| Message ID | 20180912232744.12693-1-xiyou.wangcong@gmail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | ucma: fix a use-after-free in ucma_resolve_ip() | expand |
On Wed, Sep 12, 2018 at 04:27:44PM -0700, Cong Wang wrote: > There is a race condition between ucma_close() and ucma_resolve_ip(): > > CPU0 CPU1 > ucma_resolve_ip(): ucma_close(): > > ctx = ucma_get_ctx(file, cmd.id); > > list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) { > mutex_lock(&mut); > idr_remove(&ctx_idr, ctx->id); > mutex_unlock(&mut); > ... > mutex_lock(&mut); > if (!ctx->closing) { > mutex_unlock(&mut); > rdma_destroy_id(ctx->cm_id); > ... > ucma_free_ctx(ctx); > > ret = rdma_resolve_addr(); > ucma_put_ctx(ctx); > > Before idr_remove(), ucma_get_ctx() could still find the ctx > and after rdma_destroy_id(), rdma_resolve_addr() may still > access id_priv pointer. Also, ucma_put_ctx() may use ctx after > ucma_free_ctx() too. > > ucma_close() should call ucma_put_ctx() too which tests the > refcnt and waits for the last one releasing it. The similar > pattern is already used by ucma_destroy_id(). > > Reported-and-tested-by: syzbot+da2591e115d57a9cbb8b@syzkaller.appspotmail.com > Reported-by: syzbot+cfe3c1e8ef634ba8964b@syzkaller.appspotmail.com > Cc: Jason Gunthorpe <jgg@mellanox.com> > Cc: Doug Ledford <dledford@redhat.com> > Cc: Leon Romanovsky <leon@kernel.org> > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> > --- > drivers/infiniband/core/ucma.c | 2 ++ > 1 file changed, 2 insertions(+) > Thanks, Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
On Wed, 2018-09-12 at 16:27 -0700, Cong Wang wrote: > There is a race condition between ucma_close() and ucma_resolve_ip(): > > CPU0 CPU1 > ucma_resolve_ip(): ucma_close(): > > ctx = ucma_get_ctx(file, cmd.id); > > list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) { > mutex_lock(&mut); > idr_remove(&ctx_idr, ctx->id); > mutex_unlock(&mut); > ... > mutex_lock(&mut); > if (!ctx->closing) { > mutex_unlock(&mut); > rdma_destroy_id(ctx->cm_id); > ... > ucma_free_ctx(ctx); > > ret = rdma_resolve_addr(); > ucma_put_ctx(ctx); > > Before idr_remove(), ucma_get_ctx() could still find the ctx > and after rdma_destroy_id(), rdma_resolve_addr() may still > access id_priv pointer. Also, ucma_put_ctx() may use ctx after > ucma_free_ctx() too. > > ucma_close() should call ucma_put_ctx() too which tests the > refcnt and waits for the last one releasing it. The similar > pattern is already used by ucma_destroy_id(). > > Reported-and-tested-by: syzbot+da2591e115d57a9cbb8b@syzkaller.appspotmail.com > Reported-by: syzbot+cfe3c1e8ef634ba8964b@syzkaller.appspotmail.com > Cc: Jason Gunthorpe <jgg@mellanox.com> > Cc: Doug Ledford <dledford@redhat.com> > Cc: Leon Romanovsky <leon@kernel.org> > Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Thanks, applied to for-rc.
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c index 5f437d1570fb..21863ddde63e 100644 --- a/drivers/infiniband/core/ucma.c +++ b/drivers/infiniband/core/ucma.c @@ -1759,6 +1759,8 @@ static int ucma_close(struct inode *inode, struct file *filp) mutex_lock(&mut); if (!ctx->closing) { mutex_unlock(&mut); + ucma_put_ctx(ctx); + wait_for_completion(&ctx->comp); /* rdma_destroy_id ensures that no event handlers are * inflight for that id before releasing it. */
There is a race condition between ucma_close() and ucma_resolve_ip(): CPU0 CPU1 ucma_resolve_ip(): ucma_close(): ctx = ucma_get_ctx(file, cmd.id); list_for_each_entry_safe(ctx, tmp, &file->ctx_list, list) { mutex_lock(&mut); idr_remove(&ctx_idr, ctx->id); mutex_unlock(&mut); ... mutex_lock(&mut); if (!ctx->closing) { mutex_unlock(&mut); rdma_destroy_id(ctx->cm_id); ... ucma_free_ctx(ctx); ret = rdma_resolve_addr(); ucma_put_ctx(ctx); Before idr_remove(), ucma_get_ctx() could still find the ctx and after rdma_destroy_id(), rdma_resolve_addr() may still access id_priv pointer. Also, ucma_put_ctx() may use ctx after ucma_free_ctx() too. ucma_close() should call ucma_put_ctx() too which tests the refcnt and waits for the last one releasing it. The similar pattern is already used by ucma_destroy_id(). Reported-and-tested-by: syzbot+da2591e115d57a9cbb8b@syzkaller.appspotmail.com Reported-by: syzbot+cfe3c1e8ef634ba8964b@syzkaller.appspotmail.com Cc: Jason Gunthorpe <jgg@mellanox.com> Cc: Doug Ledford <dledford@redhat.com> Cc: Leon Romanovsky <leon@kernel.org> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> --- drivers/infiniband/core/ucma.c | 2 ++ 1 file changed, 2 insertions(+)