From 6628a69c036df2aa036290e6cd71767c159c79ed Mon Sep 17 00:00:00 2001
From: Kevin Backhouse <kevinbackhouse@github.com>
Date: Wed, 21 Apr 2021 12:06:04 +0100
Subject: [PATCH] Add more bounds checks in Jp2Image::encodeJp2Header

---
 src/jp2image.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/src/jp2image.cpp b/src/jp2image.cpp
index 917d115..0825d99 100644
--- a/src/jp2image.cpp
+++ b/src/jp2image.cpp
@@ -626,15 +626,18 @@ namespace Exiv2
     void Jp2Image::encodeJp2Header(const DataBuf& boxBuf,DataBuf& outBuf)
     {
         DataBuf output(boxBuf.size_ + iccProfile_.size_ + 100); // allocate sufficient space
-        int     outlen = sizeof(Jp2BoxHeader) ; // now many bytes have we written to output?
-        int      inlen = sizeof(Jp2BoxHeader) ; // how many bytes have we read from boxBuf?
+        long     outlen = sizeof(Jp2BoxHeader) ; // now many bytes have we written to output?
+        long     inlen = sizeof(Jp2BoxHeader) ; // how many bytes have we read from boxBuf?
+	enforce(sizeof(Jp2BoxHeader) <= static_cast<size_t>(output.size_), Exiv2::kerCorruptedMetadata);
         Jp2BoxHeader* pBox   = (Jp2BoxHeader*) boxBuf.pData_;
-        int32_t       length = getLong((byte*)&pBox->length, bigEndian);
-        int32_t       count  = sizeof (Jp2BoxHeader);
+        uint32_t       length = getLong((byte*)&pBox->length, bigEndian);
+	enforce(length <= static_cast<size_t>(output.size_), Exiv2::kerCorruptedMetadata);
+        uint32_t       count  = sizeof (Jp2BoxHeader);
         char*         p      = (char*) boxBuf.pData_;
         bool          bWroteColor = false ;
 
         while ( count < length || !bWroteColor ) {
+	    enforce(sizeof(Jp2BoxHeader) <= length - count, Exiv2::kerCorruptedMetadata);
             Jp2BoxHeader* pSubBox = (Jp2BoxHeader*) (p+count) ;
 
             // copy data.  pointer could be into a memory mapped file which we will decode!
-- 
2.23.0