JPH06266551A - Program protection system - Google Patents

Abstract

PURPOSE:To early detect the runaway of a program to minimize the breakdown of the program and to facilitate the analysis of a fault by checking the program and the data to receive accesses by means of a program identification code. CONSTITUTION:When a processor 2 carries out a program A, a program identification code 221 corresponding to the start address (i) of the program A is acquired from an access check table and set to a control register 21. Then the processor 2 carries out the program A in sequence at and after the address (i). At the same time, the program identification code corresponding to the address of the access destination is acquired from the access check table and collated with the code 211 set in the register 21. Thus the access check table is collated with the code 221 when the program A is carried out. Then a collation error is detected when no coincidence is confirmed in the comparison.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a program protection system, and more particularly to a program protection system in a processor such as a computer and a communication control device.

[0002]

2. Description of the Related Art Conventionally, a program protection mechanism in a processor such as a computer or a communication controller protects a read right, a write right and an execution right between programs having different protection levels. It also protects the program read, write, and execute rights at the same protection level.

[0003]

However, the scope of the conventional program protection mechanism is that the read right, write right, execution right protection between programs having different protection levels, and program read right at the same protection level. , Write right, and execute right are protected, and even the target program that has the right to access cannot be specified, so even if data that should not be accessed can be accessed, or even if the program execution order is abnormal. There is a problem that it is not detected as an error.

The present invention has been made in view of the above points,
A program protection method that can detect runaway to a program early by checking the program or data to be accessed, stop the destruction of the program to a minimum, reduce the impact on the system, and facilitate failure analysis The purpose is to provide.

[0005]

The present invention is a computer,
In a program protection method for a processor such as a communication control device, an access check table having a program identification code corresponding to an assigned address of the program and a control register showing the state of the processor having the program identification code being executed are provided, The access check table and the program identification code of the control register are inquired, and if they do not match, it is detected as a collation error.

In the present invention, the program identification code has a hierarchical structure, and the program identification code is collated for each hierarchy.

Further, according to the present invention, the hierarchy of the program identification code can be arbitrarily assigned for the data access check and the program control right transfer check, and the check by the program identification code is omitted.

Further, according to the present invention, the program identification code is set by the program creator in the program creation unit.

Further, the present invention has a control right transfer flag in the instruction format of the processor, and when the flag in the instruction code being executed is on, the address of the control right transfer destination next to the instruction being executed It is read from the program identification code in the check table and set as the program identification code in the control register.

[0010]

The present invention protects the read right, the write right, and the execute right between programs having different protection levels, and the read right and write right of the program at the same protection level.
In addition to the technology to protect the execution right, the program identification code is used to detect the program runaway at an early stage by checking the program and data to be accessed. Can be facilitated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention. The figure shows a case where collation is performed when the program is executed. In the figure, the program identification code has two layers. In the example of the figure, the upper layer is allocated for the program control right transfer check, and the lower layer is allocated for the data access check.

First, in FIG. 1, the system of this embodiment has a creation program 1 including a creation program A11 and a creation program B12, a control register 21 and an access check table 22, and a processor 2 for executing the program and a program. Processor 2 at loading
The program identification code 3 is set to.

In FIG. 1, a creation program 1 has a creation program A composed of a program A command part and a program A data part, and a creation program B composed of a program B command part and a program B data part.

The processor 2 includes a control register 21 indicating the state of the processor and program identification codes 221, 222, 223 corresponding to the program allocation addresses i to m.
And an access check table 22 which has a program identification code 224, 225, which is set in the control register 21 by the program identification code 3 at the time of program loading, and which is collated with the control register 21 at the time of program control right transfer check and data access check. Have.

The program identification code 3 given at the time of creating the program comprises a program identification code 31 given to the program A and a program identification code 32 given to the program B. The program identification code 31 has a program identification code 311 having an upper layer 3111 of a program identification code for program control right transfer check and a lower layer 3112 of a program identification code for data access check. The program identification code 32 given to the program B has a program identification code 321 of the instruction part of the program B and a program identification code 322 of the data part of the program B.

