[PATCH] infiniband: Fix a use after free in isert_connect_request

From: Lv Yunlong
Date: Mon Mar 22 2021 - 09:55:10 EST


The device is got by isert_device_get() with refcount is 1,
and is assigned to isert_conn by isert_conn->device = device.
When isert_create_qp() failed, device will be freed with
isert_device_put().

Later, the device is used in isert_free_login_buf(isert_conn)
by the isert_conn->device->ib_device statement. My patch
exchanges the callees order to free the device late.

Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>
---
drivers/infiniband/ulp/isert/ib_isert.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/ulp/isert/ib_isert.c b/drivers/infiniband/ulp/isert/ib_isert.c
index 7305ed8976c2..d8a533e346b0 100644
--- a/drivers/infiniband/ulp/isert/ib_isert.c
+++ b/drivers/infiniband/ulp/isert/ib_isert.c
@@ -473,10 +473,10 @@ isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)

out_destroy_qp:
isert_destroy_qp(isert_conn);
-out_conn_dev:
- isert_device_put(device);
out_rsp_dma_map:
isert_free_login_buf(isert_conn);
+out_conn_dev:
+ isert_device_put(device);
out:
kfree(isert_conn);
rdma_reject(cma_id, NULL, 0, IB_CM_REJ_CONSUMER_DEFINED);
--
2.25.1