Commit 1443e76b authored by Hrvoje Ribicic's avatar Hrvoje Ribicic
Browse files

Add refusal of requests with forbidden parameters



This patch provides the meat of the patch series by wrapping method
handlers in a function which examines parameters, and determines if
any of them are forbidden, whether specific values or in general.
Signed-off-by: default avatarHrvoje Ribicic <riba@google.com>
Reviewed-by: default avatarKlaus Aehlig <aehlig@google.com>
parent 54352d1e
......@@ -460,6 +460,80 @@ def GetHandler(get_fn, aliases):
return result
# Constant used to denote that a parameter cannot be set
ALL_VALUES_FORBIDDEN = "all_values_forbidden"
def ProduceForbiddenParamDict(class_name, method_name, param_list):
"""Turns a list of parameter names and possibly values into a dictionary.
@type class_name: string
@param class_name: The name of the handler class
@type method_name: string
@param method_name: The name of the HTTP method
@type param_list: list of string or tuple of (string, list of any)
@param param_list: A list of forbidden parameters, specified in the RAPI
handler class
@return: The dictionary of forbidden param names to values or
ALL_VALUES_FORBIDDEN
"""
# A simple error-raising function
def _RaiseError(message):
raise errors.ProgrammerError(
"While examining the %s_FORBIDDEN field of class %s: %s" %
(method_name, class_name, message)
)
param_dict = {}
for value in param_list:
if isinstance(value, basestring):
param_dict[value] = ALL_VALUES_FORBIDDEN
elif isinstance(value, tuple):
if len(value) != 2:
_RaiseError("Tuples of only length 2 allowed")
param_name, forbidden_values = value
param_dict[param_name] = forbidden_values
else:
_RaiseError("Only strings or tuples allowed, found %s" % value)
return param_dict
def InspectParams(params_dict, forbidden_params, rename_dict):
"""Inspects a dictionary of params, looking for forbidden values.
@type params_dict: dict of string to anything
@param params_dict: A dictionary of supplied parameters
@type forbidden_params: dict of string to string or list of any
@param forbidden_params: The forbidden parameters, with a list of forbidden
values or the constant ALL_VALUES_FORBIDDEN
signifying that all values are forbidden
@type rename_dict: None or dict of string to string
@param rename_dict: The list of parameter renamings used by the method
@raise http.HttpForbidden: If a forbidden param has been set
"""
for param in params_dict:
# Check for possible renames to ensure nothing slips through
if rename_dict is not None and param in rename_dict:
param = rename_dict[param]
# Now see if there are restrictions on this parameter
if param in forbidden_params:
forbidden_values = forbidden_params[param]
if forbidden_values == ALL_VALUES_FORBIDDEN:
raise http.HttpForbidden("The parameter %s cannot be set via RAPI" %
param)
param_value = params_dict[param]
if param_value in forbidden_values:
raise http.HttpForbidden("The parameter %s cannot be set to the value"
" %s via RAPI" % (param, param_value))
class _MetaOpcodeResource(type):
"""Meta class for RAPI resources.
......@@ -501,6 +575,19 @@ class _MetaOpcodeResource(type):
getattr(obj, rename_attr, None),
getattr(obj, fn_attr, obj._GetDefaultData)))
# Finally, the method (generated or not) should be wrapped to handle
# forbidden values
if hasattr(obj, m_attrs.forbidden):
forbidden_dict = ProduceForbiddenParamDict(
obj.__class__.__name__, method, getattr(obj, m_attrs.forbidden)
)
setattr(
obj, method, compat.partial(obj._ForbiddenHandler,
getattr(obj, method),
forbidden_dict,
getattr(obj, m_attrs.rename))
)
return obj
......@@ -553,6 +640,14 @@ class OpcodeResource(ResourceBase):
"""
__metaclass__ = _MetaOpcodeResource
def _ForbiddenHandler(self, method_fn, forbidden_params, rename_dict):
"""Examines provided parameters for forbidden values.
"""
InspectParams(self.queryargs, forbidden_params, rename_dict)
InspectParams(self.request_body, forbidden_params, rename_dict)
return method_fn()
def _GetDefaultData(self):
return (self.request_body, None)
......
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