KR102338774B1 - Data protection method to prevent data leakage and corruption by preventing file contents from being read and written at the kernel level of the storage operating system - Google Patents

Abstract

The present invention relates to a data protection method capable of fundamentally preventing a file stored in a storage device from being viewed, leaked, or damaged. The data protection method includes a process of receiving a sealing request that blocks reading and writing of a first file among files stored in a storage device through a user's command, the user has file access rights to the first file, and the first file If this is not the sealed state, the process of receiving the seal password, the process of sending a seal command for the first file including the seal password through the POSIX API to the kernel of the operating system that provides the file system service to the storage device, the kernel The process of additionally creating a sealing flag indicating the sealing state in the metadata of the first file, a sealing password attribute, and setting the sealing flag to the sealed state in the kernel to block reading or writing to the first file. It includes the process of creating, encrypting and storing the sealed password transmitted to the sealed password attribute. According to the present invention, it is possible to fundamentally prevent the reading, leakage, and damage of file contents at the storage level without the installation and management of additional complicated software.

Description

Data protection method to prevent data leakage and corruption by preventing file contents from being read and written at the kernel level of the storage operating system}

The present invention provides a sealing function that can restrict reading and writing of specific file contents in an operating system that provides a file system service, thereby fundamentally preventing unauthorized reading, leakage, or damage to the contents of a sealed file. It is about data protection methods.

File security can be broadly divided into file corruption prevention and file content leakage prevention. In general, file corruption prevention is achieved through WORM (Write Once Read Many) storage technology that blocks unauthorized deletion and falsification of files through permission management at the kernel level. WORM storage technology generally controls the administrator's authority through a module hard-coded in the kernel so that the file cannot be modified or deleted with any authority during the retention period specified for the file.

The function to prevent the reading and leakage of file contents is to control the access rights for each user through ACL (Access Control List), which is an access right control function provided by the file system, or DLP (Data Loss Protection) which provides more extensive functions. ) or through file encryption.

However, for DLP (Data Leakage Protection) or file encryption, it is necessary to install and manage separate and complex software. In addition, leakage and damage through administrator rights cannot be prevented at the source even by methods such as ACLs and DLPs, and there is no function to block access to file contents with any authority at the storage level.

Therefore, it is possible to prevent leakage and damage through the administrator's authority, and there is a need for a technology that can fundamentally prevent the reading, leakage, and damage of file contents without individual file encryption or a complex key management system.

Accordingly, it is an object of the present invention to provide a sealing function that can restrict the reading and writing of specific file contents in an operating system that provides a file system service, thereby fundamentally preventing unauthorized viewing, leakage, and damage to the contents of a file To provide a data protection method that can be prevented.

The data protection method according to the present invention for achieving the above object includes the steps of receiving a sealing request for blocking reading and writing of a first file among files stored in a storage device through a command of a user, wherein the user receives the first file If the first file is not sealed, receiving an input of a sealing password, and sending a sealing command for the first file including the sealing password through the POSIX API to the storage device. Transmitting the system service to a kernel of an operating system providing a system service, the kernel further generating a sealing flag indicating a sealing state in the metadata of the first file and a sealing password attribute, and generating the sealing flag in the kernel and setting the sealed state to a sealed state that blocks reading or writing of the first file, and encrypting and storing the sealed password transmitted to the sealed password attribute.

When there is a read or write command for the first file, the kernel checks the seal flag of the first file, and if it is in a sealed state, an error message may be returned and execution of the read or write command may be blocked.

In addition, when there is a request to seal a specific file, checking the sealing status by obtaining the sealing flag setting value of the specific file from the kernel through the POSIX API, and if the specific file is in a sealed state, an error message It may further include the step of displaying.

In addition, receiving a request to release the seal of the second file through a user's command, if the user has file access rights to the second file and the second file is in a sealed state, receiving a seal release password Step, transmitting a seal release command for the second file including the seal release password to the kernel through a POSIX API, the seal in which the seal release password received from the kernel is stored in the seal password attribute of the second file The method may further include the step of setting a seal flag of the second file to an unsealed state to change to a state allowing reading or writing of the second file when the password matches.

In addition, the data storage system according to the present invention for achieving the above object includes a storage device, a memory, a control unit, and one or more modules stored in the memory and executed by the control unit, wherein the module includes a user's command A process of receiving a sealing request for blocking reading and writing of the first file among the files stored in the storage device through , receiving a sealing password, and transmitting a sealing command for the first file including the sealing password through a POSIX API to a kernel of an operating system that provides a file system service to the storage device, the A sealing state in which the kernel additionally generates a sealing flag indicating a sealing state in the metadata of the first file and a sealing password attribute, and sets the sealing flag to the sealed state to disallow reading or writing of the first file and the process of encrypting and storing the sealed password transmitted to the sealed password attribute can be performed.

