Implement Memory1 (RULE-8-7-1)

cpp/common/src/codingstandards/cpp/exclusions/cpp/RuleMetadata.qll

@@ -37,6 +37,7 @@ import Lambdas
 import Literals
 import Loops
 import Macros
+import Memory1
 import MoveForward
 import Naming
 import Null
@@ -99,6 +100,7 @@ newtype TCPPQuery =
   TLiteralsPackageQuery(LiteralsQuery q) or
   TLoopsPackageQuery(LoopsQuery q) or
   TMacrosPackageQuery(MacrosQuery q) or
+  TMemory1PackageQuery(Memory1Query q) or
   TMoveForwardPackageQuery(MoveForwardQuery q) or
   TNamingPackageQuery(NamingQuery q) or
   TNullPackageQuery(NullQuery q) or
@@ -161,6 +163,7 @@ predicate isQueryMetadata(Query query, string queryId, string ruleId, string cat
   isLiteralsQueryMetadata(query, queryId, ruleId, category) or
   isLoopsQueryMetadata(query, queryId, ruleId, category) or
   isMacrosQueryMetadata(query, queryId, ruleId, category) or
+  isMemory1QueryMetadata(query, queryId, ruleId, category) or
   isMoveForwardQueryMetadata(query, queryId, ruleId, category) or
   isNamingQueryMetadata(query, queryId, ruleId, category) or
   isNullQueryMetadata(query, queryId, ruleId, category) or

cpp/common/test/includes/standard-library/cstdlib

@@ -23,5 +23,8 @@ using ::strtoll;
 using ::strtoul;
 using ::strtoull;
 using ::system;
+using ::malloc;
+using ::calloc;
+using ::realloc;
 } // namespace std
 #endif // _GHLIBCPP_CSTDLIB

