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Serious Serious
Reported By: Filuta Vitaliy
Reported On: 1/17/2008
For: Version 4.26 Build 1
# 2574 Encrypted Remote Connections Can Cause Memory Overwrites with Transfers Larger than 64K

I have installed FastMM4, run my application in FullDebugMode, and got an error due to the following code:

In dbisamsv.TServerThread.DoReadAbsoluteRecordBlock:

...
Pack(TempResult,SizeOf(Word));
PackCursorInfo(TempDataCursor);
Pack(TempRecordsToGet,SizeOf(Integer));
Pack(TempRecordsBuffer^,(TempRecordsToGet*TempDataCursor.RecordSize));
Pack(TempBookmarksBuffer^,(TempRecordsToGet*TempDataCursor.BookmarkSize));

   // after that point FReceiveBufferSize = 143346 bytes

EndPack;

   // in EndPack procedure FReplyHeader.TotalReplySize evaluates to 143352 bytes
   // and DataEngine.Encrypt procedure corrupts 6 bytes of memory that are not
   // part of FReceiveBuffer memory block



Comments Comments
This issue only affected encrypted connections directly, but could possibly cause other issues due to the memory overwrite.


Resolution Resolution
Fixed Problem on 1/20/2008 in version 4.26 build 2


Products Affected Products Affected
DBISAM Additional Software and Utilities
DBISAM CLX Client-Server
DBISAM CLX Client-Server with Source
DBISAM CLX Standard
DBISAM CLX Standard with Source
DBISAM ODBC Client-Server
DBISAM ODBC Client-Server with Source
DBISAM ODBC Standard
DBISAM ODBC Standard with Source
DBISAM ODBC Trial
DBISAM VCL Client-Server
DBISAM VCL Client-Server with Source
DBISAM VCL Standard
DBISAM VCL Standard with Source
DBISAM VCL Trial

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