Andrew Prout, William Arcand, David Bestor, Chansup Byun, Bill Bergeron, Matthew Hubbell, Jeremy Kepner, Peter Michaleas, Julie Mullen, Albert Reuther, Antonio Rosa 2012 IEEE High Performance Extreme Computing Conference September 2012 Scalable Cryptographic Authentication for High Performance Computing This work is sponsored by the Department of the Air Force under Air Force contract FA C Opinions, interpretations, conclusions and recommendations are those of the author and are not necessarily endorsed by the United States Government.

HPEC AJP 9/12/2012 What is the LLGrid The Problem: External services authentication The Solution: Cryptographic authentication Results Outline

HPEC AJP 9/12/2012 LLGrid is a ~500 user ~2000 processor system World’s only desktop interactive supercomputer –Dramatically easier to use than any other supercomputer –Highest fraction of staff using (20%) supercomputing of any organization on the planet Foundation of Supercomputing in Massachusetts LLGrid System Architecture LAN Switch Network Storage Resource Manager Configuration Server Compute Nodes Service Nodes Cluster Switch To Lincoln LAN Users LLAN

HPEC AJP 9/12/2012 All jobs run on LLGrid LLGrid Usage Total Job duration (seconds) M Classic Supercomputing Interactive Supercomputing Processors used by Job TX-2500 (952 Cores) TX-X (220 Cores) TX-3d (540 Cores) TX-2500 (952 Cores) TX-X (220 Cores) TX-3d (540 Cores) Desktop Computing –CPU-time <20 minutes Classic Supercomputing – Wall-clock time >3 hours Interactive Supercomputing –Between desktop and classic supercomputing –Shortens the “time to insight” –Ten development turns/day instead of one turn/week Desktop Computing –CPU-time <20 minutes Classic Supercomputing – Wall-clock time >3 hours Interactive Supercomputing –Between desktop and classic supercomputing –Shortens the “time to insight” –Ten development turns/day instead of one turn/week Desktop Computing

HPEC AJP 9/12/2012 What is the LLGrid The Problem: External services authentication The Solution: Cryptographic authentication Results Outline

HPEC AJP 9/12/2012 As the line between a shared supercomputer and a “really powerful personal computer” blurs, users expect to have access to network resources (storage, svn, cvs, etc). Challenges with Interactive Supercomputing Challenge: Users expect seamless access to other network resources from the HPC.

HPEC AJP 9/12/2012 However these commands raise security concerns. –They store passwords as plain-text on the HPC central storage. –Password synchronization has made this password very sensitive. Challenges with Interactive Supercomputing Challenge: Ensure seamless access without putting the user’s “one common password” at risk. “S3cr3t”

HPEC AJP 9/12/2012 What is the LLGrid The Problem: External services authentication The Solution: Cryptographic authentication Results Outline

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server Connection Request

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server Connection Request Authentication Request A

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server Connection Request Authentication Request A A

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server Connection Request Authentication Request Signed Authentication Response and copy of PKI certificate A A

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server Connection Request Authentication Request Signed Authentication Response and copy of PKI certificate A AA

HPEC AJP 9/12/2012 Cryptographic authentication of clients using X509 PKI certificates has long been part of the SSL and TLS standards. The root of trust will certify that a specific keypair belongs to a specific user or process. Cryptographic Authentication User Server Connection Request Authentication Request Signed Authentication Response and copy of PKI certificate A AA Access Granted: Welcome Andy!

HPEC AJP 9/12/2012 Cryptographic authentication depends on both the security of the user’s private key and access to it. –Storing the private key on central storage is little different than storing a user’s password. Challenges with Cryptographic Authentication Challenge: Where to store the private key?

HPEC AJP 9/12/2012 Cryptographic authentication depends on both the security of the user’s private key and access to it. –Storing the private key on central storage is little different than storing a user’s password. Challenges with Cryptographic Authentication No guarantee the key won’t be lost, copied or left unprotected.

HPEC AJP 9/12/2012 One traditional solution is to store the key on the client system and forward authentication requests back to the user’s system. –Could be on the client system or in a smart card. Challenges with Cryptographic Authentication

HPEC AJP 9/12/2012 Challenges with Cryptographic Authentication Forwarding requests back doesn’t work for semi-interactive computing or background jobs. Forwarding requests back doesn’t work for semi-interactive computing or background jobs. Poof! One traditional solution is to store the key on the client system and forward authentication requests back to the user’s system. –However this fails if the user disconnects from the HPC.

