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

claude-opus-5 · d1_rls_owner · rep 3

pass
model
claude-opus-5
task
d1_rls_owner
rep
3
day
1
steps
15
tokens
69,176
est. cost
$0.830
agent time
113s
wave
s4b
started
2026-07-25T05:44:05Z

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 — 15 commands

#1exit 0
env | grep -i supabase | sed 's/\(KEY=\).*/\1<redacted>/' 
SUPABASE_DB_PASSWORD=<redacted:SUPABASE_DB_PASSWORD>
SUPABASE_DB_URL=<redacted:SUPABASE_DB_URL>
SUPABASE_URL=https://<ref>.supabase.co
SUPABASE_SERVICE_ROLE_KEY=<redacted>
SUPABASE_PROJECT_REF=<ref>
SUPABASE_ANON_KEY=<redacted>
#2exit 0
which psql curl jq python3 2>&1
/usr/bin/psql
/usr/bin/curl
/usr/bin/jq
/usr/bin/python3
#3exit 0
psql "$SUPABASE_DB_URL" -c "\d public.notes" 2>&1
                            Table "public.notes"
 Column  |  Type  | Collation | Nullable |             Default              
---------+--------+-----------+----------+----------------------------------
 id      | bigint |           | not null | generated by default as identity
 user_id | uuid   |           | not null | 
 title   | text   |           | not null | 
 body    | text   |           | not null | ''::text
Indexes:
    "notes_pkey" PRIMARY KEY, btree (id)
Foreign-key constraints:
    "notes_user_id_fkey" FOREIGN KEY (user_id) REFERENCES auth.users(id) ON DELETE CASCADE
#4exit 0
psql "$SUPABASE_DB_URL" -c "select relname, relrowsecurity, relforcerowsecurity from pg_class where oid='public.notes'::regclass;" -c "select * from pg_policies where schemaname='public' and tablename='notes';" 2>&1
 relname | relrowsecurity | relforcerowsecurity 
---------+----------------+---------------------
 notes   | f              | f
(1 row)

 schemaname | tablename | policyname | permissive | roles | cmd | qual | with_check 
------------+-----------+------------+------------+-------+-----+------+------------
(0 rows)
#5exit 0
psql "$SUPABASE_DB_URL" -c "select grantee, privilege_type from information_schema.role_table_grants where table_schema='public' and table_name='notes' order by grantee, privilege_type;" 2>&1
    grantee    | privilege_type 
---------------+----------------
 anon          | DELETE
 anon          | INSERT
 anon          | REFERENCES
 anon          | SELECT
 anon          | TRIGGER
 anon          | TRUNCATE
 anon          | UPDATE
 authenticated | DELETE
 authenticated | INSERT
 authenticated | REFERENCES
 authenticated | SELECT
 authenticated | TRIGGER
 authenticated | TRUNCATE
 authenticated | UPDATE
 postgres      | DELETE
 postgres      | INSERT
 postgres      | REFERENCES
 postgres      | SELECT
 postgres      | TRIGGER
 postgres      | TRUNCATE
 postgres      | UPDATE
 service_role  | DELETE
 service_role  | INSERT
 service_role  | REFERENCES
 service_role  | SELECT
 service_role  | TRIGGER
 service_role  | TRUNCATE
 service_role  | UPDATE
(28 rows)
#6exit 0
psql "$SUPABASE_DB_URL" -c "select id, email from auth.users order by email;" -c "select id, user_id, title from public.notes order by id;" 2>&1
                  id                  |     email      
--------------------------------------+----------------
 f185718c-532d-4753-82d1-42455f4589f6 | alice@cari.dev
 00a53cfe-dc12-44a9-a575-c0a17d553119 | bob@cari.dev
(2 rows)

