[0001]The present invention relates to an electronic control device and a security verification method for the electronic control device.
Background technology
[0002]In recent years, advances in safe driving support and autonomous driving technology have led vehicles to connect to external systems such as servers or clouds. In-vehicle devices are equipped with code verification functions such as secure boot to ensure security inside and outside the vehicle.
[0003]
　Patent Document 1 discloses a secure boot method.
Prior art literature
Patent documents
[0004]
Patent Document 1: Japanese Unexamined Patent Publication No. 2017-188826
Outline of the invention
Problems to be solved by the invention
[0005]
　In order to detect tampering with the code of the in-vehicle device, it is desirable to use a secure module such as an HSM (Hardware Security Module) mounted on the in-vehicle device and perform secure boot at startup.
[0006]
　On the other hand, in the case of an ECU that is required to start at high speed, there is a problem that the code verification process cannot be performed before the code is executed because the time for executing the secure boot cannot be secured at the time of startup, and the security cannot be ensured. However, Patent Document 1 does not disclose a method for ensuring security when the code verification process cannot be executed.
[0007]
　The present invention is for solving the above problems, and an object of the present invention is to provide a technique for ensuring security at the time of high-speed startup.
Means to solve problems
[0008]
　In order to solve the above problems, the electronic control device according to the present invention is an electronic control device mounted on a mobile body, and is a control unit that controls a microcomputer using a code and a security verification unit that performs security verification of the code. And a start code that is a part of the code and is executed when the microcomputer is started, and the control unit uses the code or the code by the security verification unit when the microcomputer shifts to the stopped state. When the verification of the activation code is completed, the activation code is enabled to be executed at the next activation.
The invention's effect
[0009]
　According to the present invention, security at the time of high-speed startup can be ensured.
A brief description of the drawing
[0010]
FIG. 1 is a block diagram showing an ECU according to the first embodiment.
FIG. 2 is a flowchart showing a security verification process according to the first embodiment.
FIG. 3 is a flowchart showing a security verification process according to the first embodiment.
FIG. 4 is a flowchart showing a security verification process according to the second embodiment.
FIG. 5 is a flowchart showing a security verification process according to the third embodiment.
Mode for carrying out the invention
[0011]
　Hereinafter, some embodiments will be described with reference to the accompanying drawings. It should be noted that this embodiment is merely an example for realizing the present invention and does not limit the technical scope of the present invention. The same reference numerals are given to the common configurations in each figure.
[0012]
　In this embodiment, an example of an electronic control unit (hereinafter, ECU) that executes a code security verification (hereinafter, also referred to as secure boot) process will be described.
[0013]
　
　FIG. 1 is a block diagram showing a configuration example of an ECU according to the first embodiment.
[0014]
　The ECU 901 includes a main control unit 10, a main code storage unit 11, a standby start code storage unit 12, a main data storage unit 15, a power supply control unit 17, a debug port 18, and the like, which are connected to each other by a bus line. A communication unit 19 is provided. Further, the bus line can be accessed from the secure control unit 20 described later. The area to which these components belong and the connection with respect to the secure area described later are referred to as the main area 1 for convenience.
[0015]
　Further, the ECU 901 includes a secure control unit 20, a secure code storage unit 21, and a secure data storage unit 25, which are connected to each other by a bus line. The area and connection to which the secure control unit 20, the secure code storage unit 21, and the secure data storage unit 25 belong are referred to as a secure area 2 for convenience. The main area 1 is a part of the ECU 901 excluding the secure area 2.
[0016]
　The bus line in the main area 1 and the bus line in the secure area 2 are not directly connected for the reason of ensuring security. The transfer of commands and data between the areas 1 and 2 is performed via the secure control unit 20.
[0017]
　The main control unit 10 has a processor (CPU, MPU, or DSP) and executes a program stored in the main code storage unit 11 or the standby activation code storage unit 12.
[0018]
　The main code storage unit 11 stores a program executed by the main control unit 10. The main code storage unit 11 may be a non-volatile storage device such as a flash memory, EEPROM, SSD, FRAM (registered trademark, the same applies hereinafter), or a magnetic disk. The main code storage unit 11 may be composed of a plurality of storage devices, and each program may be distributed and stored in the plurality of storage devices.
