c18n: Improve detection of interrupted compartment #2220
Merged
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
bsdjhb
reviewed
Sep 13, 2024
dpgao
force-pushed
the
c18n-sigdetect
branch
from
1428329
to
3b3d25b
Compare
Fix a bug where the dummy untrusted stack is not installed when a thread launches. Previously, the interrupted compartment is identified by checking whether its untrusted stack is a subset of the canonical copy of that stack. However, this subset relation should actually be inverted, that is, the untrusted stack of the interrupted compartment should be a superset of the canonical stack. Otherwise, a compartment which holds a portion of another compartment's stack would be able to impersonate it. (The SW_VMEM permission on the canonical stack has to be stripped before the comparison.) In addition, a bounds-check was missing for the tail-call scenario, which might result in reading from the stack table using an invalid index. Also, the tail-call scenario cannot be ruled-out even when the presumptive callee's stack is not allocated---we might be interrupted when a tail-call is taking place _and_ the callee's stack is unallocated.
dpgao
force-pushed
the
c18n-sigdetect
branch
from
3b3d25b
to
d7d9d69
Compare
bsdjhb
approved these changes
Oct 16, 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Outdated suggestions cannot be applied.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.
Previously, a bounds-check was missing for the tail-call scenario, which might result in reading from the stack table using an invalid index.
Also, the tail-call scenario cannot be ruled-out even when the presumptive callee's stack is not allocated---we might be interrupted when a tail-call is taking place and the callee's stack is unallocated.