From: Kaixin Wang Date: Mon, 9 Sep 2024 17:20:07 +0000 (+0800) Subject: ntb: ntb_hw_switchtec: Fix use after free vulnerability in switchtec_ntb_remove due... X-Git-Tag: v5.15.168~80 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=92728fceefdaa2a0a3aae675f86193b006eeaa43;p=thirdparty%2Fkernel%2Fstable.git ntb: ntb_hw_switchtec: Fix use after free vulnerability in switchtec_ntb_remove due to race condition [ 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 Reviewed-by: Logan Gunthorpe Signed-off-by: Jon Mason Signed-off-by: Sasha Levin --- diff --git a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c index ec9cb6c81edae..759248415b5c2 100644 --- a/drivers/ntb/hw/mscc/ntb_hw_switchtec.c +++ b/drivers/ntb/hw/mscc/ntb_hw_switchtec.c @@ -1556,6 +1556,7 @@ 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"); }