Memory device, stack protection system, computer system, compiler, stack protection method, storage medium and program transmission apparatus

A memory device for use by a computer system, said memory device having a memory pattern obtained after a function is called while said computer system is executing a program, said memory pattern comprising:

• a return address storage area for storing a return address for the source of a call for a function that is currently being executed;
• a previous frame pointer storage area is located below said return address storage area for the storage of a previous frame pointer for the source of said call;
• and
• a local variable storage area is located below said previous frame pointer storage area,
• wherein when a data array is stored in said local variable storage area, a guard variable is stored between said previous frame pointer and said data array, and
• wherein said guard variable is used as a target to confirm whether said return address has been destroyed during a process for returning from said function that is currently being executed.

A computer system comprising:

• a data processor for performing various calculations;
• and
• a memory device that is used by said data processor for said calculations and that has a memory pattern that is obtained after a function is called while said computer system is executing a program, said memory pattern including:
• a return address storage area for storing a return address for the source of a call for a function that is currently being executed,
• a previous frame pointer storage area for storing a previous frame pointer for said source of said call for the function that is currently being executed, and
• a local variable storage area that is located below said return address storage area and said previous frame pointer storage area,
• wherein, when a data array is stored in said local variable storage area, a guard variable is stored preceding said data array in said local variable area, and
• wherein, said guard variable is used as a target to confirm, during a process for the return of said function that is currently being executed, whether said return address has been destroyed.

A computer system comprising:

• a data processor for performing various calculations;
• and
• a memory device used by said data processor for said calculations, that has a memory pattern that is obtained after a function is called while said computer system is executing a program, said memory pattern including
• a return address storage area for storing a return address for a source that called a function that is currently being executed,
• a previous frame pointer storage area that is located below said return address storage area for the storage of a previous frame pointer for said source that called said function, and
• a local variable storage area that is located below said previous frame pointer storage area,
• wherein when a data array is stored in said local variable storage area, a guard variable is stored between said previous frame pointer and said data array, and
• wherein said guard variable is used as a target to confirm whether said return address has been destroyed during a process for returning from said function that is currently being executed.

A computer system, which controls a program for performing various calculations, comprising:

• a data processor for reading and executing a program to which an instruction is added for the storage, when a function is to be executed, of a guard variable between a previous frame pointer in a stack and a data array stored as a local variable in said stack;
• and
• a memory device used by said data processor to perform calculations,
• wherein, in accordance with said instruction for storing said guard variable that is added to said program, said data processor stores said guard variable in said stack of said memory device during a function calling process, and confirms the validity of said guard variable during a function return process.

A computer system, which controls a program for performing various calculations, comprising:

• a data processor for receiving a source program and for adding, to said source program, an instruction for storing a guard variable between a previous frame pointer in a stack that is obtained after a function is called, and a data array stored in said stack as a local variable, and for executing said program to which said instruction for storing said guard variable has been added;
• and
• a memory device used by said data processor to perform said calculations,
• wherein in accordance with said instruction for storing said guard variable said data processor stores said guard variable in said stack of said memory device during a function calling process, and confirms the validity of said guard variable during a function return process.

A storage medium on which input means for a computer stores a computer-readable program, said program permitting said computer to perform:

• a process for storing, before a function having a data array is executed, a guard variable between a previous frame pointer in a stack and a data array stored as a local variable in said stack;
• a process for confirming the validity of said guard variable during a function return process;
• and
• a process for, when it is detected during said function return process that said guard variable has been destroyed, halting the execution of a program and notifying a user that a stack smashing attack has occurred.

A program transmission apparatus comprising:

• storage means for storing a program that permits a computer to perform
• a process for storing, before a function having a data array is executed, a guard variable between a previous frame pointer in a stack and a data array stored as a local variable in said stack,
• a process for confirming the validity of said guard variable during a function return process, and
• a process for, when it is detected during said function return process that said guard variable has been destroyed, halting the execution of a program and notifying a user that a stack smashing attack has occurred;
• and
• transmission means for reading said program from said storage means and for transmitting said program.