> Subject: Re: RE: [PATCH] infiniband/i40iw: Fix a use after free in > i40iw_cm_event_handler > > > > > > -----原始邮件----- > > 发件人: "Saleem, Shiraz" <shiraz.saleem@xxxxxxxxx> > > 发送时间: 2021-03-12 09:13:39 (星期五) > > 收件人: "Jason Gunthorpe" <jgg@xxxxxxxxxx>, "Lv Yunlong" > > <lyl2019@xxxxxxxxxxxxxxxx> > > 抄送: "Latif, Faisal" <faisal.latif@xxxxxxxxx>, "dledford@xxxxxxxxxx" > > <dledford@xxxxxxxxxx>, "linux-rdma@xxxxxxxxxxxxxxx" > > <linux-rdma@xxxxxxxxxxxxxxx>, "linux-kernel@xxxxxxxxxxxxxxx" > > <linux-kernel@xxxxxxxxxxxxxxx> > > 主题: RE: [PATCH] infiniband/i40iw: Fix a use after free in > > i40iw_cm_event_handler > > > > > Subject: Re: [PATCH] infiniband/i40iw: Fix a use after free in > > > i40iw_cm_event_handler > > > > > > On Wed, Mar 10, 2021 at 07:14:14PM -0800, Lv Yunlong wrote: > > > > In the case of I40IW_CM_EVENT_ABORTED, i40iw_event_connect_error() > > > > could be called to free the event->cm_node. However, > > > > event->cm_node will be used after and cause use after free. It > > > > needs to add flags to inform that event->cm_node has been freed. > > > > > > > > Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx> > > > > --- > > > > drivers/infiniband/hw/i40iw/i40iw_cm.c | 5 ++++- > > > > 1 file changed, 4 insertions(+), 1 deletion(-) > > > > > > This might be OK (though I don't like the free variable), Shiraz?? > > > > > > > How was this reproduced? Do you have some call trace leading up to use after > free? > > > > The cm_node refcnt is bumped at creation time and once in i40iw_receive_ilq > before packet is processed. > > That should protect the cm_node from disappearing in the event handler in the > abort event case. > > The dec at end of i40iw_receive ilq should be point where the cm_node is freed > specifically in the abort case. > > > > Shiraz > > > > This problem was reported by a path-sensitive analyzer developed by our Security > Lab(Loccs). > The analyzer reported that there is a feasible path to free event->cm_node and use > it after, and that is what i described in the first commit. > OK. I don’t think that an extra dec refcnt in itself for the abort case is enough evidence to say that the cm_node is freed in i40iw_event_connect_error. Shiraz
