Patent Grant
12212656
This application relates to the field of computer systems and storage systems therefor and, more particularly, to the field of accessing encrypted data at storage system.
Host processor systems may store and retrieve data using a storage system containing a plurality of host interface units (I/O modules), disk drives, and disk interface units (disk adapters). The host systems access the storage systems through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage system and the storage system provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage system directly, but rather, access what appears to the host systems as a plurality of logical disk units or logical devices. The logical devices may or may not correspond to any one of the actual disk drives. Allowing multiple host systems to access the single storage system allows the host systems to share data stored therein among different host processor systems.
In some instances, it may be desirable to encrypt data at a storage system to prevent unauthorized access to the data. The data may be encrypted using a symmetric encryption key, where the same key is used for both encryption and decryption, or may be encryption using asymmetric encryption, where keys used for encryption and decryption are different. In either case, the goal is to make the data unreadable by anyone that does not have the decryption key. Thus, a malicious actor that gains access to the encrypted data still cannot decrypt the data without the appropriate decryption key. Needless to say, it is important to prevent unauthorized access to the decryption key.
It is also useful to replicate data from one storage system to another to provide failover capability so that if a primary system fails, a corresponding failover system can take over execution of production tasks. Replicating encrypted data presents challenges, however, in connection with replicating data for failover capabilities. In many cases, host systems maintain keys used for accessing encrypted data. However, in the case of a failover, a primary host system may not be available. One way to address this would be to decrypt the data prior to transferring the data from a primary storage system to a failover storage system. However, the decryption process may use significant processing resources of the primary storage system and would require that the data be encrypted again at the failover storage system. Moreover, decrypting the data prior to transmission makes the data vulnerable to the type of unauthorized access that encryption was meant to prevent. Another possibility is to make keys used for decryption generally available to applications in the system. However, this too may make the encrypted data vulnerable to unauthorized access.
Accordingly, it is desirable to be able to provide a mechanism that maintains data in an encrypted state, but allows a failover system to access the encrypted data without jeopardizing security of the data.
According to the system described herein, decrypting data at a first storage system that has been encrypted at a second, separate, storage system includes the first storage system requesting a key that decrypts the data from the second storage system, the second storage system determining if the first storage system is authorized for the key, the second storage system providing the key to the first storage system in response to the first storage system being authorized, a host that is coupled to the first storage system obtaining the key from the first storage system, and the host using the key to decrypt and access the data at the first storage system. The host and the first storage system may provide failover functionality for a system that includes the second storage system. The host may obtain the key from the first storage system in response to a failure of the system that includes the second storage system. Authorization may be determined according to a manual configuration at a time of installation. Authorization may be determined according to heuristic rules. The heuristic rules may include providing authorization storage systems that contain a replica of encrypted data from another storage system. The first and the second storage systems may share registration tables.
According further to the system described herein, non-transitory computer readable media contains software that decrypts data at a first storage system that has been encrypted at a second, separate, storage system. The software includes executable code at the first storage system that requests a key that decrypts the data from the second storage system, executable code at the second storage system that determines if the first storage system is authorized for the key, executable code at the second storage system that provides the key to the first storage system in response to the first storage system being authorized, executable code at a host that is coupled to the first storage system and that obtains the key from the first storage system, and executable code at the host that uses the key to decrypt and access the data at the first storage system. The host and the first storage system may provide failover functionality for a system that includes the second storage system. The host may obtain the key from the first storage system in response to a failure of the system that includes the second storage system. Authorization may be determined according to a manual configuration at a time of installation. Authorization may be determined according to heuristic rules. The heuristic rules may include providing authorization storage systems that contain a replica of encrypted data from another storage system. The first and the second storage systems may share registration tables.
According further to the system described herein, a system that provides failover capability includes a first host coupled to a first storage system to exchange encrypted data therewith, the data being decryptable using a key and a second host coupled to a second storage system. The first and second storage systems are coupled and the second storage system receives the encrypted data from the first storage system. The second storage system and second host provide failover support for the first storage system and first host. The second storage system receives the key from the first storage system prior to a failure and then provides the key to the second host following a failure. The first storage system may determine whether the second storage system is authorized prior to providing the key to the second storage system. Authorization may be determined according to a manual configuration at a time of installation. Authorization may be determined according to heuristic rules. The heuristic rules may include providing authorization storage systems that contain a replica of encrypted data from another storage system. The first and the second storage systems may share registration tables.
Embodiments of the system are described with reference to the several figures of the drawings, noted as follows.
The system described herein provides a mechanism for securely distributing encryption keys so that replicated encrypted data may be accessed at a failover system after the encryption key is no longer accessible at the failed corresponding primary system.
In an embodiment of the system described herein, in various operations and scenarios, data from the source storage system 24 may be copied to the remote storage system 26 via a link 29. For example, transferring data may be part of a data mirroring or replication process that causes data on the remote storage system 26 to be identical to the data on the remote storage system 24. Although only the one link 29 is shown, it is possible to have additional links between the storage systems 24, 26 and to have links between one or both of the storage systems 24, 26 and other storage systems (not shown). The source storage system 24 may include a first plurality of remote adapter units (RA's) 30a, 30b, 30c. The RA's 30a-30c may be coupled to the link 29 and be similar to the HA 28, but are used to transfer data between the storage systems 24, 26.
