Files
hermes-agent/tests/test_sqlite_wal_reset_gate.py
Teknium c4aea32317 fix(db): never downgrade journal mode on a database with concurrent openers
The WAL-reset-vulnerability gate (#70055 lineage) could flip a LIVE WAL
database to journal_mode=DELETE while another process was writing to it.
Observed on state.db (Aug 5): a pytest process on the repo .venv (SQLite
3.50.4, vulnerable) opened the live ~/.hermes/state.db while the gateway
(SQLite 3.53.1, WAL) held it, downgraded the journal mode, and destroyed
the gateway's committed-but-uncheckpointed WAL transactions (disk rows
went 10 -> 0 while memory held 185). cron/executions.db already had the
"leave WAL in place, no live downgrade under concurrent openers" rule via
the on-disk WAL probe; state.db and every other store shared the hole
whenever the mode PROBE itself was blocked by a concurrent opener's locks
("could not read the mode" was treated as "not WAL" -> flip anyway).

Generalized in the single journal-mode owner (apply_wal_with_fallback),
covering ALL call sites (state.db, kanban.db, projects.db,
cron/executions.db, delivery_ledger, async_delegation,
verification_evidence, discord recovery, response_store.db,
memory_store.db):

- _set_journal_mode_no_wait(): the only journal-mode switch primitive for
  non-WAL targets. Forces busy_timeout=0 around the pragma so SQLite's own
  exclusivity requirement for leaving WAL becomes the concurrent-opener
  detector — any other opener (this process or another) makes the flip
  fail immediately instead of waiting out a busy timeout and sneaking the
  flip in under a live writer.
- Vulnerable-SQLite gate: an unreadable journal mode (probe blocked) now
  means "ownership not provably exclusive" — leave the mode untouched and
  warn, never flip. A lock conflict on the flip itself likewise leaves the
  mode alone.
- Configured journal_mode=delete: refuses (raises) rather than downgrading
  blind when the mode cannot be verified under a concurrent opener.
- Filesystem-incompat fallback: re-raises instead of downgrading when the
  on-disk mode cannot be verified.
- New/exclusively-owned DBs on vulnerable builds behave exactly as before
  (DELETE gate retained per #70055).

Behavioral tests use a REAL second process (and a real second connection
holding an exclusive lock) with the blocked-state assertions running WHILE
the holder owns the DB, plus exclusive-ownership downgrade-still-happens
coverage.
2026-08-06 07:49:42 -07:00

414 lines
16 KiB
Python

"""SQLite WAL-reset vulnerability gate (issue #69784).
Hermes must not *enable* multi-process WAL on SQLite builds that still contain
the upstream WAL-reset corruption bug:
https://sqlite.org/wal.html#walresetbug
Existing on-disk WAL databases are left alone (no live downgrade).
"""
from __future__ import annotations
import sqlite3
import subprocess
import sys
import time
from types import SimpleNamespace
import pytest
import hermes_state
from hermes_state import (
apply_wal_with_fallback,
is_sqlite_wal_reset_vulnerable,
sqlite_source_id,
)
@pytest.fixture(autouse=True)
def _reset_wal_reset_bug_warnings():
hermes_state._wal_reset_bug_warned_paths.clear()
yield
hermes_state._wal_reset_bug_warned_paths.clear()
class TestIsSqliteWalResetVulnerable:
@pytest.mark.parametrize(
"version_info,expected",
[
((3, 6, 23), False), # pre-WAL
((3, 7, 0), True),
((3, 44, 5), True),
((3, 44, 6), False), # backport
((3, 44, 9), False),
((3, 45, 0), True),
((3, 46, 1), True),
((3, 50, 4), True),
((3, 50, 6), True),
((3, 50, 7), False), # backport
((3, 50, 99), False),
((3, 51, 0), True),
((3, 51, 2), True),
((3, 51, 3), False), # fixed line
((3, 52, 0), False),
],
)
def test_version_matrix(self, version_info, expected):
assert is_sqlite_wal_reset_vulnerable(version_info) is expected
class TestApplyWalWalResetGate:
def test_fresh_db_uses_delete_when_vulnerable(self, tmp_path, monkeypatch, caplog):
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
conn = sqlite3.connect(str(tmp_path / "fresh.db"))
with caplog.at_level("WARNING", logger="hermes_state"):
mode = apply_wal_with_fallback(conn, db_label="fresh.db")
assert mode == "delete"
assert conn.execute("PRAGMA journal_mode").fetchone()[0].lower() == "delete"
assert any("instead of enabling WAL" in r.getMessage() for r in caplog.records)
conn.close()
def test_existing_wal_left_alone_when_vulnerable(
self, tmp_path, monkeypatch, caplog
):
"""Already-WAL DBs must not be live-downgraded under concurrent openers."""