[0019]
　The standby start code storage unit 12 stores a program executed by the main control unit 10 when the standby is started. The standby activation code storage unit 12 may be a memory having a RAM which is a volatile storage element. When the standby start code storage unit 12 is composed of a volatile storage element, the value is held by sharing the power supply from the power supply control unit 17 described later in the standby state. Alternatively, it may be a non-volatile storage device such as a flash memory, EEPROM, SSD, FRAM, or a magnetic disk. The standby activation code storage unit 12 may be composed of a plurality of storage devices, and each program may be distributed and stored in the plurality of storage devices.
[0020]
　The main code storage unit 11, the standby activation code storage unit 12, and the main data storage unit 15 may be a memory having a ROM which is a non-volatile storage element and a RAM which is a volatile storage element. The ROM stores an invariant program. The RAM is a high-speed and volatile storage element such as a DRAM (Dynamic Random Access Memory), and temporarily stores a program executed by the main control unit 10 and data used when the program is executed.
[0021]
　The main code storage unit 11, the standby activation code storage unit, and the main data storage unit 15 may have a part or all of them as components of each other. Even if there is no clear distinction as a device, the main code storage unit 11 and the standby activation code storage unit indicate the part that stores the code, and the main data storage unit 15 indicates the part that stores the data. good.
[0022]
　The main code storage unit 11 includes a main control code 110 and a standby start control code 111. The main control code 110 is a program executed by the main control unit 10 and is a program for realizing the function of the ECU 901 as an in-vehicle device. The number of main control codes 110 may be plural.
[0023]
　The standby start control code 111 is a program executed by the main control unit 10, and is a program executed when the ECU 901 starts from the standby state. The standby activation control code 111 is written to the standby activation code storage unit 12 at a predetermined timing before the ECU 901 enters the standby state by a sequence described later.
[0024]
　The main data storage unit 15 stores data used when the main control unit 10 executes a program. The main data storage unit 15 may be a non-volatile storage device such as a flash memory, EEPROM, SSD, FRAM, or a magnetic disk. The main data storage unit 15 may be composed of a plurality of storage devices, and each data may be distributed and stored in the plurality of storage devices.
[0025]
　Although not particularly shown, the main data storage unit 15 includes control data. The control data of the main data storage unit 15 is data used for processing by the main control code 110 or the standby start control code 111 executed by the main control unit 10, and is data for realizing the function of the ECU 901 as an in-vehicle device. Is. A plurality of control data of the main data storage unit 15 may be used depending on the intended use.
[0026]
　The power supply control unit 17 is a component for receiving power supply from the component of the ECU 901. The power control unit 17 separately supplies electric power to each component according to the state. As an example, in the standby state, power is supplied to the standby start code storage unit 12, and control is performed so that the main control unit 10 does not share power.
[0027]
　The debug port 18 is a module for rewriting the code and data stored in the main code storage unit 11 and the main data storage unit from the outside of the ECU 901. The debug port 18 may be JTAG, SPI, or the like. It is conceivable that the debug port 18 detects the connection of a debugger or the like and resets the ECU 901 in cooperation with the power supply control unit 17.
[0028]
　The communication unit 19 is a component for the ECU 901 to communicate with other components of the vehicle 900. The communication unit 19 is a module for communicating by CAN, CAN FD, Ethernet (registered trademark), or FlexRay. The ECU 901 may include a plurality of communication units 19 depending on the application and communication method. Further, the communication unit 19 may be shared with other modules for performing communication. The communication unit 19 may include an antenna and a modulation / demodulation circuit in the case of wireless communication. The communication unit 19 may include a connector and a modulation / demodulation circuit for wired communication.
[0029]
　The secure control unit 20 is composed of an HSM, SHE, TPM, other secure microcomputer, or a processor (CPU, MPU, or DSP) called a secure core. The secure control unit 20 executes the program stored in the secure code storage unit 21. The secure control unit 20 may have tamper resistance. The HSM, SHE, or TPM shown as an example of the secure control unit 20 may include the secure code storage unit 21 and the secure data storage unit 25 described later.
[0030]
　The secure code storage unit 21 stores a program executed by the secure control unit 20. The secure code storage unit 21 may be a non-volatile storage device such as a flash memory, EEPROM, SSD, FRAM, or a magnetic disk. The secure code storage unit 21 may have tamper resistance. The secure code storage unit 21 may be composed of a plurality of storage devices, and each program may be distributed and stored in the plurality of storage devices.
[0031]
　The secure data storage unit 25 stores data used when the secure control unit 20 executes a program. The secure data storage unit 25 may be a non-volatile storage device such as a flash memory, EEPROM, SSD, FRAM, or a magnetic disk. The secure data storage unit 25 may have tamper resistance.
