5.4-stable review patch. If anyone has any objections, please let me know.
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From: Kaixin Wang kxwang23@m.fudan.edu.cn
[ Upstream commit e51aded92d42784313ba16c12f4f88cc4f973bbb ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/ntb/hw/mscc/ntb_hw_switchtec.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c index 86ffa716eaf22..db9be3ce1cd0d 100644 --- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c +++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c @@ -1558,6 +1558,7 @@ static void switchtec_ntb_remove(struct device *dev, switchtec_ntb_deinit_db_msg_irq(sndev); switchtec_ntb_deinit_shared_mw(sndev); switchtec_ntb_deinit_crosslink(sndev); + cancel_work_sync(&sndev->check_link_status_work); kfree(sndev); dev_info(dev, "ntb device unregistered\n"); }