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
path = tmp_path / "prior_wal.db"
seed = sqlite3.connect(str(path))
try:
seed.execute("PRAGMA journal_mode=WAL")
seed.execute("CREATE TABLE t (x INTEGER)")
seed.execute("INSERT INTO t VALUES (42)")
seed.commit()
assert seed.execute("PRAGMA journal_mode").fetchone()[0].lower() == "wal"
finally:
seed.close()
conn = sqlite3.connect(str(path), timeout=30.0)
try:
with caplog.at_level("WARNING", logger="hermes_state"):
mode = apply_wal_with_fallback(conn, db_label="prior_wal.db")
assert mode == "wal"
assert conn.execute("PRAGMA journal_mode").fetchone()[0].lower() == "wal"
assert conn.execute("SELECT x FROM t").fetchone()[0] == 42
assert any("already in WAL mode" in r.getMessage() for r in caplog.records)
# Must not attempt a live journal_mode flip.
assert not any(
"instead of enabling WAL" in r.getMessage() for r in caplog.records
)
finally:
conn.close()
def test_warning_deduped_per_label(self, tmp_path, monkeypatch, caplog):
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
with caplog.at_level("WARNING", logger="hermes_state"):
for name in ("a.db", "a.db", "b.db"):
conn = sqlite3.connect(str(tmp_path / name))
apply_wal_with_fallback(conn, db_label=name)
conn.close()
warnings = [r for r in caplog.records if "WAL-reset" in r.getMessage()]
assert len(warnings) == 2
_HOLDER_SCRIPT = """
import sqlite3, sys, time, os
db, ready, done = sys.argv[1], sys.argv[2], sys.argv[3]
conn = sqlite3.connect(db, timeout=30.0)
conn.execute("INSERT INTO t VALUES (777)")
conn.commit() # committed but (in WAL) very likely un-checkpointed
with open(ready, "w") as fh:
fh.write("ready")
deadline = time.time() + 60
while not os.path.exists(done) and time.time() < deadline:
time.sleep(0.05)
conn.close()
"""
class TestNoDowngradeUnderConcurrentOpeners:
"""The Aug 2026 state.db incident class: a vulnerable-SQLite process must
never flip journal modes on a database it does not exclusively own.
A concurrent WAL writer's committed-but-uncheckpointed transactions are
destroyed by a live WAL→DELETE flip (observed: disk rows went 10 → 0
while the writer's memory held 185)."""
def test_second_process_opener_keeps_wal_when_vulnerable(
self, tmp_path, monkeypatch, caplog
):
"""A REAL second process holds the WAL DB open while the vulnerable
gate runs — WAL must be left in place and its committed rows survive.
All blocked-state assertions run WHILE the holder owns the DB."""
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
db = tmp_path / "live_wal.db"
seed = sqlite3.connect(str(db))
try:
seed.execute("PRAGMA journal_mode=WAL")
seed.execute("CREATE TABLE t (x INTEGER)")
seed.execute("INSERT INTO t VALUES (1)")
seed.commit()
finally:
seed.close()
ready = tmp_path / "holder.ready"
done = tmp_path / "holder.done"
holder = subprocess.Popen(
[sys.executable, "-c", _HOLDER_SCRIPT, str(db), str(ready), str(done)]
)
try:
deadline = time.time() + 30
while not ready.exists() and time.time() < deadline:
time.sleep(0.02)
assert ready.exists(), "holder subprocess never became ready"
conn = sqlite3.connect(str(db), timeout=30.0)
try:
with caplog.at_level("WARNING", logger="hermes_state"):
mode = apply_wal_with_fallback(conn, db_label="live_wal.db")
# Asserted while the second opener still holds the DB:
assert holder.poll() is None, "holder must still be alive here"
assert mode == "wal"
assert (
conn.execute("PRAGMA journal_mode").fetchone()[0].lower()
== "wal"
)