The source storage system 24 may include one or more physical storage units (including disks, solid state storage devices, etc.), each containing a different portion of data stored on the source storage system 24.
Each of the physical storage units 33a-33c may be coupled to a corresponding disk adapter unit (DA) 35a-35c that provides data to a corresponding one of the physical storage units 33a-33c and receives data from a corresponding one of the physical storage units 33a-33c. An internal data path exists between the DA's 35a-35c, the HA 28 and the RA's 30a-30c of the source storage system 24. Note that, in other embodiments, it is possible for more than one physical storage unit to be serviced by a DA and that it is possible for more than one DA to service a physical storage unit. The source storage system 24 may also include a global memory 37 that may be used to facilitate data transferred between the DA's 35a-35c, the HA 28 and the RA's 30a-30c as well as facilitate other operations. The memory 37 may contain task indicators that indicate tasks to be performed by one or more of the DA's 35a-35c, the HA 28 and/or the RA's 30a-30c, and may contain a cache for data fetched from one or more of the physical storage units 33a-33c.
The storage space in the source storage system 24 that corresponds to the physical storage units 33a-33c may be subdivided into a plurality of volumes or logical devices. The logical devices may or may not correspond to the storage space of the physical storage units 33a-33c. Thus, for example, the physical storage unit 33a may contain a plurality of logical devices or, alternatively, a single logical device could span both of the physical storage units 33a, 33b. Similarly, the storage space for the remote storage system 26 may be subdivided into a plurality of volumes or logical devices, where each of the logical devices may or may not correspond to one or more physical storage units of the remote storage system 26.
In some embodiments, another host 22′ may be provided. The other host 22′ is coupled to the remote storage system 26 and may be used for disaster recovery so that, upon failure at a site containing the host 22 and the source storage system 24, operation may resume at a remote site containing the remote storage system 26 and the other host 22′. In some cases, the host 22 may be directly coupled to the remote storage system 26, thus protecting from failure of the source storage system 24 without necessarily protecting from failure of the host 22.
In some embodiments, one or more of the directors 42a-42n may have multiple processor systems thereon and thus may be able to perform functions for multiple discrete directors. In some embodiments, at least one of the directors 42a-42n having multiple processor systems thereon may simultaneously perform the functions of at least two different types of directors (e.g., an HA and a DA). Furthermore, in some embodiments, at least one of the directors 42a-42n having multiple processor systems thereon may simultaneously perform the functions of at least one type of director and perform other processing with the other processing system. In addition, all or at least part of the global memory 37 may be provided on one or more of the directors 42a-42n and shared with other ones of the directors 42a-42n. In an embodiment, the features discussed in connection with the source storage system 24 may be provided as one or more director boards having CPUs, memory (e.g., DRAM, etc.) and interfaces with Input/Output (I/O) modules.
Note that, although specific storage system configurations are disclosed in connection with
A storage area network (SAN) may be used to couple one or more host systems with one or more storage systems in a manner that allows reconfiguring connections without having to physically disconnect and reconnect cables from and to ports of the devices. A storage area network may be implemented using one or more switches to which the storage systems and the host systems are coupled. The switches may be programmed to allow connections between specific ports of devices coupled to the switches. A port that can initiate a data-path connection may be called an “initiator” port while the other port may be deemed a “target” port.
Referring to
The non-volatile encrypted data 404 may be maintained in an encrypted state at all times (encryption at rest), even when there is no electrical power applied being applied to the storage system 24. Thus, if physical storage hardware components from the storage system 24 were to be accessed by a malicious actor, the data thereon would be encrypted and thus inaccessible by the malicious actor. The malicious actor would need the encryption key 402 in order to be able to decrypt the encrypted data 404. Thus, securely maintaining the encryption key 402 is important in preventing unauthorized access to the encrypted data 404. The storage system 24 includes an encryption table 406 that securely stores a plurality encryption keys used by the host 22, including the encryption key 402. In some instances, the encryption table 406 may also be encrypted with a different key (not shown) that is not part of the storage system 24 but may, instead, by applied at power up (e.g., manually by an operator) or at other instances where the encryption table 406 needs to be accessed.
In an embodiment herein, the encrypted data 404 may be replicated to provide replicated encrypted data 404′ on the storage system 26. The host 22′ and the storage system 26 may use an encryption key 408 that is different from and unrelated to the encryption key 402 used by the host 22 and the storage system 24. The encryption key 408 may be stored in an encryption table 412, like the encryption table 406 discussed above, that securely stores a plurality encryption keys used by the host 22′, including the encryption key 408. The encryption key 408 may be used to encrypt and decrypt native encrypted data (not shown) on the storage system 26 in instances where the data originates with the host 22′. However, the replicated encrypted data 404′ originates with the host 22 and, moreover, the encryption keys 402, 408 are unrelated. Thus, the host 22′ cannot access the replicated encrypted data 404′ using the encryption key 408. In instances where the encrypted data 404 is being replicated from the storage system 24 to the storage system 26 to provide failover, having the replicated encrypted data 404′ be inaccessible by the host 22′ is unacceptable since a failover situation could include failure of both the host 22 and the storage system 24. If the host 22′ is unable to access the replicated encrypted data 404′, then the system cannot be restarted following a failover.
