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If you read the two pages and you concluded that both AMD with their statement on Page 1 nor servethehome on Page 1 and Page 2 provided any information about ho

If you read the two pages and you concluded that both AMD with their statement on Page 1 nor servethehome on Page 1 and Page 2 provided any information about how PSB works I can't help you.

monocasa 5y ago
Or that commenter read and understood the description of how it works, and failed to see how it increases security in a meaningful way. I also struggle to think of a threat model that this protects against.
- YXNjaGVyZWdlbgo 5y ago
  If something is not on your level of expertise you can always have a look for people that have the required level. It's just one search away. https://blog.cloudflare.com/anchoring-trust-a-hardware-secure-boot-story/ https://blog.cloudflare.com/anchoring-trust-a-hardware-secur...
  - monocasa 5y ago
    I'm a security researcher. PSB as described there is orthogonal to the specific policy of tying the board to a specific CPU key, as you can tell from per CPU keys not being in the hardware root of trust as described by cloudflare. In fact you can swap the CPUs across boards from different ODMs in your most recent citation, since the root is an AMD key that then verifies the off chip ODM cert in flash. I stand by my orignal statements.
    - YXNjaGVyZWdlbgo 5y ago
      If you really think PSB doesn't provide any security benefit or "improves security in a meaningful way" you should do more security research.
      - monocasa 5y ago
        I was pretty sure that I made it clear that the concept under discussion was using a hardware root of trust scheme like PSB to tie a specific CPU to a particular vendor's boards. As an aside I'm putting a lot of effort into staying civil; I'd appreciate seeing that effort be a bit more reciprocal.
        YXNjaGVyZWdlbgo 5y ago
        PSB is there to protect you from a compromised motherboard it protects you from malware in your UEFI firmware. It's not even a vendor lock in it's signing key lock in that is used in that manner by AWS, Gcloud and Azure. Compromised UEFI Firmware is a constant point of failure in pentesting of the secure chain of trust. That you as a security researcher are dismissing the fact is honestly just unbelievable.
        monocasa 5y ago
        > It's not even a vendor lock in it's signing key lock in that is used in that manner by AWS, Gcloud and Azure. Which is not the mechanism under discussion.
        YXNjaGVyZWdlbgo 5y ago
        No, my comment talked about that some believe PSB is only there to destroy the second hand market and I wrote that it is a false statement and PSB actually provides a higher security for servers and you persisted it's not.
        monocasa 5y ago
        You started off saying > The feature was implemented in 2017 the only vendors that are using it are lenovo and dell. With lenovo being the only one using it on lower tier cpus than epyc. All of the ODMs use PSB in some way (the PSP won't start without it); it's only Lenovo and Dell that use PSB to tie CPUs to certain boards.

If you read the two pages and you concluded that both AMD with their statement on Page 1 nor servethehome on Page 1 and Page 2 provided any information about how PSB works I can't help you.

monocasa 5y ago

Or that commenter read and understood the description of how it works, and failed to see how it increases security in a meaningful way. I also struggle to think of a threat model that this protects against.

YXNjaGVyZWdlbgo 5y ago
If something is not on your level of expertise you can always have a look for people that have the required level. It's just one search away. https://blog.cloudflare.com/anchoring-trust-a-hardware-secure-boot-story/ https://blog.cloudflare.com/anchoring-trust-a-hardware-secur...
- monocasa 5y ago
  I'm a security researcher. PSB as described there is orthogonal to the specific policy of tying the board to a specific CPU key, as you can tell from per CPU keys not being in the hardware root of trust as described by cloudflare. In fact you can swap the CPUs across boards from different ODMs in your most recent citation, since the root is an AMD key that then verifies the off chip ODM cert in flash. I stand by my orignal statements.
  - YXNjaGVyZWdlbgo 5y ago
    If you really think PSB doesn't provide any security benefit or "improves security in a meaningful way" you should do more security research.
    - monocasa 5y ago
      I was pretty sure that I made it clear that the concept under discussion was using a hardware root of trust scheme like PSB to tie a specific CPU to a particular vendor's boards. As an aside I'm putting a lot of effort into staying civil; I'd appreciate seeing that effort be a bit more reciprocal.
      - YXNjaGVyZWdlbgo 5y ago
        PSB is there to protect you from a compromised motherboard it protects you from malware in your UEFI firmware. It's not even a vendor lock in it's signing key lock in that is used in that manner by AWS, Gcloud and Azure. Compromised UEFI Firmware is a constant point of failure in pentesting of the secure chain of trust. That you as a security researcher are dismissing the fact is honestly just unbelievable.
        monocasa 5y ago
        > It's not even a vendor lock in it's signing key lock in that is used in that manner by AWS, Gcloud and Azure. Which is not the mechanism under discussion.
        YXNjaGVyZWdlbgo 5y ago
        No, my comment talked about that some believe PSB is only there to destroy the second hand market and I wrote that it is a false statement and PSB actually provides a higher security for servers and you persisted it's not.
        monocasa 5y ago
        You started off saying > The feature was implemented in 2017 the only vendors that are using it are lenovo and dell. With lenovo being the only one using it on lower tier cpus than epyc. All of the ODMs use PSB in some way (the PSP won't start without it); it's only Lenovo and Dell that use PSB to tie CPUs to certain boards.