# The concurrent opener's committed row must have survived.
rows = {r[0] for r in conn.execute("SELECT x FROM t")}
assert rows == {1, 777}
assert not any(
"instead of enabling WAL" in r.getMessage()
for r in caplog.records
)
finally:
conn.close()
finally:
done.write_text("done")
holder.wait(timeout=30)
check = sqlite3.connect(str(db))
try:
assert check.execute("PRAGMA journal_mode").fetchone()[0].lower() == "wal"
assert {r[0] for r in check.execute("SELECT x FROM t")} == {1, 777}
finally:
check.close()
def test_unreadable_mode_keeps_journal_mode_when_vulnerable(
self, tmp_path, monkeypatch, caplog
):
"""An exclusive-locking holder blocks even the journal-mode read.
Ownership is then not provably exclusive: the gate must leave the
journal mode untouched instead of treating 'could not read the mode'
as 'not WAL' and flipping anyway (the incident's exact confusion).
Assertions run WHILE the holder's exclusive lock is live."""
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
db = tmp_path / "locked_wal.db"
seed = sqlite3.connect(str(db))
try:
seed.execute("PRAGMA journal_mode=WAL")
seed.execute("CREATE TABLE t (x INTEGER)")
seed.execute("INSERT INTO t VALUES (1)")
seed.commit()
finally:
seed.close()
holder = sqlite3.connect(str(db))
try:
holder.execute("PRAGMA locking_mode=EXCLUSIVE")
holder.execute("BEGIN IMMEDIATE")
holder.execute("INSERT INTO t VALUES (2)")
conn = sqlite3.connect(str(db), timeout=0.2)
try:
# Sanity: the probe really is blocked right now.
with pytest.raises(sqlite3.OperationalError):
conn.execute("PRAGMA journal_mode").fetchone()
with caplog.at_level("WARNING", logger="hermes_state"):
mode = apply_wal_with_fallback(conn, db_label="locked_wal.db")
assert mode == "wal"
assert any(
"concurrent openers" in r.getMessage() for r in caplog.records
)
assert not any(
"instead of enabling WAL" in r.getMessage()
for r in caplog.records
)
finally:
conn.close()
finally:
holder.rollback()
holder.close()
check = sqlite3.connect(str(db))
try:
assert check.execute("PRAGMA journal_mode").fetchone()[0].lower() == "wal"
finally:
check.close()
def test_exclusively_owned_fresh_db_still_downgrades(
self, tmp_path, monkeypatch, caplog
):
"""No concurrent openers → the vulnerable-SQLite DELETE gate still
applies exactly as before."""
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
conn = sqlite3.connect(str(tmp_path / "exclusive.db"))
try:
with caplog.at_level("WARNING", logger="hermes_state"):
mode = apply_wal_with_fallback(conn, db_label="exclusive.db")
assert mode == "delete"
assert (
conn.execute("PRAGMA journal_mode").fetchone()[0].lower() == "delete"
)
assert any(
"instead of enabling WAL" in r.getMessage() for r in caplog.records
)
finally:
conn.close()
def test_flip_lock_conflict_leaves_mode_alone(self, tmp_path, caplog, monkeypatch):
"""If the DELETE flip itself hits another opener's lock (opener arrived
between probe and flip), the gate returns the observed mode instead of
raising or waiting the lock out."""
