[zwanski-start]

Closes #159

Problem

In WSL the default user is root, so Path.home() is /root. /root is in LINUX_BLOCKED, and the folder browser's first call (GET /api/filesystem/list with no path → home) returned 403 "Blocked access to restricted path: /root", so users couldn't pick a folder for a new project. projects.py and scaffold.py use the same is_path_blocked(), so creating a project under /root/... was also rejected. The same issue hits systems that keep homes under /var (e.g. /var/home/<user> on Fedora Silverblue).

Change (server/routers/filesystem.py)

• Split the blocklist into system paths (get_system_blocked_paths) and home-relative credential dirs (get_sensitive_blocked_paths).
• is_path_blocked() now:
  1. Always blocks credential dirs (~/.ssh, ~/.aws, …) — even inside home.
  2. Allows the user's own home directory and everything inside it.
  3. Otherwise applies the platform system blocklist as before.
• A home of / is ignored (get_browsable_home() returns None) so it can't unblock the whole filesystem.
• Removed the now-unused combined get_blocked_paths() (no other callers).

Other users' /root stays blocked for non-root users, and only the home subtree of /var is opened up, not /var itself.

Verification

• New test_filesystem_security.py (5 tests, monkeypatches Path.home): root home browsable, /root/.ssh still blocked, /var/home/alice browsable while /var and /var/log stay blocked, regular user still blocked from /root//etc, HOME=/ ignored.
• Exercised the router with FastAPI's TestClient and Path.home set to /root: /root gets past the blocklist, while /etc and /root/.ssh still return "Access to this directory is not allowed".
• ruff check . clean; python test_security.py passes.
• test_ws_security.py / test_devserver_security.py have 21 failures that are already on master (same count with my change stashed). They're unrelated to this fix.
• Backend-only change, so I didn't check it in the browser.

Assumptions

• The issue mentions autoforge --workspace, but the CLI has no such flag. The root cause is the home-directory default, not the workspace, so this PR doesn't add one.

🤖 Generated with Claude Code

[zwanski-start]

🔍 QA report: ✅ Passed

Tester: Ada (cubefarm agent, in a fresh session) · Round: 1 · Author: Dennis

The fix resolves #159: when the home directory sits under a blocked system path (/root in WSL, /var/home on Silverblue), the folder browser opens at home and projects can be created there, while system dirs (/etc, /var, /root for other users, /tmp) and credential dirs (~/.ssh, ~/.aws) stay blocked. I confirmed the bug on master, then exercised the fix end to end by running the server with HOME pointed at a real directory under /var and creating a project through the UI. The 5 new tests, ruff, the security suites, the other pytest files and the UI build all pass. The mypy errors and the 21 ws/devserver test failures are the same on master.

	Check	Details
✅	Issue repro on master	On origin/master with Path.home() patched to /root, is_path_blocked(/root) and is_path_blocked(/root/projects) both return True, which reproduces the 403. On the PR branch both return False.
✅	Default folder-browser listing when home is under a blocked path	Server started with HOME=/var/tmp/qa-ada-284-home (under blocked /var). GET /api/filesystem/list with no path returns 200, lists the home contents, and hides blocked .ssh/.aws.
✅	System and credential paths still blocked	GET /api/filesystem/list returns 403 for /var, /var/tmp, /etc, /root, /tmp, /.ssh and /.aws. Validating /var/tmp/x returns 'Access to this directory is not allowed'. create-directory in /var/tmp and /.ssh returns 403.
✅	Project creation under home (projects.py path check)	POST /api/projects with a path under home returns 200 and the project is registered. A path under /var/tmp or /.ssh returns 403 'Cannot create project in system or sensitive directory'. create-directory under home returns 200.
✅	UI new-project flow in the browser	New Project > name > folder browser opens at the home under /var (breadcrumbs / > var > tmp > qa-ada-284-home). I browsed into projects/existing and selected it, then Blank > Edit Templates Manually showed 'Project Created!' and redirected to the project dashboard. Console: 403s only when I clicked the blocked 'var' breadcrumb (expected). The other error, an invalid pattern regex on the project-name input, is already on master.
✅	Code review: security edge cases	Paths are resolved before the home exemption, so a symlink from home to /etc stays blocked. Credential dirs are checked before the home exemption. HOME=/ is ignored. Only the home subtree is exempted, not its blocked parent. get_blocked_paths had no other callers. scaffold.py, projects.py and filesystem.py all use the same is_path_blocked.
✅	Blocked intermediate breadcrumb UX	Minor, not blocking: clicking a blocked breadcrumb (e.g. 'var') shows an empty list with no error message and you have to press Cancel. It does not happen in the WSL /root case, where '/' and 'root' are both browsable.
✅	New unit tests	test_filesystem_security.py has 5 tests covering root home, credential dirs, home under /var, a regular user, and HOME=/. All pass.
✅	Regression vs master baseline	mypy shows 25 errors on both master and this branch (filesystem.py ones are the Windows-only ctypes.windll). test_ws_security.py and test_devserver_security.py show 21 failed / 67 passed on both.
⏭️	UI e2e (Playwright suite)	PR is backend-only (no ui/ changes). The UI build and lint were run instead.
✅	Phone-size layout	At 390x844 the project dashboard renders. The cramped layout is already on master and this PR doesn't touch the UI.
✅	Cleanup / orphan processes	Server stopped. No leftover uvicorn on 5571. Test home dir and the throwaway master worktree removed. Worktree is clean.

🧪 Commands run

Command	Result
ruff check .	All checks passed
mypy .	25 errors in 10 files (same 25 on origin/master; none new)
python test_security.py	ALL TESTS PASSED
python test_security_integration.py	ALL INTEGRATION TESTS PASSED
python -m pytest test_filesystem_security.py test_client.py test_dependency_resolver.py test_rate_limit_utils.py	60 passed, 0 failed
python -m pytest test_ws_security.py test_devserver_security.py	21 failed, 67 passed (same on origin/master)
npm --prefix ui run build	success (tsc -b && vite build)
npm --prefix ui run lint	0 errors, 6 warnings
HOME=/var/tmp/qa-ada-284-home uvicorn server.main:app --host 127.0.0.1 --port 5571 + curl probes of /api/filesystem/list, /validate, /create-directory, /api/projects	home 200; system/credential paths 403 as expected
master-branch probe script (Path.home=/root) calling is_path_blocked	/root blocked: True on master (bug reproduced)

No browser screenshots were taken in this round.

_{Posted by cubefarm · merges automatically once GitHub's checks pass}