#Example buffer overflow how to
#Example buffer overflow code

But in the end there is always some low-level language involved, so the only thing protecting you is the high-level language's design. High-level languages are (generally) designed as not to allow intentional or unintentional buffer/heap overflows (among other things that could represent vulnerabilities or could lead a programmer to introduce a bug). Tl dr: (most) high-level languages specifically protect you from that, but a very rare bug could make those protections fail.

#Example buffer overflow code

In an extreme case a hastily written glue code could even return something like a ctypes pointer object to the end user's python code. Buffer overflows can happen either in the C and C++ libraries themselves or in the glue code (which may be written in either C or python) that interfaces between python and C. That is a contrived example but because python is a relatively slow language, most python code calls into code written in other languages, most commonly C and C++ to do the 'heavy lifting'. The intended use of these functions are to allow interoperability with C code, but in order to do so they must provide mechanisms to work with C style raw pointers which cannot have bounds checking applied.įor example I was able to produce a segmentation fault with the following python code. In particular there is a module in the standard library called 'ctypes'. Still, there are ways to create buffer overflows in python. Python on the other hand does try to protect it's users from such mistakes, the regular python programmer never sees a raw pointer, they only see reference counted object references, the standard python collection objects are protected against overflows. 'level' of a programming languages is not a particularly well-defined concept.Ĭ++ for example would generally be regarded as a higher-level language then C but it still leaves the user open to the same memory safety problems, including buffer overflows, that C suffers from. High-level languages generally guard against such vulnerabilities, but the underlying runtimes of these programs are still vulnerable. Or you could say it's not vulnerable to overflows, because the overflow itself actually occurred in a C program, which just happens to be interpreting python code. One could say Python is vulnerable to overflows, because you could write a python program that causes a buffer overflow.

#Example buffer overflow how to

Now, how to interpret this is a matter of semantics. This occurs because sprintf is used unsafely. Python 3.x through 3.9.1 has a buffer overflow in P圜Arg_repr in _ctypes/callproc.c, which may lead to remote code execution in certain Python applications that accept floating-point numbers as untrusted input, as demonstrated by a 1e300 argument to c_om_param. The python runtime itself is just a process and thus susceptible to all kinds of vulnerabilities, including buffer overflows.įor example, CVE-2021-3177 has been found last year and has the following summary:

That seems like overflows are impossible, right? Well, not exactly. So instead of just overwriting some memory, the runtime caught that cars only had three elements and writing to a fourth element is therefore forbidden. Inde圎rror: list assignment index out of range This will print the following error: Traceback (most recent call last): Consider the following python code: cars = However, the runtimes those languages are based on will ensure that most of these scenarios don't happen. Specifically, a 'buffer overflow' occurs when memory is allocated on the stack and the program writes outside that memory and into following memory.Įven on a language like Python or C#, such things could happen in theory. Overflows don't occur in a language, they occur in a process.