cpp/misra/src/rules/RULE-8-7-1/PointerArithmeticFormsAnInvalidPointer.ql

@@ -0,0 +1,199 @@
+/**
+ * @id cpp/misra/pointer-arithmetic-forms-an-invalid-pointer
+ * @name RULE-8-7-1: Pointer arithmetic shall not form an invalid pointer.
+ * @description Pointers obtained as result of performing arithmetic should point to an initialized
+ *              object, or an element right next to the last element of an array.
+ * @kind problem
+ * @precision very-high
+ * @problem.severity error
+ * @tags external/misra/id/rule-8-7-1
+ *       scope/system
+ *       external/misra/enforcement/undecidable
+ *       external/misra/obligation/required
+ */
+
+import cpp
+import codingstandards.cpp.misra
+import semmle.code.cpp.dataflow.new.DataFlow
+import semmle.code.cpp.security.BufferAccess
+
+class ArrayDeclaration extends VariableDeclarationEntry {
+  int length;
+
+  ArrayDeclaration() { this.getType().getUnderlyingType().(ArrayType).getArraySize() = length }
+
+  /**
+   * Gets the declared length of this array.
+   */
+  int getLength() { result = length }
+
+  /**
+   * Gets the expression that the variable declared is initialized to, given there is such one.
+   */
+  Expr getInitExpr() { result = this.getVariable().getInitializer().getExpr() }
+}
+
+class HeapAllocationFunctionCall extends FunctionCall {
+  AllocationFunction heapAllocFunction;
+
+  HeapAllocationFunctionCall() { this.getTarget() = heapAllocFunction }
+
+  predicate isMallocCall() { heapAllocFunction.getName() = "malloc" }
+
+  predicate isCallocCall() { heapAllocFunction.getName() = "calloc" }
+
+  predicate isReallocCall() { heapAllocFunction.getName() = "realloc" }
+
+  abstract Expr getByteArgument();
+
+  int getByteLowerBound() { result = lowerBound(this.getByteArgument()) }
+}
+
+class MallocFunctionCall extends HeapAllocationFunctionCall {
+  MallocFunctionCall() { this.isMallocCall() }
+
+  override Expr getByteArgument() { result = this.getArgument(0) }
+}
+
+class CallocReallocFunctionCall extends HeapAllocationFunctionCall {
+  CallocReallocFunctionCall() { this.isCallocCall() or this.isReallocCall() }
+
+  override Expr getByteArgument() { result = this.getArgument(1) }
+}
+
+class NarrowedHeapAllocationFunctionCall extends Cast {
+  HeapAllocationFunctionCall alloc;
+
+  NarrowedHeapAllocationFunctionCall() { alloc = this.getExpr() }
+
+  int getMinNumElements() {
+    result =
+      alloc.getByteLowerBound() / this.getUnderlyingType().(PointerType).getBaseType().getSize()
+  }
+
+  HeapAllocationFunctionCall getAllocFunctionCall() { result = alloc }
+}
+
+newtype TArrayAllocation =
+  TStackAllocation(ArrayDeclaration arrayDecl) or
+  TDynamicAllocation(NarrowedHeapAllocationFunctionCall narrowedAlloc)
+
+newtype TPointerFormation =
+  TArrayExpr(ArrayExprBA arrayExpr) or
+  TPointerArithmetic(PointerArithmeticOperation pointerArithmetic)
+
+class ArrayAllocation extends TArrayAllocation {
+  ArrayDeclaration asStackAllocation() { this = TStackAllocation(result) }
+
+  NarrowedHeapAllocationFunctionCall asDynamicAllocation() { this = TDynamicAllocation(result) }
+
+  string toString() {
+    result = this.asStackAllocation().toString() or
+    result = this.asDynamicAllocation().toString()
+  }
+
+  /**
+   * Gets the number of the object that the array holds. This number is exact for a stack-allocated
+   * array, and the minimum estimated value for a heap-allocated one.
+   */
+  int getLength() {
