NX_COMPAT shims should force NX_REQUIRE in mok_policy.

Open
#757 0 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
c

Research direction

Start by tracing how mok_policy and the DllCharacteristics NX_COMPAT flag are handled during shim configuration and validation. Reproduce the insecure combination described in the issue, then verify that configurations with NX_COMPAT set without NX_REQUIRE are rejected and that valid combinations still build.

Written by the indexing model from the issue text.

Description

It is currently possible to build a shim with an insecure configuration where NX_COMPAT flag in DllCharacteristics is set but mok_policy does not have NX_REQUIRE flag set.

This should be prevented because such a shim can be booted on NX enforcing firmware and can be used to chainload non-NX binaries and thus becomes an NX bypass tool.

Dominant language
C
Stars
1.1k
Forks
348
PR merge metrics
No merged PRs in 30d

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

More from rhboot/shim

All issues in rhboot/shim

Similar issues

More C issues

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.