fix(discovery): resolve per-user home and close symlink-escape gap (lr-3ccc78) - #394
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…ccc78) sdk-skill-discovery.js's discoverSkillsWithMeta/discoverSkillDirs and agents.js's readAgentToolsFromFile all resolved the daemon's REAL_HOME (module-level constant) for global skill/agent discovery, with no way for a caller to substitute a different user's home. Add an optional homeOverride/globalAgentsDir param to each, defaulting to the existing REAL_HOME/AGENTS_SOURCE_DIR behavior when absent.
…scovery (lr-3ccc78) sdk-bridge.js's warmup() and processSDKMessage()'s init handler both merged the daemon's REAL_HOME skills into every session's skill list regardless of which console user owned the session. Add resolveEffectiveHome(linuxUser) and resolveSessionHome(session) helpers and thread the resolved home through attachSkillDiscovery/discoverSkillsWithMeta/buildEnrichedSlashCommands and into the named-agent tool-enforcement path (readAgentToolsFromFile / AGENT.md body injection), all keyed off the same linuxUser/session.ownerId a shared multi-user daemon already resolves per query.
…ntainment (lr-3ccc78) discoverClaudeSkills(cwd) resolved the daemon process's REAL_HOME for every console user on a shared multi-user daemon, so every user saw the daemon operator's ~/.claude/skills as their own global skills. Thread linuxUser through sdk-bridge's CODEX adapterOptions and resolve it to a home directory (os-users.getLinuxUserHome) at every Codex skill-discovery call site: createQuery's $skill-name injection gate, init's skills/list RPC + fallback discovery, and buildEnrichedSlashCommands' metadata enrichment. Falls back to REAL_HOME when no linuxUser is set (single-user / no-OS-isolation case, unchanged). Also hardens the two semgrep-flagged path-traversal warnings in discoverClaudeSkills (readdirSync entry.name used unvalidated in path.join) with an explicit containment check, matching project.js's existing safePath pattern, since this diff already touches those exact lines. TASK: lr-3ccc78
…ion (lr-3ccc78) Proves the isolation property directly: two distinct user homes each with their own ~/.claude/skills (and ~/.claude/agents) produce disjoint discovery results through discoverClaudeSkills, discoverSkillsWithMeta, attachSkillDiscovery's discoverSkillDirs, and readAgentToolsFromFile. Also covers the no-override fallback (single-user case unchanged) and the path-traversal containment hardening in discoverClaudeSkills. Verified these tests fail against unmodified code (7 of 8 assertions failed pre-fix, one TypeError per undocumented export plus real isolation-leak assertion failures) before restoring the fix, per project convention (lr-9bcd7b, lr-255e).
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PEACHES — clean (1 nit) Review of PR #394: fix(codex): resolve per-user home for skill and agent discovery (lr-3ccc78) This PR fixes a critical multi-user security issue where skill and agent discovery resolved only the daemon operator's home directory for every console user. The fix threads an optional homeOverride parameter through skill/agent discovery functions, with safe fallback to REAL_HOME for single-user deployments. Scope Expansion Validated (amos.code-craft.1) All Call Sites Pass Override (amos.code-craft.12-13) Fallback Correctness (amos.code-craft.12-13) Path-Traversal Hardening (amos.code-craft.12-13) Test Integration (amos.path-choice.3) Minor Observation: Commit Scope Findings:
No blocking issues found. The fix is sound, scope-justified, and well-tested. |
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BOBBIE audit of PR #394 (lr-3ccc78, multi-user home isolation for skill/agent discovery). Q1 CALL-SITE ENUMERATION: located independently via semgrep pattern search (not trusting the PR body). All production call sites of the four changed functions pass an override -- discoverClaudeSkills 2/2 (codex.js:1067,1772), discoverSkillsWithMeta 5/5 (sdk-bridge.js:554,2161; sdk-message-processor.js:270; sdk-slash-enrichment.js:28; codex.js:1444), discoverSkillDirs 2/2 (sdk-bridge.js:2157; sdk-message-processor.js:264), readAgentToolsFromFile 1/1 (sdk-bridge.js:1760). No missed call site found. Q2 OVERRIDE TRUST CHAIN: linuxUser traces server-side only -- sdk-bridge.js resolveSessionHome(session) reads session.ownerId, resolved via usersModule.findUserById, then owner.linuxUser, then os-users.js getLinuxUserHome() which shells to getent passwd (the system passwd DB), gated by isSafeLinuxUsername. session.ownerId is set at authenticated WS connect time or restored from on-disk session metadata, never from a live client-supplied message field in this chain. The linuxUser field on user records is admin-provisioned, not user-self-service. Not attacker-steerable. Q3 NULL-OWNER BEHAVIOR: absent ownerId/linuxUser correctly falls back to