From: Li Nan linan122@huawei.com
[ Upstream commit 98c598afc22d4e43c2ad91860b65996d0c099a5d ]
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: Li Nan linan122@huawei.com Reviewed-by: Yu Kuai yukuai3@huawei.com Reviewed-by: Ming Lei ming.lei@redhat.com Link: https://lore.kernel.org/r/20230911023308.3467802-1-linan666@huaweicloud.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/nbd.c | 35 ++++++++++++++++++++++------------- 1 file changed, 22 insertions(+), 13 deletions(-)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 3f03cb3dc33cc..b6414e1e645b7 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -67,6 +67,7 @@ struct nbd_sock { struct recv_thread_args { struct work_struct work; struct nbd_device *nbd; + struct nbd_sock *nsock; int index; };
@@ -505,15 +506,9 @@ 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, - struct iov_iter *iter, int msg_flags, int *sent) +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; @@ -556,6 +551,19 @@ 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? @@ -712,7 +720,7 @@ 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)}; @@ -721,7 +729,7 @@ static int nbd_read_reply(struct nbd_device *nbd, int index,
reply->magic = 0; iov_iter_kvec(&to, ITER_DEST, &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), @@ -845,14 +853,14 @@ 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; struct request *rq;
while (1) { struct nbd_reply reply;
- if (nbd_read_reply(nbd, args->index, &reply)) + if (nbd_read_reply(nbd, nsock->sock, &reply)) break;
/* @@ -887,7 +895,6 @@ 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); @@ -1231,6 +1238,7 @@ 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); @@ -1413,6 +1421,7 @@ 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); }