JP2017207952A - Processing device, access control method, and access control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately control access by an application using equipment.SOLUTION: A processing device 1 comprises: a storage device 10 for storing policy data 11 in which an address on a memory that an application accesses in the case of using equipment 2 and the access type are associated; and access control means 22 for, when it is detected that the application has tried to access the memory, determining whether or not the address on the memory that the application has tried to access and the access type are coincident with the address and access type stored in the policy data 11, and for authorizing the access when they are coincident, and for refusing the access otherwise.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a processing device, an access control method, and an access control program that connect to a device and execute an application that uses the device.

  With the development of information equipment in recent years, ensuring security has become a problem. For example, computer resources used by an application are preferably limited to the extent necessary for the application.

  For example, arbitrary access control (DAC: Discretion Access Control) is performed in a Unix-based operation system. However, discretionary access control has security problems such as information leakage due to authority setting mistakes and administrator authority capture due to vulnerabilities. To solve this problem, mandatory access control (MAC: Mandatory Access Control) May be used (see, for example, Non-Patent Document 1).

  The forced access control hooks all system calls to the OS, and determines whether to permit or deny access to resources based on a predetermined policy. In forced access control, only access rights based on a defined policy are allowed. Therefore, according to forced access control, even if an attacker has an unexpected problem due to the vulnerability of the application, access that is not defined by the policy is eliminated, and access to resources that are not permitted by the policy is prevented. be able to.

C. Wright, “Linux Security Modules: General Security Support for the Linux Kernel,” Proceedings of the 11th USENIX Security Symposium, August 5-9, 2002.

  However, since the access control method described in Non-Patent Document 1 is intended to protect the system area expanded to the lower address, access control cannot be performed on an arbitrary address. Specifically, in order to protect the system area, the upper limit value of the address of the address band to be restricted is set to “restrict access to an address band smaller than 0x0000FFFF”. Therefore, the method described in Non-Patent Document 1 cannot restrict access to a specific address.

  The application uses a device connected to the computer via a specific address on the memory. However, in the conventional access control method, since the upper limit value of the address bandwidth is set, access is permitted only to a specific address that is referred to when using the device, and access to other addresses is denied. It is not possible to properly control access. As a result, due to the vulnerability of the application, access to an address other than the address that is referred to when using the device is allowed, and security may not be ensured.

  Accordingly, an object of the present invention is to provide a processing device, a processing method, and a processing program capable of appropriately controlling access by an application that uses a device in a processing device that connects the devices.

  In order to solve the above-described problem, a first feature of the present invention relates to a processing apparatus that connects to a device and executes an application that uses the device. Here, the application uses the device by accessing the memory of the processing device. The processing device according to the first feature detects a storage device that stores policy data in which an address on a memory and an access type that are accessed when an application uses a device, and an attempt to access the memory by the application If the address and access type on the memory to which the application tried to access match the address and access type stored in the policy data, the access is permitted and the addresses do not match. Access control means for denying access in some cases.

  Here, the policy data is data in which an identifier of an interface that can be used when the device is connected to the processing device is associated with an address on the memory and an access type corresponding to the interface. If an access attempt is detected, whether the address on the memory and the access type that the application attempted to access match the address and access type associated with the interface to which the device is connected in the policy data. May be determined.

  The processing device connects to the policy providing server, and the policy providing server generates new policy data for the processing device, distributes the new policy data to the processing device, and the processing device receives the policy from the policy providing server. Update means for acquiring new policy data and updating the policy data stored in the storage device to the new policy data may be provided.

  The second feature of the present invention relates to an access control method used in a processing apparatus that executes an application that uses a device while connecting to the device. Here, the application uses the device by accessing the memory of the processing device. An access control method according to a second feature includes a storage step in which a processing device stores policy data in which a storage device is associated with an address on a memory to be accessed when an application uses the device and an access type. A detection step in which the device detects an attempt to access the memory by the application, and an address and access type on the memory in which the processing device has attempted to access the address and the access type stored in the policy data match. A determination step of permitting access if they match, and rejecting access if they do not match.

  Here, the policy data is data in which an address of the memory corresponding to the interface and an access type are associated with an interface identifier that can be used when the device connects to the processing device. It may be determined whether the address on the memory and the access type that attempted to match the address and access type associated with the interface to which the device is connected in the policy data.

