Secure paging with page change detection

Patent metadata

Field	Value
Publication number	US-2020287709-A1
Application number	US-201916296303-A
Country	US
Kind code	A1
Filing date	Mar 8, 2019
Priority date	Mar 8, 2019
Publication date	Sep 10, 2020
Grant date	—

Abstract

According to one or more embodiments of the present invention, a computer implemented method includes computing a hash value of a page of memory of a computer system and comparing the hash value with a previously computed hash value of the page. A per-encryption value per page can be used in encrypting the page based on determining that the hash value matches the previously computed hash value. A modified value of the per-encryption value per page can be used in encrypting the page based on determining that the hash value mismatches the previously computed hash value.

First claim

What is claimed is:

1 . A method comprising:
computing a hash value of a page of memory of a computer system; comparing the hash value with a previously computed hash value of the page; using a per-encryption value per page in encrypting the page based on determining that the hash value matches the previously computed hash value; and using a modified value of the per-encryption value per page in encrypting the page based on determining that the hash value mismatches the previously computed hash value.

2 . The method of claim 1 , wherein the encrypting is performed by a secure control interface responsive to a request of a host to convert the page from a secure page to a non-secure page.

3 . The method of claim 2 , further comprising:
providing the non-secure page as encrypted to the host for storage.

4 . The method of claim 3 , further comprising:
storing the hash value in a secure table of the secure control interface.

5 . The method of claim 4 , further comprising:
converting the non-secure page to the secure page; decrypting, by the secure interface control, the secure page based on the per-encryption value associated with the page to produce a decrypted page; computing a hash value of the decrypted page; comparing the hash value of the decrypted page with the hash value of the page as stored in the secure table; and validating the decrypted page based on determining that the hash value of the decrypted page matches the hash value stored in the secure table.

6 . The method of claim 2 , wherein the secure interface control comprises firmware, hardware, or a combination of firmware and hardware; the secure page is assigned to a secure container or a secure virtual machine managed by the host; and the host is a hypervisor or an operating system.

7 . The method of claim 1 , wherein encrypting the page incorporates a combination of an address value associated with the page, one or more random values, and the per-encryption value with a cryptographically-secure hash function.

8 . The method of claim 1 , wherein an initial value of the per-encryption value is established before the per-encryption value is used.

9 . A system comprising:
a memory; a processing unit; and a secure interface control interfaced with the processing unit and the memory, the secure interface control configured to perform operations comprising:
computing a hash value of a page of the memory;
comparing the hash value with a previously computed hash value of the page;
using a per-encryption value per page in encrypting the page based on determining that the hash value matches the previously computed hash value; and
using a modified value of the per-encryption value per page in encrypting the page based on determining that the hash value mismatches the previously computed hash value.

10 . The system of claim 9 , wherein the encrypting is performed by the secure control interface responsive to a request of a host to convert the page from a secure page to a non-secure page.

11 . The system of claim 10 , wherein the operations further comprise providing the non-secure page as encrypted to the host for storage.

12 . The system of claim 11 , wherein the operations further comprise storing the hash value in a secure table of the secure control interface.

13 . The system of claim 12 , wherein the operations further comprise:
converting the non-secure page to the secure page; decrypting, by the secure interface control, the secure page based on the per-encryption value associated with the page to produce a decrypted page; computing a hash value of the decrypted page; comparing the hash value of the decrypted page with the hash value of the page as stored in the secure table; and validating the decrypted page based on determining that the hash value of the decrypted page matches the hash value stored in the secure table.

14 . The system of claim 10 , wherein the secure interface control comprises firmware, hardware, or a combination of firmware and hardware; the secure page is assigned to a secure container or a secure virtual machine managed by the host; and the host is a hypervisor or an operating system.

15 . The system of claim 9 , wherein encrypting the page incorporates a combination of an address value associated with the page, one or more random values, and the per-encryption value with a cryptographically-secure hash function.

16 . The system of claim 9 , wherein an initial value of the per-encryption value is established before the per-encryption value is used.

17 . A computer program product comprising a computer readable storage medium, the computer readable storage medium comprising computer executable instructions, which when executed perform a method comprising:
computing a hash value of a page of memory of a computer system; comparing the hash value with a previously computed hash value of the page; using a per-encryption value per page in encrypting the page based on determining that the hash value matches the previously computed hash value; and using a modified value of the per-encryption value per page in encrypting the page based on determining that the hash value mismatches the previously computed hash value.

18 . The computer program product of claim 17 , wherein the encrypting is performed by a secure control interface responsive to a request of a host to convert the page from a secure page to a non-secure page.

19 . The computer program product of claim 18 , wherein the executable instructions when executed further perform the method comprising:
providing the non-secure page as encrypted to the host for storage.

20 . The computer program product of claim 19 , wherein the executable instructions when executed further perform the method comprising:
storing the hash value in a secure table of the secure control interface.

21 . The computer program product of claim 20 , wherein the executable instructions when executed further perform the method comprising:
converting the non-secure page to the secure page; decrypting, by the secure interface control, the secure page based on the per-encryption value associated with the page to produce a decrypted page; computing a hash value of the decrypted page; comparing the hash value of the decrypted page with the hash value of the page as stored in the secure table; and validating the decrypted page based on determining that the hash value of the decrypted page matches the hash value stored in the secure table.

22 . The computer program product of claim 18 , wherein the secure page is assigned to a secure container or a secure virtual machine managed by the host, and the host is a hypervisor or an operating system.

23 . The computer program product of claim 17 , wherein encrypting the page incorporates a combination of an address value associated with the page, one or more random values, and the per-encryption value with a cryptographically-secure hash function.

24 . The computer program product of claim 17 , wherein an initial value of the per-encryption value is established before the per-encryption value is used.

Assignees

• IBM

Inventors

• Bradbury Jonathan D
• Borntraeger Christian
• Carstens Heiko
• Schwidefsky Martin
• Buendgen Reinhard Theodor

Classifications

• H04L9/3239

  involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD · CPC title

• H04L9/0894 Primary

  Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage · CPC title

• G06F21/78

  to assure secure storage of data (address-based protection against unauthorised use of memory G06F12/14; record carriers for use with machines and with at least a part designed to carry digital markings G06K19/00) · CPC title

• G06F12/145 Primary

  the protection being virtual, e.g. for virtual blocks or segments before a translation mechanism · CPC title

• G06F12/1425

  the protection being physical, e.g. cell, word, block · CPC title