WO2019148447A1

WO2019148447A1 - Data protection method and data protection device

Info

Publication number: WO2019148447A1
Application number: PCT/CN2018/075086
Authority: WO
Inventors: 肖福洲; 尹友展
Original assignee: 华为技术有限公司
Priority date: 2018-02-02
Filing date: 2018-02-02
Publication date: 2019-08-08

Abstract

The present application provides a data protection method and a data protection device. The data protection method comprises: when a first processing module running in a low exception level first running space requests an attribute of a memory to be modified, a second processing module running in a high exception level second running space acquiring the request, and determining whether the memory is a protected memory; and if the memory is a protected memory, the second processing module running in the high exception level second running space rejecting the modification. The data protection method and the data protection device provided by the present application improve data security.

Description

Data protection method and data protection device

Technical field

The present application relates to the field of electronic devices, and more particularly to data protection methods and data protection devices.

Background technique

The operating data in the operating system on the electronic device is stored using memory. Some of these operational data are important to protect, that is, they cannot be changed at will.

In general, these unchangeable data changes can lead to electronic device failure or information security vulnerabilities. For example, if important data in the operating system on the electronic device is maliciously changed, the operating system may be malfunctioning, resulting in electronic device failure or information security vulnerability.

In existing electronic devices, important data can be protected by the operating system setting the attributes of the memory in which the important data is located to read-only to protect the important data from malicious modification.

However, this method of protection is less secure. For example, after the malware obtains the administrative rights of the operating system, the read-only attribute of the memory set by the operating system can be removed, so that the important data can be modified.

Therefore, there is a need to propose a more secure data protection method to protect data.

Summary of the invention

The present application provides a data protection method and a data protection device to help improve data security.

In a first aspect, the present application provides a data protection method, where the data protection method is implemented by a data protection device, where the data protection device includes a processor execution unit and a memory management unit, and the operating space of the processor execution unit partition includes the first The running space and the second running space, the abnormal level of the second running space is higher than the abnormal level of the first running space, and the data protection method comprises:

The first processing module running in the first running space sends a first message to the memory management unit, where the first message is used to request to modify the attribute of the first memory;

The memory management unit sends a second message to the second processing module running in the second running space, where the second message is used to request to determine whether the first memory is protected;

The second processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table;

The second processing module running in the second running space sends a third message to the memory management unit, where the third message is used to indicate whether to modify the attribute of the first memory;

If the third message is used to indicate that the attribute of the first memory is modified, the memory management unit modifies the attribute of the first memory according to the first message; if the third message is used to indicate that the attribute of the first memory is not modified, the memory management unit refuses to modify The first memory attribute.

In the data protection method, since the abnormal level of the second running space is higher than the abnormal level of the first running space, and the first processing module in the first running space needs to modify the attribute of the memory, it needs to go through the second running control. The authorization of the second processing module enables the first processing module in the first running control to arbitrarily modify the attributes of the memory, so that the data in the memory cannot be arbitrarily modified, and finally helps to improve the security of the data.

In a first possible implementation, before the second processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table, the data protection method further includes:

The first processing module in the first running space sends a fourth message to the second processing module in the second running space, where the fourth message is used to indicate whether the first memory is protected;

The second processing module in the second running space generates a memory protection table according to the fourth message, the memory protection table is used for recording the protected memory and/or the unprotected memory, and the protected memory includes storing the protected data. Memory, unprotected memory includes memory for storing unprotected data.

In this implementation, the first processing module in the first runtime may indicate to the second processing module in the second runtime that which memory is protected and/or which memory is unprotected.

In a possible implementation, before the second processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table, the data protection method further includes:

The second processing module running in the second running space determines that the first memory is used to store the protected data or the first memory is used to store the unprotected data;

The second processing module running in the second running space generates a memory protection table, where the memory protection table is used to record the first memory as protected memory or to record the first memory as unprotected memory, and the protected memory includes For memory that stores protected data, unprotected memory includes memory for storing unprotected data.

In this implementation, protected memory and/or unprotected memory may be predetermined.

In a possible implementation manner, the first running space is a kernel space, the first processing module is an operating system, and the second super management space is a super management space. Among them, the protected data includes: constant data written to the memory by the operating system during the compile phase, and constant data written by the operating system during the initialization phase.

In one possible implementation, the data protection device is a mobile phone, a tablet, a server, a personal computer, a network router, or a switch.

In a second aspect, the application provides a data protection device, where the data protection device includes a processor execution unit and a memory management unit, where the operating space divided by the processor execution unit includes a first running space and a second running space, and the second running The abnormal level of the space is higher than the abnormal level of the first running space, the first running space is used to run the first processing module, and the second running space is used to run the second processing module.

The first processing module is configured to send a first message to the memory management unit, where the first message is used to request to modify an attribute of the first memory;

The memory management unit is configured to send a second message to the second processing module, where the second message is used to request to determine whether the first memory is protected;

The second processing module is configured to determine, according to the pre-acquired memory protection table, whether the first memory is protected;

The second processing module is further configured to send a third message to the memory management unit, where the third message is used to indicate whether to modify the attribute of the first memory;

The memory management unit is further configured to: when the third message is used to indicate that the attribute of the first memory is modified, the attribute of the first memory is modified according to the first message, and the third message is used to indicate that the first memory is refused to be modified when the attribute of the first memory is not modified. Attributes.

In a possible implementation, the first processing module is further configured to send a fourth message to the second processing module in the second running space, where the fourth message is used to indicate whether the first memory is protected.

The second processing module determines, according to the pre-acquired memory protection table, whether the first memory is protected, and is further configured to: generate a memory protection table according to the fourth message, where the memory protection table is used to record the protected memory and/or not Protected memory, protected memory includes memory for storing protected data, and unprotected memory includes memory for storing unprotected data.