  The processing device connects to the policy providing server, the policy providing server generates new policy data for the processing device, distributes the new policy data to the processing device, and the access control method is the policy providing server. An update step of acquiring new policy data from the server and updating the policy data stored in the storage device to the new policy data may be provided.

  A third feature of the present invention relates to an access control program for causing a computer to function as the processing device described in the first feature of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, in the processing apparatus which connects an apparatus, the processing apparatus, the processing method, and processing program which can control appropriately the access by the application using an apparatus can be provided.

It is a figure explaining the hardware constitutions and functional block of the processing apparatus which concerns on embodiment of this invention. It is a figure explaining the hierarchical structure of the processing apparatus which concerns on embodiment of this invention. It is an example of the memory structure of the processing apparatus which concerns on embodiment of this invention. It is a figure explaining an example of a data structure and data of policy data concerning an embodiment of the invention. It is a flowchart explaining the access control method which concerns on embodiment of this invention. It is a figure explaining the system configuration | structure of the access control system which concerns on the modification of this invention. It is a figure explaining the hardware constitutions and functional block of the processing apparatus which concern on the modification of this invention. It is a figure explaining the hardware constitutions and functional block of the policy provision server which concern on the modification of this invention. It is a figure explaining the concept of the utilization resource data which concern on the modification of this invention. It is a figure explaining the concept of the address map data which concerns on the modification of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals.

(Embodiment)
With reference to FIG. 1, the processing apparatus 1 which concerns on embodiment of this invention is demonstrated. The processing device 1 is a general computer including a storage device 10, a processing control device 20, and a device interface 30. Here, the processing apparatus 1 is not limited to a personal computer or a smartphone, but may be a camera or the like, for example. In the processing apparatus 1, each unit shown in FIG. 1 is mounted on the processing control apparatus 20 by such a general computer executing a program for realizing a predetermined function.

  The processing device 1 is connected to the device 2 via the device interface 30. The device 2 is, for example, a sensor or an actuator that is used by an application executed by the processing device 1. The processing apparatus 1 should just connect the at least 1 apparatus 2, and the number of the apparatuses 2 connected is not ask | required.

  For example, as shown in FIG. 2, the device interface 30 is a GPIO (General Purpose Input / Output) serving as an interface for data input / output with the device 2. The device interface 30 is not limited to GPIO, but may be an interface such as a general port, or may be an interface used only for either input or output.

  In such a processing apparatus 1, the application uses the device 2 by accessing the memory in the processing apparatus 1. The application does not directly access the device 2 but uses the device via a memory area expanded in the memory in order to use the device 2. Here, the memory area for using the device 2 is specified by an address such as 0x000A0000 as shown in FIG. For example, when the device 2 is connected via an interface such as GPIO, the address of the memory area accessed from the application and the access type such as Read or Write are determined in advance for each GPIO. The application can use the device 2 via GPIO by accessing a predetermined address with a predetermined access type.

  The storage device 10 stores an application program to be executed by the processing device 1 and an operation system program, and also stores policy data 11.

  The policy data 11 is data in which an address on a memory to be accessed when an application uses the device 2 and an access type are associated with each other. The address for using the device 2 specified in the policy data 11 may be any information that can specify the address of the control register, and may be a physical address or a virtual address in the address space. May be.

  For example, as shown in FIG. 4, the policy data 11 associates the identifier of the access source application with the information of the resource permitted to the application, the access right, and the access expiration date.

  The resource information is information for identifying a resource permitted to the access source application. The resource information may be specified only by an address on the memory, or may be specified by an interface identifier and an address corresponding to this interface. The interface identifier is, for example, a GPIO or port identifier.

  The access type is the type of access permitted for the resource permitted to the access source application. In the access type, any one of Read only, Write only, or both Read and Write is set. In the access expiration date, information for specifying an accessible period is set for the resource permitted to the access source application.

  The processing control device 20 includes application execution means 21 a, 21 b and 21 c and an access control means 22.

  The application execution means 21a, 21b, and 21c execute different applications A, B, and C, respectively. Each application is executed in an application layer higher than the middleware, as shown in FIG.

  On the other hand, the access control means 22 is executed in the OS layer as shown in FIG. The access control unit 22 includes a detection unit 23 and a determination unit 24.