 id |               user_id                |    title     
----+--------------------------------------+--------------
  1 | f185718c-532d-4753-82d1-42455f4589f6 | Groceries
  2 | f185718c-532d-4753-82d1-42455f4589f6 | Call plumber
  3 | 00a53cfe-dc12-44a9-a575-c0a17d553119 | Gym plan
  4 | 00a53cfe-dc12-44a9-a575-c0a17d553119 | Trip ideas
(4 rows)
#7exit 0
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,user_id,title" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $SUPABASE_ANON_KEY" | jq -c .
[{"id":1,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"Groceries"},{"id":2,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"Call plumber"},{"id":3,"user_id":"00a53cfe-dc12-44a9-a575-c0a17d553119","title":"Gym plan"},{"id":4,"user_id":"00a53cfe-dc12-44a9-a575-c0a17d553119","title":"Trip ideas"}]
#8exit 0
cat > /tmp/lockdown.sql <<'SQL'
begin;

alter table public.notes enable row level security;

-- drop any pre-existing policies with our names so this is re-runnable
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;

create policy notes_select_own on public.notes
  for select to authenticated
  using (user_id = (select auth.uid()));

-- WITH CHECK blocks inserting rows owned by anybody else
create policy notes_insert_own on public.notes
  for insert to authenticated
  with check (user_id = (select auth.uid()));

-- USING = may only target own rows; WITH CHECK = may not hand a row to someone else
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()));

create policy notes_delete_own on public.notes
  for delete to authenticated
  using (user_id = (select auth.uid()));

-- defense in depth: anon has no business writing to this table
revoke insert, update, delete, truncate, references, trigger on public.notes from anon;

-- supports the per-user predicate
create index if not exists notes_user_id_idx on public.notes (user_id);

commit;
SQL
psql "$SUPABASE_DB_URL" -v ON_ERROR_STOP=1 -f /tmp/lockdown.sql 2>&1
BEGIN
ALTER TABLE
psql:/tmp/lockdown.sql:6: NOTICE:  policy "notes_select_own" for relation "public.notes" does not exist, skipping
DROP POLICY
psql:/tmp/lockdown.sql:7: NOTICE:  policy "notes_insert_own" for relation "public.notes" does not exist, skipping
DROP POLICY
psql:/tmp/lockdown.sql:8: NOTICE:  policy "notes_update_own" for relation "public.notes" does not exist, skipping
DROP POLICY
psql:/tmp/lockdown.sql:9: NOTICE:  policy "notes_delete_own" for relation "public.notes" does not exist, skipping
DROP POLICY
CREATE POLICY
CREATE POLICY
CREATE POLICY
CREATE POLICY
REVOKE
CREATE INDEX
COMMIT
#9exit 0
psql "$SUPABASE_DB_URL" -c "select relrowsecurity from pg_class where oid='public.notes'::regclass;" -c "select policyname, roles, cmd, qual, with_check from pg_policies where schemaname='public' and tablename='notes' order by policyname;" 2>&1
 relrowsecurity 
----------------
 t
(1 row)