In a possible implementation manner, the second processing module determines, according to the pre-acquired memory protection table, whether the first memory is protected, and is further configured to:

Determining that the first memory is used to store protected data or determining that the first memory is used to store unprotected data;

Generating a memory protection table for recording the first memory as protected memory or for recording the first memory as unprotected memory, the protected memory including memory for storing protected data, Protected memory includes memory for storing unprotected data.

In a possible implementation manner, the first running space is a kernel space, the first processing module is an operating system, and the second running space is a super management space. Among them, the protected data includes: constant data written to the memory by the operating system during the compile phase, and constant data written by the operating system during the initialization phase.

In a possible design, the data protection device is a system chip, the system chip includes a processor and an output interface, and the processor includes a processor execution unit and a memory management unit, and the output interface is used to modify the memory management unit. When a memory attribute is used, the physical address of the first memory is output to the address bus.

Optionally, the data protection device may further comprise a memory for the program code executed by the memory execution unit, the protected data, and the unprotected data.

In a third aspect, the present application provides a computer readable storage medium. Program code for execution of the data protection device is stored in the computer readable storage medium. The program code includes instructions for performing the data protection method of the first aspect or any of the possible implementations of the first aspect.

In a fourth aspect, the present application provides a computer program product comprising instructions. When the computer program product is run on the data protection device, the data protection device is caused to perform the data protection method in any one of the possible implementations of the first aspect or the first aspect.

In a fifth aspect, the application provides a data protection device, where the data protection device includes a processor execution unit and a memory management unit, and the running space of the processor execution unit partition includes a kernel space and a super management space, and an abnormality of the super management space. The level of exception is higher than the kernel space.

An operating system running in the kernel space is configured to send a first message to the memory management unit, where the first message is used to request to modify an attribute of the first memory;

The memory management unit is configured to send a second message to the critical data protection module running in the super management space, where the second message is used to request to determine whether the first memory is protected;

The key data protection module is configured to determine whether the first memory is protected according to the pre-acquired memory protection table;

The key data protection module is further configured to send a third message to the memory management unit, where the third message is used to indicate whether to modify the attribute of the first memory;

In a possible implementation, the operating system is further configured to send a fourth message to the critical data protection module, where the fourth message is used to indicate whether the first memory is protected.

The key data protection module determines whether the first memory is protected according to the pre-acquired memory protection table, and is further configured to: generate a memory protection table according to the fourth message, where the memory protection table is used to record the protected memory and/or not Protected memory, protected memory includes memory for storing protected data, and unprotected memory includes memory for storing unprotected data.

In a possible implementation manner, the critical data protection module determines whether the first memory is protected according to a pre-acquired memory protection table, and is also used to:

In a possible implementation, the protected data includes: constant data written by the operating system during the compile phase, and constant data written by the operating system during the initialization phase.

DRAWINGS

1 is a schematic diagram of dividing an abnormal level according to an embodiment of the present application;

2 is a schematic flowchart of performing address mapping by an MMU according to an embodiment of the present application;

3 is a schematic structural diagram of a data protection device according to another embodiment of the present application;

4 is a schematic structural diagram of a data protection device according to another embodiment of the present application;

FIG. 5 is a schematic flowchart of a data protection method according to an embodiment of the present application; FIG.

6 is a schematic flowchart of a data protection method according to another embodiment of the present application;

FIG. 7 is a schematic flowchart of a data protection method according to another embodiment of the present application; FIG.

8 is a schematic flowchart of a data protection method according to another embodiment of the present application;

FIG. 9 is a schematic structural diagram of a data protection device according to an embodiment of the present application.

Detailed ways

The computer to which the data protection method and the data protection device of the embodiment of the present application can be applied may be an electronic device such as a mobile phone, a tablet computer, a server, a personal computer, a network router, a wearable device, or a switch.

A processor and a memory can be included in the computer. The processor may also be referred to as a central processing unit (CPU) or a central processing unit.

An example of a processor in the computer is an Advanced RISC Machines (ARM) processor. An example of a memory in this calculation is a random access memory (RAM) or a flash memory (Flash). Among them, RAM can also be called main memory or memory. The memory has access rights attributes such as read-only, writable, executable, and inaccessible.

Virtualization technology is used in the processor of this computer. Virtualization technology can hide the underlying physical hardware in the computer, allowing multiple independent operating systems (OSs) to transparently use and share the computer's hardware resources. Simply put, virtualization technology can enable the computer to run multiple OSs concurrently.

The processor in the computer provides different levels of privilege for the program code to access resources in the computer to protect the data in the computer and prevent malicious behavior in the computer, thereby ensuring the security of the computer.

For example, as shown in Figure 1, four exception levels (EL levels) can be defined in the ARM processor, namely EL0, EL1, EL2, and EL3. Among them, the higher the level of the abnormal level, the lower the level of the abnormal level is. For example, the EL0 level is lower than the EL1 level, the EL1 level is lower than the EL2 level, and the EL2 level is lower than the EL3 level. Of course, the lower the level of the abnormal level, the lower the value, and the higher the level of the abnormality, the higher the level of the abnormality.

Different levels of anomaly levels correspond to different levels of running space. The division of the exception level or the division of the runtime space provides logically separate execution rights for the software for all operational states in the processor. It should be understood that the level of anomaly referred to in this application is similar to that of a hierarchical protection domain that is common in computer science and supports the concepts involved in the level protection domain.

An example of software running under each of these four exception levels is as follows. A normal user application runs in the runspace corresponding to EL0; an operating system kernel, such as Linux or Windows, can run in the runspace corresponding to EL1, the operating system kernel is usually considered privileged; the hypervisor runs on EL2. In the corresponding running space; low-level firmware, such as the security monitor, runs in the running space corresponding to EL3. The hypervisor can also be called a hypervisor.

The hypervisor can provide virtualization services to one or more operating system kernels when enabled.

