tdx-verifier: eventlog: handle OVMF/efistub measurements correctly #674
+135
−22
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
mythi
changed the title
mythi
changed the title
mythi
force-pushed
the
ccel-ovmf
branch
2 times, most recently
from
e5aa1d6 to
d790cc1
Compare
fitzthum
reviewed
Jan 28, 2025
The original "TDVF" kernel parser is not able to find the kernel measurement from the raw eventlog. Futhermore, it never implemented cmdline/initrd parsers similar to be aligned with the TdShim functionality. CoCo TDX uses Qemu direct boot. OVMF loads the kernel using GenericQemuLoadImageLib and it is located under a vendor media device path. This path also is found in the measured event desciption so look for that as the anchor to the kernel measurement digest. The kernel first runs the Linux efistub. Starting Linux 6.9, it adds the support for CC_MEASUREMENT_PROTOCOL which is used to extend RTMRs for cmdline (load image parameters) and initrd measurements. These are logged using EV_EVENT_TAG with the event description (and ID) identifying the measurement. Signed-off-by: Mikko Ylinen <[email protected]>
Add tests to cover the Tdvf* MeasuredEntity enums. It also requires an updated CCEL raw blob which is originated from Kata 3.13.0 based boot with the initrd set as the rootfs. Signed-off-by: Mikko Ylinen <[email protected]>
Add all of the Tdvf* MeasuredEntity results to the TDX claims under ccel. Signed-off-by: Mikko Ylinen <[email protected]>
Xynnn007
approved these changes
Feb 5, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR is a stopgap for checking the OVMF/direct boot based measurements logged in the CCEL. It merely follows the original
MeasuredEntityapproach for finding the kernel/cmdline/initrd measurements from the logs.We should look to improve this and make it more generic to allow policies to check for more of the events and to support for different boot flows as well.