I have a simple program that will crash (using strcpy) but I am having problems trying to crash it with AFL++.

int main(int argc, char *argv[])
{
    char dest[4];
    strcpy(dest, argv[1]);

    printf("%sn", dest);

    return 0;
}

My AFL++ command line is as follows

./afl-fuzz -i ./testcases/ -o ./findings_dir -Q ../src/strcpy_arm64_linux z

My input test case consists of only one file which contains “zzzz”.

My questions are

• What should I do to get it to fuzz correctly? I waited for 10 minutes or so, should I wait longer?
• Do I still need to specify an input folder with input files given that I have provided a command line parameter in my command (the single “z”)?
• How do the input files come into effect? When and how do the contents of the input files get used during the testing?