[PATCH AUTOSEL 6.2 13/17] nvme-tcp: fix a possible UAF when failing to allocate an io queue

Sasha Levin
2023-04-06T11:32:54Z

From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit 88eaba80328b31ef81813a1207b4056efd7006a6 ]

When we allocate a nvme-tcp queue, we set the data_ready callback before
we actually need to use it. This creates the potential that if a stray
controller sends us data on the socket before we connect, we can trigger
the io_work and start consuming the socket.

In this case reported: we failed to allocate one of the io queues, and
as we start releasing the queues that we already allocated, we get
a UAF [1] from the io_work which is running before it should really.

Fix this by setting the socket ops callbacks only before we start the
queue, so that we can't accidentally schedule the io_work in the
initialization phase before the queue started. While we are at it,
rename nvme_tcp_restore_sock_calls to pair with nvme_tcp_setup_sock_ops.

[1]:
[16802.107284] nvme nvme4: starting error recovery
[16802.109166] nvme nvme4: Reconnecting in 10 seconds...
[16812.173535] nvme nvme4: failed to connect socket: -111
[16812.173745] nvme nvme4: Failed reconnect attempt 1
[16812.173747] nvme nvme4: Reconnecting in 10 seconds...
[16822.413555] nvme nvme4: failed to connect socket: -111
[16822.413762] nvme nvme4: Failed reconnect attempt 2
[16822.413765] nvme nvme4: Reconnecting in 10 seconds...
[16832.661274] nvme nvme4: creating 32 I/O queues.
[16833.919887] BUG: kernel NULL pointer dereference, address: 0000000000000088
[16833.920068] nvme nvme4: Failed reconnect attempt 3
[16833.920094] #PF: supervisor write access in kernel mode
[16833.920261] nvme nvme4: Reconnecting in 10 seconds...
[16833.920368] #PF: error_code(0x0002) - not-present page
[16833.921086] Workqueue: nvme_tcp_wq nvme_tcp_io_work [nvme_tcp]
[16833.921191] RIP: 0010:_raw_spin_lock_bh+0x17/0x30
...
[16833.923138] Call Trace:
[16833.923271] <TASK>
[16833.923402] lock_sock_nested+0x1e/0x50
[16833.923545] nvme_tcp_try_recv+0x40/0xa0 [nvme_tcp]
[16833.923685] nvme_tcp_io_work+0x68/0xa0 [nvme_tcp]
[16833.923824] process_one_work+0x1e8/0x390
[16833.923969] worker_thread+0x53/0x3d0
[16833.924104] ? process_one_work+0x390/0x390
[16833.924240] kthread+0x124/0x150
[16833.924376] ? set_kthread_struct+0x50/0x50
[16833.924518] ret_from_fork+0x1f/0x30
[16833.924655] </TASK>

Reported-by: Yanjun Zhang <zhangyanjun@cestc.cn>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Tested-by: Yanjun Zhang <zhangyanjun@cestc.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/nvme/host/tcp.c | 46 +++++++++++++++++++++++------------------
1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 1ca52ac163c2f..2c15412649bab 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1605,22 +1605,7 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid)
if (ret)
goto err_init_connect;

- queue->rd_enabled = true;
set_bit(NVME_TCP_Q_ALLOCATED, &queue->flags);
- nvme_tcp_init_recv_ctx(queue);
-
- write_lock_bh(&queue->sock->sk->sk_callback_lock);
- queue->sock->sk->sk_user_data = queue;
- queue->state_change = queue->sock->sk->sk_state_change;
- queue->data_ready = queue->sock->sk->sk_data_ready;
- queue->write_space = queue->sock->sk->sk_write_space;
- queue->sock->sk->sk_data_ready = nvme_tcp_data_ready;
- queue->sock->sk->sk_state_change = nvme_tcp_state_change;
- queue->sock->sk->sk_write_space = nvme_tcp_write_space;
-#ifdef CONFIG_NET_RX_BUSY_POLL
- queue->sock->sk->sk_ll_usec = 1;
-#endif
- write_unlock_bh(&queue->sock->sk->sk_callback_lock);

return 0;

@@ -1640,7 +1625,7 @@ static int nvme_tcp_alloc_queue(struct nvme_ctrl *nctrl, int qid)
return ret;
}

-static void nvme_tcp_restore_sock_calls(struct nvme_tcp_queue *queue)
+static void nvme_tcp_restore_sock_ops(struct nvme_tcp_queue *queue)
{
struct socket *sock = queue->sock;

@@ -1655,7 +1640,7 @@ static void nvme_tcp_restore_sock_calls(struct nvme_tcp_queue *queue)
static void __nvme_tcp_stop_queue(struct nvme_tcp_queue *queue)
{
kernel_sock_shutdown(queue->sock, SHUT_RDWR);
- nvme_tcp_restore_sock_calls(queue);
+ nvme_tcp_restore_sock_ops(queue);
cancel_work_sync(&queue->io_work);
}

@@ -1673,21 +1658,42 @@ static void nvme_tcp_stop_queue(struct nvme_ctrl *nctrl, int qid)
mutex_unlock(&queue->queue_lock);
}

+static void nvme_tcp_setup_sock_ops(struct nvme_tcp_queue *queue)
+{
+ write_lock_bh(&queue->sock->sk->sk_callback_lock);
+ queue->sock->sk->sk_user_data = queue;
+ queue->state_change = queue->sock->sk->sk_state_change;
+ queue->data_ready = queue->sock->sk->sk_data_ready;
+ queue->write_space = queue->sock->sk->sk_write_space;
+ queue->sock->sk->sk_data_ready = nvme_tcp_data_ready;
+ queue->sock->sk->sk_state_change = nvme_tcp_state_change;
+ queue->sock->sk->sk_write_space = nvme_tcp_write_space;
+#ifdef CONFIG_NET_RX_BUSY_POLL
+ queue->sock->sk->sk_ll_usec = 1;
+#endif
+ write_unlock_bh(&queue->sock->sk->sk_callback_lock);
+}
+
static int nvme_tcp_start_queue(struct nvme_ctrl *nctrl, int idx)
{
struct nvme_tcp_ctrl *ctrl = to_tcp_ctrl(nctrl);
+ struct nvme_tcp_queue *queue = &ctrl->queues[idx];
int ret;

+ queue->rd_enabled = true;
+ nvme_tcp_init_recv_ctx(queue);
+ nvme_tcp_setup_sock_ops(queue);
+
if (idx)
ret = nvmf_connect_io_queue(nctrl, idx);
else
ret = nvmf_connect_admin_queue(nctrl);

if (!ret) {
- set_bit(NVME_TCP_Q_LIVE, &ctrl->queues[idx].flags);
+ set_bit(NVME_TCP_Q_LIVE, &queue->flags);
} else {
- if (test_bit(NVME_TCP_Q_ALLOCATED, &ctrl->queues[idx].flags))
- __nvme_tcp_stop_queue(&ctrl->queues[idx]);
+ if (test_bit(NVME_TCP_Q_ALLOCATED, &queue->flags))
+ __nvme_tcp_stop_queue(queue);
dev_err(nctrl->device,
"failed to connect queue: %d ret=%d\n", idx, ret);
}
--
2.39.2