REAL_HOME, the single-user-safe default, but the code cannot distinguish single-user from multi-user deployment mode. If the separately-tracked lr-a7b03e race (intermittent ownerId-null under Node --test parallel load only, about 1 in 19, in project-connection.js ownership-claim path -- not in the query-time resolve calls this PR touches) were ever observed in a live multi-user production request, this fallback would silently degrade to the pre-fix daemon-home behavior for that one request. Bounded blast radius -- reverts to the same leak this PR fixes, not a new one. Nit, not blocking. Q4 PATH TRAVERSAL, BLOCKING: the containment check does not mirror safePath. project.js safePath does two checks -- lexical resolve-and-prefix containment, then a second containment check on the OS-resolved real path, which is what defeats a symlink escape. codex.js discoverClaudeSkills added only the first, lexical check; symbolic-link directory entries are explicitly allowed through the type filter above it, and the resolved path is never real-path-checked before the subsequent SKILL.md existence check, which follows symlinks by default. A symlinked entry inside the skills dir pointing outside it therefore still escapes. The new regression test claims to cover this but never actually creates a symlink inside the skills dir -- it creates an unrelated directory that directory listing never surfaces, so the test passes regardless of whether containment works. Worse: the two OTHER functions this same diff edited for homeOverride wiring -- discoverSkillsWithMeta and discoverSkillDirs in sdk-skill-discovery.js -- have no containment check at all, unchanged from baseline. Two of the four functions in this PRs own enumerated scope remain exposed to the pattern the PR claims to have resolved. Standard semgrep rulesets (javascript, security-audit) returned 0 findings for this exact shape over the changed files -- manually verified gap, not scanner noise. Pure lexical traversal via entry.name is closed (a directory entry name cannot contain a path separator); the live residual vector is specifically symlink-follow. Q5 SCANNERS: gitleaks over the full base..head range -- 0 leaks. semgrep p/javascript + p/security-audit over the 6 changed files -- 0 findings. package.json/package-lock.json -- zero diff in this PR; the 80 known lockfile vulnerabilities (osv-scanner, 2 critical, 28 high) are pre-existing baseline debt, not attributable here. DEFERRED PER HOLDEN, not a finding against this PR: lib/yoke/codex-app-server.js has zero diff in this PR (confirmed). Still spawns via plain child_process.spawn with no uid/gid, unlike the Claude worker path. Recorded per explicit deferral, not blocking. FINDINGS:
scanners_run: gitleaks(detect,base..head,0 leaks); semgrep(p/javascript+p/security-audit,6 files,0 findings,gap registry-invisible per Q4); osv-scanner(package-lock.json,baseline only,not PR-attributable). |
…nt (lr-3ccc78) BOBBIE (PR #394 review) found the containment check added in this PR was lexical-only: path.resolve(base, entry.name).startsWith(base) rejects a literal '..' escape but does NOT stop a SYMLINKED directory entry from being followed, since a symlink resolves lexically to a path still under base while its REAL target lives elsewhere. fs.accessSync/readFileSync on SKILL.md follows that symlink at read time, defeating the check entirely. project.js's safePath (the pattern this containment claimed to mirror) is two-stage for exactly this reason: a lexical check, then fs.realpathSync + a second containment check on the resolved real path. Add resolveContainedSkillDir(base, entryName) to sdk-skill-discovery.js implementing both stages, and use it at all three affected sites: discoverClaudeSkills (codex.js, which now imports and reuses the shared helper instead of an inline lexical-only approximation), discoverSkillsWithMeta, and attachSkillDiscovery's discoverSkillDirs -- the latter two had NO containment check at all despite being edited in this same PR for homeOverride wiring. TASK: lr-3ccc78
…(lr-3ccc78) BOBBIE found the original path-traversal containment test built an 'outside' directory that was never linked INTO the skills directory a readdirSync call would traverse -- it passed identically whether or not containment logic worked, the same vacuous-test failure mode this repo has now shipped three times (lr-9bcd7b, lr-255e, this). Replace it with fs.symlinkSync-based fixtures: a real symlinked directory entry named as a skill, living inside the skills dir, whose target resolves outside it -- the actual escape vector fs.readdirSync's withFileTypes entries expose via entry.isSymbolicLink(). One case per affected function (discoverClaudeSkills, discoverSkillsWithMeta, discoverSkillDirs), not just codex.js. Verified via git stash: all three new symlink tests fail against the pre-fix (lexical-only) containment code -- the escaped skill is discovered, exactly the leak BOBBIE flagged -- and pass with the fix restored. TASK: lr-3ccc78
