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Grid Security: PKI Based Authentication Infrastructure

Grid Security: PKI Based Authentication Infrastructure. Source: The Globus Project Argonne National Laboratory USC Information Sciences Institute http://www.globus.org/ Updated/Localised: Rajkumar Buyya. Security.

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Grid Security: PKI Based Authentication Infrastructure

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  1. Grid Security: PKI Based Authentication Infrastructure Source: The Globus Project Argonne National LaboratoryUSC Information Sciences Institute http://www.globus.org/ Updated/Localised: Rajkumar Buyya

  2. Security • As Grid Resources and Users are Distributed and Owned by different organizations, only authorized users should be allowed to access them. • A simple authentication infrastructure is needed. • Also, both users and owners should be protected from each other. • The Users need be assured about security of their: • Data • Code • Message

  3. jobmanager key key services map cert cert ExampleSecure Remote Startup 1. Exchange certificates, authenticate, delegate 2. Check gridmap file 3. Lookup service 4. Run service program (e.g. jobmanager) 4. 2. 3. 1. client gatekeeper GSC GSP

  4. Grid Security Infrastructure (GSI) based on PKI – as realized in Globus Proxies and delegation (GSI Extensions) for secure single Sign-on • GSI is: Proxies and Delegation SSL/ TLS PKI (CAs and Certificates) SSL for Authentication And message protection PKI for credentials PKI: Public Key Infrastructure, SSL: Secure Socket Layer TLS: Transport Level Security

  5. Owner Public Key Infrastructure (PKI) • PKI allows you to know that a given public key belongs to a given user • PKI builds on asymmetric encryption: • Each entity has two keys: public and private • Data encrypted with one key can only be decrypted with other. • The private key is known only to the entity • The public key is given to the world encapsulated in a X.509 certificate

  6. Owner Public Key Infrastructure (PKI) Overview • X.509 Certificates • Certificate Authorities (CAs) • Certificate Policies • Namespaces • Requesting a certificate • Certificate Request • Registration Authority

  7. X.509 • A widely used standard for defining digital certificates. X.509 is actually an ITU (International Telecommunication Union) Recommendation, which means that it has not yet been officially defined or approved for standardized usage. As a result, companies have implemented the standard in different ways. For example, both Netscape and Microsoft use X.509 certificates to implement SSL in their Web servers and browsers. But an X.509 Certificate generated by Netscape may not be readable by Microsoft products, and vice versa.

  8. Name Issuer Public Key Signature Certificates • A X.509 certificate binds a public key to a name • It includes a name and a public key (among other things) bundled together and signed by a trusted party (Issuer)

  9. Name Issuer Public Key Signature State of Victoria Rajkumar Buyya 111, Barry St. Carlton, 3053 State of Victoria Seal BD 01-06-1970 Male 165cms, 65Kg B&W Eyes Certificates • Similar to passport or driver’s license

  10. Name Issuer Public Key Signature Issuer Certificates • By checking the signature, one can determine that a public key belongs to a given user. Hash Hash =? Decrypt Hash Public Key from Issuer

  11. Name: CA Issuer: CA CA’s Public Key CA’s Signature Certificate Authorities (CAs) • A small set of trusted entities known as Certificate Authorities (CAs) are established to sign certificates • A Certificate Authority is an entity that exists only to sign user certificates • The CA signs it’s own certificate which is distributed in a trusted manner

  12. Name Issuer Public Key Signature Name: CA Issuer: CA CA’s Public Key CA’s Signature Certificate Authorities (CAs) • The public key from the CA certificate can then be used to verify other certificates Hash Hash =? Decrypt Hash

  13. Requesting a Certificate • To request a certificate a user starts by generating a key pair • The private key is stored encrypted with a pass phrase the user gives • The public key is put into a certificate request Encrypted On local disk Certificate Request Public Key

  14. Certificate Issuance • The user then takes the certificate to the CA • The CA usually includes a Registration Authority (RA) which verifies the request: • The name is unique with respect to the CA • It is the real name of the user • Etc. Certificate Authority Certificate Request Public Key State of Victoria ID

  15. Name Issuer Public Key Signature Certificate Issuance Certificate Request Public Key • The CA then signs the certificate request and issues a certificate for the user Certificate Authority Sign

  16. Secure Socket Layer (SSL) • Also known as TLS (Transport Layer Security) • Uses certificates and TCP sockets to provide a secured connection • Authentication of one or both parties using the certificates • Message protection • Confidentiality (encryption) • Integrity SSL/TLS Certificates TCP Sockets

  17. Mutual Authentication • A and B are two parties: Both need to trust each others’ CA. • A  B (A establishes connection to B and gives his certificate (name,pub. Key) to B). • B makes sure that it can trust CA of A. • B generates random message A and asks it encrypt it. • A encrypts it and send to B • B decrypts using A’s public key. If the msg. is same as what B has sent, then A is who it is claiming to be.