Firmware is the first thing that runs when the processor starts. The firmware provides a number of services, such as platform initialization, installation of trusted operating systems, and routing of commands for security monitors.

In general, a piece of software (such as a user's application, the operating system's kernel or hypervisor) occupies a separate level of exception, or a separate run space. Of course, there are exceptions. For example, a kernel management program, such as a kernel virtual machine (KVM), can be run in either the run space corresponding to EL2 or in the run space corresponding to EL1.

In the processor of the computer, the CPU execution unit can manage or access the memory through a memory management unit (MMU). For example, the MMU can perform address mapping and provide operations such as memory access authorization.

In the processor, when the program code running in the running space corresponding to different abnormal levels accesses the memory, the MMU performs different address mapping and different memory access authorization processes.

For example, as shown in Figure 2, the MMU performs a two-stage address mapping process for an application with an exception level of EL0 and an operating system with an exception level of EL1, a hypervisor with an exception level of EL3 and a security monitor with an exception level of EL4. Perform a phased address mapping process.

In the two-stage address mapping process, in the first phase, the virtual address (VA) of the memory is converted to an intermediate physical address (IPA); in the second phase, the IPA is converted into a physical address (physical address). , PA).

In the first stage of address translation, an example of a translation table base register (TTBR) used by the MMU is TTBRn_EL1; in the second stage of address translation, the base address of the conversion table used by the MMU is virtualized. The conversion translation table base register (VTTBR) 0_EL2 is specified. For example, a contiguous address space at the bottom of the memory is specified in VTTBR0_EL2 as the base address in the translation table.

In one stage of the address mapping process, the MMU can directly derive the PA according to the VA conversion. Among them, the management program EL2 and the security supervisor EL3 have their own one-stage conversion tables. The hypervisor EL2 and the security supervisor EL3 can directly convert from a virtual address to a physical address through respective corresponding tables. The base address of the conversion table corresponding to the hypervisor EL2 is specified in TTNR0_EL2, and the base address of the conversion table corresponding to the security supervisor EL3 is specified in TTNR0_EL3. In these two registers, a continuous and variable-size address space at the bottom of the memory is respectively designated as the base address of the translation address table of the hypervisor EL2 and the security supervisor EL3.

It should be understood that the above mentioned TTBRn_EL1, TTNR0_EL2 and TTNR0_EL3 are only an example, and different names may be referred to in different materials.

In the above two stages of the address mapping process, the first phase is usually executed under the control of the operating system, and the second phase is usually executed under the control of the hypervisor.

The execution of the management program under the control of the management program can be understood as follows: the management program determines that the IPA or the VA corresponding to the IPA can be accessed, and then the MMU is authorized to perform IPA to PA conversion.

The data protection method of the embodiment of the present application is mainly implemented in the address mapping process of the second stage described above under the control of the management program. Specifically, the memory protection table is pre-stored in the computer, and the memory protection table records address information of the memory that needs to be protected and/or does not need to be protected, and a processing module is added in the management program, and the processing module queries the memory protection table whether Includes address information for the memory that the operating system or application requests to modify access properties. If the processing module queries the memory protection table and determines that the memory requested to modify the access attribute is a protected memory, the MMU is denied to modify the access attribute of the memory.

An example of a memory protection table is shown in Table 1. In Table 1, both protected memory and unprotected memory are recorded, the first column records the virtual address of the protected memory, and the second column records the virtual address of the unprotected memory.

Table 1 memory protection table

受保护的内存的虚拟地址Protected memory virtual address	不受保护的内存的虚拟地址Virtual address of unprotected memory
0x40000000-0x600000000x40000000-0x60000000	0x00000000-0x300000000x00000000-0x30000000

For example, if a computer downloads malware, or if a web page is viewed with a malicious plugin, the malware or

The malicious plug-in attacks the operating system, obtains the management rights of the operating system, and controls the operating system to change the access attribute of the memory whose virtual address is 0x41115000 to 0x41116000 from writable to read-only, so that the malware or malicious plug-in can modify the in-memory. Data time, the management program in the process of the second stage mapping of the address of the memory by the MMU, the memory protection table is queried to know that the memory is protected, thereby rejecting the MMU to perform the second stage address mapping process, that is, rejecting Attacks by malware or malicious plugins protect the data in memory.

Optionally, after the hypervisor rejects the malware or the malicious plug-in to modify the access attribute of the memory, the management program may also issue a prompt message that the protected memory is attacked, for example, popping up a display box or sending an alarm sound.

The data protection device 300 shown in FIG. 3 is taken as an example to describe the data protection method proposed in the present application. It should be understood that the data protection device 300 shown in FIG. 3 is only an example, and the data protection device of the embodiment of the present application may further include other modules or units, or include modules similar to those of the modules in FIG. 3, or Includes all the modules in Figure 3.

The data protection device 300 shown in FIG. 3 includes a processor 310 and a memory 320. The memory can exchange data with the processor 310.

An example of the memory 320 is a random access memory (RAM). RAM can also be called main memory or memory. Another example of the memory 320 is a flash memory. It should be understood that the memory in subsequent embodiments may be replaced with a flash memory.

One example of processor 310 is a central processing unit (CPU). The CPU can also be called a central processor.

A CPU execution unit 311 and a memory management unit 312 may be included in the processor 310. It should be understood that the integration of the MMU herein within the processor 310 is just one example, and the MMU may also be located outside of the processor 310.

As shown in FIG. 4, four exception levels (ELs) are defined in the processor 310. Alternatively, it can be said that the program code executed by the CPU execution unit 311 can be classified into four types of abnormalities. The four exception levels are EL0, EL1, EL2, and EL3 from low to high. EL0, EL1, EL2 and EL3 correspond to four operating spaces.

The running space corresponding to EL0 is the user program space, and the user program space is used to run the user program. User programs can also be called applications.

