fix(deploy): chown read-only-rootfs tmpfs in root-init; drop podman-rejected tmpfs uid= (#333 deploy fix) (#337)

The droplet's podman 5.6.2 rejects `--tmpfs=...:uid=1001,gid=1001` outright
(`Error: unknown mount option "uid=1001": invalid mount option`; and there is no
working `--mount type=tmpfs,tmpfs-uid=` either). This fail-closed #333's
pre-cutover BOOT_CHECK gate on the first push-to-main deploy. build+test were
green because nothing there runs podman -- and test_tmpfs_options_pinned even
pinned the rejected string, so the test agreed with the workflow but not with
reality. The gate aborted before cutover, so prod kept serving the pre-#333
image (no outage; the gate did its job).

Restore uid1001 ownership the way podman 5.6.2 supports:
- mount /home/fingpt and /app/staticfiles at mode=0755 (owner-writable once
  chowned, not the tmpfs-default world-writable 1777), on both the gate and the
  ExecStart podman run (flag parity preserved);
- chown both dirs to fingpt in entrypoint.sh root-init, before the setpriv drop,
  while PID1 still holds CAP_CHOWN. Non-recursive is sufficient: only the tmpfs
  mount point comes up root-owned; tmpcopyup content (baked ~/.cache/fontconfig)
  is already fingpt-owned. This is behaviorally identical to the intended-but-
  rejected uid=1001 tmpfs.

Correct the invariant that hid the bug: test_tmpfs_options_pinned now asserts no
uid=/gid= on the tmpfs (+ mode=0755), and a new
test_entrypoint_chowns_read_only_tmpfs_dirs pins the root-init chown ordering.

Verified on the droplet against the real #333 image: podman accepts the new
flags, root-init chown yields `drwxr-xr-x 1001 1001`, and a setpriv-dropped
uid1001 writes both dirs successfully.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: FlyM1ss

