codeql/python/ql/src/Classes/MutatingDescriptor.ql at codeql-cli-2.17.4 · github/codeql

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/**

* @name Mutation of descriptor in `__get__` or `__set__` method.

* @description Descriptor objects can be shared across many instances. Mutating them can cause strange side effects or race conditions.

* @kind problem

* @tags reliability

* correctness

* @problem.severity error

* @sub-severity low

* @precision very-high

* @id py/mutable-descriptor

import python

predicate mutates_descriptor(ClassObject cls, SelfAttributeStore s) {

cls.isDescriptorType() and

exists(PyFunctionObject f, PyFunctionObject get_set |

exists(string name | cls.lookupAttribute(name) = get_set |

name = "__get__" or name = "__set__" or name = "__delete__"

) and

cls.lookupAttribute(_) = f and

get_set.getACallee*() = f and

not f.getName() = "__init__" and

s.getScope() = f.getFunction()

)

}

from ClassObject cls, SelfAttributeStore s

where mutates_descriptor(cls, s)

select s,

"Mutation of descriptor $@ object may lead to action-at-a-distance effects or race conditions for properties.",

cls, cls.getName()