The running space corresponding to EL1 is a kernel space, and the kernel space is used to run an operating system (OS). An operating system running in kernel space can also be referred to as a guest operating system.

The running space corresponding to EL2 is the super management space. The super management space is used to run the hypervisor. The hypervisor can also be called a virtual machine monitor. The hypervisor is an intermediate layer of software that runs between physical hardware and the operating system, allowing multiple operating systems and applications to share a single set of physical hardware.

From a system security perspective, the main function of the hypervisor is memory management and interrupt interception. In these two ways, the hypervisor can well monitor the operation of the operating system in kernel space.

The hypervisor can implement memory management through the MMU 312's two-stage (stage 2) memory mapping function. The MMU 312 can implement storage management through techniques such as a shadow page table or an EPT page table.

As shown in FIG. 4, after the MMU 312 receives the VA sent from the user program space or the kernel space, in stage 1 (stage-1), the address can be sent by the user program in the kernel space or the user program in the user program space. Map to intermediate physical address; in stage 2 (stage-2), IPA can be mapped to the address of the memory chip.

The address sent by the user program in the kernel space or the user program space in the user program space may be referred to as a virtual address, or the address visible to the operating system or the user program is VA; the real address of the memory chip is called a physical address; VA The address used in the process of mapping to the PA can be referred to as IPA.

It should be noted that the stage-2 memory map function is only valid for operating systems running in kernel space and user programs in user program space. That is to say, the stage-2 memory mapping function is required only when the operating system running in kernel space and the user program in the user program space access memory.

The implementation of the two-stage memory mapping feature of the MMU 312 described above is only an example. For the implementation of the two-stage memory mapping function of the MMU 312, reference may be made to the prior art, and details are not described herein again.

Memory has access rights properties. For the description, the access permission attribute of the memory is simply referred to as the attribute of the memory in the embodiment of the present application.

Memory attributes can include read-only, writable, inaccessible, and executable. The memory attribute is read-only, which means that only the content in the memory can be read, and the content in the memory cannot be modified; if the attribute of the memory is writable, the content in the memory can be read, or can be modified. The contents of this memory.

After receiving the address sent by the user program in the kernel space or the user program space in the user program space, the MMU 312 can access the content in the memory corresponding to the address according to the attribute of the memory corresponding to the address.

For example, if the operating system in the kernel space or the user program in the user program space requests the MMU 312 to write data to the memory corresponding to an address, and the attribute of the memory corresponding to the address is writable, the MMU 312 will After the address is mapped to the physical address of the memory, the physical address is sent to the address bus for data to be written to.

For example, if the operating system in the kernel space or the user program in the user program space requests the MMU 312 to write data to the memory corresponding to an address, but the attribute of the memory corresponding to the address is read-only, the MMU 312 rejects the request. An example of the MMU 312 rejecting the request is to make an exception prompt.

In the data protection device 300, an operating system running in kernel space can invoke a hypervisor through a hypervisor call (HVC) instruction.

The security monitor space corresponding to the EL4 is used to run the security monitoring module of the processor.

It should be understood that the division of the running space in the processor shown in FIG. 4 is only an example, and more or less running space may be divided in the processor, which is not limited in this application.

The data protection method proposed by the present application mainly includes: when the program code running in the running space of the low abnormal level requests to modify the attribute of the memory, the program code running in the running space of the high abnormal level captures the request, and determines whether the memory is subjected to the request. Protected memory; if the memory is the protected memory, the program code running in the high exception level runtime rejects this modification.

A schematic flowchart of a data protection method of an embodiment of the present application is shown in FIG. 5. This data protection method can be performed by the data protection device 300. The data protection method shown in FIG. 5 includes S510, S520, S530, S540, and S550.

It should be understood that FIG. 5 shows the steps or operations of the data protection method, but these steps or operations are merely examples, and other embodiments of the present application may also perform other operations or variations of the operations in FIG. 5. Moreover, the various steps in FIG. 5 may be performed in a different order than that presented in FIG. 5, and it is possible that not all operations in FIG. 5 are to be performed.

S510. The processing module running in the first running space sends a first message to the MMU, where the first message is used to request to modify the attribute of the first memory. Accordingly, the MMU receives the message.

For convenience of description, the processing module running in the first running space may be referred to as a first processing module. The first memory refers to the memory of the first message requesting modification of the attribute.

The first run space may be the user program space or kernel space shown in FIG. When the first running space is a user program space, the first processing module may be a user program; when the first running space is a kernel space, the first processing module may be an operating system.

The first message may include a VA of the first memory and a target attribute of the first memory. That is, the first message is used to request the MMU to modify the attribute of the first memory to the target attribute. The target attribute of the first memory may include at least one of read-only, writable, executable, and inaccessible.

An example of requesting to modify the target attribute of the first memory to be writable is an instance of set_memory_RW; an instance of the first message requesting modification of the target attribute of the first memory to read-only is set_memory_RO.

S520, the MMU sends a second message to the processing module running in the second running space, where the second message is used to request the processing module to determine whether the first memory is protected, and the abnormality level of the second running space is higher than the first running space. The level of exception. Correspondingly, the processing module running in the second runtime space receives the second message.

For convenience of description, the processing module running in the second running space may be referred to as a second processing module or a kernel critical data protection module. The second processing module or the kernel critical data protection module may be a processing module in the hypervisor.

The second run space may be the super management space shown in FIG.

Optionally, the second message is also understood to be used to request the second processing module to determine whether the attribute of the first memory can be modified, or can be understood to be used to request the second processing module to determine whether the data in the first memory is protected. of.

The address of the first memory may be included in the second message. For example, the VA of the first memory may be included in the second message.

Optionally, the information included in the second message may be the same as the information included in the first message.

S530. The processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table, where the memory protection table is used to record the protected memory and/or the unprotected memory.