  The detection unit 23 detects an attempt to access the memory by the application when the application tries to use the device 2 via the memory. The detection unit 23 detects that the API is called when an application tries to use the device 2 via the memory by a system call function or the like, and notifies the determination unit 24 of the call.

  When an attempt to access the memory by the application is detected, the determination unit 24 determines whether the address on the memory and the access type that the application tried to access match the address and the access type stored in the policy data 11. Determine whether. The determination unit 24 permits access when they match, and denies access when they do not match. The determination unit 24 refers to the policy data 11 referred to in FIG. 4, and the address and access type associated with the GPIO to which the device 2 to be used by the application is connected are stored in the memory that the application has attempted to access. It may be determined whether the address and access type match.

  Further, the determination unit 24 may determine whether not only the address and the access type but also the identifier of the access source application and the access expiration date match the policy defined by the policy data 11.

  In the embodiment of the present invention, permitted access conditions are set in the policy data 11. Therefore, when the access by the application detected by the detection unit 23 is contrary to the policy data 11, the determination unit 24 denies the access and controls the application to execute only the access permitted by the policy data 11.

  With reference to FIG. 5, the access control method by the access control means 22 which concerns on embodiment of this invention is demonstrated.

  First, in step S1, when the access control means 22 detects that the application attempts to access the memory in order to use the device 2, the process proceeds to step S2. In step S <b> 2, the access control unit 22 extracts a policy related to the access source application detected in step S <b> 1 from the policy data 11.

  In step S3, the access control means 22 determines whether or not the policy extracted from the policy data 11 in step S3 matches the access detected in step S1. If they match, in step S4, the access control means 22 permits the access detected in step S1 and causes the application to access the memory. On the other hand, if they do not match, the access control means 22 rejects the access detected in step S1 in step S5 and does not allow the application to access the memory.

  As described above, the processing device 1 according to the embodiment of the present invention holds in advance an address and an access type used when an application accesses the memory of the processing device 1 to use the device 2. Thereby, even if an unexpected problem occurs due to the vulnerability of the application, only a predetermined address and access authority are permitted. Therefore, according to the processing device 1 according to the embodiment of the present invention, since access restriction can be realized in units of addresses, appropriate access control can be performed without allowing an application access to a wide address range. Can be executed.

(Modification)
In the embodiment of the present invention, the case where the policy data 11 is stored in the storage device 10 in advance has been described, but in the modification, the case where the policy data 11 is updated will be described. As the operation system is updated, the address on the memory and the access type to be accessed when the application uses the device 2 may change.

  Therefore, the access control system 5 according to the modification includes a policy providing server 3, a first processing device 1a, a second processing device 1b, and a third processing device via a communication network N as shown in FIG. 1c are connected to each other so that they can communicate with each other.

  The first processing apparatus 1a will be described with reference to FIG. The second processing device 1b and the third processing device 1c have the same configuration as that of the first processing device 1a.

  The first processing device 1a according to the modification is different from the processing device 1 according to the embodiment shown in FIG. 1 in that the updating device 25 and the communication control device 40 are provided. The communication control device 40 is an interface for connecting the first processing device 1a to the communication network N.

  The updating unit 25 acquires new policy data from the policy providing server 3 and updates the policy data 11 stored in the storage device 10 to new policy data. For example, the updating unit 25 inquires the policy providing server 3 for an update of the policy data 11 periodically or when any access expiration date set in the policy data 11 has expired. The new policy data is downloaded and stored in the storage device 10.

  The policy providing server 3 generates new policy data for the first processing device 1a and the like, and distributes the new policy data to the first processing device 1a and the like.

  As shown in FIG. 8, the policy providing server 3 is a general computer including a storage device 50, a processing control device 60, and a communication control device 70. Each means shown in FIG. 8 is implemented by a general computer executing a policy providing program for executing a predetermined process.

  The storage device 50 stores use resource data 51, address map data 52, first processing device policy data 53a, second processing device policy data 53b, and third processing device policy data 53c.

  The first processing device policy data 53a, the second processing device policy data 53b, and the third processing device policy data 53c are respectively the first processing device 1a, the second processing device 1b, and the third processing. Policy data distributed to the device 1c.

