Messages in this thread | | | Date | Mon, 4 Jun 2018 10:42:49 -0600 | From | Jason Gunthorpe <> | Subject | Re: [PATCH] infiniband: fix a possible use-after-free bug |
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On Fri, Jun 01, 2018 at 11:31:44AM -0700, Cong Wang wrote: > ucma_process_join() will free the new allocated "mc" struct, > if there is any error after that, especially the copy_to_user(). > > But in parallel, ucma_leave_multicast() could find this "mc" > through idr_find() before ucma_process_join() frees it, since it > is already published. > > So "mc" could be used in ucma_leave_multicast() after it is been > allocated and freed in ucma_process_join(), since we don't refcnt > it. > > Fix this by separating "publish" from ID allocation, so that we > can get an ID first and publish it later after copy_to_user(). > > Fixes c8f6a362bf3e ("RDMA/cma: Add multicast communication support") > Reported-by: Noam Rathaus <noamr@beyondsecurity.com> > Cc: Sean Hefty <sean.hefty@intel.com> > Cc: Doug Ledford <dledford@redhat.com> > Cc: Jason Gunthorpe <jgg@ziepe.ca> > Cc: linux-rdma@vger.kernel.org > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> > --- > drivers/infiniband/core/ucma.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-)
Looks good to me, and we already fixed the same sort of bug in the non-multicast IDs.. Applied to for-next
Jason
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