[PATCH 5.4/5.10 1/1] RDMA/i40iw: Fix potential NULL-ptr-dereference

[Nikita Zhandarovich]

From: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>

commit 5d9745cead1f121974322b94ceadfb4d1e67960e upstream.

in_dev_get() can return NULL which will cause a failure once idev is
dereferenced in in_dev_for_each_ifa_rtnl(). This patch adds a
check for NULL value in idev beforehand.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Changes made to the original patch during backporting:
Apply patch to drivers/infiniband/hw/i40iw/i40iw_cm.c instead of
drivers/infiniband/hw/irdma/cm.c due to the fact that kernel versions
5.10 and below use i40iw driver, not irdma.

Fixes: f27b4746f378 ("i40iw: add connection management code")
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230126185230.62464-1-n.zhandarovich@xxxxxxxxxx
---
 drivers/infiniband/hw/i40iw/i40iw_cm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/infiniband/hw/i40iw/i40iw_cm.c b/drivers/infiniband/hw/i40iw/i40iw_cm.c
index 3053c345a5a3..e1236ac502f2 100644
--- a/drivers/infiniband/hw/i40iw/i40iw_cm.c
+++ b/drivers/infiniband/hw/i40iw/i40iw_cm.c
@@ -1776,6 +1776,8 @@ static enum i40iw_status_code i40iw_add_mqh_4(
 			const struct in_ifaddr *ifa;
 
 			idev = in_dev_get(dev);
+			if (!idev)
+				continue;
 
 			in_dev_for_each_ifa_rtnl(ifa, idev) {
 				i40iw_debug(&iwdev->sc_dev,
-- 
2.25.1