Protected memory can be understood as storing protected data. The protected data may include at least one of the following: constant data of the operating system or data generated by the operating system during operation that needs to be protected. The constant data of the operating system may include at least one of the following: constant data that appears during the compilation phase of the operating system and constant data that appears during the initialization phase of the operating system.

From another perspective, the interpretation of the protected memory may include that the attributes of the memory may not be modified from write-only, inaccessible, executable to writable; the interpretation of the unprotected memory may include: The properties of this memory can be modified from any property to any other property.

One way in which the memory protection table records protected memory and/or unprotected memory may include: recording the address of the protected memory and/or the address of the unprotected memory in the memory protection table.

For example, the memory protection table can record the VA address of the protected memory and/or the VA address of the unprotected memory.

In one possible implementation, only the protected memory can be recorded in the memory protection table. In this implementation manner, the processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table, and may include: if the protected memory recorded in the memory protection table is included The first memory, the processing module running in the second running space determines that the first memory is protected; if the protected memory recorded in the memory protection does not include the first memory, the processing module running in the second running space Make sure the first memory is unprotected.

In one possible implementation, only unprotected memory can be recorded in the memory protection table. According to the implementation manner, the processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table, and may include: if the unprotected memory recorded in the memory protection table is not Including the first memory, the processing module running in the second running space determines that the first memory is protected; if the unprotected memory recorded in the memory protection includes the first memory, the processing running in the second running space The module determines that the first memory is unprotected.

In a possible implementation, the memory protection table can record both protected memory and unprotected memory. In this implementation manner, the processing module running in the second running space determines whether the first memory is protected according to the pre-acquired memory protection table, and may include: if the protected memory recorded in the memory protection table includes the first a memory, the processing module running in the second running space determines that the first memory is protected; if the unprotected memory recorded in the memory protection table includes the first memory, the processing module running in the second running space Make sure the first memory is unprotected.

S540: The processing module running in the second running space sends a third message to the MMU, where the third message is used to indicate whether the MMU modifies the attribute of the first memory. Accordingly, the MMU receives the third message.

For example, in S530, if the second processing module determines that the first memory is unprotected, the third message is used to instruct the MMU to modify the attribute of the first memory; if the second processing module determines that the first memory is protected, The third message is used to indicate that the MMU does not modify the attributes of the first memory.

S550, if the third message is used to instruct the MMU to modify the attribute of the first memory, the MMU modifies the attribute of the first memory according to the first message; if the third message is used to indicate that the MMU does not modify the attribute of the first memory, the MMU refuses to modify The first memory attribute.

For example, if the third message is used to instruct the MMU to modify the attribute of the first memory, and the first message includes the address of the first memory and the target attribute of the first memory, the MMU modifies the attribute of the first memory to the target attribute.

For example, if the third message is used to indicate that the MMU does not modify the attributes of the first memory, the MMU may return an abnormal operation prompt to the first processing module.

In the data protection method shown in FIG. 5, since the processing module running in the running space of the low abnormal level cannot modify the code logic and function in the running space of the special level, the processing module in the running space of the low abnormal level When the permissions are acquired by malicious programs or external devices, important data that needs to be protected can still be protected, thereby improving data security.

For example, even if the operating system administrator rights and accounts are acquired by malicious programs, important data in the operating system can be protected, thereby improving the security of data in the operating system.

In another embodiment of the present application, a schematic flowchart of a method for assisting in protecting data is shown in FIG. 6. The method shown in FIG. 6 may include S610 and S620. The method can be performed by data protection device 300.

It should be understood that FIG. 6 illustrates the steps or operations of the method, but these steps or operations are merely examples, and other embodiments of the present application may also perform other operations or variations of the various operations in FIG. 6. Moreover, the various steps in FIG. 6 may be performed in a different order than that presented in FIG. 6, and it is possible that not all operations in FIG. 6 are to be performed.

S610. The processing module running in the third running space sends a fourth message to the processing module running in the second running space, where the fourth message is used to indicate whether the second memory should be protected. Correspondingly, the processing module in the second runtime receives the fourth message.

The third running space may be the user program space or the kernel space shown in FIG. 4. The second run space may be the super management space shown in FIG.

Optionally, the third running space and the first running space may be the same running space. The processing module running in the second running space may be a second processing module or a kernel critical data protection module.

The fourth message may also be understood to indicate that the data stored in the second memory should be protected, or may be understood to indicate that the attribute of the second memory cannot be modified from any of read-only, executable, and inaccessible to Writable, or, can be understood as indicating that the data stored in the second memory should not be modified.

Data that should be protected or should not be modified may include at least one of the following: constant data stored by the operating system in memory during the compilation phase, constant data stored in memory during the initialization phase of the operating system, operating system or user program at Data that is stored in memory during the run phase and cannot be modified.

The address of the second memory may be included in the fourth message. For example, the VA of the second memory may be included in the fourth message.

In a possible implementation, the sending, by the processing module running in the third running space, the fourth message to the processing module running in the second running space may include: the processing module running in the third running space is called in the second running space. The processing module is executed, and when invoked, the fourth message is delivered to the processing module running in the second running space through the interface.

For example, an operating system running in kernel space can invoke a hypervisor running in a hypervisor space through an HVC instruction, so that the hypervisor generates a memory protection table based on the fourth message.

S620. The processing module running in the second running space obtains a memory protection table according to the fourth message, where the memory protection table is used to record the protected and/or unprotected memory. The abnormality level of the second running space is higher than the abnormal level of the third running space.

For example, when the memory protection table is only used to record the protected memory, if the fourth message is used to indicate that the second memory should be protected, the processing module running in the second running space can record the second memory into the memory protection table. If the fourth message is used to indicate that the second memory should not be protected, the processing module running in the second running space does not record the second memory into the memory protection table.

