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RULE-8-2-6 - IntToPointerCastProhibited
Detects casts from integral, enumerated, or void pointer types to object pointer types that may lead to unspecified behavior. [a]
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‎cpp/misra/src/rules/RULE-8-2-6/IntToPointerCastProhibited.ql‎

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/**
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* @id cpp/misra/int-to-pointer-cast-prohibited
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* @name RULE-8-2-6: An object with integral, enumerated, or pointer to void type shall not be cast to a pointer type
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* @description Casting from an integral type, enumerated type, or pointer to void type to a pointer
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* type leads to unspecified behavior and is error prone.
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* @kind problem
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* @precision very-high
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* @problem.severity error
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* @tags external/misra/id/rule-8-2-6
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* scope/single-translation-unit
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* external/misra/enforcement/decidable
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* external/misra/obligation/required
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*/
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import cpp
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import codingstandards.cpp.misra
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from Cast cast, Type sourceType, Type targetType
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where
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not isExcluded(cast, Conversions2Package::intToPointerCastProhibitedQuery()) and
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sourceType = cast.getExpr().getType().stripTopLevelSpecifiers() and
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targetType = cast.getType().stripTopLevelSpecifiers() and
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targetType instanceof PointerType and
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not targetType instanceof FunctionPointerType and
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not (
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// Exception: casts between void pointers are allowed
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targetType.(PointerType).getBaseType().stripTopLevelSpecifiers() instanceof VoidType and
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sourceType instanceof PointerType and
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sourceType.(PointerType).getBaseType().stripTopLevelSpecifiers() instanceof VoidType
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) and
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(
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// Integral types
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sourceType instanceof IntegralType
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or
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// Enumerated types
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sourceType instanceof Enum
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or
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// Pointer to void type
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sourceType instanceof PointerType and
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sourceType.(PointerType).getBaseType().stripTopLevelSpecifiers() instanceof VoidType
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)
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select cast,
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"Cast from '" + sourceType.toString() + "' to '" + targetType.toString() + "' is prohibited."

‎cpp/misra/test/rules/RULE-8-2-6/IntToPointerCastProhibited.expected‎

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| test.cpp:15:20:15:53 | reinterpret_cast<TestStruct *>... | Cast from 'signed int' to 'TestStruct *' is prohibited. |
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| test.cpp:16:20:16:53 | reinterpret_cast<TestStruct *>... | Cast from 'signed long' to 'TestStruct *' is prohibited. |
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| test.cpp:17:22:17:57 | reinterpret_cast<int32_t *>... | Cast from 'signed long' to 'int32_t *' is prohibited. |
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| test.cpp:24:20:24:53 | reinterpret_cast<TestStruct *>... | Cast from 'TestEnum' to 'TestStruct *' is prohibited. |
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| test.cpp:25:22:25:57 | reinterpret_cast<int32_t *>... | Cast from 'TestEnum' to 'int32_t *' is prohibited. |
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| test.cpp:32:20:32:48 | static_cast<TestStruct *>... | Cast from 'void *' to 'TestStruct *' is prohibited. |
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| test.cpp:33:20:33:53 | reinterpret_cast<TestStruct *>... | Cast from 'void *' to 'TestStruct *' is prohibited. |
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| test.cpp:34:22:34:52 | static_cast<int32_t *>... | Cast from 'void *' to 'int32_t *' is prohibited. |
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| test.cpp:35:22:35:57 | reinterpret_cast<int32_t *>... | Cast from 'void *' to 'int32_t *' is prohibited. |
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| test.cpp:43:14:43:41 | reinterpret_cast<void *>... | Cast from 'signed int' to 'void *' is prohibited. |
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| test.cpp:44:14:44:41 | reinterpret_cast<void *>... | Cast from 'signed long' to 'void *' is prohibited. |

‎cpp/misra/test/rules/RULE-8-2-6/IntToPointerCastProhibited.qlref‎

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rules/RULE-8-2-6/IntToPointerCastProhibited.ql

‎cpp/misra/test/rules/RULE-8-2-6/test.cpp‎

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#include <cstdint>
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struct TestStruct {
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std::int32_t m1;
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std::int32_t m2;
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};
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enum TestEnum { VALUE1, VALUE2 };
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void test_integral_to_pointer_cast() {
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std::int32_t l1 = 42;
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std::int64_t l2 = 0x1000;
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// Casting integral types to pointer types
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TestStruct *l4 = reinterpret_cast<TestStruct *>(l1); // NON_COMPLIANT
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TestStruct *l5 = reinterpret_cast<TestStruct *>(l2); // NON_COMPLIANT
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std::int32_t *l7 = reinterpret_cast<std::int32_t *>(l2); // NON_COMPLIANT
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}
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void test_enumerated_to_pointer_cast() {
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TestEnum l1 = VALUE1;
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// Casting enumerated types to pointer types
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TestStruct *l3 = reinterpret_cast<TestStruct *>(l1); // NON_COMPLIANT
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std::int32_t *l5 = reinterpret_cast<std::int32_t *>(l1); // NON_COMPLIANT
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}
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void test_void_pointer_to_object_pointer_cast() {
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void *l1 = nullptr;
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// Casting void pointer to object pointer types
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TestStruct *l2 = static_cast<TestStruct *>(l1); // NON_COMPLIANT
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TestStruct *l3 = reinterpret_cast<TestStruct *>(l1); // NON_COMPLIANT
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std::int32_t *l4 = static_cast<std::int32_t *>(l1); // NON_COMPLIANT
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std::int32_t *l5 = reinterpret_cast<std::int32_t *>(l1); // NON_COMPLIANT
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}
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void test_integral_to_void_pointer_cast() {
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std::int32_t l1 = 42;
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std::int64_t l2 = 0x1000;
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// Casting integral types to void pointer
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void *l3 = reinterpret_cast<void *>(l1); // NON_COMPLIANT
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void *l4 = reinterpret_cast<void *>(l2); // NON_COMPLIANT
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}
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void test_compliant_void_pointer_casts() {
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void *l1 = nullptr;
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const void *l2 = nullptr;
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// Casts between void pointers are allowed
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const void *l3 = const_cast<const void *>(l1); // COMPLIANT
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void *l4 = const_cast<void *>(l2); // COMPLIANT
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volatile void *l5 = static_cast<volatile void *>(l1); // COMPLIANT
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}
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void f1() {}
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void f2(int) {}
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void test_compliant_function_pointer_exceptions() {
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std::int64_t l1 = 0x1000;
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// Function pointer casts are exceptions to this rule
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void (*l2)() = reinterpret_cast<void (*)()>(l1); // COMPLIANT
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void (*l3)(int) = reinterpret_cast<void (*)(int)>(l1); // COMPLIANT
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}
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struct TestClass {
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void memberFunc();
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std::int32_t m1;
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};
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void test_compliant_member_function_pointer_exceptions() {
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void *l1 = nullptr;
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// Member function pointer casts are technically exceptions to this rule, but
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// are prohibited by the compiler.
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// void (TestClass::*l2)() =
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// reinterpret_cast<void (TestClass::*)()>(l1); // COMPLIANT
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}
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void test_compliant_regular_pointer_operations() {
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TestStruct l1;
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TestStruct *l2 = &l1;
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std::int32_t *l3 = &l1.m1;
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// Regular pointer operations that don't involve forbidden casts
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TestStruct *l4 = l2; // COMPLIANT
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std::int32_t *l5 = l3; // COMPLIANT
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}

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