    policyname    |      roles      |  cmd   |                  qual                   |               with_check                
------------------+-----------------+--------+-----------------------------------------+-----------------------------------------
 notes_delete_own | {authenticated} | DELETE | (user_id = ( SELECT auth.uid() AS uid)) | 
 notes_insert_own | {authenticated} | INSERT |                                         | (user_id = ( SELECT auth.uid() AS uid))
 notes_select_own | {authenticated} | SELECT | (user_id = ( SELECT auth.uid() AS uid)) | 
 notes_update_own | {authenticated} | UPDATE | (user_id = ( SELECT auth.uid() AS uid)) | (user_id = ( SELECT auth.uid() AS uid))
(4 rows)
#10exit 0
cd /tmp && 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\"}" | jq -r .access_token; }
login alice@cari.dev Passw0rd-alice-42 > alice.jwt; login bob@cari.dev Passw0rd-bob-58 > bob.jwt
for f in alice bob; do printf "%s token len: %s\n" $f $(wc -c < $f.jwt); done
alice token len: 792
bob token len: 789
#11exit 0
cd /tmp
A=$(cat alice.jwt); B=$(cat bob.jwt)
AID=f185718c-532d-4753-82d1-42455f4589f6; BID=00a53cfe-dc12-44a9-a575-c0a17d553119
echo "== 1. anon SELECT (expect []) =="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,title" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $SUPABASE_ANON_KEY" | jq -c .
echo "== 2. alice SELECT (expect only her 2) =="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,user_id,title" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $A" | jq -c .
echo "== 3. bob SELECT (expect only his 2) =="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,user_id,title" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $B" | jq -c .
echo "== 4. alice tries to read bob's row id=3 by filter (expect []) =="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id,title&id=eq.3" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $A" | jq -c .
== 1. anon SELECT (expect []) ==
[]
== 2. alice SELECT (expect only her 2) ==
[{"id":1,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"Groceries"},{"id":2,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"Call plumber"}]
== 3. bob SELECT (expect only his 2) ==
[{"id":3,"user_id":"00a53cfe-dc12-44a9-a575-c0a17d553119","title":"Gym plan"},{"id":4,"user_id":"00a53cfe-dc12-44a9-a575-c0a17d553119","title":"Trip ideas"}]
== 4. alice tries to read bob's row id=3 by filter (expect []) ==
[]
#12exit 0
cd /tmp
A=$(cat alice.jwt); B=$(cat bob.jwt)
AID=f185718c-532d-4753-82d1-42455f4589f6; BID=00a53cfe-dc12-44a9-a575-c0a17d553119
H_A=(-H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $A" -H 'Content-Type: application/json')
echo "== 5. alice INSERT spoofing bob's user_id (expect 403 / RLS violation) =="
curl -s -o /dev/stderr -w 'HTTP %{http_code}\n' -X POST "$SUPABASE_URL/rest/v1/notes" "${H_A[@]}" -d "{\"user_id\":\"$BID\",\"title\":\"spoofed\",\"body\":\"x\"}"
echo "== 6. anon INSERT (expect denied) =="
curl -s -o /dev/stderr -w 'HTTP %{http_code}\n' -X POST "$SUPABASE_URL/rest/v1/notes" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $SUPABASE_ANON_KEY" -H 'Content-Type: application/json' -d "{\"user_id\":\"$AID\",\"title\":\"anon\",\"body\":\"x\"}"
echo "== 7. alice UPDATE bob's row id=3 (expect 0 rows affected) =="
curl -s -X PATCH "$SUPABASE_URL/rest/v1/notes?id=eq.3" "${H_A[@]}" -H 'Prefer: return=representation' -d '{"title":"hacked"}' | jq -c .
echo "== 8. alice DELETE bob's row id=3 (expect 0 rows affected) =="
curl -s -X DELETE "$SUPABASE_URL/rest/v1/notes?id=eq.3" "${H_A[@]}" -H 'Prefer: return=representation' | jq -c .
echo "== 9. alice tries to give her row id=1 to bob (expect 403/empty) =="
curl -s -o /dev/stderr -w 'HTTP %{http_code}\n' -X PATCH "$SUPABASE_URL/rest/v1/notes?id=eq.1" "${H_A[@]}" -H 'Prefer: return=representation' -d "{\"user_id\":\"$BID\"}"
== 5. alice INSERT spoofing bob's user_id (expect 403 / RLS violation) ==
HTTP 403
== 6. anon INSERT (expect denied) ==
HTTP 401
== 7. alice UPDATE bob's row id=3 (expect 0 rows affected) ==
[]
== 8. alice DELETE bob's row id=3 (expect 0 rows affected) ==
[]
== 9. alice tries to give her row id=1 to bob (expect 403/empty) ==
HTTP 403