  18. Globus Security: Review • GSI extends existing standard protocols & APIs • Based on standards: SSL/TLS, X.509, GSS-API • Extensions for single sign-on and delegation • The Globus Toolkit provides: • Generic Security Services API (GSS-API) on GSI protocols • The GSS-API is the IETF standard for adding authentication, delegation, message integrity, and message confidentiality to applications. • Various tools for credential management, login/logout, etc.

  19. Obtaining a Certificate • The programgrid-cert-request is used to create a public/private key pair and unsigned certificate in ~/.globus/: • usercert_request.pem: Unsigned certificate file • userkey.pem: Encrypted private key file • Must be readable only by the owner • Mail usercert_request.pem to ca@ausgrid.org • Receive a Globus-signed certificate Place in ~/.globus/usercert.pem • Other organizations use different approaches • NCSA, NPACI, NASA, etc. have their own CA

  20. My Certificate (certified by CA) Certificate: Data: Version: 3 (0x2) Serial Number: 26 (0x1a) Signature Algorithm: md5WithRSAEncryption Issuer: O=Australian Grid Forum, OU=AusGrid Testbed, CN=ausgrid.org Validity Not Before: Feb 8 03:40:20 2004 GMT Not After : Feb 7 03:40:20 2005 GMT Subject: O=Australian Grid Forum, OU=AusGrid Testbed, OU=cs.mu.oz.au, CN=Rajkumar Buyya Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (1024 bit) Modulus (1024 bit): 00:bb:c7:92:a8:14:75:81:2c:38:b6:45:e9:db:12: a3:6b:e2:66:41:62:44:ef:1a:56:5c:42:71:ec:8b: 04:1e:01:53:43:84:1a:cb:8e:a9:d1:99:67:1f:ef: .. 07:5f:92:04:6e:ca:29:77:ec:9d:f3:36:c2:49:40: 8f:51:8e:63:4e:82:2b:c7:c9:0c:bc:55:ce:01:d1: 8a:f4:dc:19:c4:01:37:f9:9f Exponent: 65537 (0x10001) X509v3 extensions: Netscape Cert Type: SSL Client, SSL Server, S/MIME, Object Signing Signature Algorithm: md5WithRSAEncryption b2:f0:a2:79:bc:2d:0f:02:15:f2:4d:8a:e8:5f:7c:79:1e:43: 09:d9:6e:59:7b:7c:71:87:8c:4a:10:9c:0e:74:ea:26:48:8c: .. 4e:fb:d7:f9:81:eb:d8:74:59:17:fa:c9:64:8d:88:0e:98:1e: Validity Start/End

  21. Sample usercert.pem: (public key) Sample userkey.pem (private key): -----BEGIN CERTIFICATE----- MIICAzCCAWygAwIBAgIBCDANBgkqhkiG9w0BAQQFADBHMQswCQY <snip> u5tX5R1m7LrBeI3dFMviJudlihloXfJ2BduIg7XOKk5g3JmgauK4 -----END CERTIFICATE----- -----BEGIN RSA PRIVATE KEY----- Proc-Type: 4,ENCRYPTED DEK-Info: DES-EDE3-CBC,1E924694DBA7D9D1 +W4FEPdn/oYntAJPw2tfmrGZ82FH611o1gtvjSKH79wdFxzKhnz474Ijo5Bl <snip> et5QnJ6hAO4Bhya1XkWyKHTPs/2tIflKn0BNIIIYM+s= -----END RSA PRIVATE KEY----- Certificate and Key Data