For example, when the memory protection table is only used to record unprotected memory, if the fourth message is used to indicate that the second memory should not be protected, the processing module running in the second running space can record the second memory to the memory protection. In the table, if the fourth message is used to indicate that the second memory should be protected, the processing module running in the second running space does not record the second memory into the memory protection table.

For example, when the memory protection table is used to record both the protected memory and the unprotected memory, if the fourth message is used to indicate that the second memory should be protected, the processing module running in the second running space may Recording the second memory into the memory protection table and identifying the second memory as protected memory; if the fourth message is used to indicate that the second memory should not be protected, the processing module running in the second running space may be The second memory is logged to the memory protection table and identifies the second memory as unprotected memory.

An example of the embodiment of the present application includes: the operating system writes constant data into the memory during the compiling phase, and after identifying the attribute of the memory as read-only, the hypervisor is called by the HVC instruction, and the memory is recorded as the protected memory.

Another example of the embodiment of the present application includes: the operating system writes constant data into the memory during the initialization phase, and after identifying the attribute of the memory as read-only, calls the hypervisor through HVC therapy, and records the memory as protected memory. .

In another example of the embodiment of the present application, the operating system writes data into the memory during the running phase, and after identifying the attribute of the memory as read-only, the hypervisor is invoked by the HVC treatment, and the memory is recorded as the protected memory.

In one embodiment of the present application, the memory protection table used in S530 can be obtained by the method shown in FIG. 6. In other words, the memory protection table used in S530 can be the memory protection table obtained in S620.

When the memory protection table used in the S530 is the memory protection table obtained in the S620, the second memory and the first memory may be the same memory; the third running space and the first running space may be the same running space, or may be different. Running space.

When the third running space and the first running space are the same running space, the processing module running in the third running space and the first processing module may be the same processing module. For example, the first running space and the third running space are both kernel spaces, and the processing module and the first processing module running in the third running space are both operating systems.

For example, after the operating system writes constant data in the compile phase or writes the constant data in the initialization phase or writes the data to the first memory in the running phase, and identifies the attribute of the first memory as read-only, the hypervisor can be called by the HVC instruction. The first memory is recorded as protected memory in the memory protection table. In this way, when the operating system sends a first message to the MMU requesting to modify the attribute of the first memory, the MMU may send a second message to the hypervisor requesting the hypervisor to determine whether the first memory is protected. Since the first memory is protected memory in the memory protection table, the hypervisor indicates that the MMU cannot modify the attributes of the first memory.

An example of the running space that is not the same as the first running space is that the first running space is a user program space, the third running space is a kernel space, the first processing module is an operating system, and the third running space is in a third running space. The processing module is a user program.

In another embodiment of the present application, a schematic flowchart of a method for assisting in protecting data is shown in FIG. 7. The method shown in FIG. 7 may include S710 and S720. The method can be performed by data protection device 300.

It should be understood that FIG. 7 illustrates the steps or operations of the method, but these steps or operations are merely examples, and other embodiments of the present application may also perform other operations or variations of the various operations in FIG. Moreover, the various steps in FIG. 7 may be performed in a different order than that presented in FIG. 7, and it is possible that not all operations in FIG. 7 are to be performed.

S710. The processing module running in the second running space determines that the third memory is used to store the protected data and/or the fourth memory is used to store the unprotected data.

Or it can be said that the processing module running in the second run space determines which memory is used to store the protected data and/or which memory is used to store the unprotected data. The memory used to store protected data is the third memory, and the memory used to store unprotected data is the fourth memory.

The second run space may be the super management space shown in FIG.

The protected data may include at least one of the following: constant data stored in the operating system during the compilation phase, constant data stored in the operating system during the initialization phase, and the operating system or user program being stored in the memory during the run phase. Data that cannot be modified.

Optionally, the third memory and/or the fourth memory may be determined by the processing module running in the second running space according to the pre-configured information, wherein the third memory is recorded in the pre-configured information for storing the protected data and / or fourth memory is used to store unprotected data.

Or it can be said that the pre-configured information records which memory is used to store protected data, and/or records which memory is used to store unprotected data.

For example, in the data protection device 300, a memory for storing constant data of an operating system may be allocated in advance to an operating system in the kernel space. Since the constant data of the operating system is data that needs to be protected, the memory can be pre-configured as the information of the third memory. In this way, the processing module running in the second running space can determine, according to the pre-configured information, that the third memory is used to store the protected data.

For example, the VA of the memory allocated for the constant data of the operating system can be recorded in the pre-configured information. In this way, the processing module running in the second running space can determine, according to the pre-configured information, that the memory corresponding to the VA is used to store the protected data, that is, the memory is the third memory.

S720. The processing module running in the second running space generates a memory protection table, where the third memory is protected memory and/or the fourth memory is unprotected memory.

For example, after the processing module running in the second running space determines that the third memory is the memory for storing the protected data, the third memory is recorded into the memory protection table, and the third memory is identified as the protected memory.

For example, after the processing module running in the second running space determines that the fourth memory is the memory for storing the unprotected data, the fourth memory is recorded into the memory protection table, and the fourth memory is identified as unprotected memory. .

In one embodiment of the present application, the memory protection table used in S530 can be obtained by the method shown in FIG. In other words, the memory protection table used in S530 can be the memory protection table obtained in S720.

When the memory protection table used in the S530 is the memory protection table obtained in the S720, the third memory and the first memory may be the same memory, or the fourth memory and the first memory may be the same memory.

For example, after the operating system writes the constant data to the third memory allocated for the constant data in the compile phase, and the operating system identifies the attribute of the third memory as read-only, the hypervisor can record the third memory in the memory protection table. Protected memory. In this way, when the operating system sends a first message to the MMU requesting to modify the attributes of the third memory, the MMU may send a second message to the hypervisor requesting the hypervisor to determine whether the third memory is protected. Since the third memory is protected memory in the memory protection table, the hypervisor indicates that the MMU cannot modify the attributes of the third memory.

