DownUnder CTF: shell this [pwn]

Somebody told me that this program is vulnerable to something called remote code execution? I’m not entirely sure what that is, but could you please figure it out for me?

Baby pwn challenge for the competition. Source code is provided which makes it easier to analyze the challenge. From what we can see, we have a buffer overflow vulnerability due to gets and there is a get_shell function which we need to execute. Plan is simply to overwrite the buffer then redirect code execution to get_shell.

void get_shell() {
    execve("/bin/sh", NULL, NULL);
}

void vuln() {
    char name[40];

    printf("Please tell me your name: ");
    gets(name);
}

First we need to figure out the offset to control RIP, which in this case is 56. After which we need to print the address of the get_shell function which we can simply do with gdb.

pwndbg> p get_shell
$1 = {void ()} 0x4006ca <get_shell>

Since we now have everything we need, we can create an exploit script and get the flag.