| Message ID | 1542676728-15881-2-git-send-email-tyhicks@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | CVE-2018-14734 - Denial of Service in Infiniband core | expand |
On 20.11.18 02:18, Tyler Hicks wrote: > From: Cong Wang <xiyou.wangcong@gmail.com> > > 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> > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> > Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> > > CVE-2018-14734 > > (cherry picked from commit cb2595c1393b4a5211534e6f0a0fbad369e21ad8) > Signed-off-by: Tyler Hicks <tyhicks@canonical.com> Acked-by: Stefan Bader <stefan.bader@canonical.com> > --- > drivers/infiniband/core/ucma.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c > index e47baf0950e3..a22b992cde38 100644 > --- a/drivers/infiniband/core/ucma.c > +++ b/drivers/infiniband/core/ucma.c > @@ -218,7 +218,7 @@ static struct ucma_multicast* ucma_alloc_multicast(struct ucma_context *ctx) > return NULL; > > mutex_lock(&mut); > - mc->id = idr_alloc(&multicast_idr, mc, 0, 0, GFP_KERNEL); > + mc->id = idr_alloc(&multicast_idr, NULL, 0, 0, GFP_KERNEL); > mutex_unlock(&mut); > if (mc->id < 0) > goto error; > @@ -1404,6 +1404,10 @@ static ssize_t ucma_process_join(struct ucma_file *file, > goto err3; > } > > + mutex_lock(&mut); > + idr_replace(&multicast_idr, mc, mc->id); > + mutex_unlock(&mut); > + > mutex_unlock(&file->mut); > ucma_put_ctx(ctx); > return 0; >
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c index e47baf0950e3..a22b992cde38 100644 --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -218,7 +218,7 @@ static struct ucma_multicast* ucma_alloc_multicast(struct ucma_context *ctx) return NULL; mutex_lock(&mut); - mc->id = idr_alloc(&multicast_idr, mc, 0, 0, GFP_KERNEL); + mc->id = idr_alloc(&multicast_idr, NULL, 0, 0, GFP_KERNEL); mutex_unlock(&mut); if (mc->id < 0) goto error; @@ -1404,6 +1404,10 @@ static ssize_t ucma_process_join(struct ucma_file *file, goto err3; } + mutex_lock(&mut); + idr_replace(&multicast_idr, mc, mc->id); + mutex_unlock(&mut); + mutex_unlock(&file->mut); ucma_put_ctx(ctx); return 0;