[0032]
　The secure code storage unit 21 and the secure data storage unit 25 may be a memory having a ROM which is a non-volatile storage element and a RAM which is a volatile storage element. The ROM stores an invariant program. The RAM is a high-speed and volatile storage element such as a DRAM (Dynamic Random Access Memory), and temporarily stores a program executed by the secure control unit 20 and data used when the program is executed.
[0033]
　Further, the secure code storage unit 21 and the secure data storage unit 25 may have a part or all of them as components of each other. Even if there is no clear distinction as a device, the secure code storage unit 21 indicates a portion that stores a code in the secure area 2, and the secure data storage unit 25 indicates a portion that stores data in the secure area 2. It may be shown.
[0034]
　The secure code storage unit 21 includes a secure control code 210. The secure control code 210 is a program executed by the secure control unit 20, and is a program for realizing the security function of the ECU 901 as an in-vehicle device. The number of secure control codes 210 may be plural. In the sequence described later, the secure control code 210 verifies the validity of the code of the ECU 901.
[0035]
　The secure data storage unit 25 includes a standby activation control code storage unit 251 and a verification cost determination flag. The standby activation control code storage unit 251 is an area for temporarily or permanently storing the standby activation code 111, and the details will be described in the second embodiment described later. The verification necessity determination flag 252 is a flag for determining whether or not code verification by the secure control unit 20 is necessary, and details will be described in the third embodiment described later.
[0036]
　Further, the secure data storage unit 25 may hold the secure control data used for processing by the secure control code 210 executed by the secure control unit 20. The secure control data held by the secure data storage unit 25 is data for realizing the security function of the ECU 901 as an in-vehicle device, and may be plural depending on the application.
[0037]
　Hereinafter, an example of the security verification process will be described with reference to FIGS. 2 and 3.
[0038]
　FIG. 2 is a flowchart showing a security verification process according to the first embodiment.
[0039]
　Hereinafter, when the program of the main code storage unit 11 is described as the execution subject, it is assumed that the program is executed by the main control unit 10. Further, when the program of the secure code storage unit 21 is described as the execution subject, it is assumed that the program is executed by the secure control unit 20.
[0040]
　Further, the arrows in the following figures indicate the conceptual command and data flow, and do not limit the communication direction and the instruction direction. There may be processing instructions and data flows not shown by the arrows.
[0041]
　The illustrated sequence starts from the state in which the ECU 901 has started the transition to the standby state (S101). The transition of the ECU 901 to the standby state is started, for example, when the engine is turned off.
[0042]
　First, the main control unit 11 requests the secure control unit 21 to execute code verification (S102). In response to this, the secure control unit 21 verifies the code of the control code of the main code storage unit 11 (S103). S102 may be omitted, and if S102 is not present, the secure control unit 21 may execute S103 as the next step after S101. Alternatively, the secure control unit 21 may execute S103 by driving a timer or the like. When the code verification in S103 fails (S104 NG), the secure control unit 21 executes a predetermined error processing (S105). When the code verification is successful (S104 OK), the secure control unit 21 notifies the main control unit 11 of the completion of the verification (S106). Upon receiving the correct completion of the code verification, the main control unit 11 writes the standby start control code 111 to the standby start code storage unit 12 (S107) and enters the standby mode (S108).
[0043]
　Although not particularly shown in FIG. 2, in the standby mode, power is supplied to the standby start code storage unit 12 from the power control unit 17, and the standby start code storage unit 12 holds the value even during the standby mode. Can be done. Further, in the standby mode, the power supply to the main control unit 11 and the secure control unit 21 may be stopped.
[0044]
　Subsequently, when the standby start of the ECU 901 is started by a trigger such as turning on the engine (S109), power is supplied from the power supply unit 17 to the main control unit 11, and the main control unit 11 is stored in the standby start code storage unit 12. The standby start control code 11 is executed (S110). The main control unit 11 may execute the main control code 110 following S110 (S111).
[0045]
　Further, although not shown in FIG. 2, the standby activation control code 110 may make a code verification request to the secure control unit 21 in the process. In response to this, the code verification by the secure control unit 21 may have the same verification range as S103, and is parallel to the execution of the standby start control code 111 or the execution of the main control code 110 by the main control unit 11. May be done.
