[PATCH] net: qrtr: Allocate workqueue before kernel_bind

From: Chris Lew
Date: Thu May 28 2020 - 19:06:10 EST


A null pointer dereference in qrtr_ns_data_ready() is seen if a client
opens a qrtr socket before qrtr_ns_init() can bind to the control port.
When the control port is bound, the ENETRESET error will be broadcasted
and clients will close their sockets. This results in DEL_CLIENT
packets being sent to the ns and qrtr_ns_data_ready() being called
without the workqueue being allocated.

Allocate the workqueue before setting sk_data_ready and binding to the
control port. This ensures that the work and workqueue structs are
allocated and initialized before qrtr_ns_data_ready can be called.

Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace")
Signed-off-by: Chris Lew <clew@xxxxxxxxxxxxxx>
---
net/qrtr/ns.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
index e7d0fe3f4330..c5b3202a14ca 100644
--- a/net/qrtr/ns.c
+++ b/net/qrtr/ns.c
@@ -712,6 +712,10 @@ void qrtr_ns_init(void)
goto err_sock;
}

+ qrtr_ns.workqueue = alloc_workqueue("qrtr_ns_handler", WQ_UNBOUND, 1);
+ if (!qrtr_ns.workqueue)
+ goto err_sock;
+
qrtr_ns.sock->sk->sk_data_ready = qrtr_ns_data_ready;

sq.sq_port = QRTR_PORT_CTRL;
@@ -720,17 +724,13 @@ void qrtr_ns_init(void)
ret = kernel_bind(qrtr_ns.sock, (struct sockaddr *)&sq, sizeof(sq));
if (ret < 0) {
pr_err("failed to bind to socket\n");
- goto err_sock;
+ goto err_wq;
}

qrtr_ns.bcast_sq.sq_family = AF_QIPCRTR;
qrtr_ns.bcast_sq.sq_node = QRTR_NODE_BCAST;
qrtr_ns.bcast_sq.sq_port = QRTR_PORT_CTRL;

- qrtr_ns.workqueue = alloc_workqueue("qrtr_ns_handler", WQ_UNBOUND, 1);
- if (!qrtr_ns.workqueue)
- goto err_sock;
-
ret = say_hello(&qrtr_ns.bcast_sq);
if (ret < 0)
goto err_wq;
--
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