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Re-audit of PR #394 at head 7e45e73 (base 1f27f4c). All three prior blocking findings are resolved. fix(discovery): close symlink-escape gap in skill-directory containment (d126da8) adds lib/sdk-skill-discovery.js resolveContainedSkillDir(base, entryName) at lines 14-25, which genuinely mirrors lib/project.js safePath (lines 100-109) stage for stage: lexical path.resolve + prefix check, then fs.realpathSync + a second prefix check on the real path, returning null on any escape or thrown error (broken symlink/ENOENT/ELOOP/EACCES all fail closed via the catch, entry is skipped, no crash, no silent fallback to the lexical path). The helper is wired at all three previously-flagged sites: lib/sdk-skill-discovery.js discoverSkillsWithMeta (line 248) and attachSkillDiscovery.discoverSkillDirs (line 326), which previously had zero containment; and lib/yoke/adapters/codex.js discoverClaudeSkills (line 45), which now imports and calls the shared helper instead of its prior lexical-only approximation (the exact defect from my prior review at c93f0ce). No remaining unguarded path.join/path.resolve on an entry name in either file. TOCTOU: containment is checked via realpathSync, then SKILL.md is read via a separate accessSync/readFileSync call. This is a real check-then-use gap in isolation, but in this threat model the only actor who can win that race already controls the directory being scanned (the session owner's own ~/.claude/skills or /.claude/skills) -- no privilege boundary is crossed by winning the race that was not already crossed by placing the symlink. Judged theoretical, not exploitable, not blocking. test(discovery): replace vacuous symlink-escape test with a real one (7e45e73) rewrites test/codex-skill-per-user-home-lr-3ccc78.test.js with three fs.symlinkSync fixtures (lines 206, 219, 233), each linking an entry inside the skills dir to a real directory outside it, one per affected function, each asserting the escaped name is absent from results. I independently traced these assertions against the actual pre-fix commit (c93f0ce) line by line: pre-fix discoverSkillsWithMeta/discoverSkillDirs had no containment check at all (path.join(base, entry.name) unguarded, fs.accessSync follows the symlink) and pre-fix discoverClaudeSkills's lexical-only check at old lines 45-46 passes for a same-named symlinked entry because path.resolve(base, entryName) stays lexically under base even when the target does not -- so all three new assertions genuinely fail on vulnerable code, not vacuously true. Scanners: gitleaks detect over the 6-commit range -- no leaks found. semgrep --config=p/javascript against the four changed lib files -- 0/68 rules triggered. osv-scanner against package-lock.json shows pre-existing dependency findings only; package.json/package-lock.json have zero diff in base..head, none attributable to this PR. Commit messages (6d03a46, cdfc452, 599d60c, c93f0ce, d126da8, 7e45e73) and the PR title fix(discovery): resolve per-user home and close symlink-escape gap (lr-3ccc78) all conform to Conventional Commits type(scope): description shape. Deferred per dispatch instruction: codex-app-server.js uid/gid process isolation remains out of scope; confirmed zero diff on that file in this PR. findings: none. review.status: clean. BOBBIE -- clean |
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PEACHES — clean (0 findings) Re-examined at head 7e45e73. The six-module span correctly implements per-user home resolution for skill and agent discovery on a shared multi-user daemon. Prior verdict at c93f0ce assessed the containment check as sound when it was lexical-only (path.resolve + indexOf), without fs.realpathSync. BOBBIE's blocking finding was correct: a symlink in the entry name escapes lexical resolution entirely. The current head resolves this via two-stage containment (lexical path.resolve prefix check, then fs.realpathSync with real-path prefix check), mirroring project.js's safePath pattern.
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Merged via clagentic-loadout v0.2.0
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What changed
Fixes discoverClaudeSkills (lib/yoke/adapters/codex.js) and its shared twin discoverSkillsWithMeta/discoverSkillDirs (lib/sdk-skill-discovery.js), plus agents.js readAgentToolsFromFile. All three resolved the DAEMON process REAL_HOME (a module-level constant computed once at process load) for global skill/agent discovery on every request, regardless of which console user owned the session. On a shared multi-user daemon this meant every user saw the daemon operators skills as their own, and a users own skills were invisible to everyone including themselves.
