DasharoVariablesLib: fix non-deterministic measurements #52
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
This fixes "SecurityPkg: measure Dasharo variables before boot". gRT->GetNextVariableName() doesn't return variables in any fixed order. Seems like the order matches order in SMMSTORE. This means that measuring variables while enumerating them will produce different results depending on which variables were update last (setting a variable in SMMSTORE is marking old entry as deleted and appending of a new one). Sort list of variables that share the same GUID before measuring any of them to impose a fixed order. Also fix spacing in several places. Signed-off-by: Sergii Dmytruk <[email protected]>
miczyg1
approved these changes
Jul 19, 2024
This was referenced Jul 19, 2024
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Outdated suggestions cannot be applied.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 fixes "SecurityPkg: measure Dasharo variables before boot".
gRT->GetNextVariableName() doesn't return variables in any fixed order. Seems like the order matches order in SMMSTORE. This means that measuring variables while enumerating them will produce different results depending on which variables were update last (setting a variable in SMMSTORE is marking old entry as deleted and appending of a new one). Sort list of variables that share the same GUID before measuring any of them to impose a fixed order.
Also fix spacing in several places.
Dasharo/edk2#139 (comment)