  22. Certificate Information • To get cert information run grid-cert-info % grid-cert-info –subject /O=Australian Grid Forum/OU=AusGrid Testbed/OU=cs.mu.oz.au/CN=Rajkumar Buyya • Options for printing cert information-all -startdate-subject -enddate-issuer -help • [raj@belle .globus]$ grid-proxy-info • subject : /O=Australian Grid Forum/OU=AusGrid Testbed/OU=cs.mu.oz.au/CN=Rajkumar Buyya/CN=proxy • issuer : /O=Australian Grid Forum/OU=AusGrid Testbed/OU=cs.mu.oz.au/CN=Rajkumar Buyya • identity : /O=Australian Grid Forum/OU=AusGrid Testbed/OU=cs.mu.oz.au/CN=Rajkumar Buyya • type : full legacy globus proxy • strength : 512 bits • path : /tmp/x509up_u501 • timeleft : 0:59:25

  23. “Logging on” to the Grid • To run programs, authenticate to Globus: % grid-proxy-init Enter PEM pass phrase: ****** • Creates a temporary, local, short-lived proxy credential for use by our computations • Options for grid-proxy-init: -hours <lifetime of credential> -bits <length of key> -help

  24. grid-proxy-init Details • grid-proxy-init creates the local proxy file. • User enters pass phrase, which is used to decrypt private key. • Private key is used to sign a proxy certificate with its own, new public/private key pair. • User’s private key not exposed after proxy has been signed • Proxy placed in /tmp, read-only by user • NOTE: No network traffic! • grid-proxy-info displays proxy details

  25. Grid Sign-On With grid-proxy-init User certificate file User Proxy certificate file Private Key (Encrypted) Pass Phrase

  26. Destroying Your Proxy (logout) • To destroy your local proxy that was created by grid-proxy-init: % grid-proxy-destroy • This does NOT destroy any proxies that were delegated from this proxy. • You cannot revoke a remote proxy • Usually create proxies with short lifetimes

  27. Proxy Information • To get proxy information run grid-proxy-info % grid-proxy-info -subject /O=Grid/O=Globus/OU=cs.mu.oz.au/CN=Rajkumar Buyya • Options for printing proxy information-subject -issuer-type -timeleft-strength -help • Options for scripting proxy queries-exists -hours <lifetime of credential>-exists -bits <length of key> • Returns 0 status for true, 1 for false:

  28. Important Files • /etc/grid-security • hostcert.pem: certificate used by the server in mutual authentication • hostkey.pem: private key corresponding to the server’s certificate (read-only by root) • grid-mapfile: maps grid subject names to local user accounts (really part of gatekeeper) • /etc/grid-security/certificates • CA certificates: certs that are trusted when validating certs, and thus needn’t be verified • ca-signing-policy.conf: defines the subject names that can be signed by each CA

  29. Important Files • $HOME/.globus • usercert.pem: User’s certificate (subject name, public key, CA signature) • userkey.pem: User’s private key (encrypted using the user’s pass phrase) • /tmp • Proxy file(s): Temporary file(s) containing unencrypted proxy private key and certificate (readable only by user’s account) • Same approach Kerberos uses for protecting tickets

  30. Secure Services • On most Unix machines, inetd listens for incoming service connections and passes connections to daemons for processing. • On Grid servers, the gatekeeper securely performs the same function for many services • It handles mutual authentication using files in /etc/grid-security • It maps to local users via the gridmap file

  31. Sample Gridmap File • Gridmap file maintained by Globus administrator • Entry maps Grid-id into local user name(s) # Distinguished name Local # username "/O=Australian Grid Forum/OU=AusGrid Testbed/OU=cs.mu.oz.au/CN=Rajkumar Buyya" bellegrid "/O=Australian Grid Forum/OU=AusGrid Testbed/OU=cs.mu.oz.au/CN=Srikumar Venugopal" bellegrid "/O=Grid/O=Globus/OU=cs.mu.oz.au/CN=Jia Yu" jiayu "/C=JP/O=AIST GTRC/CN=Peerapon Vateekul/Email=griddemo@mike-33-98.cpe.ku.ac.th" mikegrid

  32. jobmanager key key services map cert cert ExampleSecure Remote Startup 1. Exchange certificates, authenticate, delegate 2. Check gridmap file 3. Lookup service 4. Run service program (e.g. jobmanager) 4. 2. 3. 1. client gatekeeper

