From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: [bpf PATCH v2 3/4] bpf: sockmap, consume_skb in close path Date: Thu, 05 Jul 2018 08:50:10 -0700 Message-ID: <20180705155009.17483.71272.stgit@john-Precision-Tower-5810> References: <20180705154828.17483.44366.stgit@john-Precision-Tower-5810> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, john.fastabend@gmail.com To: ast@kernel.org, daniel@iogearbox.net Return-path: Received: from [184.63.162.180] ([184.63.162.180]:39890 "EHLO john-Precision-Tower-5810" rhost-flags-FAIL-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753625AbeGEPuO (ORCPT ); Thu, 5 Jul 2018 11:50:14 -0400 In-Reply-To: <20180705154828.17483.44366.stgit@john-Precision-Tower-5810> Sender: netdev-owner@vger.kernel.org List-ID: Currently, when a sock is closed and the bpf_tcp_close() callback is used we remove memory but do not free the skb. Call consume_skb() if the skb is attached to the buffer. Reported-by: syzbot+d464d2c20c717ef5a6a8@syzkaller.appspotmail.com Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks") Signed-off-by: John Fastabend --- kernel/bpf/sockmap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 9c67e96..dfc8a8a 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -571,7 +571,8 @@ static int free_sg(struct sock *sk, int start, struct sk_msg_buff *md) while (sg[i].length) { free += sg[i].length; sk_mem_uncharge(sk, sg[i].length); - put_page(sg_page(&sg[i])); + if (!md->skb) + put_page(sg_page(&sg[i])); sg[i].length = 0; sg[i].page_link = 0; sg[i].offset = 0; @@ -580,6 +581,8 @@ static int free_sg(struct sock *sk, int start, struct sk_msg_buff *md) if (i == MAX_SKB_FRAGS) i = 0; } + if (md->skb) + consume_skb(md->skb); return free; }