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=-10.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 E9D4FC47080 for ; Tue, 1 Jun 2021 14:25:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 688C9613A9 for ; Tue, 1 Jun 2021 14:25:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 688C9613A9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:49338 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lo5L2-0004Ln-EJ for qemu-devel@archiver.kernel.org; Tue, 01 Jun 2021 10:25:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55824) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lo5K8-00034v-Jg; Tue, 01 Jun 2021 10:24:52 -0400 Received: from mail-pg1-x536.google.com ([2607:f8b0:4864:20::536]:39910) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lo5K6-0003cX-QT; Tue, 01 Jun 2021 10:24:52 -0400 Received: by mail-pg1-x536.google.com with SMTP id v14so10826476pgi.6; Tue, 01 Jun 2021 07:24:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HhYSfI+QPQnPm76A5iC5aR58yw6gRQkObuaWZQUUTJw=; b=EePR9kdrHQ+qgi0p+goS+NKl/L93hxGOEe0sQQ0UdQVGKbrXTtznZo+b2R29FUrEaQ grqCMrzTxKAO9T30KbVo0hjsjUo45vUDt6MteN7fWF2YCiQGame6lL/FQvoK36MDhjIe lTuVC4VSKIItCvd8quLuiLOb6Z3GnIteIfNSJxOsPbSBJNAaQ/7tTQbC6QtyL5yud2wO YSePl3RJdtljodDP2X9jY+hPGlGnHomePtvb5DYdVynvQQkKkQkqaTjm4VfcS5M4rXqA j4/y0mbSOwmCXjbo/qjPTvefuwAZ5oZi95oPhMz9397NN6oy45+V2me/HY4Wp+fivgm2 ev4w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HhYSfI+QPQnPm76A5iC5aR58yw6gRQkObuaWZQUUTJw=; b=pBZJiUlhJ5EulAXnT7FAU3iKCcaHI+w28x+uJ5u1MlMxZHMLudiG8T2nRAlxUsk8P8 D8i++lDTerIijiVAwhyakijTsNlnuIv+iR+nJeFQWllvrzgv8DlCR8J3DV/pt5N8xjwZ BNnFVAb52RBFdFpoYwdo8ZTf8G5trPXWfaCRooEtJg6dHA48PCQXb0kOrKvcfVD4H3Ov UTT1RiOSZQSV8/OIhwiR40v6PnlgvrA2C8H/8qg0UDkx5DLnBZZtSqdqVwWWJCMam85g iUxTz5MYbM9Hi6P6Is+f6uIaOKphqJNwcKWCn3hIe0SFWkq3U2hMQ06P3Arpp4Ea7GIr PBtQ== X-Gm-Message-State: AOAM531LQbROsAjW+LzSo1EBKl3MejQ5uKDiCcgeqdxPQdsy68ClX9cY drHkCfoxi94wa34Z5gLAlZFzg600EhJWEIepL1A= X-Google-Smtp-Source: ABdhPJzZ9Ew+EFUhPUbB/wnQB8VRDA/mo7Z/VcQ7ML8J2bex096OmLaGkoHk0kB1lMQ8xiP3cEbj9UUvkG/jLxA+pS8= X-Received: by 2002:a65:6899:: with SMTP id e25mr11815192pgt.393.1622557488788; Tue, 01 Jun 2021 07:24:48 -0700 (PDT) MIME-Version: 1.0 References: <20210310173004.420190-1-stefanha@redhat.com> In-Reply-To: <20210310173004.420190-1-stefanha@redhat.com> From: Stefan Hajnoczi Date: Tue, 1 Jun 2021 15:24:37 +0100 Message-ID: Subject: Re: [PATCH] sockets: update SOCKET_ADDRESS_TYPE_FD listen(2) backlog To: michael.roth@amd.com Content-Type: text/plain; charset="UTF-8" Received-SPF: pass client-ip=2607:f8b0:4864:20::536; envelope-from=stefanha@gmail.com; helo=mail-pg1-x536.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?UTF-8?Q?Daniel_P=2E_Berrang=C3=A9?= , Juan Quintela , qemu-stable , "Richard W . M . Jones" , qemu-devel , Gerd Hoffmann , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Please consider this patch for the QEMU 6.0 stable release. The bug was introduced in QEMU 6.0. Thanks, Stefan On Wed, Mar 10, 2021 at 5:54 PM Stefan Hajnoczi wrote: > > socket_get_fd() fails with the error "socket_get_fd: too many > connections" if the given listen backlog value is not 1. > > Not all callers set the backlog to 1. For example, commit > 582d4210eb2f2ab5baac328fe4b479cd86da1647 ("qemu-nbd: Use SOMAXCONN for > socket listen() backlog") uses SOMAXCONN. This will always fail with in > socket_get_fd(). > > This patch calls listen(2) on the fd to update the backlog value. The > socket may already be in the listen state. I have tested that this works > on Linux 5.10 and macOS Catalina. > > As a bonus this allows us to detect when the fd cannot listen. Now we'll > be able to catch unbound or connected fds in socket_listen(). > > Drop the num argument from socket_get_fd() since this function is also > called by socket_connect() where a listen backlog value does not make > sense. > > Fixes: e5b6353cf25c99c3f08bf51e29933352f7140e8f ("socket: Add backlog parameter to socket_listen") > Reported-by: Richard W.M. Jones > Cc: Juan Quintela > Cc: Eric Blake > Signed-off-by: Stefan Hajnoczi > --- > util/qemu-sockets.c | 29 ++++++++++++++++++++++------- > 1 file changed, 22 insertions(+), 7 deletions(-) > > diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c > index 8af0278f15..2463c49773 100644 > --- a/util/qemu-sockets.c > +++ b/util/qemu-sockets.c > @@ -1116,14 +1116,10 @@ fail: > return NULL; > } > > -static int socket_get_fd(const char *fdstr, int num, Error **errp) > +static int socket_get_fd(const char *fdstr, Error **errp) > { > Monitor *cur_mon = monitor_cur(); > int fd; > - if (num != 1) { > - error_setg_errno(errp, EINVAL, "socket_get_fd: too many connections"); > - return -1; > - } > if (cur_mon) { > fd = monitor_get_fd(cur_mon, fdstr, errp); > if (fd < 0) { > @@ -1159,7 +1155,7 @@ int socket_connect(SocketAddress *addr, Error **errp) > break; > > case SOCKET_ADDRESS_TYPE_FD: > - fd = socket_get_fd(addr->u.fd.str, 1, errp); > + fd = socket_get_fd(addr->u.fd.str, errp); > break; > > case SOCKET_ADDRESS_TYPE_VSOCK: > @@ -1187,7 +1183,26 @@ int socket_listen(SocketAddress *addr, int num, Error **errp) > break; > > case SOCKET_ADDRESS_TYPE_FD: > - fd = socket_get_fd(addr->u.fd.str, num, errp); > + fd = socket_get_fd(addr->u.fd.str, errp); > + if (fd < 0) { > + return -1; > + } > + > + /* > + * If the socket is not yet in the listen state, then transition it to > + * the listen state now. > + * > + * If it's already listening then this updates the backlog value as > + * requested. > + * > + * If this socket cannot listen because it's already in another state > + * (e.g. unbound or connected) then we'll catch the error here. > + */ > + if (listen(fd, num) != 0) { > + error_setg_errno(errp, errno, "Failed to listen on fd socket"); > + closesocket(fd); > + return -1; > + } > break; > > case SOCKET_ADDRESS_TYPE_VSOCK: > -- > 2.29.2 >