Can Agents Run It? · evidence — Issue 1: Supabase

claude-opus-4-8 · d1_rls_owner · rep 1

pass
model
claude-opus-4-8
task
d1_rls_owner
rep
1
day
1
steps
6
tokens
26,607
est. cost
$0.319
agent time
57s
wave
s4c
started
2026-07-26T01:48:52Z

The task as the agent received it

You have operator access to a hosted Supabase project. Credentials are in environment variables: SUPABASE_URL, SUPABASE_PROJECT_REF, SUPABASE_ANON_KEY, SUPABASE_SERVICE_ROLE_KEY, SUPABASE_DB_URL, SUPABASE_DB_PASSWORD. The project has a public.notes table (id, user_id references auth.users, title, body) that currently exposes every user's notes to anyone through the REST API. Lock it down to owner-only access: - an authenticated user must be able to read, insert, update and delete ONLY rows where user_id equals their own auth user id; - a user must NOT be able to insert a row with someone else's user_id; - anonymous (anon key only) requests must see no rows; - legitimate owners must keep working through the REST API — do not break their access path. Two existing users for your own testing: alice@cari.dev / Passw0rd-alice-42 and bob@cari.dev / Passw0rd-bob-58. Each currently owns 2 notes. Do not modify the data.

What it ran — 6 commands

#1exit 0
echo "URL: $SUPABASE_URL"; echo "REF: $SUPABASE_PROJECT_REF"; echo "DB_URL set: ${SUPABASE_DB_URL:+yes}"; which psql || echo "no psql"
URL: https://<ref>.supabase.co
REF: <ref>
DB_URL set: yes
/usr/bin/psql
#2exit 0
psql "$SUPABASE_DB_URL" -c "\d public.notes" 2>&1; echo "---RLS---"; psql "$SUPABASE_DB_URL" -c "SELECT relrowsecurity, relforcerowsecurity FROM pg_class WHERE oid='public.notes'::regclass;" 2>&1; echo "---POLICIES---"; psql "$SUPABASE_DB_URL" -c "SELECT policyname, cmd, roles, qual, with_check FROM pg_policies WHERE schemaname='public' AND tablename='notes';" 2>&1; echo "---GRANTS---"; psql "$SUPABASE_DB_URL" -c "SELECT grantee, privilege_type FROM information_schema.role_table_grants WHERE table_schema='public' AND table_name='notes';" 2>&1
                            Table "public.notes"
 Column  |  Type  | Collation | Nullable |             Default              
---------+--------+-----------+----------+----------------------------------
 id      | bigint |           | not null | generated by default as identity
 user_id | uuid   |           | not null | 
 title   | text   |           | not null | 
 body    | text   |           | not null | ''::text
Indexes:
    "notes_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
    "notes_user_id_fkey" FOREIGN KEY (user_id) REFERENCES auth.users(id) ON DELETE CASCADE

---RLS---
 relrowsecurity | relforcerowsecurity 
----------------+---------------------
 f              | f
(1 row)

---POLICIES---
 policyname | cmd | roles | qual | with_check 
------------+-----+-------+------+------------
(0 rows)

---GRANTS---
    grantee    | privilege_type 
---------------+----------------
 postgres      | INSERT
 postgres      | SELECT
 postgres      | UPDATE
 postgres      | DELETE
 postgres      | TRUNCATE
 postgres      | REFERENCES
 postgres      | TRIGGER
 anon          | INSERT
 anon          | SELECT
 anon          | UPDATE
 anon          | DELETE
 anon          | TRUNCATE
 anon          | REFERENCES
 anon          | TRIGGER
 authenticated | INSERT
 authenticated | SELECT
 authenticated | UPDATE
 authenticated | DELETE
 authenticated | TRUNCATE
 authenticated | REFERENCES
 authenticated | TRIGGER
 service_role  | INSERT
 service_role  | SELECT
 service_role  | UPDATE
 service_role  | DELETE
 service_role  | TRUNCATE
 service_role  | REFERENCES
 service_role  | TRIGGER
(28 rows)
#3exit 0
echo "=== anon sees all rows (vulnerable) ==="; curl -s "$SUPABASE_URL/rest/v1/notes?select=id,user_id,title" -H "apikey: $SUPABASE_ANON_KEY" | head -c 1000; echo
=== anon sees all rows (vulnerable) ===
[{"id":1,"user_id":"9dc9142e-314f-4ab6-aa66-b38a05f42de0","title":"Groceries"}, 
 {"id":2,"user_id":"9dc9142e-314f-4ab6-aa66-b38a05f42de0","title":"Call plumber"}, 
 {"id":3,"user_id":"db26f1f9-f973-4159-80ed-5adb76135cad","title":"Gym plan"}, 
 {"id":4,"user_id":"db26f1f9-f973-4159-80ed-5adb76135cad","title":"Trip ideas"}]
#4exit 0
psql "$SUPABASE_DB_URL" <<'SQL'
BEGIN;

