a ColorHeader, a length is extracted
from the input file and fed directly into DataBuf() (which calls
malloc). A crafted input file can provide arbitrarily (up to
max(uint32_t)-8) large values and result in excessive memory
allocation.

This commit adds a check for the new size of DataBuf so that it is not
larger than the remaining size of the file.

This fixes #202 aka CVE-2018-4868
---
 src/jp2image.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/jp2image.cpp b/src/jp2image.cpp
index a308bfd9..3cebc2a8 100644
--- a/src/jp2image.cpp
+++ b/src/jp2image.cpp
@@ -272,7 +272,12 @@ namespace Exiv2
 #endif
 
                             const long pad = 3 ; // 3 padding bytes 2 0 0
-                            DataBuf data(Safe::add(subBox.length, static_cast<uint32_t>(8)));
+			    const size_t data_length = Safe::add(subBox.length, static_cast<uint32_t>(8));
+			    // data_length makes no sense if it is larger than the rest of the file
+			    if (data_length > io_->size() - io_->tell()) {
+				throw Error(58);
+			    }
+                            DataBuf data(data_length);
                             io_->read(data.pData_,data.size_);
                             const long    iccLength = getULong(data.pData_+pad, bigEndian);
                             // subtracting pad from data.size_ is safe:
-- 
2.17.0