seccomp_strict.c

#include <fcntl.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <linux/seccomp.h>
#include <sys/prctl.h>


int main(int argc, char **argv)
{
        int output = open("output.txt", O_WRONLY);
        const char *val = "test";

        printf("Calling prctl() to set seccomp strict mode...\n");
        prctl(PR_SET_SECCOMP, SECCOMP_MODE_STRICT);

        printf("Writing to an already open file...\n");
        write(output, val, strlen(val)+1);

        printf("Trying to open file for reading...\n");
        int input = open("output.txt", O_RDONLY);

        printf("You will not see this message--the process will be killed first\n");
}