[0046]
　FIG. 3 is a flowchart showing the security verification process according to the first embodiment, and is a branch process of the flowchart described with reference to FIG. The security verification process according to FIG. 3 describes a case where the ECU 901 is reset during the standby mode in the security verification process according to FIG. 2, and the other configurations are the reprogramming process according to FIG. The same is true. Therefore, the differences from FIG. 2 will be mainly described.
[0047]
　When the debugger 901 is in the standby mode in S108 and a debugger or the like is connected (S201), the debug port 18 and the power supply control unit 17 cooperate to cause a reset (S202). At this time, the standby mode is released by resetting, and the standby activation code storage unit 12 is cleared (S203). In S203, when the standby activation code storage unit 12 is a non-volatile memory, explicit rewriting processing may be performed.
[0048]
　The ECU 901, which is activated from the reset after the standby mode is released, verifies the code of the control code of the main code storage unit 11 with the secure control unit 22 (S204). As in the relationship between S102 and S103, S204 may be executed in response to a code verification request from the trusted code of the main control unit 11. When the code verification in S205 fails (S205 NG), the secure control unit 21 executes a predetermined error processing (S206). When the code verification is successful (S205 OK), the secure control unit 21 notifies the main control unit 11 of the completion of the verification (S207). After that, the main control unit 11 that has received the correct completion of the code verification proceeds to the process of S111.
[0049]
　Detecting a debugger connection in S201 is an example of a sequence, and is not limited to this example as long as it is a processing flow in which the reset operation of S202 occurs. That is, when the reset of S202 occurs due to an arbitrary event including S201, which is suspected to be an attack such as code tampering of the ECU 901, the processing after S204 is executed.
[0050]
　According to this configuration, it is possible to secure the security at the time of high-speed startup from the standby mode while detecting the illegal code rewriting accompanied by the reset.
[0051]
　If any error occurs during the steps described in the present embodiment, the error may be notified to the control unit of each component of the vehicle information system.
[0052]
　Further, each program included in the main control code 110, the standby start control code 111, and the secure control code 210 may display information indicating the processing being executed on the display device, if necessary. It is particularly desirable for each of these programs to display information indicating the completion of a series of processes or the occurrence of branch processing on a display device. Further, the determination in the branch processing may be executed by the user via the input device.
[0053]
　Further, in the present embodiment, the exchange of information between each step may be omitted. However, in reality, they may form a pair of responses to the command. Further, even when the exchange of information between each step is indicated by a set of two-way arrows, the exchange may include a plurality of commands and responses. Further, even when the content of transmitting / receiving data between entities is described, in actual communication, one entity may serve as a client and the other entity may serve as a server. In this case, the actual communication may be carried out through commands and responses, and as a result the aforementioned data may be transmitted.
[0054]
　
　The security verification process according to the second embodiment will be described. The security verification process according to the second embodiment is different from the security verification process according to the first embodiment only in the writing subject of the standby activation control code 111, and the other configurations are the same as those in the first embodiment. This is the same as the security verification process. Therefore, the differences from the first embodiment will be mainly described.
[0055]
　FIG. 4 is a flowchart showing the security verification process according to the second embodiment.
[0056]
　In FIG. 4, instead of S107 in FIG. 3, the secure control unit 21 writes the standby activation control code 111 stored in the standby activation control code storage unit 251 to the standby activation code storage unit 12 after S104 (OK) (S301). .. The secure control unit 20 may copy the standby start control code 111 from the main code storage unit 11 to the standby start control code storage unit 251 in advance. Alternatively, the standby start control code 111 may be permanently held in the standby start control code storage unit 251. After that, the same process as the flow shown in FIG. 2 is executed.
[0057]
　In the second embodiment, it is desirable that the standby activation code storage unit 12 is controlled so that it can be written only from the secure area 2 and can only be read from the main area 1.
[0058]
　According to this configuration, since the code of the standby activation code storage unit 12 read at the start of standby activation is guaranteed to be written only from the secure area 2, security at high-speed startup is ensured with higher strength. be able to.
[0059]
　
　The security verification process according to the third embodiment will be described. The security verification process according to the third embodiment is different from the security verification process according to the first embodiment only in the method of determining whether or not the security verification is necessary. This is the same as the reprogramming process. Therefore, the differences from the first embodiment will be mainly described.
[0060]
　FIG. 5 is a flowchart showing the security verification process according to the third embodiment.