.github/workflows/backend-deploy.yml

@@ -237,7 +237,7 @@ jobs:
             # and ops/egress_firewall.py consume REDIS_URL, and the firewall
             # self-test checks host:port reachability only, DB-agnostic).
             echo "Validating full boot (root-init + read-only rootfs + /health/) on the new image (pre-cutover)..."
-            podman run --rm --cap-drop=ALL --cap-add=NET_ADMIN --cap-add=CHOWN --cap-add=SETUID --cap-add=SETGID --cap-add=SETPCAP --pids-limit=1024 --read-only --tmpfs=/tmp:rw,size=512m,mode=1777 --tmpfs=/app/staticfiles:rw,uid=1001,gid=1001 --tmpfs=/home/fingpt:rw,uid=1001,gid=1001 --tmpfs=/app/runtime:rw,size=512m --memory=1.7g --memory-swap=2g --network fingpt-net \
+            podman run --rm --cap-drop=ALL --cap-add=NET_ADMIN --cap-add=CHOWN --cap-add=SETUID --cap-add=SETGID --cap-add=SETPCAP --pids-limit=1024 --read-only --tmpfs=/tmp:rw,size=512m,mode=1777 --tmpfs=/app/staticfiles:rw,mode=0755 --tmpfs=/home/fingpt:rw,mode=0755 --tmpfs=/app/runtime:rw,size=512m --memory=1.7g --memory-swap=2g --network fingpt-net \
               --env-file /home/deploy/fingpt/envs/.env.production \
               --env REDIS_URL=redis://fingpt-redis:6379/15 \
               --env BOOT_CHECK_ONLY=1 \
@@ -287,10 +287,16 @@ jobs:
             #                     (--disable-dev-shm-usage), nft mktemp at root-init,
             #                     /tmp/fingpt_cache; sized + world-writable-sticky;
             #   /app/staticfiles  collectstatic writes it at boot (0 files today, kept
-            #                     writable as future-proofing); uid1001 tmpfs;
+            #                     writable as future-proofing); mode=0755 tmpfs,
+            #                     chowned to fingpt by root-init (see below);
             #   /home/fingpt      fontconfig cache, edgartools ~/.edgar import-time
-            #                     marker, yfinance cache; MUST carry uid=1001,gid=1001
-            #                     or the MCP-child EACCES bug (#331 class) returns.
+            #                     marker, yfinance cache; MUST end up fingpt-owned or
+            #                     the MCP-child EACCES bug (#331 class) returns. podman
+            #                     5.6.2 rejects tmpfs uid=/gid= mount options outright,
+            #                     so ownership is NOT set here -- entrypoint.sh root-init
+            #                     chowns both dirs while PID1 still holds CAP_CHOWN.
+            #                     mode=0755 (not the tmpfs default 1777) lands them
+            #                     owner-writable, not world-writable.
             # /app/logs and /app/media are vestigial with ZERO writers -- deliberately
             # NOT tmpfs, so a future stray write fails LOUDLY instead of vanishing
             # into RAM. Playwright's DEPENDENCIES_VALIDATED marker is pre-baked at
@@ -307,7 +313,7 @@ jobs:
             cat > "$OVERRIDE_DIR/override.conf" <<EOF
             [Service]
             ExecStart=
-            ExecStart=/usr/bin/podman run --name ${SYSTEMD_UNIT} --replace --rm --cap-drop=ALL --cap-add=NET_ADMIN --cap-add=CHOWN --cap-add=SETUID --cap-add=SETGID --cap-add=SETPCAP --pids-limit=1024 --read-only --tmpfs=/tmp:rw,size=512m,mode=1777 --tmpfs=/app/staticfiles:rw,uid=1001,gid=1001 --tmpfs=/home/fingpt:rw,uid=1001,gid=1001 --cgroups=split --sdnotify=conmon -d --memory=1.7g --memory-swap=2g --network fingpt-net -v /home/deploy/fingpt/runtime:/app/runtime:U,Z --publish 127.0.0.1:8000:8000 --env-file /home/deploy/fingpt/envs/.env.production --env REDIS_URL=redis://fingpt-redis:6379/0 ${REMOTE_IMAGE}
+            ExecStart=/usr/bin/podman run --name ${SYSTEMD_UNIT} --replace --rm --cap-drop=ALL --cap-add=NET_ADMIN --cap-add=CHOWN --cap-add=SETUID --cap-add=SETGID --cap-add=SETPCAP --pids-limit=1024 --read-only --tmpfs=/tmp:rw,size=512m,mode=1777 --tmpfs=/app/staticfiles:rw,mode=0755 --tmpfs=/home/fingpt:rw,mode=0755 --cgroups=split --sdnotify=conmon -d --memory=1.7g --memory-swap=2g --network fingpt-net -v /home/deploy/fingpt/runtime:/app/runtime:U,Z --publish 127.0.0.1:8000:8000 --env-file /home/deploy/fingpt/envs/.env.production --env REDIS_URL=redis://fingpt-redis:6379/0 ${REMOTE_IMAGE}
             EOF
 
             systemctl --user daemon-reload

Main/backend/entrypoint.sh

@@ -32,6 +32,15 @@ if [ "$(id -u)" = "0" ]; then
     echo "SSRF egress firewall loaded and self-tested."
     # :U chowned the runtime mount to root (PID1 is root); hand it to the app user.
     chown -R fingpt:fingpt /app/runtime
+    # Under --read-only rootfs (#333), /home/fingpt and /app/staticfiles are fresh
+    # tmpfs mounts that MASK the image's build-time ownership and come up root-owned.
+    # The droplet's podman (5.6.2) has no tmpfs uid= option to fix that at mount time
+    # -- it rejects `--tmpfs=...:uid=1001` outright (see backend-deploy.yml and
+    # test_dockerfile_nonroot.test_tmpfs_options_pinned) -- so hand them to the app
+    # user HERE, while PID1 still holds CAP_CHOWN. Non-recursive: both are freshly
+    # mounted empty tmpfs. Without this, uid1001 (and every MCP stdio child writing
+    # $HOME) hits EACCES -- the #331 class the BOOT_CHECK_ONLY gate exists to catch.
+    chown fingpt:fingpt /home/fingpt /app/staticfiles
     # Marker (env survives setpriv) so the app phase can refuse to serve if it was ever
     # reached WITHOUT this root-init firewall load (e.g. a mistaken non-root PID1 start).
     # A MISTAKE-GUARD ONLY, not a security boundary: trivially spoofable via -e/--env-file,

Main/backend/tests/test_dockerfile_nonroot.py

@@ -126,6 +126,31 @@ def test_runtime_user_has_writable_home(self):
         chown = next(l for l in self.lines if "chown -R fingpt:fingpt" in l)
         self.assertIn("/home/fingpt", chown)
 
