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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 93707C282C4 for ; Mon, 4 Feb 2019 10:54:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F0E02082E for ; Mon, 4 Feb 2019 10:54:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549277670; bh=xoNhoR+rKYw9MmGfTDix/BtPU0qYJg5moRoqm9wqqSI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ul5Shwbd5b5XawQSAYQG3YdiWgKBZ6i6Monq7Rh8tcjlrr31lG+cTFLmXpVTPUoZN p6e+mpUpkmu3Y6YRDtUYL7uCJMiX1+NFJQNBhOjH2mLHVmHR6kNRxTP9axiIX8fkmt kGU9dEa1TEWYz3kuy/rlNjbGS6uCp6Bm4BvPnjz4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732962AbfBDKy3 (ORCPT ); Mon, 4 Feb 2019 05:54:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:52278 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732424AbfBDKy2 (ORCPT ); Mon, 4 Feb 2019 05:54:28 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A0B172176F; Mon, 4 Feb 2019 10:54:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549277667; bh=xoNhoR+rKYw9MmGfTDix/BtPU0qYJg5moRoqm9wqqSI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uvUNFIAR8e/zGNWTKhFbU/Q8YPFVPJk4FCaA8zNdC/mG4jKwt4bbXRZIC5k7do277 3kXAVAo18F3qFS8uBe4Z+EVEYyQ6F5Ag6NoYZIHWj5KzMxZcDmr0kxCp3Dlt6HJu82 7AxncTqvd6Baec1sZh+rqDJ2hdG+FCmCw5m5S94Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Steve French , Paulo Alcantara , Pavel Shilovsky Subject: [PATCH 4.20 80/80] cifs: Always resolve hostname before reconnecting Date: Mon, 4 Feb 2019 11:37:40 +0100 Message-Id: <20190204103631.047605879@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190204103620.287366543@linuxfoundation.org> References: <20190204103620.287366543@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paulo Alcantara commit 28eb24ff75c5ac130eb326b3b4d0dcecfc0f427d upstream. In case a hostname resolves to a different IP address (e.g. long running mounts), make sure to resolve it every time prior to calling generic_ip_connect() in reconnect. Suggested-by: Steve French Signed-off-by: Paulo Alcantara Signed-off-by: Steve French Signed-off-by: Pavel Shilovsky Signed-off-by: Greg Kroah-Hartman --- fs/cifs/connect.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -50,6 +50,7 @@ #include "cifs_unicode.h" #include "cifs_debug.h" #include "cifs_fs_sb.h" +#include "dns_resolve.h" #include "ntlmssp.h" #include "nterr.h" #include "rfc1002pdu.h" @@ -319,6 +320,53 @@ static int cifs_setup_volume_info(struct const char *devname, bool is_smb3); /* + * Resolve hostname and set ip addr in tcp ses. Useful for hostnames that may + * get their ip addresses changed at some point. + * + * This should be called with server->srv_mutex held. + */ +#ifdef CONFIG_CIFS_DFS_UPCALL +static int reconn_set_ipaddr(struct TCP_Server_Info *server) +{ + int rc; + int len; + char *unc, *ipaddr = NULL; + + if (!server->hostname) + return -EINVAL; + + len = strlen(server->hostname) + 3; + + unc = kmalloc(len, GFP_KERNEL); + if (!unc) { + cifs_dbg(FYI, "%s: failed to create UNC path\n", __func__); + return -ENOMEM; + } + snprintf(unc, len, "\\\\%s", server->hostname); + + rc = dns_resolve_server_name_to_ip(unc, &ipaddr); + kfree(unc); + + if (rc < 0) { + cifs_dbg(FYI, "%s: failed to resolve server part of %s to IP: %d\n", + __func__, server->hostname, rc); + return rc; + } + + rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr, + strlen(ipaddr)); + kfree(ipaddr); + + return !rc ? -1 : 0; +} +#else +static inline int reconn_set_ipaddr(struct TCP_Server_Info *server) +{ + return 0; +} +#endif + +/* * cifs tcp session reconnection * * mark tcp session as reconnecting so temporarily locked @@ -418,6 +466,11 @@ cifs_reconnect(struct TCP_Server_Info *s rc = generic_ip_connect(server); if (rc) { cifs_dbg(FYI, "reconnect error %d\n", rc); + rc = reconn_set_ipaddr(server); + if (rc) { + cifs_dbg(FYI, "%s: failed to resolve hostname: %d\n", + __func__, rc); + } mutex_unlock(&server->srv_mutex); msleep(3000); } else {