From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 24A09C433DF for ; Thu, 18 Jun 2020 02:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E835A20776 for ; Thu, 18 Jun 2020 02:46:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592448407; bh=gQ+2o7PW7t3IXq8X3hPmf/IAe1h0el2iVacA1Qw7i/A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=O3ZTmxqqh5hjM8dXseo3fFm6PXjZeie67nlCxXctHVjqIQ1uPlHYIGufUelPqrt0F 2WOiOmN4wQZywMcGibqvRUsvhUHTqYrcnPq/Q6TzzSCmEgm2lFqWWgJMqRNmQm1ulX kmhU/rFzkzRS3gKatTQkMrUCsmiHE/0MjR86TZDM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387815AbgFRCqp (ORCPT ); Wed, 17 Jun 2020 22:46:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:37848 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728538AbgFRBKf (ORCPT ); Wed, 17 Jun 2020 21:10:35 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C937F21927; Thu, 18 Jun 2020 01:10:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592442634; bh=gQ+2o7PW7t3IXq8X3hPmf/IAe1h0el2iVacA1Qw7i/A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LqFPd0j8aOkawlakcLEhBUJqAcOj2a3Xhyv2gfE6ameoYTk3XKGAZgwpx1ZuV4+J5 xEOxF4UjVIAcbt1b0yxdYSOx3WJYMAiRbbV7dOjoST+GGCgf4nxKnrE0hmfJ4RT2k7 fSq7ZWTfkbxtcKjtJ7jl8bkNdBBv9DR/zJcQTAbs= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sabrina Dubroca , Alexei Starovoitov , Jakub Sitnicki , Sasha Levin , netdev@vger.kernel.org, bpf@vger.kernel.org Subject: [PATCH AUTOSEL 5.7 111/388] bpf: tcp: Recv() should return 0 when the peer socket is closed Date: Wed, 17 Jun 2020 21:03:28 -0400 Message-Id: <20200618010805.600873-111-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200618010805.600873-1-sashal@kernel.org> References: <20200618010805.600873-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sabrina Dubroca [ Upstream commit 2c7269b231194aae23fb90ab65842573a91acbc9 ] If the peer is closed, we will never get more data, so tcp_bpf_wait_data will get stuck forever. In case we passed MSG_DONTWAIT to recv(), we get EAGAIN but we should actually get 0. >>From man 2 recv: RETURN VALUE When a stream socket peer has performed an orderly shutdown, the return value will be 0 (the traditional "end-of-file" return). This patch makes tcp_bpf_wait_data always return 1 when the peer socket has been shutdown. Either we have data available, and it would have returned 1 anyway, or there isn't, in which case we'll call tcp_recvmsg which does the right thing in this situation. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Sabrina Dubroca Signed-off-by: Alexei Starovoitov Acked-by: Jakub Sitnicki Link: https://lore.kernel.org/bpf/26038a28c21fea5d04d4bd4744c5686d3f2e5504.1591784177.git.sd@queasysnail.net Signed-off-by: Sasha Levin --- net/ipv4/tcp_bpf.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c index 629aaa9a1eb9..9c5540887fbe 100644 --- a/net/ipv4/tcp_bpf.c +++ b/net/ipv4/tcp_bpf.c @@ -242,6 +242,9 @@ static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock, DEFINE_WAIT_FUNC(wait, woken_wake_function); int ret = 0; + if (sk->sk_shutdown & RCV_SHUTDOWN) + return 1; + if (!timeo) return ret; -- 2.25.1