GCC STACK SMASHING DETECTED CODE

We need to track where it's stored on stack. Canary is emitted by the compiler if with -enable-default-ssp configure option which enables this option by default. You don't really need to know much of assembly to find the canary. Canary is a value placed on stack and checked by the compiler to see if anything corrupts canary value. Now the hardest part: we need to find in assembly where canary value was stored and loaded on stack. The interesting part here is the caller of _stack_chk_fail. #3 0x00007fcbdefbd0a2 in _GI_fortify_fail 'stack smashing detected') at fortify_fail.c:26 Program terminated with signal SIGABRT, Aborted.

To disable ASLR, on linux it is disabled by setting randomize_va_space to 0.User $ gdb -quiet. To get the consistent behaviour every time, you need to disable ASLR as well.

Sometimes the overflown buffer does not reaches to canary and sometimes it does. It means the address space allocation is random and the bytes between your vectors is different every time. In order to prevent an attacker from reliably jumping to, for example, a particular exploited function in memory, ASLR randomly arranges the address space positions of key data areas of a process, including the base of the executable and the positions of the stack, heap and libraries. When you compile your program your compiler gcc/g++ optimize your executable for security mechanisms to prevent buffer overflow exploits.ДЄddress space layout randomization (ASLR) is a computer security technique involved in preventing exploitation of memory corruption vulnerabilities. Your program behaviour is random because probably you have not disabled ASLR (Address space layout randomization). You need to configure your compiler to make it easier for buffer overflow. The fact this error is not consistent because sometimes the canary does not get overwritten (fine run of program) or overwritten by the same exact value and sometimes the canary gets overwritten with a different value leading to this error. To see if a data from vector 1 appears in vector 2 this indeed seems like buffer overflow kind of assignment where you are required to overwrite contents of arrays from one another.

GCC STACK SMASHING DETECTED CODE

If it is a computer security assignment where you are working on a buffer overflow exploit then you need to figure out to bybass these security mechanism, if you are not familiar with it, then somehow you are overflowing buffer and without looking at code I can't comment much where exactly the problem is. However, disabling stack-protection will remove this error but you might get segmentation fault as a result of overwriting stack. To avoid this error, disable fstack-protector in gcc while compiling the code using g++ myProgram.c -o myProgram -fno-stack-protector This is a security mechanism implemented by gcc/g++ to prevent buffer overflow exploits using -fstack-protector. *** stack smashing detected *** error occurs when as the name suggests, you smash the stack, meaning that you have a buffer overflow and the canary gets overwritten by a different value.

Gcc stack smashing detected