1 / 29

Trusted Platform Modules: Building a Trusted Software Stack and Remote Attestation

Trusted Platform Modules: Building a Trusted Software Stack and Remote Attestation. Dane Brandon, Hardeep Uppal CSE551 University of Washington. Overview. Motivation Trusted Computing and Trusted Platform Modules (TPM) Trusted Software Stacks Attestation Measurements

nusa
Download Presentation

Trusted Platform Modules: Building a Trusted Software Stack and Remote Attestation

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Trusted Platform Modules: Building a Trusted Software Stack and Remote Attestation Dane Brandon, HardeepUppal CSE551 University of Washington

  2. Overview • Motivation • Trusted Computing and Trusted Platform Modules (TPM) • Trusted Software Stacks • Attestation • Measurements • Future Work and Conclusion

  3. Motivation • An End to the Middle • Our ongoing research. • Networked computers and trust. • How can we validate a computer? • Even with a password, can we trust they are who they say they are? Hardware offers a potential solution…

  4. Trusted Computing and TPMs • Trusted Computing Group • Spec for TPM and trusted software stack. • TPM - Hardware chip on most new business laptops and some other PCs. • Dell Latitude, Lenovo ThinkPad, etc… • Offers some help that software can’t. • NOT protection against physical attacks.

  5. TPM Functionality

  6. TPM Functionality • Persistent memory • Endorsement key (EK) • Permanent private unique key • Storage Root Key (SRK) • Encrypts other keys, data with pub key out to disk. • Volatile memory • Platform Configuration Registers (PCR) • Attestation identity keys • Storage keys

  7. TPM Functionality • Crypto-processor • RSA key generator • Random number generator • Encryption / decryption • SHA-1 hash and append • PCRs are append only. • PCR[i] = SHA-1(PCR[i] | new value)

  8. Trusted Software Stacks • Core root of trust for measurement (CRTM). • Boot block in BIOS. Never changes. • Chain of trust. • Each software component measures the next. • Append measurements to PCRs. TrustedGRUB • TrouSerS (TSS API)

  9. Trusted Software Stacks

  10. Attestation • We have a snapshot of state which can be signed. • How do we deliver it? • We can’t just send it over… • Replay attacks

  11. Attestation • We have a snapshot of state which can be signed. • How do we deliver it? • We can’t just send it over… • Replay attacks

  12. Attestation • Use a nonce • When request to join comes, challenge with a random number. • Append to PCRs and sign. Funky fresh. • Note: Measurements only represent state immediately after boot. • No guarantees of events after boot! • Still need to prove that the TPM is a TPM • Certificate Authority • Validate TPM

  13. Attestation Manf.Cert. PCA Cert. Privacy CA New Node AIK AIK AIK EK EK EK Trusted Nodes

  14. Attestation Manf.Cert. PCA Cert. Privacy CA New Node AIK AIK AIK EK EK EK Trusted Nodes

  15. Attestation Manf.Cert. PCA Cert. Privacy CA New Node AIK AIK AIK EK EK EK Trusted Nodes

  16. Attestation Manf.Cert. PCA Cert. Privacy CA New Node AIK AIK AIK EK EK Trusted Nodes

  17. Attestation Manf.Cert. PCA Cert. Privacy CA New Node AIK AIK AIK EK EK Trusted Nodes

  18. Attestation Manf.Cert. PCA Cert. Privacy CA Challenge! ? New Node AIK AIK AIK EK EK Trusted Nodes

  19. Attestation Manf.Cert. PCA Cert. Privacy CA 02895… New Node AIK AIK AIK EK EK Trusted Nodes

  20. Attestation Manf.Cert. PCA Cert. Privacy CA Append nonce and sign PCRs with priv_AIK 10110… New Node AIK AIK AIK EK EK Trusted Nodes

  21. Attestation Manf.Cert. PCA Cert. Privacy CA 10110… New Node AIK AIK AIK AIK EK EK Trusted Nodes

  22. Attestation Manf.Cert. PCA Cert. Privacy CA 10110… New Node AIK AIK AIK AIK EK EK Trusted Nodes

  23. Attestation Manf.Cert. PCA Cert. Privacy CA 10110… New Node AIK AIK AIK AIK EK EK Trusted Nodes

  24. Attestation Manf.Cert. PCA Cert. Privacy CA SUCCESS! Verify bits match: SHA-1(expected PCRs | nonce) 10110… New Node AIK AIK AIK AIK EK EK Trusted Nodes

  25. Measurements Verify PCRvalues change

  26. Measurements • Time in seconds • Extends are fast • Creating keys is very slow • Load and sign, not too bad…

  27. Future Work • Create a privacy CA. • Implement complete attestation process and benchmark major components. • Put Xen in the middle of the chain of trust. • Add trusted software stack to ETTM project.

  28. Conclusion • TPMs show promise. • Building a trusted software stack is possible with open-source software. • Time cost not negligible, but reasonable. • Hardware should get better. • Need more software support.

  29. Other Thoughts • Lots of laptops have TPMs, no one uses them. • TrustedGRUB has 5400+ extra lines of code. We didn’t write them. • The Dell Latitude e5400 is garbage. • Two thumbs down!

More Related