HPEC AJP 9/12/2012 Challenges with Cryptographic Authentication Poof! Connecting smart cards to the HPC is not practical. –Some network-attached key storage devices exist, but their practical benefit in this scenario is questionable.

HPEC AJP 9/12/2012 Challenges with Cryptographic Authentication Poof! We implemented a virtual smart card to run on each node. –Allows for keys to be used on any node, connected or disconnected. –Allows for different keys on each node.

HPEC AJP 9/12/2012 Uses the smart card communication API: PKCS#11. Authenticates users and allows authorized users to perform cryptographic operations. Protects private keys from being copied, even by authorized users of the key. High throughput capability & low latency. –Physical smart cards have a latency approximately ms. Virtual Smart Card Defined

HPEC AJP 9/12/2012 We created the keyd daemon to be the brains of our virtual smartcard. –Runs as it’s own user account. The keyd Daemon: A Virtual Smartcard Keyd

HPEC AJP 9/12/2012 We created the keyd daemon to be the brains of our virtual smartcard. –Runs as it’s own user account. –Has access to all the keys. The keyd Daemon: A Virtual Smartcard Keyd

HPEC AJP 9/12/2012 We created the keyd daemon to be the brains of our virtual smartcard. –Runs as it’s own user account. –Has access to all the keys. We then created a library that conformed to the PKCS#11 standard and could talk to this daemon. –Loaded by applications running as a HPC user. The keyd Daemon: A Virtual Smartcard Keyd PKCS#11

HPEC AJP 9/12/2012 We created the keyd daemon to be the brains of our virtual smartcard. –Runs as it’s own user account. –Has access to all the keys. We then created a library that conformed to the PKCS#11 standard and could talk to this daemon. –Loaded by applications running as a HPC user. –Connects through a unix socket. –User credentials passed through the socket  Secure, provided you trust your linux kernel. The keyd Daemon: A Virtual Smartcard Keyd PKCS#11

HPEC AJP 9/12/2012 We created the keyd daemon to be the brains of our virtual smartcard. –Runs as it’s own user account. –Has access to all the keys. We then created a library that conformed to the PKCS#11 standard and could talk to this daemon. –Loaded by applications running as a HPC user. –Connects through a unix socket. –User credentials passed through the socket  Secure, provided you trust your linux kernel. The SVN client can then load the PKCS#11 library and use the keys to authenticate to the SVN server. The keyd Daemon: A Virtual Smartcard Keyd PKCS#11

HPEC AJP 9/12/2012 We created the keyd daemon to be the brains of our virtual smartcard. –Runs as it’s own user account. –Has access to all the keys. We then created a library that conformed to the PKCS#11 standard and could talk to this daemon. –Loaded by applications running as a HPC user. –Connects through a unix socket. –User credentials passed through the socket  Secure, provided you trust your linux kernel. The SVN client can then load the PKCS#11 library and use the keys to authenticate to the SVN server. –Other applications can be enabled in the future. The keyd Daemon: A Virtual Smartcard Keyd PKCS#11

HPEC AJP 9/12/2012 The SVN server was configured to accept the LLGrid’s root of trust. The SVN client on the LLGrid was configured to load the keyd daemon PKCS#11 library. –One configuration entry: ssl-pkcs11-provider=libkeyd_pkcs11 Configuring SVN for TLS Client Auth SVN User SVN Server Connection Request Authentication Request Signed Authentication Response and copy of PKI certificate A AA Keyd Daemon

HPEC AJP 9/12/2012 What is the LLGrid The Problem: External services authentication The Solution: Cryptographic authentication Results Outline

HPEC AJP 9/12/2012 Keypair generation and X509 PKI certificate creation is performed during user account creation. –LLGrid Adminstrators act as the root of trust. We developed scripts that execute parallel key generation across nodes in the cluster. X509 PKI Certificate Enrollment Nodes Time (seconds) Keypair & Certificate Generation –Each certificate asserts both the user identity and the node identity to meet the guidelines to be used for either server or client TLS authentication.

HPEC AJP 9/12/2012 Created a general purpose key storage and certificate management solution for HPC. –Keys are not managed by the end-user, ensuring a low risk of compromise requiring revocation. Demonstrated that it can be used to enable single sign-on integration to systems outside of the HPC. –Mitigated security concerns over passwords being stored on the LLGrid central storage. –Avoided the issue of periodic password changes impacting batch processing. Results

HPEC AJP 9/12/2012 Future work will look to use these PKI certificates to secure inter-node web services communication. –Certificates are valid for both TLS client or server authentication. Future Work

HPEC AJP 9/12/2012 Questions?