+    def test_entrypoint_chowns_read_only_tmpfs_dirs(self):
+        # Under the #333 --read-only rootfs, /home/fingpt and /app/staticfiles are
+        # fresh tmpfs mounts that MASK the image's build-time ownership, so they
+        # come up root-owned. podman 5.6.2 has no tmpfs uid= option to fix that at
+        # mount time (test_tmpfs_options_pinned), so the root-init phase must chown
+        # them to fingpt itself -- before the setpriv drop, while it still holds
+        # CAP_CHOWN as root-in-userns. Without it uid1001 cannot write $HOME and the
+        # sec-edgar MCP child dies with EACCES (the #331 class the BOOT_CHECK_ONLY
+        # gate exists to catch).
+        lines = _read(ENTRYPOINT_SH).splitlines()
+        start = next(i for i, l in enumerate(lines) if "id -u" in l and "then" in l)
+        end = next(i for i in range(start + 1, len(lines)) if lines[i].strip() == "fi")
+        root_init_chowns = [
+            l for l in lines[start + 1:end]
+            if "chown" in l and not l.strip().startswith("#")
+        ]
+        joined = " ".join(root_init_chowns)
+        for d in ("/home/fingpt", "/app/staticfiles"):
+            self.assertIn(d, joined, f"root-init must chown {d} (read-only tmpfs ownership)")
+        # Every chown must precede the setpriv drop, or it runs as uid1001 and EPERMs.
+        setpriv_idx = next(i for i, l in enumerate(lines) if l.lstrip().startswith("exec setpriv"))
+        for i, l in enumerate(lines):
+            if "chown" in l and not l.strip().startswith("#"):
+                self.assertLess(i, setpriv_idx, f"chown on line {i} must precede setpriv")
+
     def test_playwright_dependencies_marker_prebaked_for_read_only_rootfs(self):
         # Playwright writes a 0-byte DEPENDENCIES_VALIDATED marker next to the
         # browser executable at FIRST launch (host-requirements validation cache).
@@ -461,14 +486,24 @@ def test_tmpfs_target_sets_frozen(self):
 
     def test_tmpfs_options_pinned(self):
         # /tmp must be sized (unbounded tmpfs is a memory-DoS surface) and
-        # world-writable-sticky (1777: Chromium/nft/cache all write it as
-        # uid1001); the uid1001 dirs must carry uid=1001,gid=1001 -- a bare tmpfs
-        # mounts root-owned and resurrects the EACCES class documented at the
-        # Dockerfile HOME comment.
+        # world-writable-sticky (1777: Chromium/nft/cache all write it as uid1001).
+        #
+        # The uid1001 dirs (/home/fingpt, /app/staticfiles) must NOT carry
+        # uid=/gid= tmpfs mount options: the droplet's podman (5.6.2) rejects them
+        # outright -- `Error: unknown mount option "uid=1001": invalid mount
+        # option` -- which fail-closed the #333 pre-cutover gate on the very first
+        # push-to-main deploy (build+test were green because nothing here ever runs
+        # podman). A tmpfs always mounts root-owned, so ownership is instead
+        # restored inside the container by the root-init chown
+        # (test_entrypoint_chowns_read_only_tmpfs_dirs); mode=0755 lands them
+        # owner-writable (not world-writable) once chowned to fingpt.
         for line in (self._execstart_line(), self._gate_line()):
             self.assertIn("--tmpfs=/tmp:rw,size=512m,mode=1777", line)
-            self.assertIn("--tmpfs=/app/staticfiles:rw,uid=1001,gid=1001", line)
-            self.assertIn("--tmpfs=/home/fingpt:rw,uid=1001,gid=1001", line)
+            self.assertIn("--tmpfs=/app/staticfiles:rw,mode=0755", line)
+            self.assertIn("--tmpfs=/home/fingpt:rw,mode=0755", line)
+            # podman 5.6.2 rejects tmpfs uid=/gid=; never reintroduce them.
+            self.assertNotIn("uid=1001", line)
+            self.assertNotIn("gid=1001", line)
         self.assertIn("--tmpfs=/app/runtime:rw,size=512m", self._gate_line())
 
     def test_execstart_read_only_rootfs(self):