Secure recovery in a serverless distributed file system

• US 7,428,751 B2
• Filed: 12/05/2002
• Issued: 09/23/2008
• Est. Priority Date: 12/05/2002
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bolosky, William J., Douceur, John R., Adya, Atul, Oom Temudo de Castro, Miguel
• Primary Examiner(s): Barron, Jr.; Gilberto
• Assistant Examiner(s): Dinh; Minh
• Application Number:
  US10/310,440
• Publication Number:
  US 20040111608A1
• Time in Patent Office: 2,119 Days
• Field of Search: None
• US Class Current: 726/10
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: G06F 21/40 by quorum, i.e. whereby two or more security principals are required
• CPC Class Codes: G06F 21/62 Protecting access to data via a platform, e.g. using keys or access control rules
• CPC Class Codes: G06F 2221/2101 Auditing as a secondary aspect
• CPC Class Codes: H04L 63/0435 wherein the sending and receiving network entities apply symmetric encryption, i.e. same key used for encryption and decryption cryptographic mechanisms or cryptographic arrangements for symmetric key encryption H04L9/06
• CPC Class Codes: H04L 63/0442 wherein the sending and receiving network entities apply asymmetric encryption, i.e. different keys for encryption and decryption cryptographic mechanisms or cryptographic arrangements for public-key encryption H04L9/30
• CPC Class Codes: H04L 63/0823 using certificates cryptographic mechanisms or cryptographic arrangements for entity authentication involving certificates H04L9/3263
• CPC Class Codes: H04L 9/3236 using cryptographic hash functions
• CPC Class Codes: H04L 9/3247 involving digital signatures
• CPC Class Codes: H04L 9/3255 using group based signatures, e.g. ring or threshold signatures

Abstract

Systems and methods for secure file writes after a catastrophic event are allowed over an unauthenticated channel in a serverless distributed file system if an authenticator accompanies the secure file writes. The authenticator can be a power-of-attorney certificate with time limitations, a vector of message authenticated code, or a single message authenticator with secured with a secret shared among members of the serverless distributed file system. The serverless distributed file system includes at least 3f+1 participating computer members, with f representing a number of faults tolerable by the system. The group requires at least one authenticator for file creation and file uploads. Any changes to files stored among the members can be made over an unauthenticated channel if the file changes are secured by the authenticator and the group is able to verify the authenticator.

Claims

1. A method for secure file write processes in a serverless distributed file system, the method comprising:

in the serverless distributed file system, requiring a certificate for file creation;

requiring the certificate for file uploads to the serverless distributed file system;

receiving a request to change a file created using the certificate;

in response to receiving the request to change the file created using the certificate, determining if predetermined criteria indicated by the certificate are satisfied, wherein the determining comprises;

determining an expiration indicator that identifies a time period during which the certificate is valid;

determining a version indicia for the created file; and

determining whether the certificate is out of sequence based on a serial number of the certificate, wherein the distributed file system denies authorization for out-of-sequence certificates thereby preventing selective choice of certificates; and

accepting changes to the file created using the certificate if the predetermined criteria indicated by the certificate are satisfied.

2. The method of claim 1 wherein the certificate is a power-of-attorney certificate.

3. The method of claim 1 wherein the certificate is associated with one or more files, the certificate signed by a user authorizing a machine to send files and changes to preexisting files.

4. A computer storage medium storing computer-executable instructions for performing acts comprising:

in a serverless distributed file system, requiring a certificate for file creation;

requiring the certificate for file uploads to the serverless distributed file system;

receiving a request to change a file created using the certificate;

in response to receiving the request to change the file created using the certificate, determining if predetermined criteria indicated by the certificate are satisfied, wherein the determining comprises;

determining an expiration indicator that identifies a time period during which the certificate is valid;

determining a version indicia for the created file; and

determining whether the certificate is out-of-sequence based on a serial number of the certificate, wherein the distributed file system denies authorization for out-of sequence certificates thereby preventing selective choice of certificates; and

accepting changes to the file created using the certificate if the predetermined criteria indicated by the certificate are satisfied.

5. The computer storage medium according to claim 4, wherein the certificate is associated with one or more files, the certificate signed by a user authorizing a machine to send files and changes to preexisting files.

6. A method, comprising:

issuing a certificate with predetermined criteria that allows a user to update a file located on a serverless distributed file system, wherein the predetermined criteria include;

an expiration indicator that identifies a time period during which the certificate is valid; and

a version indicia for the file;

storing the certificate on the user'"'"'s local machine;

creating a log of updates that includes changes in the file contents, the log for updating the file in the serverless distributed file system;

after a catastrophic event at a local machine;

sending the log of updates and the certificate to the serverless distributed file system; and

accepting the changes in the file contents included in the log of updates if the certificate meets the predetermined criteria; and

authorizing the log of updates, wherein the log is only authorized if each update contains a unique serial number and each serial number is received by the distributed file system in a predetermined order.

7. The method of claim 6, wherein the certificate is associated with one or more files, the certificate signed by the user authorizing the machine to send files and changes to preexisting files.

8. The method of claim 6, wherein the sending of the log of updates allows for updating of the file and one or more replicas of the file on the serverless distributed file system.

9. The method of claim 8, wherein the file and the one or more replicas are stored on one or more distributed system portions of one or more computers on the serverless distributed file system.