Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

docs: explain the role of PCR[10] and why it is not reproducible #2011

Merged
merged 1 commit into from
Jul 4, 2023
Merged

docs: explain the role of PCR[10] and why it is not reproducible #2011

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 9 additions & 3 deletions docs/docs/architecture/attestation.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -144,7 +144,7 @@ The latter means that the value can be generated offline and compared to the one
| 7 | Secure Boot State | Azure, Constellation Bootloader | No |
| 8 | - | - | - |
| 9 | initramfs | Linux Kernel | Yes |
| 10 | Reserved | - | No |
| 10 | Userspace[^1] | Linux IMA[^1] | No[^1] |
malt3 marked this conversation as resolved.
Show resolved Hide resolved
| 11 | Reserved for Unified Kernel Image components | (Constellation Bootloader) | Yes |
| 12 | Kernel command line | Constellation Bootloader | Yes |
| 13 | Reserved | (Constellation Bootloader) | Yes |
Expand Down Expand Up @@ -177,7 +177,7 @@ The latter means that the value can be generated offline and compared to the one
| 7 | GCP Secure Boot Policy | GCP, Constellation Bootloader | No |
| 8 | - | - | - |
| 9 | initramfs | Linux Kernel | Yes |
| 10 | Reserved | - | No |
| 10 | Userspace[^1] | Linux IMA[^1] | No[^1] |
| 11 | Reserved for Unified Kernel Image components | (Constellation Bootloader) | Yes |
| 12 | Kernel command line | Constellation Bootloader | Yes |
| 13 | Reserved | (Constellation Bootloader) | Yes |
Expand Down Expand Up @@ -209,7 +209,7 @@ The latter means that the value can be generated offline and compared to the one
| 7 | Secure Boot Policy | AWS, Constellation Bootloader | No |
| 8 | - | - | - |
| 9 | initramfs | Linux Kernel | Yes |
| 10 | Reserved | - | No |
| 10 | User space | Linux IMA | No[^1] |
| 11 | Reserved for Unified Kernel Image components | (Constellation Bootloader) | Yes |
| 12 | Kernel command line | Constellation Bootloader | Yes |
| 13 | Reserved | (Constellation Bootloader) | Yes |
Expand Down Expand Up @@ -308,3 +308,9 @@ flowchart LR
D["Public key"]-- "verifies" -->E["Runtime measurements"]
E["Runtime measurements"]-- "verify" -->F["Constellation cluster"]
```

## References

[^1]: Linux IMA produces runtime measurements of user space binaries.
However, these measurements aren't deterministic and thus, PCR\[10] can't be compared to a constant value.
Instead, a policy engine must be used to verify the TPM event log against a policy.