![c++ stack smashing detected low memory c++ stack smashing detected low memory](https://cdncontribute.geeksforgeeks.org/wp-content/uploads/memoryLayoutC.jpg)
You shouldn’t need the -fno-stack-protector flag when compiling on a 32-bit machine. The stack smashing detected error is because the x86 64-bit architecture on my Linux machine will protect the stack from buffer overruns by default. Let’s compile that again with a flag to turn off the memory protection: $ gcc -fno-stack-protector -o cat_pictures cat_pictures.c The “string” ( there are no strings in C) is larger than the buffer, and C will continue to happily write the characters into the adjacent memory, corrupting it and causing a runtime error. The second example, however, is a different story. You can see that the character array foobar, being six bytes in length, is printed to stdout without a complaint. *** stack smashing detected ***: terminated The strcpy man page warns that the function is susceptible to a buffer overrun and that the recommended function call is strncpy, where the programmer specifies the length of the copy. By overwriting adjacent memory, a clever hacker can gain control of the process and possibly even the machine.įor example, since there is no bounds checking, the call to strcpy can overflow the buf buffer if the function parameter s is larger than 10 bytes. The idea is to give the program input that is larger than the length that the buf buffer expects. Here’s a simple and contrived example, which is close to the canonical example you’ll see on most websites that demonstrate the technique: #include In this article, I’m going to assume a certain familiarity with the basics of the aforementioned, so if you are completely new to any one of them, I suggest finding a tutorial to get you up to speed. I posit that taking the time to understand how and why these exploits work is an excellent educational experience, whether one codes in “low-level” language such as C/C++ or a high-level interpreted language such as Python or JavaScript.įor example, to implement a buffer overflow attack, it is necessary to have at least a basic understanding of the following (in no specific order):
C++ stack smashing detected low memory software#
There have been security measures put in place both at the hardware ( NX bit) and software ( ASLR, stack canaries) layers to prevent these, but any subscriber to an OS bug mailing list will know that these exploits still happen frequently.
C++ stack smashing detected low memory code#
This is also known as arbitrary code execution. This is usually accomplished by executing a stack-based buffer overflow, or overrun, whereby a contiguous area of memory is filled up and overflowed into the adjacent memory locations. Stack smashing is accomplished by exploiting a running process by injecting executable code or taking control of the instruction pointer in order to have it do something it wasn’t designed to do.