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
class _FlipLockedConnection(sqlite3.Connection):
def execute(self, sql, *args, **kwargs): # type: ignore[override]
if "journal_mode=delete" in sql.lower().replace(" ", ""):
raise sqlite3.OperationalError("database is locked")
return super().execute(sql, *args, **kwargs)
conn = sqlite3.connect(
str(tmp_path / "race.db"), factory=_FlipLockedConnection
)
try:
with caplog.at_level("WARNING", logger="hermes_state"):
mode = apply_wal_with_fallback(conn, db_label="race.db")
assert mode == "delete" # observed pre-flip mode, not a forced flip
assert any(
"concurrent openers" in r.getMessage() for r in caplog.records
)
finally:
conn.close()
def test_configured_delete_refuses_when_probe_blocked(
self, tmp_path, monkeypatch
):
"""Operator-configured DELETE on a non-vulnerable build must also
refuse to downgrade when the mode probe is blocked by a concurrent
opener's exclusive lock — raise, never flip blind."""
monkeypatch.setattr(
hermes_state,
"is_sqlite_wal_reset_vulnerable",
lambda version_info=None: False,
)
monkeypatch.setattr(hermes_state, "resolve_journal_mode", lambda: "delete")
db = tmp_path / "cfg_delete.db"
seed = sqlite3.connect(str(db))
try:
seed.execute("PRAGMA journal_mode=WAL")
seed.execute("CREATE TABLE t (x INTEGER)")
seed.commit()
finally:
seed.close()
holder = sqlite3.connect(str(db))
try:
holder.execute("PRAGMA locking_mode=EXCLUSIVE")
holder.execute("BEGIN IMMEDIATE")
holder.execute("INSERT INTO t VALUES (1)")
conn = sqlite3.connect(str(db), timeout=0.2)
try:
with pytest.raises(
sqlite3.OperationalError, match="refusing to downgrade"
):
apply_wal_with_fallback(conn, db_label="cfg_delete.db")
finally:
conn.close()
finally:
holder.rollback()
holder.close()
check = sqlite3.connect(str(db))
try:
assert check.execute("PRAGMA journal_mode").fetchone()[0].lower() == "wal"
finally:
check.close()
def test_nfs_fallback_reraises_when_mode_unreadable(self, tmp_path, monkeypatch):
"""The filesystem-incompat fallback must not downgrade when the on-disk
mode cannot be verified (possible concurrent openers)."""
monkeypatch.setattr(
hermes_state,
"is_sqlite_wal_reset_vulnerable",
lambda version_info=None: False,
)
hermes_state._wal_fallback_warned_paths.clear()
class _LockedProbeConnection(sqlite3.Connection):
def execute(self, sql, *args, **kwargs): # type: ignore[override]
normalized = sql.lower().replace(" ", "")
if "journal_mode=wal" in normalized:
raise sqlite3.OperationalError("locking protocol")
if normalized == "pragmajournal_mode":
raise sqlite3.OperationalError("database is locked")
return super().execute(sql, *args, **kwargs)
conn = sqlite3.connect(
str(tmp_path / "nfs.db"), factory=_LockedProbeConnection
)
try:
with pytest.raises(sqlite3.OperationalError, match="locking protocol"):
apply_wal_with_fallback(conn, db_label="nfs.db")
finally:
conn.close()
def test_doctor_warns_without_adding_issues(monkeypatch, tmp_path, capsys):
"""Vulnerable SQLite is warn-only in doctor — not a blocking issues[] entry."""
from hermes_cli.doctor import run_doctor
home = tmp_path / ".hermes"
home.mkdir()
monkeypatch.setenv("HERMES_HOME", str(home))
monkeypatch.setattr("hermes_constants.get_hermes_home", lambda: home)
monkeypatch.setattr(
hermes_state, "is_sqlite_wal_reset_vulnerable", lambda version_info=None: True
)
monkeypatch.setattr(hermes_state, "sqlite_source_id", lambda: "testid-abc")
monkeypatch.setattr(sqlite3, "sqlite_version", "3.50.4", raising=False)
args = SimpleNamespace(fix=False, ack=None)
try:
run_doctor(args)
except SystemExit:
pass
out = capsys.readouterr().out
assert "SQLite" in out
assert "3.50.4" in out
assert "WAL-reset" in out
assert "hermes update" in out
# No longer appended to the blocking issues summary.
assert "Linked SQLite is vulnerable" not in out