From 8bee683384087a6275c9183a483435225f7bb209 Mon Sep 17 00:00:00 2001 From: Magnus Karlsson Date: Mon, 14 Dec 2020 09:51:27 +0100 Subject: [PATCH] xsk: Fix memory leak for failed bind MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/20201214085127.3960-1-magnus.karlsson@gmail.com --- net/xdp/xsk.c | 4 ++++ net/xdp/xsk_buff_pool.c | 2 -- 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index ac4a317038f1bb..c6532d77fde769 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -878,6 +878,10 @@ static int xsk_bind(struct socket *sock, struct sockaddr *addr, int addr_len) } } + /* 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; diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c index 67a4494d63b681..818b750609220e 100644 --- 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_assign_umem(struct xdp_sock *xs, 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];