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qubespolicy: move all syntax-level validation to one place

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This will make analyzing the policy code slightly easier. While it makes
verify_special_value function more complex, other places are much
simpler now.
This commit is contained in:
Marek Marczykowski-Górecki 2017-09-11 14:21:46 +02:00
parent 5e870e4b6a
commit d4716832e2
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GPG Key ID: 063938BA42CFA724
1 changed files with 34 additions and 18 deletions
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42
qubespolicy/__init__.py
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@ -85,30 +85,43 @@ def verify_target_value(system_info, value):
return value in system_info['domains']
def verify_special_value(value, for_target=True):
def verify_special_value(value, for_target=True, specific_target=False):
'''
Verify if given special VM-specifier ('$...') is valid
:param value: value to verify
:param for_target: should classify target-only values as valid (
'$default', '$dispvm')
:param specific_target: allow only values naming specific target
(for use with target=, default= etc)
:return: True or False
'''
# pylint: disable=too-many-return-statements
# values used only for matching VMs, not naming specific one (for actual
# call target)
if not specific_target:
if value.startswith('$tag:') and len(value) > len('$tag:'):
return True
elif value.startswith('$type:') and len(value) > len('$type:'):
if value.startswith('$type:') and len(value) > len('$type:'):
return True
elif value == '$anyvm':
if for_target and value.startswith('$dispvm:$tag:') and \
len(value) > len('$dispvm:$tag:'):
return True
elif value == '$adminvm':
if value == '$anyvm':
return True
elif value.startswith('$dispvm:') and for_target:
if for_target and value == '$default':
return True
elif value == '$dispvm' and for_target:
# those can be used to name one specific call VM
if value == '$adminvm':
return True
elif value == '$default' and for_target:
# allow only specific dispvm, not based on any $xxx keyword - don't name
# $tag here specifically, to work also with any future keywords
if for_target and value.startswith('$dispvm:') and \
not value.startswith('$dispvm:$'):
return True
if for_target and value == '$dispvm':
return True
return False
@ -179,12 +192,12 @@ class PolicyRule(object):
# verify special values
if self.source.startswith('$'):
if not verify_special_value(self.source, False):
if not verify_special_value(self.source, False, False):
raise PolicySyntaxError(filename, lineno,
'invalid source specification: {}'.format(self.source))
if self.target.startswith('$'):
if not verify_special_value(self.target, True):
if not verify_special_value(self.target, True, False):
raise PolicySyntaxError(filename, lineno,
'invalid target specification: {}'.format(self.target))
@ -196,10 +209,13 @@ class PolicyRule(object):
if self.override_target is not None:
if self.override_target.startswith('$') and \
(not self.override_target.startswith('$dispvm') or
self.override_target.startswith('$dispvm:$tag:') or
self.override_target.startswith('$tag:')) and \
self.override_target != '$adminvm':
not verify_special_value(self.override_target, True, True):
raise PolicySyntaxError(filename, lineno,
'target= option needs to name specific target')
if self.default_target is not None:
if self.default_target.startswith('$') and \
not verify_special_value(self.default_target, True, True):
raise PolicySyntaxError(filename, lineno,
'target= option needs to name specific target')