| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.9 104/125] iser-target: Avoid isert_conn->cm_id dereference in isert_login_recv_done | Date | Tue, 25 Jul 2017 12:20:19 -0700 |
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4.9-stable review patch. If anyone has any objections, please let me know.
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From: Nicholas Bellinger <nab@linux-iscsi.org>
commit fce50a2fa4e9c6e103915c351b6d4a98661341d6 upstream.
This patch fixes a NULL pointer dereference in isert_login_recv_done() of isert_conn->cm_id due to isert_cma_handler() -> isert_connect_error() resetting isert_conn->cm_id = NULL during a failed login attempt.
As per Sagi, we will always see the completion of all recv wrs posted on the qp (given that we assigned a ->done handler), this is a FLUSH error completion, we just don't get to verify that because we deref NULL before.
The issue here, was the assumption that dereferencing the connection cm_id is always safe, which is not true since:
commit 4a579da2586bd3b79b025947ea24ede2bbfede62 Author: Sagi Grimberg <sagig@mellanox.com> Date: Sun Mar 29 15:52:04 2015 +0300
iser-target: Fix possible deadlock in RDMA_CM connection error
As I see it, we have a direct reference to the isert_device from isert_conn which is the one-liner fix that we actually need like we do in isert_rdma_read_done() and isert_rdma_write_done().
Reported-by: Andrea Righi <righi.andrea@gmail.com> Tested-by: Andrea Righi <righi.andrea@gmail.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/infiniband/ulp/isert/ib_isert.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/infiniband/ulp/isert/ib_isert.c +++ b/drivers/infiniband/ulp/isert/ib_isert.c @@ -1447,7 +1447,7 @@ static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc) { struct isert_conn *isert_conn = wc->qp->qp_context; - struct ib_device *ib_dev = isert_conn->cm_id->device; + struct ib_device *ib_dev = isert_conn->device->ib_device; if (unlikely(wc->status != IB_WC_SUCCESS)) { isert_print_wc(wc, "login recv");
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