Referring to
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Processing for the flow diagram 700 begins at a first step 702 where a native storage system (e.g., a primary storage system) receives a request from a foreign storage system (e.g., the storage system 26) for a particular encryption key that is used by the local storage system and by one or more hosts coupled thereto in connection with accessing encrypted data at the native storage system. The foreign storage system may be any other storage system for which the particular encryption key is not native (did not originate), such as a corresponding failover storage system. Note, by the way, that the processing illustrated by the flow diagram 700 needs to be performed by the native storage system prior to failure of the native storage system. In some embodiments, the processing illustrated by the flow diagram may be performed by a foreign storage system as part of an overall initialization process. That is, upon initialization, the foreign storage system determines which encryption keys will be needed in case of a subsequent failover and then requests the encryption keys from appropriate other storage systems. Of course, waiting until after a failover to request any encryption keys is not possible because the failed storage system may not be operational and/or communication with the failed storage system may not be possible.
Following the step 702 is a test step 704 where it is determined if the foreign storage system is authorized to receive the requested encryption key. Note that the test at the step 704 may use any of a number of appropriate mechanisms for appropriately restricting access to native encryption keys. In some cases, authorization may be based on manual configuration at a time of installation. For example, the storage system 24 may be provided with a secure list of foreign storage systems, such as the storage system 26, that are authorized to receive particular native encryption keys. It is also possible to provide heuristic rules for authorization, such as providing authorization for all foreign storage systems that contain a replica of encrypted data stored on the native storage system. It some embodiments, the storage systems may share registration tables based on the primary/secondary relationship that has been established. Generally, whatever mechanism is used, the only foreign storage systems that are authorized to receive encryption keys from a native storage system are foreign storage systems that legitimately possesses encrypted data from the native storage system.
If it is determined at the test step 704 that the request for a particular encryption key is not authorized, then control transfers from the test step 704 to a step 706 where the request is refused (e.g., by returning a particular message to the requestor). Following the step 706, processing is complete. Otherwise, if it is determined at the test step 704 that the request for the particular encryption key is authorized, then control transfers from the test step 704 to a step 708 where the requested encryption key is provided. In an embodiment herein, the encryption key may be provided using any appropriate secure mechanism, such as being itself encrypted with a symmetric or asymmetric key so that the encryption key may only be accessed by the requesting foreign storage system. As discussed elsewhere herein, the foreign storage system may store the encryption key in a supplemented encryption table. Following the step 708, processing is complete.
Referring to
Following the step 804 is a test step 806 where it is determined if the application has received the foreign encryption key from the storage system 26. If not, then control transfers from the step 806 to a step 808 where error processing is performed. Note generally that it is an error condition if the storage system 26 does not already have the foreign encryption key since the foreign encryption key should have been requested and received by the storage system 26 before failure of the storage system 24. The error processing at the step 808 can be whatever is appropriate for the system, such as providing a message to a user and possibly logging the error. Following the step 808, processing is complete.
If it is determined at the test step 806 that the requested foreign key is received by the application from the storage system 26, then control transfers from the test step 806 to a step 812 where the application uses the foreign encryption key to access the encrypted data from the storage system 24 that had been replicated to the storage system 26. This is illustrated by the diagram 600 of
Various embodiments discussed herein may be combined with each other in appropriate combinations in connection with the system described herein. Additionally, in some instances, the order of steps in the flow diagrams, flowcharts and/or described flow processing may be modified, where appropriate. Further, various aspects of the system described herein may be implemented using software, hardware, a combination of software and hardware and/or other computer-implemented modules or devices having the described features and performing the described functions. The system may further include a display and/or other computer components for providing a suitable interface with a user and/or with other computers.
Software implementations of the system described herein may include executable code that is stored in a non-transitory computer-readable medium and executed by one or more processors. The computer-readable medium may include volatile memory and/or non-volatile memory, and may include, for example, a computer hard drive, ROM, RAM, flash memory, portable computer storage media such as a CD-ROM, a DVD-ROM, an SD card, a flash drive or other drive with, for example, a universal serial bus (USB) interface, and/or any other appropriate tangible or non-transitory computer-readable medium or computer memory on which executable code may be stored and executed by a processor. The system described herein may be used in connection with any appropriate operating system.
Other embodiments of the invention will be apparent to those skilled in the art from a consideration of the specification or practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.
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| Number | Date | Country | |
|---|---|---|---|
| 20220345295 A1 | Oct 2022 | US |