+    result = this.asStackAllocation().getLength() or
+    result = this.asDynamicAllocation().getMinNumElements()
+  }
+
+  Location getLocation() {
+    result = this.asStackAllocation().getLocation() or
+    result = this.asDynamicAllocation().getLocation()
+  }
+}
+
+class PointerFormation extends TPointerFormation {
+  ArrayExprBA asArrayExpr() { this = TArrayExpr(result) }
+
+  PointerArithmeticOperation asPointerArithmetic() { this = TPointerArithmetic(result) }
+
+  string toString() {
+    result = this.asArrayExpr().toString() or
+    result = this.asPointerArithmetic().toString()
+  }
+
+  int getOffset() {
+    result = this.asArrayExpr().getArrayOffset().getValue().toInt()
+    or
+    exists(PointerAddExpr pointerAddition | pointerAddition = this.asPointerArithmetic() |
+      result = pointerAddition.getAnOperand().getValue().toInt() // TODO: only get the number being added
+    )
+    or
+    exists(PointerSubExpr pointerSubtraction | pointerSubtraction = this.asPointerArithmetic() |
+      result = -pointerSubtraction.getAnOperand().getValue().toInt()
+    )
+  }
+
+  Expr asExpr() {
+    result = this.asArrayExpr() or
+    result = this.asPointerArithmetic()
+  }
+
+  DataFlow::Node getNode() {
+    result.asExpr() = this.asExpr() or
+    result.asIndirectExpr() = this.asExpr()
+  }
+
+  Location getLocation() {
+    result = this.asArrayExpr().getLocation() or
+    result = this.asPointerArithmetic().getLocation()
+  }
+}
+
+module TrackArrayConfig implements DataFlow::ConfigSig {
+  predicate isSource(DataFlow::Node node) {
+    /* 1. Declaring / Initializing an array-type variable */
+    exists(ArrayAllocation arrayAllocation |
+      node.asExpr() = arrayAllocation.asStackAllocation().getInitExpr()
+    )
+    or
+    /* 2. Allocating dynamic memory as an array */
+    none() // TODO
+  }
+
+  predicate isSink(DataFlow::Node node) {
+    exists(PointerFormation pointerFormation | node = pointerFormation.getNode())
+  }
+}
+
+module TrackArray = DataFlow::Global<TrackArrayConfig>;
+
+private predicate arrayDeclarationAndAccess(
+  DataFlow::Node arrayDeclarationNode, DataFlow::Node pointerFormationNode
+) {
+  TrackArray::flow(arrayDeclarationNode, pointerFormationNode)
+}
+
+private predicate arrayIndexExceedsOutOfBounds(
+  DataFlow::Node arrayDeclarationNode, DataFlow::Node pointerFormationNode
+) {
+  /* 1. Ensure the array access is reachable from the array declaration. */
+  arrayDeclarationAndAccess(arrayDeclarationNode, pointerFormationNode) and
+  exists(ArrayAllocation arrayAllocation, PointerFormation pointerFormation |
+    arrayDeclarationNode.asExpr() = arrayAllocation.asStackAllocation().getInitExpr() and
+    pointerFormationNode = pointerFormation.getNode()
+  |
+    /* 2. Cases where a pointer formation becomes illegal. */
+    (
+      /* 2-1. An offset cannot be negative. */
+      pointerFormation.getOffset() < 0
+      or
+      /* 2-2. The offset should be at most (number of elements) + 1 = (the declared length). */
+      arrayAllocation.getLength() < pointerFormation.getOffset()
+    )
+  )
+}
+
+from PointerFormation pointerFormation
+where
+  not isExcluded(pointerFormation.asExpr(),
+    Memory1Package::pointerArithmeticFormsAnInvalidPointerQuery()) and
+  exists(DataFlow::Node pointerFormationNode | pointerFormationNode = pointerFormation.getNode() |
+    arrayIndexExceedsOutOfBounds(_, pointerFormationNode)
+  )
+select pointerFormation, "TODO"

