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ntb: ntb_hw_switchtec: Fix use after free vulnerability in switchtec_ntb_remove due to race condition

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In the switchtec_ntb_add function, it can call switchtec_ntb_init_sndev
function, then &sndev->check_link_status_work is bound with
check_link_status_work. switchtec_ntb_link_notification may be called
to start the work.

If we remove the module which will call switchtec_ntb_remove to make
cleanup, it will free sndev through kfree(sndev), while the work
mentioned above will be used. The sequence of operations that may lead
to a UAF bug is as follows:

CPU0                                 CPU1

                        | check_link_status_work
switchtec_ntb_remove    |
kfree(sndev);           |
                        | if (sndev->link_force_down)
                        | // use sndev

Fix it by ensuring that the work is canceled before proceeding with
the cleanup in switchtec_ntb_remove.

Signed-off-by: Kaixin Wang <kxwang23@m.fudan.edu.cn>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
This commit is contained in:
Kaixin Wang 2024-09-10 01:20:07 +08:00 committed by Jon Mason
parent 87a7d71505
commit e51aded92d
1 changed files with 1 additions and 0 deletions
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drivers/ntb/hw/mscc/ntb_hw_switchtec.c
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@ -1554,6 +1554,7 @@ static void switchtec_ntb_remove(struct device *dev)
switchtec_ntb_deinit_db_msg_irq(sndev); switchtec_ntb_deinit_db_msg_irq(sndev);
switchtec_ntb_deinit_shared_mw(sndev); switchtec_ntb_deinit_shared_mw(sndev);
switchtec_ntb_deinit_crosslink(sndev); switchtec_ntb_deinit_crosslink(sndev);
cancel_work_sync(&sndev->check_link_status_work);
kfree(sndev); kfree(sndev);
dev_info(dev, "ntb device unregistered\n"); dev_info(dev, "ntb device unregistered\n");
} }