And, in order to achieve the above object, the present invention provides a processor-readable recording medium in which a program for executing the data protection method in the processor is recorded.

According to the present invention, a file sealing function is provided in a storage operating system that provides a file system service, so that file contents can be read and leaked completely at the storage level without the installation and management of separate complex software such as DLP (Data Leakage Protection) or encryption. and damage can be fundamentally prevented. Thereby, it is possible to prevent illegally reading or leaking the contents of a file directly from the storage device through the administrator's authority, which cannot be prevented by the existing DLP solution. In addition, it is possible to provide a function of protecting the contents of a file from malicious software or malicious tampering by preventing not only viewing the file but also modifying the contents of the file.

1 is a view showing an example of a data storage system to which a data protection method according to the present invention is applied;
2 and 3 are flowcharts provided for explaining a file sealing process in a data protection method according to an embodiment of the present invention;
4 is a flowchart provided for explaining an operation process in a kernel of an operating system in a data protection method according to an embodiment of the present invention; and
5 and 6 are flowcharts provided to explain a file seal release process in a data protection method according to an embodiment of the present invention.

In this specification, when a component is referred to as being “connected” or “connected” to another component, the component may be directly connected or connected to another component, but another component in the middle. It should be understood that elements may exist. In addition, other expressions describing the relationship between elements, such as "between" or "neighboring to", and expressions such as that one element "transmits" a signal to another element, should be interpreted similarly. do.

Hereinafter, the present invention will be described in more detail with reference to the drawings.

1 shows an example of a data storage system to which a data protection method according to the present invention is applied.

Referring to FIG. 1 , the data storage system 100 may include a communication unit 110 , a memory 120 , a storage interface unit 130 , a storage device 140 , and a control unit 150 . When these components are implemented in actual applications, two or more components may be combined into one component, or one component may be subdivided into two or more components as needed.

The communication unit 110 enables data transmission and reception with the client device 200 or other devices through a network. Through the client device 200 or other external device, the user may store a file in the storage device 140 or read or modify the stored file.

The memory 120 may store program codes for processing and control of the controller 150 , and may perform a function of temporarily storing input or output data. A storage operating system 125 that provides a file system service that logically configures directories and files as a hierarchical structure in the storage device 140 may be installed in the memory 120 .

The storage interface unit 130 functions as an interface for data transmission/reception with the storage device 140 .

The storage device 140 is a device that stores data in an electromagnetic form so that the controller 150 or other computer processors can access it, and may be configured as a hard disk or a solid state disk (SSD).

The control unit 150 controls the overall operation of the data storage system 100 by generally controlling the operation of the respective units. For example, the controller 150 manages one or more volumes including an array of disks in the storage device 140 , and transmits data to the storage device 140 according to a request from the client device 200 or other external device. You can perform operations such as recording, editing, or adding or deleting.

In such a data storage system, a user having administrator authority has authority to change or delete any data stored in the storage device 140 . However, there may be cases where an administrator who is normally granted administrator rights damages data by mistake or intentionally, or an intruder who has illegally obtained administrator rights destroys data.

In order to prevent this, a write once read many (WORM) function can be added. The data storage system in which the WORM function is implemented has a structure that does not allow tampering or deletion of data no matter what path the administrator authority is obtained.

In addition, in the present invention, it is possible to set a seal that can restrict read and write of a specific file, and for the sealed file, a function to block the contents of the file from being read or modified by any authority is built into the kernel. implement At this time, the software that provides these functions is implemented as a fixed code in the storage operating system 125 or implemented as firmware to fundamentally block the method of changing it from the outside, so that the data can be read without any authority until the seal is released, Forgery can be prevented.

2 and 3 are flowcharts provided to explain a file sealing process in a data protection method according to an embodiment of the present invention.

Referring to FIG. 2 , when there is a file sealing request that blocks reading and writing of a first file selected from among files stored in the storage device 140 according to a user's command ( S300 ), the controller 150 controls the user's selected file ( S300 ). It is checked whether the first file has file access authority (S305).

As a result of the inspection in step S305, if the user has the file access right to the first file, the sealing state of the first file is checked (S315).

The confirmation of the sealing state can be confirmed by fetching sealing-flag, which is a sealing flag indicating the sealing state of the first file, from the kernel of the operating system through the POSIX API. The command to get the seal flag can be expressed in the following format.

getxattr file-path sealing-flag

In addition, POSIX is an abbreviation of Portable Operating System Interface, which is a standard that prescribes common rules of operating systems, and provides API standards for applications to communicate with operating systems. The content of this specification includes not only the system call, which is the C language interface to the kernel, but also various fields such as the process environment, files and directories, system database, and compression format.

