Method and computer program product for processing signed applets

• US 6,910,128 B1
• Filed: 11/21/2000
• Issued: 06/21/2005
• Est. Priority Date: 11/21/2000
• Status: Expired due to Term

• Current Assignee: Trend Micro Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Rich, Bruce Arland, Skibbie, Donna, Nadalin, Anthony Joseph, Shrader, Theodore Jack London, Yarsa, Julianne
• Primary Examiner(s): Morse, Gregory
• Assistant Examiner(s): Baum, Ronald
• Application Number:
  US09/717,524
• Time in Patent Office: 1,673 Days
• Field of Search: 713167-170, 713200-201, 713187-189, 717/107, 717/177
• US Class Current: 713/170
• CPC Class Codes: G06F 21/51 at application loading time, e.g. accepting, rejecting, starting or inhibiting executable software based on integrity or source reliability
• CPC Class Codes: G06F 21/53 by executing in a restricted environment, e.g. sandbox or secure virtual machine
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/126 the source of the received data
• CPC Class Codes: H04L 63/20 for managing network security; network security policies in general filtering policies H04L63/0227

Abstract

A framework for processing signed applets that are distributed over the Internet. Using the framework, an applet that is packaged as a Netscape- or JDK-signed jar file, or as an Internet Explorer-signed cab file, is processed within the same Java runtime environment irrespective of the browser type (i.e. Netscape Communicator, Internet Explorer or JDK) used to execute the applet. When the applet is executed, the framework verifies one or more applet signatures using the same algorithm that was used to sign the applet, verifies the signer(s) of the applet, and stores information about the signers so that they can be honored by a security policy when permissions for the applet are determined.

Claims

1. A method for executing a signed applet packaged in a given file, comprising:

upon loading a class, determining whether a signature in the given file type applies to the class;

if so, executing a verification procedure to verify the signature and the identity of a signer that generated the signature;

following a successful verification, determining whether the signer is identified in a policy entry;

if the signer is identified in the policy entry, populating a permission set for the class;

wherein the signature is verified using a given algorithm used to sign the applet; and

wherein the step of populating the permission set for the class awards the class a permission as specified in the policy entry.

2. The method as described in claim 1 wherein the given algorithm is selected from the set of algorithms consisting of

DSA/SHA1,

RSA/MD5 and

RSA/SHA1.

3. The method as described in claim 1 further including the steps of:

determining whether the applet has made a request that requires permission; and

if so, using the permission set of the class to determine whether the class has the permission.

4. The method as described in claim 3 further including the step of:

responding to the request if the class has the permission.

5. The method as described in claim 1 wherein the step of verifying the identity of the signer verifies that the signer is in a default certificate database and that a certificate of the signer has not expired.

6. The method as described in claim 1 wherein the step of verifying the identity of the signer verifies that the signer contains a certificate chain to a trusted certificate authority, that each certificate in the certificate chain contains a signature that can be verified by a given key, and that each certificate in the certification chain has not expired.

7. The method as described in claim 1 wherein the given file is selected from the set of file types consisting of a first signed jar file, a second signed jar file, and a signed cab file.

8. The method as described in claim 1 wherein the signed applet is executable in a given one of a set of different browser types.

9. A method for executing a signed applet packaged in a given file, comprising:

upon loading each class, determining whether any signatures in the given file applies to the class;

if so, executing a verification procedure to verify the signature and the identity of a signer that generated the signature;

following a successful verification, determining whether the signer is identified in a policy entry;

if the signer is identified in the policy entry, awarding the class a permission as identified in the policy entry;

responsive to a request that requires a permission, using the permission set for the class to determine whether the class has the permission; and

wherein the signature is verified using a given algorithm used to sign the applet.

10. The method as described in claim 9 further including the step of responding to the request if the class has the permission.

11. The method as described in claim 9 wherein the step of verifying the identity of the signer verifies that the signer is in a default certificate database and that a certificate of the signer has not expired.

12. The method as described in claim 9 wherein the step of verifying the identity of the signer verifies that the signer contains a certificate chain to a trusted certificate authority, that each certificate certificate in the certificate chain contains a signature that can be verified by a given key, and that each certificate in the certification chain has not expired.

13. The method as described in claim 9 wherein the given file is selected from the set of file types consisting of a first signed jar file, a second signed jar file, and a signed cab file.

14. The method as described in claim 9 wherein the signed applet is executable in a given one of a set of different browser types.

15. A computer program product on a computer readable media including computer usable code for use in a Java runtime environment (JRE), comprising:

an applet class loader for loading a set of applet classes archived in a signed file;

a set of signature engine classes for verifying applet class signatures;

a security manager class callable by the applet class loader upon receipt of an initial request that requires a given permission and, in response thereto invoking a policy file class that verifies a signer based on the existence of a matching certificate in a set of keystores;

wherein at least one signature engine verifies signatures using a given algorithm used to sign the applet classes archived in a signed file; and

wherein for populating a permission set for the class, wherein the class is awarded a permission as specified in the policy file class managed by the security manager class.

16. The computer program product as described in claim 15 wherein the set of signature engine classes includes a DSA/SHA1 class, an RSA/MD5 class, and a RSA/SHA1 class.

17. The computer program product as described claim 15 wherein the applet class loader is invoked by a Java Plug-in of the Java runtime environment.

18. The computer program product as described in claim 15 wherein the applet classes are archived in a jar file.

19. The computer program product as described in claim 15 wherein the applet classes are archived in a cab file.

20. A system, comprising:

a browser;

a Java runtime environment;

a set of keystores;

an applet class loader for loading a set of applet classes archived in a signed file;

a set of signature engine classes for verifying applet class signatures;

a security manager class callable by the applet class loader upon receipt of an initial request that requires a given permission and, in response thereto, invoking a policy file class that verifies a signer based on the existence of a matching certificate in the set of keystores;

a means for populating a permission set for the class, wherein the class is awarded a permission as specified in a policy entry in a database managed by the security manager class; and

wherein at least one signature engine verifies signatures using a given algorithm used to sign the applet.

21. The system as described in claim 20 wherein the signed file is selected from the set of file types consisting of a first signed jar file, a second signed jar file, and a signed cab file.