Vulnerability in OpenSSL CVE-2016-2177

Avoid some undefined pointer arithmetic A common idiom in the codebase is to check limits in the following manner: "p + len > limit" Where "p" points to some malloc'd data of SIZE bytes and limit == p + SIZE "len" here could be from some externally supplied data (e.g. from a TLS message). The rules of C pointer arithmetic are such that "p + len" is only well defined where len <= SIZE. Therefore the above idiom is actually undefined behaviour. For example this could cause problems if some malloc implementation provides an address for "p" such that "p + len" actually overflows for values of len that are too big and therefore p + len < limit.