  The used resource data 51 is data in which an application is associated with a resource used by the application. A resource used by an application is specified by an interface identifier and an access type. As shown in FIG. 9, in the use resource data 51, a GPIO identifier and an access type are stored in association with each other as a resource used by an application. Here, GPIO is merely an example, and the usage resource data 51 may correspond to an interface identifier and an access type.

  The address map data 52 is data that associates an interface identifier in each processing apparatus with an address assigned to the interface. As shown in FIG. 10, the address map data 52 includes data in which the identifier of the GPIO in the first processing device 1a is associated with the address assigned to the GPIO. The address map data 52 includes the same data for the second processing device 1b and the third processing device 1c.

  The processing control device 60 includes a generation unit 61 and a distribution unit 62.

  The generation unit 61 generates policy data for each processing apparatus as shown in FIG. 4 from the use resource data 51 and the address map data 52. At this time, the generation unit 61 may set an expiration date of each record, other access conditions, and the like.

  The distribution unit 62 distributes the policy data for each processing device generated by the generation unit 61 to each device. For example, the distribution unit 62 receives an update inquiry from the first processing device 1a, and distributes the first processing device policy data 53a to the first processing device 1a at the timing of the update.

  According to such a modification, the policy data 11 can be prevented from being obsolete and can be automatically updated to the latest policy data 11.

(Other embodiments)
As described above, the embodiments of the present invention and the modifications thereof have been described. However, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples, and operational techniques will be apparent to those skilled in the art.

  For example, in the embodiment of the present invention, the policy data 11 describes a case in which a permitted access condition is set, but a denied access condition may be set.

  It goes without saying that the present invention includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 Processing apparatus 2 Apparatus 3 Policy provision server 5 Access control system 10, 50 Storage apparatus 11 Policy data 20, 60 Processing control apparatus 21a, 21b, 21c Application execution means 22 Access control means 23 Detection means 24 Judgment means 25 Update means 30 Equipment Interfaces 40 and 70 Communication control device 51 Resource data 52 Address map data 61 Generation means 62 Distribution means N Communication network

Claims (7)

A processing device that connects to a device and executes an application that uses the device,
The application uses the device by accessing the memory of the processing device,
A storage device that stores policy data that associates an address and an access type on a memory to be accessed when the application uses the device;
When an attempt to access the memory by the application is detected, it is determined whether or not the address and access type on the memory to which the application tried to access match the address and access type stored in the policy data. A processing apparatus comprising: an access control unit that determines and permits access when they match, and denies access when they do not match. The policy data is data in which an address on the memory corresponding to the interface and an access type are associated with an identifier of an interface that can be used when the device connects to the processing device,
When an access attempt to the memory is detected, the access control means associates the address and access type on the memory to which the application tried to access with the interface to which the device is connected in the policy data. The processing apparatus according to claim 1, wherein it is determined whether or not the received address and the access type match. The processing device connects to a policy providing server,
The policy providing server generates new policy data for the processing device, distributes the new policy data to the processing device,
The processor is
The update means for acquiring the new policy data from the policy providing server and updating the policy data stored in the storage device to the new policy data. Processing equipment. An access control method used for a processing device that connects to a device and executes an application that uses the device,
The application uses the device by accessing the memory of the processing device,
The access control method includes:
A storage step in which the processing device stores, in the storage device, policy data in which an address and an access type on a memory to be accessed when the application uses the device is associated;
A detecting step in which the processing device detects an attempt to access the memory by the application;
The processing device determines whether or not the address and access type on the memory to which the application has attempted access matches the address and access type stored in the policy data, and permits access if they match. An access control method comprising: a determination step of denying access when they do not match. The policy data is data in which an address on the memory corresponding to the interface and an access type are associated with an identifier of an interface that can be used when the device connects to the processing device,
In the determination step, it is determined whether an address and an access type on a memory to which the application has attempted access match an address and an access type associated with an interface to which the device is connected in the policy data. The access control method according to claim 4, wherein: The processing device connects to a policy providing server,
The policy providing server generates new policy data for the processing device, distributes the new policy data to the processing device,
The access control method includes:
The update step of acquiring the new policy data from the policy providing server and updating the policy data stored in the storage device to the new policy data is provided. Access control method.   The access control program for functioning as a processing apparatus of any one of Claim 1 thru | or 3 while connecting the apparatus and running the application which utilizes the said apparatus.

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