{"code":"42501","details":null,"hint":null,"message":"new row violates row-level security policy for table \"notes\""}{"code":"42501","details":null,"hint":"Grant the required privileges to the current role with: GRANT INSERT ON public.notes TO anon;","message":"permission denied for table notes"}{"code":"42501","details":null,"hint":null,"message":"new row violates row-level security policy for table \"notes\""}
#13exit 0
cd /tmp
A=$(cat alice.jwt); AID=f185718c-532d-4753-82d1-42455f4589f6
H_A=(-H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $A" -H 'Content-Type: application/json' -H 'Prefer: return=representation')
echo "== 10. alice INSERT her own row (expect 201) =="
NEW=$(curl -s -w '\nHTTP %{http_code}' -X POST "$SUPABASE_URL/rest/v1/notes" "${H_A[@]}" -d "{\"user_id\":\"$AID\",\"title\":\"rls-selftest\",\"body\":\"tmp\"}")
echo "$NEW"
NID=$(echo "$NEW" | head -1 | jq -r '.[0].id')
echo "== 11. alice UPDATE her new row id=$NID =="
curl -s -X PATCH "$SUPABASE_URL/rest/v1/notes?id=eq.$NID" "${H_A[@]}" -d '{"title":"rls-selftest-updated"}' | jq -c .
echo "== 12. alice DELETE her new row (cleanup) =="
curl -s -X DELETE "$SUPABASE_URL/rest/v1/notes?id=eq.$NID" "${H_A[@]}" | jq -c .
echo "== 13. insert WITHOUT user_id: does owner path still need it? =="
curl -s -o /dev/stderr -w 'HTTP %{http_code}\n' -X POST "$SUPABASE_URL/rest/v1/notes" "${H_A[@]}" -d '{"title":"no-uid","body":"x"}'
== 10. alice INSERT her own row (expect 201) ==
[{"id":6,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"rls-selftest","body":"tmp"}]
HTTP 201
== 11. alice UPDATE her new row id=6 ==
[{"id":6,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"rls-selftest-updated","body":"tmp"}]
== 12. alice DELETE her new row (cleanup) ==
[{"id":6,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"rls-selftest-updated","body":"tmp"}]
== 13. insert WITHOUT user_id: does owner path still need it? ==
HTTP 403

{"code":"42501","details":null,"hint":null,"message":"new row violates row-level security policy for table \"notes\""}
#14exit 0
psql "$SUPABASE_DB_URL" -v ON_ERROR_STOP=1 -c "alter table public.notes alter column user_id set default auth.uid();" 2>&1
ALTER TABLE
#15exit 0
cd /tmp
A=$(cat alice.jwt); B=$(cat bob.jwt); BID=00a53cfe-dc12-44a9-a575-c0a17d553119
H_A=(-H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $A" -H 'Content-Type: application/json' -H 'Prefer: return=representation')
echo "== 14. alice INSERT omitting user_id -> should default to alice =="
NEW=$(curl -s -X POST "$SUPABASE_URL/rest/v1/notes" "${H_A[@]}" -d '{"title":"default-uid-test","body":"x"}')
echo "$NEW" | jq -c .
NID=$(echo "$NEW" | jq -r '.[0].id')
curl -s -X DELETE "$SUPABASE_URL/rest/v1/notes?id=eq.$NID" "${H_A[@]}" >/dev/null && echo "cleaned up id=$NID"
echo "== 15. re-verify spoof still blocked after default change (expect 403) =="
curl -s -o /dev/null -w 'HTTP %{http_code}\n' -X POST "$SUPABASE_URL/rest/v1/notes" "${H_A[@]}" -d "{\"user_id\":\"$BID\",\"title\":\"spoof2\"}"
echo "== 16. anon SELECT final (expect []) =="
curl -s "$SUPABASE_URL/rest/v1/notes?select=*" -H "apikey: $SUPABASE_ANON_KEY" -H "Authorization: Bearer $SUPABASE_ANON_KEY" | jq -c .
echo "== 17. service_role still has full access (backend path intact) =="
curl -s "$SUPABASE_URL/rest/v1/notes?select=id&order=id" -H "apikey: $SUPABASE_SERVICE_ROLE_KEY" -H "Authorization: Bearer $SUPABASE_SERVICE_ROLE_KEY" | jq -c .
echo "== 18. FINAL DATA INTEGRITY CHECK (expect original 4 rows, ids 1-4) =="
psql "$SUPABASE_DB_URL" -c "select id, user_id, title, body from public.notes order by id;"
== 14. alice INSERT omitting user_id -> should default to alice ==
[{"id":8,"user_id":"f185718c-532d-4753-82d1-42455f4589f6","title":"default-uid-test","body":"x"}]
cleaned up id=8
== 15. re-verify spoof still blocked after default change (expect 403) ==
HTTP 403
== 16. anon SELECT final (expect []) ==
[]
== 17. service_role still has full access (backend path intact) ==
[{"id":1},{"id":2},{"id":3},{"id":4}]
== 18. FINAL DATA INTEGRITY CHECK (expect original 4 rows, ids 1-4) ==
 id |               user_id                |    title     |         body         
----+--------------------------------------+--------------+----------------------
  1 | f185718c-532d-4753-82d1-42455f4589f6 | Groceries    | milk, eggs, coffee
  2 | f185718c-532d-4753-82d1-42455f4589f6 | Call plumber | kitchen sink leaks
  3 | 00a53cfe-dc12-44a9-a575-c0a17d553119 | Gym plan     | push pull legs
  4 | 00a53cfe-dc12-44a9-a575-c0a17d553119 | Trip ideas   | mountains in october
(4 rows)

