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cpp/ql/src/experimental/Security/CWE/CWE-570/WrongInDetectingAndHandlingMemoryAllocationErrors.cpp

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+// BAD: no memory allocation errors are detected
+void f(const int *array, std::size_t size) noexcept {
+  int *copy = new int[size];
+  std::memcpy(copy, array, size * sizeof(*copy));
+  // ...
+  delete [] copy;
+}
+// GOOD: memory allocation errors are detected
+void f(const int *array, std::size_t size) noexcept {
+  int *copy;
+  try {
+    copy = new int[size];
+  } catch(std::bad_alloc) {
+    // Handle error
+    return;
+  }
+  // At this point, copy has been initialized to allocated memory
+  std::memcpy(copy, array, size * sizeof(*copy));
+  // ...
+  delete [] copy;
+}
+// GOOD: memory allocation errors are detected
+void f(const int *array, std::size_t size) noexcept {
+  int *copy = new (std::nothrow) int[size];
+  if (!copy) {
+    // Handle error
+    return;
+  }
+  std::memcpy(copy, array, size * sizeof(*copy));
+  // ...
+  delete [] copy;
+}

cpp/ql/src/experimental/Security/CWE/CWE-570/WrongInDetectingAndHandlingMemoryAllocationErrors.qhelp

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+<!DOCTYPE qhelp PUBLIC
+  "-//Semmle//qhelp//EN"
+  "qhelp.dtd">
+<qhelp>
+<overview>
+<p>when using the new operator to allocate memory, you need to pay attention to the different way of detecting errors. so <code> ::operator new(std::size_t) </code> throws an exception on error, and <code> ::operator new(std::size_t, const std::nothrow_t &) </code> returns zero on error. the programmer can get confused and check the error that occurs when allocating memory incorrectly. That can lead to an unhandled program termination or to a violation of the program logic.</p>
+
+<p>Loss of detection probably refers to use cases where memory allocation using your own solutions with strong nesting. It is also possible when using a buffer in the form of fields of different structures with the same names.</p>
+
+</overview>
+<recommendation>
+
+<p>We recommend using the error detection method, depending on the selected memory allocation method.</code>.</p>
+
+</recommendation>
+<example>
+<p>The following file demonstrates various approaches to detecting memory allocation errors using the new operator.</p>
+<sample src="WrongInDetectingAndHandlingMemoryAllocationErrors.cpp" />
+
+</example>
+<references>
+
+<li>
+  CERT C++ Coding Standard:
+<a href="https://wiki.sei.cmu.edu/confluence/display/cplusplus/MEM52-CPP.+Detect+and+handle+memory+allocation+errors">MEM52-CPP. Detect and handle memory allocation errors</a>.
+</li>
+
+</references>
+</qhelp>

cpp/ql/src/experimental/Security/CWE/CWE-570/WrongInDetectingAndHandlingMemoryAllocationErrors.ql

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+/**
+ * @name Сonfusion In Detecting And Handling Memory Allocation Errors
+ * @description --::operator new(std::size_t) throws an exception on error, and ::operator new(std::size_t, const std::nothrow_t &) returns zero on error.
+ *              --the programmer can get confused when check the error that occurs when allocating memory incorrectly.
+ *              --Making a call of this type may result in a zero byte being written just outside the buffer.
+ * @kind problem
+ * @id cpp/detect-and-handle-memory-allocation-errors
+ * @problem.severity warning
+ * @precision medium
+ * @tags correctness
+ *       security
+ *       external/cwe/cwe-570
+ */
+
+import cpp
+
+/**
+ * Lookup if condition compare with 0
+ */
+class IfCompareWithZero extends IfStmt {
+  IfCompareWithZero() {
+    this.getCondition().(EQExpr).getAChild().getValue() = "0"
+    or
+    this.getCondition().(NEExpr).getAChild().getValue() = "0" and
+    this.hasElse()
+  }
+}
+
+/**
+ * lookup for calls to `operator new`, with incorrect error handling.
+ */
+class WrongCheckErrorOperatorNew extends FunctionCall {
+  Expr exp;
+
+  WrongCheckErrorOperatorNew() {
+    this = exp.(NewOrNewArrayExpr).getAChild().(FunctionCall) and
+    (
+      this.getTarget().hasGlobalOrStdName("operator new")
+      or
+      this.getTarget().hasGlobalOrStdName("operator new[]")
+    )
+  }
+
+  /**
+   * Holds if handler `try ... catch` exists.
+   */
+  predicate isExistsTryCatchBlock() {
+    exists(TryStmt tb, AssignExpr aex, Initializer it |
+      tb.getAChild*() = exp
+      or
+      exp = it.getExpr() and
+      tb.getAChild*().(DeclStmt).getADeclaration() = it.getDeclaration()
+      or
+      aex.getAChild*() = exp and
+      tb.getAChild*().(AssignExpr) = aex
+    )
+  }
+
+  /**
+   * Holds if results call `operator new` check in `operator if`.
+   */
+  predicate isExistsIfCondition() {
+    exists(IfCompareWithZero ifc, AssignExpr aex, Initializer it |
+      // call `operator new` directly from the condition of `operator if`.
+      this = ifc.getCondition().getAChild()
+      or
+      // check results call `operator new` with variable appropriation
+      postDominates(ifc, this) and
+      aex.getAChild() = exp and
+      ifc.getCondition().getAChild().(VariableAccess).getTarget() =
+        aex.getLValue().(VariableAccess).getTarget()
+      or
+      // check results call `operator new` with declaration variable
+      postDominates(ifc, this) and
+      exp = it.getExpr() and
+      it.getDeclaration() = ifc.getCondition().getAChild().(VariableAccess).getTarget()
+    )
+  }
+
+  /**
+   * Holds if `(std::nothrow)` exists in call `operator new`.
+   */
+  predicate isExistsNothrow() { this.getAChild().toString() = "nothrow" }
+}
+
+from WrongCheckErrorOperatorNew op
+where
+  // use call `operator new` with `(std::nothrow)` and checking error using `try ... catch` block and not `operator if`
+  op.isExistsNothrow() and not op.isExistsIfCondition() and op.isExistsTryCatchBlock()
+  or
+  // use call `operator new` without `(std::nothrow)` and checking error using `operator if` and not  `try ... catch` block
+  not op.isExistsNothrow() and not op.isExistsTryCatchBlock() and op.isExistsIfCondition()
+select op, "memory allocation error check is incorrect or missing"