Merge "Add isSafeArraySize for new array size checks" into lmp-dev

    name(const name &); \

    name &operator=(const name &)

/* Returns true if the size parameter is safe for new array allocation (32-bit)

 *

 * Example usage:

 *

 * if (!isSafeArraySize<uint32_t>(arraySize)) {

 *     return BAD_VALUE;

 * }

 * ...

 * uint32_t *myArray = new uint32_t[arraySize];

 *

 * There is a bug in gcc versions earlier than 4.8 where the new[] array allocation

 * will overflow in the internal 32 bit heap allocation, resulting in an

 * underallocated array. This is a security issue that allows potential overwriting

 * of other heap data.

 *

 * An alternative to checking is to create a safe new array template function which

 * either throws a std::bad_alloc exception or returns NULL/nullptr_t; NULL considered

 * safe since normal access of NULL throws an exception.

 *

 * https://securityblog.redhat.com/2012/10/31/array-allocation-in-cxx/

 */

template <typename T, typename S>

bool isSafeArraySize(S size) {

    return size >= 0                            // in case S is signed, ignored if not.

            && size <= 0xffffffff / sizeof(T);  // max-unsigned-32-bit-int / element-size.

}

#endif  // A_BASE_H_