cpp/misra/test/rules/RULE-8-7-1/PointerArithmeticFormsAnInvalidPointer.expected

@@ -0,0 +1 @@
+No expected results have yet been specified

cpp/misra/test/rules/RULE-8-7-1/PointerArithmeticFormsAnInvalidPointer.qlref

@@ -0,0 +1 @@
+rules/RULE-8-7-1/PointerArithmeticFormsAnInvalidPointer.ql

cpp/misra/test/rules/RULE-8-7-1/test.cpp

@@ -0,0 +1,91 @@
+#include <cstdlib>
+
+void f1(int *array) {
+  /* 1. Pointer formed from performing arithmetic */
+  int *valid1 = array;     // COMPLIANT: pointer is within boundary
+  int *valid2 = array + 1; // COMPLIANT: pointer is within boundary
+  int *valid3 = array + 2; // COMPLIANT: pointer is within boundary
+  int *valid4 =
+      array + 3; // COMPLIANT: pointer points one beyond the last element
+  int *invalid1 =
+      array +
+      4; // NON_COMPLIANT: pointer points more than one beyond the last element
+  int *invalid2 = array - 1; // NON_COMPLIANT: pointer is outside boundary
+}
+
+void f2(int *array) {
+  /* 2. Array Access (entails pointer arithmetic) */
+  int valid1 = array[0];   // COMPLIANT: pointer is within boundary
+  int valid2 = array[1];   // COMPLIANT: pointer is within boundary
+  int valid3 = array[2];   // COMPLIANT: pointer is within boundary
+  int valid4 = array[3];   // COMPLIANT: pointer points one beyond the last
+                           // element, but non-compliant to Rule 4.1.3
+  int invalid1 = array[4]; // NON_COMPLIANT: pointer points more than one beyond
+                           // the last element
+  int invalid2 = array[-1]; // NON_COMPLIANT: pointer is outside boundary
+}
+
+void f1_realloc(int *array) {
+  /* 1. Pointer formed from performing arithmetic */
+  int *valid1 = array;     // COMPLIANT: pointer is within boundary
+  int *valid2 = array + 1; // COMPLIANT: pointer is within boundary
+  int *valid3 = array + 2; // COMPLIANT: pointer is within boundary
+  int *valid4 =
+      array + 3; // COMPLIANT: pointer points one beyond the last element
+  int *invalid1 =
+      array +
+      4; // NON_COMPLIANT: pointer points more than one beyond the last element
+  int *invalid2 = array - 1; // NON_COMPLIANT: pointer is outside boundary
+}
+
+void f2_realloc(int *array) {
+  /* 2. Array Access (entails pointer arithmetic) */
+  int valid1 = array[0];   // COMPLIANT: pointer is within boundary
+  int valid2 = array[1];   // COMPLIANT: pointer is within boundary
+  int valid3 = array[2];   // COMPLIANT: pointer points one beyond the last
+  int invalid1 = array[3]; // NON_COMPLIANT: pointer points one beyond the last
+                           // element, but non-compliant to Rule 4.1.3
+  int invalid2 = array[4]; // NON_COMPLIANT: pointer points more than one beyond
+                           // the last element
+  int invalid3 = array[-1]; // NON_COMPLIANT: pointer is outside boundary
+}
+
+int main(int argc, char *argv[]) {
+  /* 1. Array initialized on the stack */
+  int array[3] = {0, 1, 2};
+
+  f1(array);
+  f2(array);
+
+  /* 2. Array initialized on the heap */
+  int num_of_elements_malloc;
+  int num_of_elements_calloc;
+  int num_of_elements_realloc;
+
+  if (argc) {
+    num_of_elements_malloc = 1;
+    num_of_elements_calloc = 2;
+    num_of_elements_realloc = 3;
+  } else {
+    num_of_elements_malloc = 4;
+    num_of_elements_calloc = 5;
+    num_of_elements_realloc = 6;
+  }
+
+  int *array_malloc = (int *)std::malloc(num_of_elements_malloc * sizeof(int));
+  int *array_calloc = (int *)std::calloc(num_of_elements_calloc, sizeof(int));
+
+  int *array_realloc =
+      (int *)std::realloc(array_malloc, num_of_elements_realloc * sizeof(int));
+
+  f1(array_malloc);
+  f2(array_malloc);
+
+  f1(array_calloc);
+  f2(array_calloc);
+
+  f1_realloc(array_realloc);
+  f2_realloc(array_realloc);
+
+  return 0;
+}

rule_packages/cpp/Memory1.json

@@ -0,0 +1,24 @@
+{
+  "MISRA-C++-2023": {
+    "RULE-8-7-1": {
+      "properties": {
+        "enforcement": "undecidable",
+        "obligation": "required"
+      },
+      "queries": [
+        {
+          "description": "Pointers obtained as result of performing arithmetic should point to an initialized object, or an element right next to the last element of an array.",
+          "kind": "problem",
+          "name": "Pointer arithmetic shall not form an invalid pointer.",
+          "precision": "very-high",
+          "severity": "error",
+          "short_name": "PointerArithmeticFormsAnInvalidPointer",
+          "tags": [
+            "scope/system"
+          ]
+        }
+      ],
+      "title": "Pointers obtained as result of performing arithmetic should point to an initialized object, or an element right next to the last element of an array."
+    }
+  }
+}

rule_packages/cpp/Memory2.json

@@ -0,0 +1,24 @@
+{
+  "MISRA-C++-2023": {
+    "RULE-8-7-2": {
+      "properties": {
+        "enforcement": "undecidable",
+        "obligation": "required"
+      },
+      "queries": [
+        {
+          "description": "Pointer difference should be taken from pointers that belong to a same array.",
+          "kind": "problem",
+          "name": "Subtraction between pointers shall only be applied to ones that address elements of the same array.",
+          "precision": "very-high",
+          "severity": "error",
+          "short_name": "PointerDifferenceTakenBetweenDifferentArrays",
+          "tags": [
+            "scope/system"
+          ]
+        }
+      ],
+      "title": "Pointer difference should be taken from pointers that belong to a same array."
+    }
+  }
+}