[Bug bounty] macOS launchd fast path regex-matches drifted auth configuration

[aikinley]

Stage

connect

Coding agent

OpenAI Codex

Coding agent version

Codex desktop; Monk plugin v0.1.54 (2a4f9cf)

Repro steps

The macOS launcher's healthy-agent reuse gate reads the generated launchd plist with regular-expression grep patterns even though it is comparing literal configuration values.

I reproduced the exact Darwin branch with a network-free fixture:

1. Use an isolated HOME, stub uname to Darwin, and return the expected protected-resource document from the health probe.
2. Put a launchd plist at ~/Library/LaunchAgents/io.monk.agent.plist containing all current values except the previous auth URL is the distinct, valid URL https://auth-monk-io.
3. Invoke scripts/start-monk-agent.sh with the requested default MONK_AUTH_URL=https://auth.monk.io.
4. Record whether the fixture launchctl is invoked to restart the companion.

The current release fails the regression:

launchd fast path falsely accepted a different stored auth URL

The requested value is interpolated into this regex:

grep -q "<string>$auth_url</string>" "$launchd_plist"

Each . in https://auth.monk.io is therefore a wildcard, so it incorrectly matches the stored <string>https://auth-monk-io</string>.

Expected behavior

The launcher should compare launch configuration literally. When the requested auth issuer differs from the one in the launchd plist, it should restart the healthy companion once so the new process inherits the current value.

Actual behavior

Regex metacharacters in the requested auth URL can match different stored characters. launchd_configured returns true, the launcher exits through its healthy fast path, and the process keeps the previous authentication configuration even though startup reports success.

The same non-literal comparison is used for auth client ID, audience, autospin URL, local mode, and plugin version. URLs contain dots by default, making this more than a hypothetical regex-input surface.

I validated the minimal fix locally: use grep -Fq for every literal launchd value, matching the existing fixed-string check already used for agent_path. The focused regression then forces the expected launchd restart and passes; the Antigravity config regression, sh -n, and git diff --check also pass.

Collision check

• [Bug bounty] healthy Linux launcher ignores changed auth configuration #21 covered the old Linux/non-Darwin fast path omitting auth configuration entirely. Its report explicitly noted that the macOS path checked the generated launchd configuration; this report shows that the macOS check can return a false match.
• [Bug bounty] macOS launcher writes unescaped values into its launchd plist #181 covers XML escaping while writing the launchd plist, not the later equality comparison.
• [Bug bounty] Linux healthy fast path ignores local-mode and plugin-version changes #183/[Bug bounty] Healthy-agent fast path ignores MONK_AGENT_LOCAL / MONK_PLUGIN_VERSION drift on Linux/Windows #229 cover omitted local-mode/plugin-version fields on Linux/Windows; these fields are present here but compared as regexes.

Searches for launchd auth URL drift, launchd regex configuration, fixed-string plist matching, and launchd_configured found no matching report.

Severity (your guess)

major

The launcher reports success while the running companion can remain bound to an old OAuth issuer/client/audience or autospin endpoint. Authentication can then fail in a way that contradicts the visible environment. Removing the old agent/plist or causing an unrelated restart is a workaround.

OS

Windows 11 with an isolated shell fixture selecting the exact Darwin branch; no native-macOS claim.

monkd version

Not involved; the defect is in companion reuse before runtime operations.

Target cloud

None; network-free launcher fixture.

Integration

Monk plugin macOS launchd lifecycle

Fix PR

Draft PR #268 adds the current-release red-to-green regression and the validated fixed-string comparison across all three shipped launcher mirrors. It remains draft only because GitHub limits contributors without write access to four ready PRs at once.

[jihadMo]

I have implemented the fix for macOS launchd auth configuration matching in scripts/start-monk-agent.sh. Updated launchd_configured to use grep -Fq fixed-string matching instead of regex grep -q for literal config values (auth_url, auth_client_id, auth_audience, autospin_url), preventing dot wildcard false matches on drifted auth URLs, along with automated test coverage in tests/launchd_fastpath_test.sh.

Fix branch: https://github.com/jihadMo/capgo/tree/fix/launchd-fastpath-fixed-string-match