feat: implement imix execution guardrails by hulto · Pull Request #2061 · spellshift/realm

hulto · 2026-03-08T16:00:57Z

Implements the requested execution guardrails capability for the imix agent.

Changes

New Library Crate (guardrails): Created a dedicated guardrails crate mirroring the design of host_unique. Includes a Guardrail trait.
Guardrail Implementations:
- File: Checks if a specific file exists on disk.
- Process: Checks if a specific process is currently running via the sysinfo crate.
- Registry: Checks if a specific registry subkey (and optionally a value name) exists. This is conditionally compiled for Windows using the winreg crate.
Configuration (pb/src/config.rs): Integrated guardrails::check_guardrails() into the initial beacon configuration phase. If the check returns false, the agent safely logs and exits std::process::exit(0).
Build-time Validation: Configured a build.rs script in the guardrails crate to parse the IMIX_GUARDRAILS environment variable into a typed JSON structure. If the JSON format is invalid, compilation will fail, preventing misconfigured payloads.
Documentation: Updated docs/_docs/user-guide/imix.md adding a "Guardrails" section that explains usage and provides JSON configuration examples.
Testing: Added inline unit tests within the guardrails crate to test the various implementations and deserialization logic.

All workspace tests continue to pass successfully.

PR created automatically by Jules for task 5041236407544312228 started by @hulto

Adds a modular `guardrails` capability to `imix` similar to `host_unique`. This allows operators to enforce that an implant only executes if specific conditions (file presence, running process, or registry keys) are met on the host. - Adds new `guardrails` workspace library crate. - Supports `file`, `process`, and `registry` (Windows) rules. - Integrates `IMIX_GUARDRAILS` JSON configuration loading at compile time via `build.rs` - Validates guardrails at runtime startup, exiting gracefully if checks fail. - Updates documentation with usage examples. Co-authored-by: hulto <7121375+hulto@users.noreply.github.com>

google-labs-jules · 2026-03-08T16:00:58Z

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github-actions · 2026-03-08T16:16:49Z

Summary

Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
2795 ±0	2795 ±0	0 ±0	0 ±0	0 ±0	0 ±0	1ms ±0

Previous Results

Build 🏗️	Result 🧪	Tests 📝	Passed ✅	Failed ❌	Skipped ⏭️	Other ❓	Flaky 🍂	Duration ⏱️
#1669	✅	2795	2795	0	0	0	0	38.9s

Insights

Average Tests per Run	Total Flaky Tests	Total Failed	Slowest Test (p95)
2795	0	0	5.8s

Slowest Tests

Test 📝	Results 📊	Duration (avg) ⏱️	Duration (p95) ⏱️
TestDockerExecutor_Build_ContextCancellation	1	5.8s	5.8s
eldritch-libsys: std::dll_inject_impl::tests::test_dll_inject_simple	1	5.1s	5.1s
TestInteractiveShell	1	5.1s	5.1s
TestOtherStreamOutput	1	5.0s	5.0s
imix::bin/imix: install::tests::test_install_execution	3	1.7s	4.9s
imix::bin/imix: install::tests::test_install_execution	3	1.7s	4.9s
imix::bin/imix: install::tests::test_install_execution	3	1.7s	4.9s
TestDockerExecutor_Build_SimpleEcho	1	3.3s	3.3s
imix::bin/imix: tests::task_tests::test_task_streaming_output	3	3.0s	3.0s
imix::bin/imix: tests::task_tests::test_task_streaming_output	3	3.0s	3.0s

_{🎉 No failed tests in this run. | 🍂 No flaky tests in this run.}

Github Test Reporter by CTRF 💚

🔄 This comment has been updated

hulto · 2026-03-08T21:10:51Z

implants/lib/pb/src/config.rs

        };

+        let guardrails = parse_guardrails();
+        if !guardrails::check_guardrails(guardrails) {


Update check_guardrails such that only one needs to be succesful not all.
Clarify this behavior in the docs.

Hi! You mentioned me here. Is there anything specific you would like me to change or review regarding the guardrails check?

@jules Update check_guardrails such that only one needs to be succesful not all.
Clarify this behavior in the docs.

Done. Updated the check_guardrails implementation to pass if any guardrail matches (OR condition) and return true if the guardrails list is empty. Docs were updated to reflect this.

hulto · 2026-03-08T21:11:55Z

implants/lib/guardrails/src/process.rs

+        sys.refresh_processes();
+
+        for (_, process) in sys.processes() {
+            if process.name().eq_ignore_ascii_case(&self.name) {


Update names and matches to always be lower case clarify in docs.

Is there an issue with how the process name is being checked?

@jules Update names and matches to always be lower case clarify in docs.

Updated the docs to clarify that these matches are evaluated as case-insensitive.

hulto · 2026-03-08T21:12:08Z

implants/lib/guardrails/src/file.rs

+        if self.path.is_empty() {
+            return false;
+        }
+        Path::new(&self.path).exists()


Update names and matches to always be lower case.

Did you have any questions or feedback about the file existence check?

@jules Update names and matches to always be lower case.

Updated the process check and the file check (for Windows) to use to_lowercase() for case-insensitive matching.

Adds a modular `guardrails` capability to `imix` similar to `host_unique`. This allows operators to enforce that an implant only executes if specific conditions (file presence, running process, or registry keys) are met on the host. - Adds new `guardrails` workspace library crate. - Supports `file`, `process`, and `registry` (Windows) rules. - Integrates `IMIX_GUARDRAILS` JSON configuration loading at compile time via `build.rs` - Validates guardrails at runtime startup, exiting gracefully if checks fail. - Updates documentation with usage examples. Co-authored-by: hulto <7121375+hulto@users.noreply.github.com>

hulto commented Mar 8, 2026

View reviewed changes

google-labs-jules bot and others added 2 commits March 8, 2026 21:15

hulto marked this pull request as ready for review March 8, 2026 22:39

hulto added 3 commits March 14, 2026 10:00

Merge branch 'main' into feat/imix-guardrails-5041236407544312228

13d00e1

Merge branch 'main' into feat/imix-guardrails-5041236407544312228

2fd388c

Merge branch 'main' into feat/imix-guardrails-5041236407544312228

19ab6a4

hulto merged commit 1fde9c7 into main Mar 14, 2026
8 checks passed

hulto deleted the feat/imix-guardrails-5041236407544312228 branch March 14, 2026 18:45

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github-actions bot commented Mar 8, 2026 •

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