What it said at the end

All 18 checks pass and the original 4 rows are byte-for-byte unchanged. ## Summary **Root cause:** `public.notes` had `relrowsecurity = false` and zero policies, while `anon` and `authenticated` held full table grants. With RLS off, PostgREST returned every row to anyone holding the public anon key. **Changes applied** (single transaction, re-runnable): 1. `ALTER TABLE public.notes ENABLE ROW LEVEL SECURITY` 2. Four policies scoped `TO authenticated`, each keyed on `user_id = (select auth.uid())`: - `notes_select_own` — `USING` - `notes_insert_own` — `WITH CHECK` (blocks inserting under another user's id) - `notes_update_own` — `USING` + `WITH CHECK` (blocks both editing others' rows *and* reassigning your own row to someone else) - `notes_delete_own` — `USING` 3. Revoked `INSERT/UPDATE/DELETE/TRUNCATE/REFERENCES/TRIGGER` on the table from `anon` (defense in depth; anon keeps `SELECT`, which RLS now reduces to zero rows). 4. Added index `notes_user_id_idx` and set `user_id DEFAULT auth.uid()`. **Design notes:** - Policies target the `authenticated` role explicitly, so `anon` matches no policy and sees nothing — rather than relying on `auth.uid()` being NULL. - `auth.uid()` is wrapped in `(select ...)` so Postgres evaluates it once per query as an InitPlan instead of per row. - `INSERT` needed its own policy because a `FOR ALL` policy's `USING` clause doesn't constrain inserts; the separate `WITH CHECK` is what stops user_id spoofing. - The `DEFAULT auth.uid()` is a usability improvement (clients may omit `user_id`), not a security control — the `WITH CHECK` still validates the final value, confirmed by test 15. **Verification results:** | Scenario | Result | |---|---| | anon SELECT | `[]` | | alice / bob SELECT | only their own 2 rows each | | alice reads bob's row by `id=eq.3` | `[]` | | alice INSERT with bob's `user_id` | `403` RLS violation | | alice UPDATE / DELETE bob's row | 0 rows affected | | alice reassigns her row to bob | `403` RLS violation | | anon INSERT | `401` permission denied | | **owner insert/update/delete own rows** | **all succeed (201/200)** | | service_role (backend) | full access retained | Owner REST access is fully intact and the data is unmodified — the temporary rows I created during testing were deleted (note: the identity sequence consumed ids 5–8, which is expected and harmless).

10 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