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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hulk Robot <hulkci@huawei.com>,
        Mike Christie <michael.christie@oracle.com>,
        Qinglang Miao <miaoqinglang@huawei.com>,
        "Martin K. Petersen" <martin.petersen@oracle.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 358/717] scsi: iscsi: Fix inappropriate use of put_device()
Date:   Mon, 28 Dec 2020 13:45:56 +0100
Message-Id: <20201228125038.163858685@linuxfoundation.org>
In-Reply-To: <20201228125020.963311703@linuxfoundation.org>
References: <20201228125020.963311703@linuxfoundation.org>
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From: Qinglang Miao <miaoqinglang@huawei.com>

[ Upstream commit 6dc1c7ab6f047f45b62986ffebc5324e86ed5f5a ]

kfree(conn) is called inside put_device(&conn->dev) which could lead to
use-after-free. In addition, device_unregister() should be used here rather
than put_deviceO().

Link: https://lore.kernel.org/r/20201120074852.31658-1-miaoqinglang@huawei.com
Fixes: f3c893e3dbb5 ("scsi: iscsi: Fail session and connection on transport registration failure")
Reported-by: Hulk Robot <hulkci@huawei.com>
Reviewed-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Qinglang Miao <miaoqinglang@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/scsi/scsi_transport_iscsi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/scsi_transport_iscsi.c b/drivers/scsi/scsi_transport_iscsi.c
index 2eb3e4f9375a5..2e68c0a876986 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -2313,7 +2313,9 @@ iscsi_create_conn(struct iscsi_cls_session *session, int dd_size, uint32_t cid)
 	return conn;
 
 release_conn_ref:
-	put_device(&conn->dev);
+	device_unregister(&conn->dev);
+	put_device(&session->dev);
+	return NULL;
 release_parent_ref:
 	put_device(&session->dev);
 free_conn:
-- 
2.27.0