kernel/linux.git/drivers/block/nbd.c, branch v4.14.263

nbd: freeze the queue while we're adding connections

2021-02-03T22:22:20+00:00

commit b98e762e3d71e893b221f871825dc64694cfb258 upstream. When setting up a device, we can krealloc the config->socks array to add new sockets to the configuration. However if we happen to get a IO request in at this point even though we aren't setup we could hit a UAF, as we deref config->socks without any locking, assuming that the configuration was setup already and that ->socks is safe to access it as we have a reference on the configuration. But there's nothing really preventing IO from occurring at this point of the device setup, we don't want to incur the overhead of a lock to access ->socks when it will never change while the device is running. To fix this UAF scenario simply freeze the queue if we are adding sockets. This will protect us from this particular case without adding any additional overhead for the normal running case. Cc: stable@vger.kernel.org Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd: fix a block_device refcount leak in nbd_release

2020-11-18T17:27:56+00:00

[ Upstream commit 2bd645b2d3f0bacadaa6037f067538e1cd4e42ef ] bdget_disk needs to be paired with bdput to not leak a reference on the block device inode. Fixes: 08ba91ee6e2c ("nbd: Add the nbd NBD_DISCONNECT_ON_CLOSE config flag.") Signed-off-by: Christoph Hellwig Reviewed-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: don't update block size after device is started

2020-11-18T17:27:52+00:00

[ Upstream commit b40813ddcd6bf9f01d020804e4cb8febc480b9e4 ] Mounted NBD device can be resized, one use case is rbd-nbd. Fix the issue by setting up default block size, then not touch it in nbd_size_update() any more. This kind of usage is aligned with loop which has same use case too. Cc: stable@vger.kernel.org Fixes: c8a83a6b54d0 ("nbd: Use set_blocksize() to set device blocksize") Reported-by: lining Signed-off-by: Ming Lei Cc: Josef Bacik Cc: Jan Kara Tested-by: lining Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: make the config put is called before the notifying the waiter

2020-11-05T10:06:58+00:00

[ Upstream commit 87aac3a80af5cbad93e63250e8a1e19095ba0d30 ] There has one race case for ceph's rbd-nbd tool. When do mapping it may fail with EBUSY from ioctl(nbd, NBD_DO_IT), but actually the nbd device has already unmaped. It dues to if just after the wake_up(), the recv_work() is scheduled out and defers calling the nbd_config_put(), though the map process has exited the "nbd->recv_task" is not cleared. Signed-off-by: Xiubo Li Reviewed-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: Fix memory leak in nbd_add_socket

2020-07-22T07:22:17+00:00

[ Upstream commit 579dd91ab3a5446b148e7f179b6596b270dace46 ] When adding first socket to nbd, if nsock's allocation failed, the data structure member "config->socks" was reallocated, but the data structure member "config->num_connections" was not updated. A memory leak will occur then because the function "nbd_config_put" will free "config->socks" only when "config->num_connections" is not zero. Fixes: 03bf73c315ed ("nbd: prevent memory leak") Reported-by: syzbot+934037347002901b8d2a@syzkaller.appspotmail.com Signed-off-by: Zheng Bin Reviewed-by: Eric Biggers Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: add a flush_workqueue in nbd_start_device

2020-02-28T15:35:58+00:00

[ Upstream commit 5c0dd228b5fc30a3b732c7ae2657e0161ec7ed80 ] When kzalloc fail, may cause trying to destroy the workqueue from inside the workqueue. If num_connections is m (2 < m), and NO.1 ~ NO.n (1 < n < m) kzalloc are successful. The NO.(n + 1) failed. Then, nbd_start_device will return ENOMEM to nbd_start_device_ioctl, and nbd_start_device_ioctl will return immediately without running flush_workqueue. However, we still have n recv threads. If nbd_release run first, recv threads may have to drop the last config_refs and try to destroy the workqueue from inside the workqueue. To fix it, add a flush_workqueue in nbd_start_device. Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Signed-off-by: Sun Ke Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

nbd: fix shutdown and recv work deadlock v2

2019-12-31T11:38:07+00:00

commit 1c05839aa973cfae8c3db964a21f9c0eef8fcc21 upstream. This fixes a regression added with: commit e9e006f5fcf2bab59149cb38a48a4817c1b538b4 Author: Mike Christie Date: Sun Aug 4 14:10:06 2019 -0500 nbd: fix max number of supported devs where we can deadlock during device shutdown. The problem occurs if the recv_work's nbd_config_put occurs after nbd_start_device_ioctl has returned and the userspace app has droppped its reference via closing the device and running nbd_release. The recv_work nbd_config_put call would then drop the refcount to zero and try to destroy the config which would try to do destroy_workqueue from the recv work. This patch just has nbd_start_device_ioctl do a flush_workqueue when it wakes so we know after the ioctl returns running works have exited. This also fixes a possible race where we could try to reuse the device while old recv_works are still running. Cc: stable@vger.kernel.org Fixes: e9e006f5fcf2 ("nbd: fix max number of supported devs") Signed-off-by: Mike Christie Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd: prevent memory leak

2019-12-01T08:14:23+00:00

commit 03bf73c315edca28f47451913177e14cd040a216 upstream. In nbd_add_socket when krealloc succeeds, if nsock's allocation fail the reallocted memory is leak. The correct behaviour should be assigning the reallocted memory to config->socks right after success. Reviewed-by: Josef Bacik Signed-off-by: Navid Emamdoost Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd:fix memory leak in nbd_get_socket()

2019-12-01T08:13:13+00:00

commit dff10bbea4be47bdb615b036c834a275b7c68133 upstream. Before returning NULL, put the sock first. Cc: stable@vger.kernel.org Fixes: cf1b2326b734 ("nbd: verify socket is supported during setup") Reviewed-by: Josef Bacik Reviewed-by: Mike Christie Signed-off-by: Sun Ke Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

nbd: handle racing with error'ed out commands

2019-11-10T10:25:20+00:00

[ Upstream commit 7ce23e8e0a9cd38338fc8316ac5772666b565ca9 ] We hit the following warning in production print_req_error: I/O error, dev nbd0, sector 7213934408 flags 80700 ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 25 PID: 32407 at lib/refcount.c:190 refcount_sub_and_test_checked+0x53/0x60 Workqueue: knbd-recv recv_work [nbd] RIP: 0010:refcount_sub_and_test_checked+0x53/0x60 Call Trace: blk_mq_free_request+0xb7/0xf0 blk_mq_complete_request+0x62/0xf0 recv_work+0x29/0xa1 [nbd] process_one_work+0x1f5/0x3f0 worker_thread+0x2d/0x3d0 ? rescuer_thread+0x340/0x340 kthread+0x111/0x130 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x1f/0x30 ---[ end trace b079c3c67f98bb7c ]--- This was preceded by us timing out everything and shutting down the sockets for the device. The problem is we had a request in the queue at the same time, so we completed the request twice. This can actually happen in a lot of cases, we fail to get a ref on our config, we only have one connection and just error out the command, etc. Fix this by checking cmd->status in nbd_read_stat. We only change this under the cmd->lock, so we are safe to check this here and see if we've already error'ed this command out, which would indicate that we've completed it as well. Reviewed-by: Mike Christie Signed-off-by: Josef Bacik Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin