From patchwork Wed Mar 10 17:30:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 12128869 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=-11.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MIME_BASE64_TEXT,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 2A6FAC433E0 for ; Wed, 10 Mar 2021 17:55:13 +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 763CC64F3A for ; Wed, 10 Mar 2021 17:55:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 763CC64F3A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56472 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lK339-0003LK-KT for qemu-devel@archiver.kernel.org; Wed, 10 Mar 2021 12:55:11 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40648) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lK2fB-00068s-4l for qemu-devel@nongnu.org; Wed, 10 Mar 2021 12:30:25 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:42742) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lK2f8-0006XM-Gm for qemu-devel@nongnu.org; Wed, 10 Mar 2021 12:30:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1615397420; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=gb5rQs4qgMFQU9uP6U3Hzen8MciKVUJAaBQygwm38pA=; b=FWouAwXZ1XBEzrAyZATY8iz5PIruqzm53pCKGkbTWTbnGNi8Xev4V7jnI9z+rC/8x3ZwEG DAiXRDSPfNrHUclRYrBBSc79u+zCfMFb/SXRVd66qbpib/m+WTc2BXypHb35fdyd6MmLQD QNcBVJytkM3XcJiS66ExkoH4RVlktxw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-386-NxfZ19CPM_GMeR9iQ01h_Q-1; Wed, 10 Mar 2021 12:30:13 -0500 X-MC-Unique: NxfZ19CPM_GMeR9iQ01h_Q-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 744E4108BD10 for ; Wed, 10 Mar 2021 17:30:12 +0000 (UTC) Received: from localhost (ovpn-114-250.ams2.redhat.com [10.36.114.250]) by smtp.corp.redhat.com (Postfix) with ESMTP id D94A75C255; Wed, 10 Mar 2021 17:30:05 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Subject: [PATCH] sockets: update SOCKET_ADDRESS_TYPE_FD listen(2) backlog Date: Wed, 10 Mar 2021 17:30:04 +0000 Message-Id: <20210310173004.420190-1-stefanha@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=stefanha@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=63.128.21.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -12 X-Spam_score: -1.3 X-Spam_bar: - X-Spam_report: (-1.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.243, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MIME_BASE64_TEXT=1.741, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, 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 , "Richard W . M . Jones" , Gerd Hoffmann , Stefan Hajnoczi Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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 Tested-by: Richard W.M. Jones Reviewed-by: Eric Blake Reviewed-by: Stefano Garzarella --- 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: