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Agent firewall long hostname crash #559

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Merged
merged 3 commits into from
Mar 17, 2025
Merged

Agent firewall long hostname crash #559

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2c80b1c
firewall: avoid crash on qubesdb long path errors
troyjfarrell Mar 13, 2025
86fecb9
Remove accidentally duplicated test function
troyjfarrell Mar 13, 2025
7518028
Fix the issue URL in the log message
troyjfarrell Mar 13, 2025
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13 changes: 12 additions & 1 deletion qubesagent/firewall.py
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Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,18 @@
self.qdb.rm('/dns/{}/'.format(source))

for host, hostaddrs in dns.items():
self.qdb.write('/dns/{}/{}'.format(source, host), str(hostaddrs))
path = '/dns/{}/{}'.format(source, host)
try:
self.qdb.write(path, str(hostaddrs))
except Exception as err:
if len(path) > 64 and err.args == (0, 'Error'):
self.log.error(('Unable to add DNS information for {} ({})'
' due to qubesdb path length limit').format(
host, source))
self.log.error('See https://github.com/QubesOS/'
'qubes-issues/issues/9084')
else:
raise

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Added line #L181 was not covered by tests

def update_handled(self, addr):
"""
Expand Down
21 changes: 21 additions & 0 deletions qubesagent/test_firewall.py
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,8 @@ def rm(self, path):
self.entries.pop(path)

def write(self, path, val):
if len(path) > 64:
raise DummyQubesDBError(0, 'Error')
self.entries[path] = val

def multiread(self, prefix):
Expand All @@ -65,6 +67,8 @@ def read_watch(self):
except IndexError:
return None

class DummyQubesDBError(Exception):
"Raised by QubesDB"

class FirewallWorker(qubesagent.firewall.FirewallWorker):
def __init__(self):
Expand Down Expand Up @@ -159,6 +163,23 @@ def test_701_dns_info(self):
self.obj.apply_rules('10.137.0.1', [{'action': 'drop'}])
self.assertIsNone(self.obj.qdb.read('/dns/10.137.0.1/ripe.net'))

def test_702_dns_info_qubesdb_path_length_crash(self):
self.obj.conntrack_get_connections = Mock(return_value=[])
rules = [
{'action': 'accept', 'proto': 'tcp',
'dstports': '443-443', 'dsthost': 'www.google.com'},
{'action': 'accept', 'proto': 'tcp',
'dstports': '443-443', 'dsthost': 'prod-dynamite-prod-05-us-signaler-pa.clients6.google.com'},
{'action': 'drop'},
]
self.obj.apply_rules('10.137.0.22', rules)
self.assertIsNotNone(self.obj.qdb.read('/dns/10.137.0.22/www.google.com'))
# Unfortunately, this is assertIsNone until the QubesDB path length limit is raised.
self.assertIsNone(self.obj.qdb.read('/dns/10.137.0.22/prod-dynamite-prod-05-us-signaler-pa.clients6.google.com'))
self.obj.apply_rules('10.137.0.22', [{'action': 'drop'}])
self.assertIsNone(self.obj.qdb.read('/dns/10.137.0.22/www.google.com'))
self.assertIsNone(self.obj.qdb.read('/dns/10.137.0.22/prod-dynamite-prod-05-us-signaler-pa.clients6.google.com'))

class TestNftablesWorker(TestCase, WorkerCommon):
def setUp(self):
super(TestNftablesWorker, self).setUp()
Expand Down