Commit 92050518 authored by Li Nan's avatar Li Nan
Browse files

nbd: pass nbd_sock to nbd_read_reply() instead of index 

hulk inclusion
category: bugfix
bugzilla: 189113, https://gitee.com/openeuler/kernel/issues/I7T755


CVE: NA

--------------------------------

If a socket is processing ioctl 'NBD_SET_SOCK', config->socks might be
krealloc in nbd_add_socket(), and a garbage request is received now, a UAF
may occurs.

  T1
  nbd_ioctl
   __nbd_ioctl
    nbd_add_socket
     blk_mq_freeze_queue
				T2
  				recv_work
  				 nbd_read_reply
  				  sock_xmit
     krealloc config->socks
				   def config->socks

Pass nbd_sock to nbd_read_reply(). And introduce a new function
sock_xmit_recv(), which differs from sock_xmit only in the way it get
socket.

==================================================================
BUG: KASAN: use-after-free in sock_xmit+0x525/0x550
Read of size 8 at addr ffff8880188ec428 by task kworker/u12:1/18779

Workqueue: knbd4-recv recv_work
Call Trace:
 __dump_stack
 dump_stack+0xbe/0xfd
 print_address_description.constprop.0+0x19/0x170
 __kasan_report.cold+0x6c/0x84
 kasan_report+0x3a/0x50
 sock_xmit+0x525/0x550
 nbd_read_reply+0xfe/0x2c0
 recv_work+0x1c2/0x750
 process_one_work+0x6b6/0xf10
 worker_thread+0xdd/0xd80
 kthread+0x30a/0x410
 ret_from_fork+0x22/0x30

Allocated by task 18784:
 kasan_save_stack+0x1b/0x40
 kasan_set_track
 set_alloc_info
 __kasan_kmalloc
 __kasan_kmalloc.constprop.0+0xf0/0x130
 slab_post_alloc_hook
 slab_alloc_node
 slab_alloc
 __kmalloc_track_caller+0x157/0x550
 __do_krealloc
 krealloc+0x37/0xb0
 nbd_add_socket
 +0x2d3/0x880
 __nbd_ioctl
 nbd_ioctl+0x584/0x8e0
 __blkdev_driver_ioctl
 blkdev_ioctl+0x2a0/0x6e0
 block_ioctl+0xee/0x130
 vfs_ioctl
 __do_sys_ioctl
 __se_sys_ioctl+0x138/0x190
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Freed by task 18784:
 kasan_save_stack+0x1b/0x40
 kasan_set_track+0x1c/0x30
 kasan_set_free_info+0x20/0x40
 __kasan_slab_free.part.0+0x13f/0x1b0
 slab_free_hook
 slab_free_freelist_hook
 slab_free
 kfree+0xcb/0x6c0
 krealloc+0x56/0xb0
 nbd_add_socket+0x2d3/0x880
 __nbd_ioctl
 nbd_ioctl+0x584/0x8e0
 __blkdev_driver_ioctl
 blkdev_ioctl+0x2a0/0x6e0
 block_ioctl+0xee/0x130
 vfs_ioctl
 __do_sys_ioctl
 __se_sys_ioctl+0x138/0x190
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x61/0xc6

Signed-off-by: default avatarLi Nan <linan122@huawei.com>
parent 6cbfc80d

drivers/block/nbd.c

+22 −13
Original line number Diff line number Diff line
@@ -62,6 +62,7 @@ struct nbd_sock { 
struct recv_thread_args {

	struct work_struct work;

	struct nbd_device *nbd;

	struct nbd_sock *nsock;

	int index;

};
@@ -453,15 +454,9 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req, 
	return BLK_EH_DONE;

}



/*

 *  Send or receive packet. Return a positive value on success and

 *  negtive value on failue, and never return 0.

 */

static int sock_xmit(struct nbd_device *nbd, int index, int send,

static int __sock_xmit(struct nbd_device *nbd, struct socket *sock, int send,

		       struct iov_iter *iter, int msg_flags, int *sent)

{

	struct nbd_config *config = nbd->config;

	struct socket *sock = config->socks[index]->sock;

	int result;

	struct msghdr msg;

	unsigned int noreclaim_flag;
@@ -503,6 +498,19 @@ static int sock_xmit(struct nbd_device *nbd, int index, int send, 
	return result;

}



/*

 *  Send or receive packet. Return a positive value on success and

 *  negtive value on failure, and never return 0.

 */

static int sock_xmit(struct nbd_device *nbd, int index, int send,

		     struct iov_iter *iter, int msg_flags, int *sent)

{

	struct nbd_config *config = nbd->config;

	struct socket *sock = config->socks[index]->sock;



	return __sock_xmit(nbd, sock, send, iter, msg_flags, sent);

}



/*

 * Different settings for sk->sk_sndtimeo can result in different return values

 * if there is a signal pending when we enter sendmsg, because reasons?
@@ -664,7 +672,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index) 
	return 0;

}



static int nbd_read_reply(struct nbd_device *nbd, int index,

static int nbd_read_reply(struct nbd_device *nbd, struct socket *sock,

			  struct nbd_reply *reply)

{

	struct kvec iov = {.iov_base = reply, .iov_len = sizeof(*reply)};
@@ -673,7 +681,7 @@ static int nbd_read_reply(struct nbd_device *nbd, int index, 


	reply->magic = 0;

	iov_iter_kvec(&to, READ | ITER_KVEC, &iov, 1, sizeof(*reply));

	result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);

	result = __sock_xmit(nbd, sock, 0, &to, MSG_WAITALL, NULL);

	if (result < 0) {

		if (!nbd_disconnected(nbd->config))

			dev_err(disk_to_dev(nbd->disk),
@@ -798,13 +806,13 @@ static void recv_work(struct work_struct *work) 
	struct nbd_device *nbd = args->nbd;

	struct nbd_config *config = nbd->config;

	struct request_queue *q = nbd->disk->queue;

	struct nbd_sock *nsock;

	struct nbd_sock *nsock = args->nsock;

	struct nbd_cmd *cmd;



	while (1) {

		struct nbd_reply reply;



		if (nbd_read_reply(nbd, args->index, &reply))

		if (nbd_read_reply(nbd, nsock->sock, &reply))

			break;



		/*
@@ -829,7 +837,6 @@ static void recv_work(struct work_struct *work) 
		percpu_ref_put(&q->q_usage_counter);

	}



	nsock = config->socks[args->index];

	mutex_lock(&nsock->tx_lock);

	nbd_mark_nsock_dead(nbd, nsock, 1);

	mutex_unlock(&nsock->tx_lock);
@@ -1164,6 +1171,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg) 
		INIT_WORK(&args->work, recv_work);

		args->index = i;

		args->nbd = nbd;

		args->nsock = nsock;

		nsock->cookie++;

		mutex_unlock(&nsock->tx_lock);

		sockfd_put(old);
@@ -1354,6 +1362,7 @@ static int nbd_start_device(struct nbd_device *nbd) 
		refcount_inc(&nbd->config_refs);

		INIT_WORK(&args->work, recv_work);

		args->nbd = nbd;

		args->nsock = config->socks[i];

		args->index = i;

		queue_work(nbd->recv_workq, &args->work);

	}