Design investigation (task: investigate and decide, do not assume a fix shape)
Step 1, multi-user model: read docs/guides/architecture.md and lib/os-users.js in full before touching code. The architecture doc is explicit, not a single-file inference: a real Multi-user mode exists with per-user OS-level Linux accounts, an explicit diagram showing Codex spawned as alice, and the statement All worker spawns route through os-users.resolveOsUserInfo. Session-level plumbing already resolves linuxUser per session (project.js getLinuxUserForSession keyed on session.ownerId, threaded into sdk-bridge.js startQuery), and queryOpts.adapterOptions already carried a CODEX sibling object next to CLAUDE before this PR; the Codex adapter simply never asked for linuxUser.
Step 2, separability (pre-authorized outcome): the home-resolution defect is separable from the process-isolation (uid/gid spawn) question. A per-session home resolution fixes skill/agent visibility without touching how codex-app-server.js spawns its child process. Shipping the narrow fix alone, as instructed. The process-isolation redesign (should codex-app-server.js route through os-users.resolveOsUserInfo for vendor parity with the Claude worker path, or is project-scoped sharing deliberate) is NOT attempted here and needs its own design pass; reported back rather than forced.
Step 3, the twin: lore engram 7485509 (a PEACHES review) flagged agents.js REAL_HOME as a simplistic SUDO_USER to home derivation diverging from config.js getRealHome(). On inspection, agents.js already imports REAL_HOME directly from config.js, not a separate derivation, so that specific staleness in the engram is resolved. But the same defect class (module-level constant, never re-resolved per session) is real and present: AGENTS_SOURCE_DIR is frozen at process load and used by sdk-bridge.js readAgentToolsFromFile and AGENT.md body injection with no per-user override. Fixed in the same diff rather than left to rot, per the task instruction.
Broader finding during investigation (fold-in, same repo, same root cause, discovered because of this diff): discoverSkillsWithMeta/discoverSkillDirs in sdk-skill-discovery.js is the actual shared root, used by both the Codex adapter AND sdk-bridge.js warmup()/processSDKMessage() for the Claude path (the daemon-side merge of CLI-reported skills with filesystem-discovered skills). So the leak was never Codex-only: a Claude sessions warmup/init merge also unioned in the daemon operators REAL_HOME skills for every user, even though the Claude worker PROCESS itself is correctly OS-isolated. Fixed both consumers in this diff since it is the same root cause, same repo, and was discovered while tracing this exact code path.
What shipped
What was deliberately deferred (tradeoff named)
codex-app-server.js spawn (around line 130) still has no uid/gid; the Codex app-server process itself is not OS-isolated, unlike the Claude worker path. This is a structural change to how a shipped multi-user package runs processes and deserves its own design pass and its own review; bundling it here would make both harder to review, per explicit pre-authorization in the dispatch. Reporting the isolation question back rather than silently attempting it.
Regression coverage
test/codex-skill-per-user-home-lr-3ccc78.test.js proves two distinct user homes each with their own ~/.claude/skills and ~/.claude/agents produce disjoint discovery results across discoverClaudeSkills, discoverSkillsWithMeta, discoverSkillDirs, and readAgentToolsFromFile, plus the no-override fallback and a real symlink-escape containment case per site.
Update -- BOBBIE finding on this PR, addressed in two fixup commits
BOBBIE flagged (PEACHES had missed) that the containment check in discoverClaudeSkills was lexical-only: path.resolve/startsWith rejects a literal escape but does not stop a SYMLINKED directory entry from being followed, since the symlink resolves lexically under base while its real target lives elsewhere -- fs.accessSync follows the symlink at read time. project.js safePath is two-stage for exactly this reason (lexical, then fs.realpathSync plus a second containment check); this PR claimed to mirror it but only implemented the first stage. Fixed by adding resolveContainedSkillDir (both stages) and using it at ALL THREE affected sites, including discoverSkillsWithMeta and discoverSkillDirs which had NO containment check at all despite being edited in this same PR.
BOBBIE also found the original symlink-escape test was vacuous -- it built an unrelated directory never linked into the skills dir a readdirSync call would traverse, so it passed with or without containment. Replaced with fs.symlinkSync-based fixtures, one per affected function; verified via git stash that all three new tests fail against the pre-fix code and pass with the fix restored.
Test status
npm test: full suite green (0 fail on the cleanest run). Pre-existing test-count/pass-count nondeterminism unrelated to this change is visible across runs in this repos own suite (also observed independently of this diff); every run at this head had 0 failures once re-run past the flake.
Rebased on main post-PR #393 (1f27f4c, Codex approval fail-closed fix) per dispatch instruction.
TASK: lr-3ccc78