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Verification of Invoking Environment by DOS ".EXE" Program Files

IP.com Disclosure Number: IPCOM000060213D
Original Publication Date: 1986-Mar-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chang, PY: AUTHOR [+2]

Abstract

A method is described to prevent potentially hazardous side effects caused by a DOS ".EXE" program file being invoked from an environment other than that from which it was designed to be invoked. From the DOS command environment, it is not always obvious which program files are designed to be invoked from other programs and which are safe to be invoked from DOS command level. Program files which are not designed to be invoked from DOS command level and that make no verification of invoking environment frequently "hang" the system and could conceivably result in loss of or damage to data. A DOS ".EXE" program file can be loaded and executed from another program with an input parameter being an address of a memory area which the .EXE program file modifies.

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Verification of Invoking Environment by DOS ".EXE" Program Files

A method is described to prevent potentially hazardous side effects caused by a DOS ".EXE" program file being invoked from an environment other than that from which it was designed to be invoked. From the DOS command environment, it is not always obvious which program files are designed to be invoked from other programs and which are safe to be invoked from DOS command level. Program files which are not designed to be invoked from DOS command level and that make no verification of invoking environment frequently "hang" the system and could conceivably result in loss of or damage to data. A DOS ".EXE" program file can be loaded and executed from another program with an input parameter being an address of a memory area which the .EXE program file modifies. This same program file could conceivably be executed directly from DOS command level with a random address supplied as a parameter, potentially causing loss of or damage to data and/or a system "hang." In accordance with this new method, a signature is included in the memory area at the address specified by the input parameter to the .EXE program. If this signature does not match the predefined value, the program will "know" that it was not invoked from the proper environment; in which case, it returns to the invoking environment without doing anything. If the signature does match that which is expected, the program can assume with a high degree of...