A schematic flowchart of a data protection method of an embodiment of the present application is shown in FIG. 8. The data protection method includes S810 and S820.

It should be understood that FIG. 8 illustrates the steps or operations of the data protection method, but these steps or operations are merely examples, and other embodiments of the present application may also perform other operations or variations of the operations in FIG. Moreover, the various steps in FIG. 8 may be performed in a different order than that presented in FIG. 8, and it is possible that not all operations in FIG. 8 are to be performed.

S810. The processing module in the fourth running space sends a fifth message to the processing module in the second running space, where the fifth message is used to request that the first data is written into the fifth memory, where the abnormality level of the second running space is high. The level of exception in the fourth run space.

The fourth run space may be the user program space or kernel space shown in FIG. 4, and the second run space may be the super management space shown in FIG.

The address of the first data and the fifth memory may be carried in the fifth message. For example, the VA of the first data and the fifth memory may be carried in the fifth message.

The first data may include at least one of the following: constant data of the operating system at the compile stage, and constant data of the operating system during the initialization phase.

The fifth memory is a memory for storing the first data.

S820. The processing module running in the second running space writes the first data into the fifth memory according to the fifth message.

In this embodiment, the processing module in the fourth running space needs to modify the data in the memory through the processing module in the second running space that is higher than the abnormal level, that is, the processing module in the fourth running space. You can't directly modify the data in memory, so this method can improve the security of the data.

In addition, the method in the embodiment of the present application can modify the data in the memory as compared with the method in FIG. 5, and thus the flexibility is higher.

In the embodiment of the present application, optionally, the processing module running in the second running space may write the first data to the fifth according to the request of the fifth message if the fifth message is sent by a predetermined module. Memory to further improve the security of the data, thereby improving the security of the operating system.

For example, the hypervisor writes the first data to the fifth memory only if the operating system's patch calls the hypervisor via the HVC instruction.

That is, in an implementation manner of the embodiment of the present application, the S820 may specifically include: when the fifth message is sent by the pre-specified processing module to the processing module running in the second running space, in the second running space The running processing module writes the first data into the fifth memory according to the request of the fifth message.

In another embodiment of the present application, the data protection method shown in FIG. 8 can be used in combination with the method shown in at least one of FIGS. 5 to 7.

For example, the data protection device 300 can generate a memory protection table by the method of FIG. 6 and/or FIG. 7, and then can determine whether the memory is protected by the method shown in FIG. 5, and can pass the data protection method shown in FIG. To modify the data.

If the data protection method shown in FIG. 5 is used in combination with the data protection method described in FIG. 6, the fourth running space and the first running space may be the same running space.

For example, the fourth running space and the first running space may both be kernel space, the processing module in the first running space may be an operating system, and the processing module in the fourth running space may be a patch of an operating system.

FIG. 9 is a schematic structural diagram of a data protection device according to an embodiment of the present application. It should be understood that the data protection device 900 shown in FIG. 9 is only an example, and the data protection device of the embodiment of the present application may further include other modules or units, or include modules similar to those of the modules in FIG. 9, or Includes all the modules in Figure 9.

The data protection device 900 includes a processor execution unit 910 and a memory management unit 920. The operating space divided by the processor execution unit 910 includes a first running space 911 and a second running space 912, and the abnormality level of the second running space is higher than the first An exception level of the running space, the first running space is for running the first processing module, and the second running control is for running the second processing module.

The data protection device 900 can be used to perform the steps performed by the data protection device in the data protection method shown in any of Figures 4-8.

For example, the first processing module is configured to send a first message to the memory management unit 920, the first message being used to request to modify an attribute of the first memory.

The memory management unit 920 is configured to send a second message to the second processing module, where the second message is used to request to determine whether the first memory is protected.

The second processing module is configured to determine, according to the pre-acquired memory protection table, whether the first memory is protected.

The second processing module sends a third message to the memory management unit 920, where the third message is used to indicate whether to modify the attribute of the first memory.

The memory management unit is configured to: when the third message is used to indicate that the attribute of the first memory is modified, modify an attribute of the first memory according to the first message; and use the third message in the third message Instructing not to modify the attribute of the first memory, and refusing to modify the attribute of the first memory.

Optionally, the first processing module is configured to send a fourth message to the second processing module in the second running space, where the fourth message is used to indicate whether the first memory is protected.

The second processing module is specifically configured to generate, according to the fourth message, the memory protection table, where the memory protection table is used to record protected memory and/or unprotected memory, where the protected memory includes A memory for storing protected data, including memory for storing unprotected data.

Optionally, the second processing module is specifically configured to: determine that the first memory is used to store protected data or determine that the first memory is used to store unprotected data; and generate the memory protection table, The memory protection table is configured to record the first memory as protected memory or to record the first memory as unprotected memory, where the protected memory includes memory for storing protected data. The unprotected memory includes memory for storing unprotected data.

Optionally, the first running space is a kernel space, and the first processing module is an operating system; wherein the protected data includes: constant data written by the operating system into a memory during a compiling phase, The constant data that the operating system writes to memory during the initialization phase.

Optionally, the data protection device 900 may further include a memory for storing program codes and data executed by the processor execution unit 910.

Alternatively, the data protection device 900 can be a cell phone, a tablet, a server, a personal computer, a network router, or a switch.

Those of ordinary skill in the art will appreciate that the elements and algorithm steps of the various examples described in connection with the embodiments disclosed herein can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the solution. A person skilled in the art can use different methods to implement the described functions for each particular application, but such implementation should not be considered to be beyond the scope of the present application.

A person skilled in the art can clearly understand that for the convenience and brevity of the description, the specific working process of the device and the unit described above can refer to the corresponding process in the foregoing method embodiment, and details are not described herein again.