ALTER TABLE public.notes ENABLE ROW LEVEL SECURITY;

DROP POLICY IF EXISTS notes_select_own ON public.notes;
DROP POLICY IF EXISTS notes_insert_own ON public.notes;
DROP POLICY IF EXISTS notes_update_own ON public.notes;
DROP POLICY IF EXISTS notes_delete_own ON public.notes;

-- SELECT: only rows owned by the current authenticated user
CREATE POLICY notes_select_own ON public.notes
  FOR SELECT TO authenticated
  USING (user_id = (SELECT auth.uid()));

-- INSERT: can only create rows with their own user_id
CREATE POLICY notes_insert_own ON public.notes
  FOR INSERT TO authenticated
  WITH CHECK (user_id = (SELECT auth.uid()));

-- UPDATE: can only update own rows, and cannot reassign to another user
CREATE POLICY notes_update_own ON public.notes
  FOR UPDATE TO authenticated
  USING (user_id = (SELECT auth.uid()))
  WITH CHECK (user_id = (SELECT auth.uid()));

-- DELETE: can only delete own rows
CREATE POLICY notes_delete_own ON public.notes
  FOR DELETE TO authenticated
  USING (user_id = (SELECT auth.uid()));

COMMIT;
SQL
echo "---verify---"
psql "$SUPABASE_DB_URL" -c "SELECT relrowsecurity FROM pg_class WHERE oid='public.notes'::regclass;"
psql "$SUPABASE_DB_URL" -c "SELECT policyname, cmd, roles::text, qual, with_check FROM pg_policies WHERE tablename='notes' ORDER BY policyname;"
BEGIN
ALTER TABLE
DROP POLICY
DROP POLICY
DROP POLICY
DROP POLICY
CREATE POLICY
CREATE POLICY
CREATE POLICY
CREATE POLICY
COMMIT
---verify---
 relrowsecurity 
----------------
 t
(1 row)

    policyname    |  cmd   |      roles      |                  qual                   |               with_check                
------------------+--------+-----------------+-----------------------------------------+-----------------------------------------
 notes_delete_own | DELETE | {authenticated} | (user_id = ( SELECT auth.uid() AS uid)) | 
 notes_insert_own | INSERT | {authenticated} |                                         | (user_id = ( SELECT auth.uid() AS uid))
 notes_select_own | SELECT | {authenticated} | (user_id = ( SELECT auth.uid() AS uid)) | 
 notes_update_own | UPDATE | {authenticated} | (user_id = ( SELECT auth.uid() AS uid)) | (user_id = ( SELECT auth.uid() AS uid))
(4 rows)


NOTICE:  policy "notes_select_own" for relation "public.notes" does not exist, skipping
NOTICE:  policy "notes_insert_own" for relation "public.notes" does not exist, skipping
NOTICE:  policy "notes_update_own" for relation "public.notes" does not exist, skipping
NOTICE:  policy "notes_delete_own" for relation "public.notes" does not exist, skipping
#5exit 0
login() {
  curl -s "$SUPABASE_URL/auth/v1/token?grant_type=password" \
    -H "apikey: $SUPABASE_ANON_KEY" -H "Content-Type: application/json" \
    -d "{\"email\":\"$1\",\"password\":\"$2\"}" | python3 -c "import sys,json;print(json.load(sys.stdin)['access_token'])"
}
ALICE=$(login alice@cari.dev Passw0rd-alice-42)
BOB=$(login bob@cari.dev Passw0rd-bob-58)
echo "alice token: ${ALICE:0:15}..."; echo "bob token: ${BOB:0:15}..."

ALICE_ID="9dc9142e-314f-4ab6-aa66-b38a05f42de0"
BOB_ID="db26f1f9-f973-4159-80ed-5adb76135cad"

echo; echo "=== TEST 1: anon sees no rows ==="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,title" -H "apikey: $SUPABASE_ANON_KEY"

echo; echo; echo "=== TEST 2: alice reads only her own ==="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,user_id,title" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $ALICE"

echo; echo; echo "=== TEST 3: bob reads only his own ==="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,user_id,title" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $BOB"

echo; echo; echo "=== TEST 4: alice inserts own note (should succeed) ==="
curl -s -w "\nHTTP:%{http_code}\n" "$SUPABASE_URL/rest/v1/notes" -X POST \
  -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $ALICE" \
  -H "Content-Type: application/json" -H "Prefer: return=representation" \
  -d "{\"user_id\":\"$ALICE_ID\",\"title\":\"__test_own\",\"body\":\"x\"}"

echo; echo "=== TEST 5: alice inserts as BOB (should fail) ==="
curl -s -w "\nHTTP:%{http_code}\n" "$SUPABASE_URL/rest/v1/notes" -X POST \
  -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $ALICE" \
  -H "Content-Type: application/json" -H "Prefer: return=representation" \
  -d "{\"user_id\":\"$BOB_ID\",\"title\":\"__evil\",\"body\":\"x\"}"