  33. Simple job submission • globus-job-run provides a simple RSH compatible interface • % grid-proxy-init Enter PEM pass phrase: ***** • % globus-job-run host program [args] • Authentication Test • % globusrun –a –r hostname

  34. Delegation • Delegation = remote creation of a (second level) proxy credential • New key pair generated remotely on server • Proxy cert and public key sent to client • Clients signs proxy cert and returns it • Server (usually) puts proxy in /tmp • Allows remote process to authenticate on behalf of the user • Remote process “impersonates” the user

  35. Limited Proxy • During delegation, the client can elect to delegate only a “limited proxy”, rather than a “full” proxy • GRAM (job submission) client does this • Each service decides whether it will allow authentication with a limited proxy • Job manager service requires a full proxy • GridFTP server allows either full or limited proxy to be used

  36. Restricted Proxies • A generalization of the simple limited proxies • Desirable to have fine-grained restrictions • Reduces exposure from compromised proxies • Embed restriction policy in proxy cert • Policy is evaluated by resource upon proxy use • Reduces rights available to the proxy to a subset of those held by the user • A proxy no longer grants full impersonation rights • Extensible to support any policy language

  37. ExerciseSign-On & Remote Process Creation • Use grid-cert-info to examine your cert:% grid-cert-info -all • Use grid-proxy-init to create a proxy certificate: % grid-proxy-init Enter PEM pass phrase: ......................................+++++ .....+++++ • Use grid-proxy-info to query proxy:% grid-proxy-info -subject • Use globus-job-run to start remote programs:% globus-job-run jupiter.isi.edu /usr/bin/ls -l /tmp

  38. Generic Security Service API • The GSS-API is the IETF draft standard for adding authentication, delegation, message integrity, and message confidentiality to apps • For secure communication between two parties over a reliable channel (e.g. TCP) • GSS-API separates security from communication, which allows security to be easily added to existing communication code. • Filters on each end of the communications link • GSS-API Extensions defined in GGF draft • Globus Toolkit components all use GSS-API

  39. gss_inquire_cred() • Extract information (e.g. the subject name) from a credential gss_inquire_cred_by_oid() Extract information associated with a OID (owner ID) from a credential (e.g. information in certificate extensions) Will be in future version > GT 2.0

  40. Authorization • GSI handles authentication, but authorization is a separate issue • Authorization issues: • Management of authorization on a multi-organization grid is still an interesting problem. • The grid-mapfile doesn’t scale well, and works only at the resource level, not the collective level. • Large communities that share resources exacerbates authorization issues, which has led us to CAS (Community Authorization Service)… • Why not use Grid Bank Services ? • All those GSPs providing services through the Grid Marketplace can allow any consumer to access their services as long as GridBank guarantees the payment,

  41. Access Scalability Problem Resource access authorization file (grid-mapfile) “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Alexander Barmouta” alex “/O=Grid/O=Globus/OU=cs.mu.oz.au/CN=Rajkumar Buyya” rajkumar “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Chris McDonald” chris Resources Clients X509v3 Digital Certificate ………… Subject: “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Alexander Barmouta” ………… X509v3 Digital Certificate ………… Subject: “/O=Grid/O=Globus/OU=cs.mu.oz.au/CN=Rajkumar Buyya” ………… X509v3 Digital Certificate ………… Subject: “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Chris McDonald” …………

  42. GridBank’s Solution to Access Scalability Problem: Modified gatekeeper GridBank GridBank Accounts “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Alexander Barmouta” “/O=Grid/O=Globus/OU=cs.mu.oz.au/CN=Rajkumar Buyya” “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Chris McDonald” Request to access resource Passing client’s Certificate Subject Execute job Template (local) accounts gbaccount1 gbaccount2 gbaccount3 Template (local) accounts gbaccount2 gbaccount3 Resource access authorization file (grid-mapfile) “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=GridBank” gridbank “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=Alexander Barmouta” gbaccount1 Resource access authorization file (grid-mapfile) “/O=Grid/O=Globus/OU=cs.uwa.edu.au/CN=GridBank” gridbank

  43. Security Summary • Programs for credential management • grid-cert-info, grid-proxy-init, grid-proxy-destroy, grid-proxy-info • GSS-API: The Globus Toolkit Grid Security Infrastructure (GSI) uses this API, which allows programs to easily add security • globus_gss_assist: This is a simple wrapper around GSS-API, making it easier to use

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