getting canaries https://medium.com/@cedriczirtacic/peque%C3%B1o-texto-canarios-en-el-stack-3ce23f6c033b

main.c

// gcc -O1 -fstack-protector-all -o main main.c
#include <stdio.h>
#include <linux/types.h>

#ifndef uint64_t
    typedef unsigned long   uint64_t;
#endif

uint64_t get_canary() {
    uint64_t a;
    __asm__(
            "leaq 0x8(%%rsp), %0\n\t"
            : "=r" (a)
    );
    printf("canary_address: %p\n", a);
    return(a);
}

int main(int argc, char *argv[]) {
    uint64_t *v = get_canary();
    return printf("canary_value: %p\n", *v);
}