When it is confirmed from the sealing flag setting value that the first file is not sealed (S320), the control unit 150 receives a sealing password by a user command or the like (S325).

Next, the control unit 150 transmits a sealing command for the first file including the sealing password to the kernel of the operating system through the POSIX AIP (S330). The seal command can be expressed in the following format.

setxattr file-path sealing sealing password

Upon receiving the sealing command, the kernel creates two file extension attributes, sealing-flag, which is a sealing flag indicating the sealing state, and sealing-password, which is a sealing password attribute, in the metadata of the first file to create additional file extension attributes. Go (S350), set the sealing flag, sealing-flag to 1, to make it sealed, encrypt and store the sealing password transmitted to sealing-password, which is the sealing password attribute, and set the first file to the sealed state (S355). And returns a processing completion message (S360).

Referring to FIG. 3 , if the user does not have file access rights in step S310 , the controller 150 displays that the user does not have file access rights for the first file ( S515 ) and returns an error message ( S345 ).

And, when the first file is already sealed in step S320, the controller 150 displays that the first file is already a sealed file (S340) and returns an error message (S345).

By this process, a sealing state that can block reading and writing of the user-selected file can be set.

4 is a flowchart provided to explain an operation process in a kernel of an operating system in a data protection method according to an embodiment of the present invention.

Referring to FIG. 4 , the kernel of the operating system classifies file-related operations requested from applications, etc. (S400), whether operations related to processing metadata for files, operations related to reading or writing the contents of files, etc. separate the

When the requested file-related operation is a metadata-related operation (S405), when the setting of a sealing-flag, which is a sealing flag, is requested in the metadata (S430), the requested operation is blocked (S445), an error message returns (S450).

That is, the sealing flag, Sealing-flag, is a property that is set while setting the sealing password inside the kernel during the file sealing process.

Except for the operation of setting the sealing flag, the requested operation is performed according to a general procedure for a request for an operation related to other metadata (S435), and when the operation is completed, processing indicating that the requested operation has been successfully processed A completion message is returned (S440).

When the requested file-related operation is an operation related to reading or writing the contents of the file (S410), and the file is sealed because the sealing-flag is set (S415), the requested operation is not performed. Block (S420) and return an error message (S425)

If the requested file-related operation is not a command related to reading or writing the file contents (S410), the requested operation is performed according to the general procedure (S435), and when the operation is completed, the requested operation is successfully performed A process completion message indicating that the process has been completed is returned (S440).

In this way, whenever there is a file-related operation request inside the kernel, it is checked whether the file is sealed. For the sealed file, access to the metadata of the file is allowed, but reading and writing to the file contents are not allowed.

5 and 6 are flowcharts provided to explain a file seal release process in a data protection method according to an embodiment of the present invention.

Referring to FIG. 5 , in response to a user's command or the like, if there is a file seal release request for a second file selected from among the files stored in the storage device 140 ( S500 ), the controller 150 controls the second file selected by the user. It is checked whether there is a file access right (S505).

As a result of the inspection in step S505, if the user has the file access right to the second file, the sealing state of the second file is checked (S515).

The confirmation of the sealing state can be confirmed by fetching sealing-flag, which is a sealing flag indicating the sealing state of the second file, from the kernel through the POSIX API.

When it is confirmed that the second file is sealed from the sealing flag setting value (S520), the control unit 150 receives a seal release password by a user command or the like (S525).

Next, the control unit 150 transmits a seal release command for the second file including the seal release password to the kernel of the operating system through the POSIX API (S530). The seal release command can be expressed in the following format.

setxattr file-path unsealing unsealing password

The kernel, which has received the sealing command, compares the sealing password stored in the sealing-password attribute, which is the sealing-password in the metadata of the second file, with the received sealing release password, and if the two match (S550), the sealing flag The sealing-flag is set to 0 to release the sealing setting for the second file (S560). And returns a processing completion message (S560).

If the sealing password stored in sealing-password, which is the sealing password attribute, and the received sealing release password do not match (S550), the second file is not released and an error message is returned (S565)) .

Referring to FIG. 6 , if the user does not have the file access right in step S510 , the controller 150 displays that there is no file access right for the second file ( S515 ) and returns an error message ( S545 ).

And, if the second file is not in a sealed state in step S520, the controller 150 displays that the second file is an unsealed file (S540), and an error message because a file that is not in a sealed state is not subject to unsealing. returns (S545).

Through this process, the user can block reading and writing of the sealed file by performing the file sealing process for a specific file. By configuring to change the sealing flag only in , it is possible to prevent arbitrary manipulation at the source.