echo; echo "=== TEST 6: alice updates bob's note id=3 (should affect 0 rows) ==="
curl -s -w "\nHTTP:%{http_code}\n" "$SUPABASE_URL/rest/v1/notes?id=eq.3" -X PATCH \
  -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $ALICE" \
  -H "Content-Type: application/json" -H "Prefer: return=representation" \
  -d "{\"title\":\"hacked\"}"

echo; echo "=== TEST 7: alice deletes bob's note id=3 (should affect 0 rows) ==="
curl -s -w "\nHTTP:%{http_code}\n" "$SUPABASE_URL/rest/v1/notes?id=eq.3" -X DELETE \
  -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $ALICE" \
  -H "Prefer: return=representation"
alice token: eyJhbGciOiJFUzI...
bob token: eyJhbGciOiJFUzI...

=== TEST 1: anon sees no rows ===
[]

=== TEST 2: alice reads only her own ===
[{"id":1,"user_id":"9dc9142e-314f-4ab6-aa66-b38a05f42de0","title":"Groceries"}, 
 {"id":2,"user_id":"9dc9142e-314f-4ab6-aa66-b38a05f42de0","title":"Call plumber"}]

=== TEST 3: bob reads only his own ===
[{"id":3,"user_id":"db26f1f9-f973-4159-80ed-5adb76135cad","title":"Gym plan"}, 
 {"id":4,"user_id":"db26f1f9-f973-4159-80ed-5adb76135cad","title":"Trip ideas"}]

=== TEST 4: alice inserts own note (should succeed) ===
[{"id":5,"user_id":"9dc9142e-314f-4ab6-aa66-b38a05f42de0","title":"__test_own","body":"x"}]
HTTP:201

=== TEST 5: alice inserts as BOB (should fail) ===
{"code":"42501","details":null,"hint":null,"message":"new row violates row-level security policy for table \"notes\""}
HTTP:403

=== TEST 6: alice updates bob's note id=3 (should affect 0 rows) ===
[]
HTTP:200

=== TEST 7: alice deletes bob's note id=3 (should affect 0 rows) ===
[]
HTTP:200
#6exit 0
psql "$SUPABASE_DB_URL" -c "DELETE FROM public.notes WHERE title='__test_own';"
echo "--- final data (should be original 4 rows, untouched) ---"
psql "$SUPABASE_DB_URL" -c "SELECT id, user_id, title FROM public.notes ORDER BY id;"
DELETE 1
--- final data (should be original 4 rows, untouched) ---
 id |               user_id                |    title     
----+--------------------------------------+--------------
  1 | 9dc9142e-314f-4ab6-aa66-b38a05f42de0 | Groceries
  2 | 9dc9142e-314f-4ab6-aa66-b38a05f42de0 | Call plumber
  3 | db26f1f9-f973-4159-80ed-5adb76135cad | Gym plan
  4 | db26f1f9-f973-4159-80ed-5adb76135cad | Trip ideas
(4 rows)

What it said at the end

Done. The `public.notes` table is now locked down to owner-only access. ## What I did **Diagnosis:** Row Level Security was disabled on `public.notes`, and the `anon`/`authenticated` roles held full table grants — so the REST API exposed every user's notes to anyone (confirmed: the anon key returned all 4 rows). **Fix (applied via SQL in a transaction):** 1. `ALTER TABLE public.notes ENABLE ROW LEVEL SECURITY;` 2. Created four policies scoped to the `authenticated` role, each keyed on `user_id = auth.uid()`: - **SELECT** (`USING`): read only your own rows - **INSERT** (`WITH CHECK`): can only create rows with your own `user_id` - **UPDATE** (`USING` + `WITH CHECK`): can only modify your own rows and can't reassign ownership to someone else - **DELETE** (`USING`): can only delete your own rows I used `(SELECT auth.uid())` so the JWT lookup is evaluated once per query (an initplan) rather than per-row — better performance without changing semantics. No policy exists for the `anon` role, so anonymous requests match nothing and see zero rows. Existing owner grants remain intact, so legitimate REST access still works. **Verification through the live REST API:** - Anon (anon key only) → `[]` (no rows) ✅ - Alice (authenticated) → only her 2 notes ✅ - Bob (authenticated) → only his 2 notes ✅ - Alice inserting a note with her own `user_id` → `201 Created` ✅ - Alice inserting a note with Bob's `user_id` → `403` RLS violation ✅ - Alice updating/deleting Bob's note → 0 rows affected ✅ **Data integrity:** I removed the single test row I created during verification; the original 4 notes remain exactly as they were.

5 earlier narration turn(s) are in the raw transcript.

How it was graded

A shell script executed against the live project and asserted on the state the agent left behind. No model judged another model.

exit 0 OK

Check it yourself

Raw transcript · Task definition and verifier · Every attempt