In the several embodiments provided herein, it should be understood that the disclosed apparatus and method can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the unit is only a logical function division. In actual implementation, there may be another division manner, for example, multiple units or components may be combined or Can be integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection through some interface, device or unit, and may be in an electrical, mechanical or other form.

The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed to multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

The functions may be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a standalone product. Based on such understanding, the technical solution of the present application, which is essential or contributes to the prior art, or a part of the technical solution, may be embodied in the form of a software product, which is stored in a storage medium, including The instructions are used to cause a computer device (which may be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory, a magnetic disk, or an optical disk, and the like, which can store program codes.

The foregoing is only a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto, and any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application. It should be covered by the scope of protection of this application. Therefore, the scope of protection of the present application should be determined by the scope of the claims.

Claims

A data protection method, wherein the data protection method is performed by a data protection device, where the data protection device includes a processor execution unit and a memory management unit, and the operating space of the processor execution unit partition includes the first a running space and a second running space, wherein an abnormal level of the second running space is higher than an abnormal level of the first running space;

The data protection method includes:

The first processing module running in the first running space sends a first message to the memory management unit, where the first message is used to request to modify an attribute of the first memory;

The memory management unit sends a second message to the second processing module running in the second running space, where the second message is used to request to determine whether the first memory is protected;

The second processing module running in the second running space determines whether the first memory is protected according to a pre-acquired memory protection table;

The second processing module of the second running space sends a third message to the memory management unit, where the third message is used to indicate whether to modify an attribute of the first memory;

If the third message is used to indicate that the attribute of the first memory is modified, the memory management unit modifies an attribute of the first memory according to the first message; if the third message is used to indicate that the attribute is not modified And the attribute of the first memory, the memory management unit refuses to modify the attribute of the first memory.
The data protection method according to claim 1, wherein the second processing module running in the second running space determines whether the first memory is protected before according to a memory protection table acquired in advance. The data protection method further includes:

The first processing module in the first running space sends a fourth message to the second processing module in the second running space, where the fourth message is used to indicate whether the first memory is received protected;

The second processing module in the second running space generates the memory protection table according to the fourth message, where the memory protection table is used to record protected memory and/or unprotected memory, Protected memory includes memory for storing protected data, including memory for storing unprotected data.
The data protection method according to claim 1, wherein the second processing module running in the second running space determines whether the first memory is protected before according to a memory protection table acquired in advance. The data protection method further includes:

The second processing module running in the second running space determines that the first memory is used to store protected data or the first memory is used to store unprotected data;

The second processing module running in the second running space generates the memory protection table, where the memory protection table is configured to record the first memory as a protected memory or to record the first memory as Unprotected memory, the protected memory includes memory for storing protected data, and the unprotected memory includes memory for storing unprotected data.
The data protection method according to claim 2 or 3, wherein the first running space is a kernel space, the first processing module is an operating system, and the second running space is a super management space;

The protected data includes: constant data written by the operating system to the memory during the compiling phase, and the operating system writes constant data of the memory during the initialization phase.
The data protection method according to any one of claims 1 to 4, wherein the data protection device is a mobile phone, a tablet, a server, a personal computer, a network router or a switch.
A data protection device, comprising: a processor execution unit and a memory management unit, wherein the operating space divided by the processor execution unit comprises a first running space and a second running space, and the second running space is abnormal The level is higher than the abnormal level of the first running space, the first running space is used to run the first processing module, and the second running space is used to run the second processing module;

The first processing module is configured to send a first message to the memory management unit, where the first message is used to request to modify an attribute of the first memory;

The memory management unit is configured to send a second message to the second processing module, where the second message is used to request to determine whether the first memory is protected;

The second processing module is configured to determine, according to the pre-acquired memory protection table, whether the first memory is protected;

The second processing module is further configured to send a third message to the memory management unit, where the third message is used to indicate whether to modify an attribute of the first memory;

The memory management unit is further configured to: when the third message is used to indicate that the attribute of the first memory is modified, modify an attribute of the first memory according to the first message, where the third message is used to indicate that The modification of the attribute of the first memory refuses to modify the attribute of the first memory.
The data protection device according to claim 6, wherein the first processing module is further configured to send a fourth message to the second processing module in the second running space, where the fourth message is used Instructing whether the first memory is protected;

And the second processing module is configured to: before the first memory is protected according to the pre-acquired memory protection table, and configured to: generate the memory protection table according to the fourth message, where the memory protection table is used Recording protected memory and/or unprotected memory, the protected memory including memory for storing protected data, the memory for storing unprotected data .
The data protection device according to claim 6, wherein the second processing module determines whether the first memory is protected according to a pre-acquired memory protection table, and is further configured to:

Determining that the first memory is for storing protected data or determining that the first memory is for storing unprotected data;

Generating the memory protection table, where the memory protection table is configured to record the first memory as protected memory or to record the first memory as unprotected memory, where the protected memory is included A memory that stores protected data, including memory for storing unprotected data.
The data protection device according to claim 7 or 8, wherein the first running space is a kernel space, and the first processing module is an operating system;

The protected data includes: constant data written by the operating system to the memory during the compiling phase, and the operating system writes constant data of the memory during the initialization phase.
The data protection device according to any one of claims 6 to 9, wherein the data protection device is a mobile phone, a tablet, a server, a personal computer, a network router or a switch.
A computer storage medium, wherein the computer readable storage medium stores program code for execution by a data protection device, the program code comprising data for performing the method of any one of claims 1 to 5. The instruction to protect the method.
A chip, characterized in that the chip comprises a processor for performing the data protection method according to any one of claims 1 to 5.
A computer program product, wherein the computer program product, when run on a data protection device, causes the data protection device to perform the data protection method of any one of claims 1 to 5.