From: Magnus Karlsson magnus.karlsson@intel.com
commit 8bee683384087a6275c9183a483435225f7bb209 upstream.
Fix a possible memory leak when a bind of an AF_XDP socket fails. When the fill and completion rings are created, they are tied to the socket. But when the buffer pool is later created at bind time, the ownership of these two rings are transferred to the buffer pool as they might be shared between sockets (and the buffer pool cannot be created until we know what we are binding to). So, before the buffer pool is created, these two rings are cleaned up with the socket, and after they have been transferred they are cleaned up together with the buffer pool.
The problem is that ownership was transferred before it was absolutely certain that the buffer pool could be created and initialized correctly and when one of these errors occurred, the fill and completion rings did neither belong to the socket nor the pool and where therefore leaked. Solve this by moving the ownership transfer to the point where the buffer pool has been completely set up and there is no way it can fail.
Fixes: 7361f9c3d719 ("xsk: Move fill and completion rings to buffer pool") Reported-by: syzbot+cfa88ddd0655afa88763@syzkaller.appspotmail.com Signed-off-by: Magnus Karlsson magnus.karlsson@intel.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Björn Töpel bjorn.topel@intel.com Link: https://lore.kernel.org/bpf/20201214085127.3960-1-magnus.karlsson@gmail.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/xdp/xsk.c | 4 ++++ net/xdp/xsk_buff_pool.c | 2 -- 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -772,6 +772,10 @@ static int xsk_bind(struct socket *sock, } }
+ /* FQ and CQ are now owned by the buffer pool and cleaned up with it. */ + xs->fq_tmp = NULL; + xs->cq_tmp = NULL; + xs->dev = dev; xs->zc = xs->umem->zc; xs->queue_id = qid; --- a/net/xdp/xsk_buff_pool.c +++ b/net/xdp/xsk_buff_pool.c @@ -75,8 +75,6 @@ struct xsk_buff_pool *xp_create_and_assi
pool->fq = xs->fq_tmp; pool->cq = xs->cq_tmp; - xs->fq_tmp = NULL; - xs->cq_tmp = NULL;
for (i = 0; i < pool->free_heads_cnt; i++) { xskb = &pool->heads[i];