The program identification code 221 of the access check table 22 in the processor 2 has an upper layer 2211 of the program identification code for the program control right transfer check and a lower layer 2212 of the program identification code for the data access check. At the time of program loading, the content of the program identification code 2211 for program control right transfer check is "A1", and the content of the program identification code 2212 for data access check is "A11".

The program identification code 222 is set in the same manner as the program identification code 221 when the program is loaded, like the program identification code 221.

Regarding the program identification code 223,
When the program is loaded, the program identification code 312 (#, A11) corresponding to the program A data part is set.

Next, an example of collation during program execution will be described.

In FIG. 1, first, when the program A and the program B are created and used as the execution module, the program creator adds the identification codes of the program A and the program B to the program. In the example of the figure, for the program A command part of the program A, the program identification code 311 of the command part of the program A, which is composed of the program identification code upper layer 3111 (A1) and the program identification code lower device 3112 (A11). "A1, A1
1 "is added. Further, for the program A data part, the program identification code 3 of the data part of the program A is added.
12 “#, A11” is added.

Similarly, for the program B12, the program identification code 321 "B
1, B11 ", and a program identification code 322"#, B11 "is added to the data part of the program B.

Here, "#" set as the program control right transfer check code of the program identification code corresponding to the data part of the program is a special fixed code, which is used when the executable module is created. It is automatically given to the department. This special code "#" needs to be given differently from the control right transfer code given to the instruction part of the program. These program identification codes 31, 32 are stored in the executable module.

Next, when the processor 1 loads the executable module into the memory, the access check table 22 is created from the program identification codes 31 and 32 of the executable module. The access check table 22 has a program identification code in memory size units to which the program identification code is added.

When the processor 1 executes the program A in such a situation, first, the program identification code 221 corresponding to the starting address i of the program A is obtained from the access check table 22 and set in the control register 21. Here, the program identification code of the program identification code 221 corresponding to the starting address i of the program A is "A1, A11".

Next, the processor 1 sequentially executes the program from the address i. At this time, the program identification code corresponding to the address of the access destination is obtained from the access check table 22 and collated with the program identification code 211 set in the control register 21.

For example, assuming that the next access destination is the address j, the program identification code 222 corresponding to the instruction code of the address j of the program A is obtained from the address j by the access check table 22, and the program identification set in the control register 21 is determined. Match with code 211. In this case, the code for transferring the program control right is the same "A11".
Therefore, the access is executed as normal. At the time of data access, the program identification code for data access check is similarly used.

That is, when the instruction at the address j is executed and the data access destination is the address k, the program identification code 223 is obtained from the address k by the access check table 22 and the program identification code set in the control register 21 is obtained. Collate. In this case, the code for transferring the program control right is "#", which is normal because it is the data part, and the code for data access check is the same "A11", so it is executed as normal. It At the time of data access, the program identification code for data access check is similarly used.

That is, when the data access destination is the address k when the instruction at the address j is executed, the program identification code 223 is obtained from the access table 22 at the address k, and the program identification at the time of executing the instruction set in the control register 21. Match with code 211. In this case, the code for transferring the program control right is #, which is normal because it is the data part, and because the code for data access check is the same A11, it is executed as normal.

However, when the instruction at address j is executed and the data access destination is address p, the code for program right transfer in the access check table 22 corresponding to address p is B1, and it is an error because it is not data. To be detected. If the data access destination is the address m when the instruction at the address j is executed, the code for transferring the program control right of the access check table 22 corresponding to the address m is #, which is the data part. However, the code for the next data access check is B
11 and does not match the code A11 of the control register 21, and is detected as an error.

Next, the transfer of the program control right will be described.

FIG. 2 shows a state in which the executable module according to the embodiment of the present invention is loaded in the memory.
The figure shows a memory 100, in which a program A2 similar to the program A shown in FIG.
00 and a program B300 similar to the program B shown in FIG.