On the other hand, the data protection method according to the present invention can not be applied limitedly to the configuration of the described embodiments as described above, but all or part of each embodiment is selectively applied to the above-described embodiments so that various modifications can be made. It may be configured in combination.

In addition, the present invention can be implemented as a computer program on a programmable computer. Such a computer may include a processor, a storage device, an input device, and an output device. In order to implement the contents described in the present invention, the program code may be input with a mouse or keyboard input device. These programs can be implemented in a high-level language or an object-oriented language. It can also be implemented as a computer system implemented in assembly or machine code.

In addition, the content of the present invention is not limited to the use of hardware or software, and is applicable to any other computing or processing environment. It may be implemented by hardware, software, or a combination of hardware and software described in the present invention. The present invention can be implemented using circuits. That is, it may be implemented as one or more programmable logic circuits, that is, an application specific integrated circuit (ASIC) or logic circuits (AND, OR NAND gates) or a processing device (eg, a microprocessor, a controller).

The present invention can also be implemented as processor-readable codes on a processor-readable recording medium. The processor-readable recording medium includes all types of recording devices in which data readable by the processor is stored. Examples of the processor-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage device. In addition, the processor-readable recording medium is distributed in a computer system connected to a network, so that the processor-readable code can be stored and executed in a distributed manner.

In addition, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the technical field to which the present invention belongs without departing from the gist of the present invention as claimed in the claims Various modifications may be made by those of ordinary skill in the art, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

100: data storage system 110: communication unit
120: memory 130: storage interface unit
140: storage device 150: control unit
200: client device

Claims (10)

receiving a sealing request for blocking reading and writing of a first file among files stored in a storage device through a user's command;
receiving a sealing password when the user has a file access right to the first file and the first file is not in a sealed state;
transmitting a sealing command for the first file including the sealing password through a POSIX API to a kernel of an operating system that provides a file system service to the storage device;
generating, in the kernel, a sealing flag indicating a sealing state and a sealing password attribute in the metadata of the first file; and
Data protection method comprising the steps of setting the sealing flag in the kernel to a sealed state, making it a sealed state that blocks reading and writing of the first file, and encrypting and storing the sealed password transmitted to the sealed password attribute. . According to claim 1,
When there is a read or write command for the first file, the kernel checks the seal flag of the first file, and if it is in a sealed state, returns an error message and blocks execution of the read or write command data protection method. According to claim 1,
when there is a request to seal a specific file, checking a sealing state by obtaining a sealing flag setting value of the specific file from the kernel through the POSIX API; and
If the specific file is in a sealed state, the data protection method further comprising the step of returning an error message. According to claim 1,
wherein the kernel blocks execution of a read or write command on the sealed file, but permits access to metadata of the sealed file. According to claim 1,
The data protection method, characterized in that the kernel blocks execution of a command to change the setting of the sealing flag. The method of claim 1,
receiving a request to release the seal of the second file through a user's command;
receiving a seal release password when the user has a file access right to the second file and the second file is in a sealed state;
transmitting a seal release command for the second file including the seal release password to the kernel through the POSIX API; and
When the seal release password transmitted from the kernel matches the seal password stored in the seal password attribute of the second file, reading or writing the second file by setting the seal flag of the second file to an unsealed state A data protection method further comprising transitioning to a state that allows A processor-readable recording medium recording a program for executing the data protection method of any one of claims 1 to 6 in the processor. storage device;
a communication unit that enables data transmission and reception with other devices;
a memory in which a kernel of an operating system providing a file system service to the storage device is installed; and
When a sealing request for blocking reading and writing of a first file among files stored in the storage device is received through a user's command transmitted from the other device, the user has file access rights to the first file, When the first file is not in a sealed state, a control unit that receives a sealing password and transmits a sealing command for the first file including the sealing password to the kernel through a POSIX API;
In the kernel, a sealing flag indicating a sealing state and a sealing password attribute are additionally generated in the metadata of the first file, and the sealing flag is set to the sealed state to disallow reading or writing of the first file. A data storage system, characterized in that the encrypted password is stored in the state, and the sealed password transmitted to the sealed password attribute is encrypted. 9. The method of claim 8,
The control unit is
When a request to release the seal of the second file is received through a user's command transmitted from the other device, if the user has file access authority to the second file and the second file is in a sealed state, the seal is released receiving a password, and transmitting a seal release command for the second file including the seal release password to the kernel through the POSIX API;
In the kernel, when the received unlock password matches the seal password stored in the seal password attribute of the second file, the second file's seal flag is set to an unsealed state to read or write the second file A data storage system, characterized in that it transitions to a state that allows

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