[0061]
　In FIG. 5, the ECU 901 starts from the state where the transition to shutdown has started (S401). Similar to the first and second embodiments, it may be triggered by the subsequent transition to the standby state. After that, from S102 to S104 (OK), after processing in the same manner as in the second, the verified flag is written in the verification cost determination flag 252 in response to the success of the verification (S402). After that, the ECU 901 shifts to the power-off state (S403). Similar to the first and second embodiments, the standby mode may be entered.
[0062]
　When the power supply of the ECU 901 is turned off in S403 and a debugger or the like is connected (S404), the debug port 18 and the secure control unit 21 cooperate to clear the verified flag of the verification necessity determination flag 252.
[0063]
　When the power of the ECU 901 is turned on or reset by turning on the engine or the like (S405), the secure control unit 22 checks the verification possibility determination flag 252, and if it has been verified (S406 YES), proceeds to S207. If it has not been verified (S406 NO), proceed to S204 to perform code verification. Here, when verified, a process occurs in which a flag indicating verification is written in the verification necessity determination flag 252 by S402 before shutdown, and a flag indicating verification such as S404 is cleared. If you didn't.
[0064]
　Detecting a debugger connection in S404 is an example of a sequence, and is not limited to this example as long as it is a processing flow in which the verified flag is cleared in S404. That is, when the verified flag of the verification necessity determination flag 252 is cleared by an arbitrary event suspected of being an attack such as code tampering of the ECU 901 including S404, the processing after S204 is executed.
[0065]
　According to this configuration, it is possible for the secure control unit 21 to determine whether or not verification is necessary, and not only standby startup but also high-speed startup while maintaining security is possible.
[0066]
　The present invention is not limited to the above-described embodiments, and includes various modifications. Each of the above-described embodiments has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and further, it is possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace other configurations with respect to a part of the configurations of each embodiment.
[0067]
　Further, each of the above configurations, functions, processing units, and processing means may be realized by hardware by designing a part or all of them by an integrated circuit. Further, each of the above configurations and functions may be realized by software by the processor interpreting and executing a program that realizes each function. Information such as programs, tables, and files that realize each function may be stored in a memory, a hard disk, or an SSD recording device, or a recording medium such as an IC card, an SD card, or a DVD.
[0068]
　Furthermore, the control lines and information lines indicate what is considered necessary for explanation, and not all control lines and information lines are necessarily shown in the product. In practice, almost all configurations may be interconnected.
Code description
[0069]
　1 ... Main area, 2 ... Secure area, 10 ... Main control unit, 11 ... Main code storage unit, 12 ... Standby start code storage unit, 15 ... Main data storage unit, 17 ... Power control unit, 18 ... Debug port, 19 ... Communication unit, 20 ... Secure control unit, 21 ... Secure code storage unit, 22 ... Secure data storage unit, 110 ... Main control code, 111 ... Standby start control code, 210 ... Secure control code, 251 ... Standby start control code storage Part, 252 ... Verification necessity judgment flag, 901 ... ECU

WE CLAIMS

[Claim 1]An electronic control device mounted on a mobile body, which is
　a control unit that controls a microcomputer using a code, a security verification unit that verifies the security of the
　code, and a part of the code that activates the microcomputer. The
　control unit includes an activation code to be executed when the microcomputer is stopped, and when the
　verification of the code or the activation code by the security verification unit is completed , the control unit
　executes the activation code. An electronic controller that is enabled to run at the next boot.
[Claim 2]
　The stopped state is the standby state of the microcomputer, the
　activation code is a standby activation code executed when the microcomputer is activated from the standby state, and the
　electronic control device uses the standby activation code. comprising a standby activation code storage unit for storing,
　wherein, when the microcomputer shifts to the standby state,
　if the verification of the code or the standby activation code by the security verification unit is completed,
　the standby activation code The electronic control device according to claim 1, which is stored in the standby activation code storage unit.
[Claim 3]
　The security verification unit 　enables the activation code to be executed at the next activation when
　the verification of the code or the activation code by the security verification unit is completed when the microcomputer shifts to the stopped state.
Item 2. The electronic control device according to item 1 or 2.
[Claim 4]
　A control unit for controlling the microcomputer using the code, and the security verifying unit that performs security verification of the code,
　a part of the code, with the activation code which the microcomputer is performed if activated,
　the The control unit is 　an electronic control device that enables the activation code to be executed at the next activation when
　the verification of the code or the activation code by the security verification unit is completed when the microcomputer shifts to the stopped state.
Security verification method.