The program A200 has instruction codes corresponding to addresses i to k, and the instruction codes have control right transfer flags 2110 and 2210, respectively. here,
There is an instruction code 210 corresponding to the address i and an instruction code 220 corresponding to the address j, and the instruction code 210 is currently "O".
The control code transfer flag 2110 is set to "FF". Further, the instruction code 220 corresponding to the address j has the control code transfer flag 2210 that is currently "ON". The program B300 is set to the addresses p and m. It has a corresponding instruction code.

Here, in FIG. 2, it is assumed that the program configuration is such that the p address of the program B is called from the instruction of the program j address. As a result, when the executable module of the program A200 is created in FIG. 2, for the instruction code 220 that calls a program other than its own module, the control right transfer flag 2
210 is “ON”. When the instruction 210 at the address i of the program A200 is executed, the instruction control right transfer flag 2110 is "OFF", so that the program identification code of the control register 21 remains unchanged.

Next, at the address j, this instruction code 22
Since the control right transfer flag 2210 of 0 is “ON”,
Since the control right transfer flag 2210 of the control right transfer destination address check table 22 is "ON", the program identification code corresponding to the control right transfer destination address check table 22 is set in the control register 21, and the instruction at the address p is set. Go to execution. At this time, the program control right transfer check is not performed.

After that, the program identification code of the program B is set in the control register, and the code is used for collation at the time of program execution.

[0037]

As described above, according to the present invention, the program can be protected by the conventional technique and the program and data to be accessed can be checked by using the program identification code. Can detect a program runaway that could not be found early, stop the destruction of the program to a minimum, reduce the impact on the system, and facilitate failure analysis, thus building a highly reliable system. You can Also, the efficiency of debugging can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a diagram showing a state in which an executable module according to an embodiment of the present invention is loaded in a memory.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Creation program 2 Processor 3 Program identification code given at program creation 11 Creation program A 12 Creation program B 21 Control register 22 Access check table 31 Program identification code given to program A 32 Program identification code given to program B 100 Memory 200 program A 210 Command code corresponding to i address 211 Program identification code when command is executed 220 Command code corresponding to j address 221 Program identification code corresponding to command code at i address of program A 222 Command code at j address of program A Corresponding program identification code 223 Program identification code corresponding to data at address k of program A 224 Program identification code corresponding to instruction code at address p of program B Code 225 Program identification code corresponding to data at address m of program B 300 Program B 310 Instruction code at address p 311 Program identification code assigned to instruction code portion of program A 312 Program identification code assigned to data of program A 321 program Program identification code 322 given to the instruction code part of B. Program identification code given to the data part of program B 400 Execution order of programs 2110 Instruction control right migration flag 2210 Address j control right migration flag 2211 Program identification Upper layer of code (for program control right transfer check) 2212 Lower layer of program identification code (for data access check) 3111 Upper layer of program identification code (program control right transfer) Ekku for) 3112 program identification code of the lower layer (for data access check)

Claims (5)

[Claims] 1. In a program protection system for a processor such as a computer and a communication control device, an access check table having a program identification code corresponding to an assigned address of the program and a control register showing the state of the processor having the program identification code being executed. A program protection system comprising: a program identification code of the access check table and the control register when the program is executed, and detecting a collation error when they do not match. 2. The program protection system according to claim 1, wherein the program identification code has a hierarchical structure, and the program identification code is collated for each hierarchy. 3. The program protection according to claim 1, wherein the hierarchy of the program identification code is arbitrarily assigned for data access check and program control right transfer check, and the check by the program identification code is omitted. method. 4. The program protection system according to claim 1, wherein the program identification code is set by a program creator in program creation units. 5. A control right transfer flag is provided in the instruction format of the processor, and when the flag in the instruction code being executed is on, the address check table of the control right transfer destination next to the instruction being executed is set. 2. The program protection system according to claim 1, wherein the program protection code is read from the program identification code and set in the program identification code of the control register.