From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Israel Rukshin <israelr@nvidia.com>,
        Max Gurtovoy <mgurtovoy@nvidia.com>,
        Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 161/355] nvmet-tcp: fix use-after-free when a port is removed
Date:   Mon, 15 Nov 2021 18:01:25 +0100
Message-Id: <20211115165318.990923502@linuxfoundation.org>
In-Reply-To: <20211115165313.549179499@linuxfoundation.org>
References: <20211115165313.549179499@linuxfoundation.org>
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From: Israel Rukshin <israelr@nvidia.com>

[ Upstream commit 2351ead99ce9164fb42555aee3f96af84c4839e9 ]

When removing a port, all its controllers are being removed, but there
are queues on the port that doesn't belong to any controller (during
connection time). This causes a use-after-free bug for any command
that dereferences req->port (like in nvmet_alloc_ctrl). Those queues
should be destroyed before freeing the port via configfs. Destroy
the remaining queues after the accept_work was cancelled guarantees
that no new queue will be created.

Signed-off-by: Israel Rukshin <israelr@nvidia.com>
Reviewed-by: Max Gurtovoy <mgurtovoy@nvidia.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/tcp.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index 6b3d1ba7db7ee..fac1985870765 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -1667,6 +1667,17 @@ err_port:
 	return ret;
 }
 
+static void nvmet_tcp_destroy_port_queues(struct nvmet_tcp_port *port)
+{
+	struct nvmet_tcp_queue *queue;
+
+	mutex_lock(&nvmet_tcp_queue_mutex);
+	list_for_each_entry(queue, &nvmet_tcp_queue_list, queue_list)
+		if (queue->port == port)
+			kernel_sock_shutdown(queue->sock, SHUT_RDWR);
+	mutex_unlock(&nvmet_tcp_queue_mutex);
+}
+
 static void nvmet_tcp_remove_port(struct nvmet_port *nport)
 {
 	struct nvmet_tcp_port *port = nport->priv;
@@ -1676,6 +1687,11 @@ static void nvmet_tcp_remove_port(struct nvmet_port *nport)
 	port->sock->sk->sk_user_data = NULL;
 	write_unlock_bh(&port->sock->sk->sk_callback_lock);
 	cancel_work_sync(&port->accept_work);
+	/*
+	 * Destroy the remaining queues, which are not belong to any
+	 * controller yet.
+	 */
+	nvmet_tcp_destroy_port_queues(port);
 
 	sock_release(port->sock);
 	kfree(port);
-- 
2.33.0