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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EB45C7EE23 for ; Mon, 8 May 2023 10:52:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235238AbjEHKw6 (ORCPT ); Mon, 8 May 2023 06:52:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54986 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235251AbjEHKwk (ORCPT ); Mon, 8 May 2023 06:52:40 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 188D12CFF4 for ; Mon, 8 May 2023 03:52:08 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C59F262941 for ; Mon, 8 May 2023 10:52:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8E4DC4339B; Mon, 8 May 2023 10:52:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1683543128; bh=vWfUcu/zjsURsKCR8GJ6ach5pMEOT+i814vX2hmW724=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YOoIzhwYBv1PpbfODo3nssGmAS6+e9ni2yKTvNHsGlrCR4uFSzSscXEHcu9jeSWi7 MyMzIvJDpgLqlna8ftUL0Kf2AUnlTZxBajKBL9CYRuBMK/1ydzd3rqKhBz6D4NdYMV eVKCDOSIA1yffU29k22RCd/CAzHdQ0GyADd95lKM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Paulo Alcantara (SUSE)" , Steve French Subject: [PATCH 6.2 656/663] cifs: protect access of TCP_Server_Info::{origin,leaf}_fullpath Date: Mon, 8 May 2023 11:48:02 +0200 Message-Id: <20230508094451.440993007@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230508094428.384831245@linuxfoundation.org> References: <20230508094428.384831245@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Paulo Alcantara commit 3dc9c433c9dde15477d02b609ccb4328e2adb6dc upstream. Protect access of TCP_Server_Info::{origin,leaf}_fullpath when matching DFS connections, and get rid of TCP_Server_Info::current_fullpath while we're at it. Cc: stable@vger.kernel.org # v6.2+ Signed-off-by: Paulo Alcantara (SUSE) Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/cifsglob.h | 20 +++++++++++++------- fs/cifs/connect.c | 10 ++++++---- fs/cifs/dfs.c | 14 ++++++++------ fs/cifs/dfs.h | 13 +++++++++++-- fs/cifs/dfs_cache.c | 6 +++++- 5 files changed, 43 insertions(+), 20 deletions(-) --- a/fs/cifs/cifsglob.h +++ b/fs/cifs/cifsglob.h @@ -742,17 +742,23 @@ struct TCP_Server_Info { #endif struct mutex refpath_lock; /* protects leaf_fullpath */ /* - * Canonical DFS full paths that were used to chase referrals in mount and reconnect. + * origin_fullpath: Canonical copy of smb3_fs_context::source. + * It is used for matching existing DFS tcons. * - * origin_fullpath: first or original referral path - * leaf_fullpath: last referral path (might be changed due to nested links in reconnect) + * leaf_fullpath: Canonical DFS referral path related to this + * connection. + * It is used in DFS cache refresher, reconnect and may + * change due to nested DFS links. * - * current_fullpath: pointer to either origin_fullpath or leaf_fullpath - * NOTE: cannot be accessed outside cifs_reconnect() and smb2_reconnect() + * Both protected by @refpath_lock and @srv_lock. The @refpath_lock is + * mosly used for not requiring a copy of @leaf_fullpath when getting + * cached or new DFS referrals (which might also sleep during I/O). + * While @srv_lock is held for making string and NULL comparions against + * both fields as in mount(2) and cache refresh. * - * format: \\HOST\SHARE\[OPTIONAL PATH] + * format: \\HOST\SHARE[\OPTIONAL PATH] */ - char *origin_fullpath, *leaf_fullpath, *current_fullpath; + char *origin_fullpath, *leaf_fullpath; }; static inline bool is_smb1(struct TCP_Server_Info *server) --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -486,7 +486,6 @@ static int reconnect_target_unlocked(str static int reconnect_dfs_server(struct TCP_Server_Info *server) { int rc = 0; - const char *refpath = server->current_fullpath + 1; struct dfs_cache_tgt_list tl = DFS_CACHE_TGT_LIST_INIT(tl); struct dfs_cache_tgt_iterator *target_hint = NULL; int num_targets = 0; @@ -499,8 +498,10 @@ static int reconnect_dfs_server(struct T * through /proc/fs/cifs/dfscache or the target list is empty due to server settings after * refreshing the referral, so, in this case, default it to 1. */ - if (!dfs_cache_noreq_find(refpath, NULL, &tl)) + mutex_lock(&server->refpath_lock); + if (!dfs_cache_noreq_find(server->leaf_fullpath + 1, NULL, &tl)) num_targets = dfs_cache_get_nr_tgts(&tl); + mutex_unlock(&server->refpath_lock); if (!num_targets) num_targets = 1; @@ -544,7 +545,9 @@ static int reconnect_dfs_server(struct T mod_delayed_work(cifsiod_wq, &server->reconnect, 0); } while (server->tcpStatus == CifsNeedReconnect); - dfs_cache_noreq_update_tgthint(refpath, target_hint); + mutex_lock(&server->refpath_lock); + dfs_cache_noreq_update_tgthint(server->leaf_fullpath + 1, target_hint); + mutex_unlock(&server->refpath_lock); dfs_cache_free_tgts(&tl); /* Need to set up echo worker again once connection has been established */ @@ -1621,7 +1624,6 @@ cifs_get_tcp_session(struct smb3_fs_cont rc = -ENOMEM; goto out_err; } - tcp_ses->current_fullpath = tcp_ses->leaf_fullpath; } if (ctx->nosharesock) --- a/fs/cifs/dfs.c +++ b/fs/cifs/dfs.c @@ -248,11 +248,12 @@ static int __dfs_mount_share(struct cifs tcon = mnt_ctx->tcon; mutex_lock(&server->refpath_lock); + spin_lock(&server->srv_lock); if (!server->origin_fullpath) { server->origin_fullpath = origin_fullpath; - server->current_fullpath = server->leaf_fullpath; origin_fullpath = NULL; } + spin_unlock(&server->srv_lock); mutex_unlock(&server->refpath_lock); if (list_empty(&tcon->dfs_ses_list)) { @@ -366,10 +367,11 @@ static int update_server_fullpath(struct rc = PTR_ERR(npath); } else { mutex_lock(&server->refpath_lock); + spin_lock(&server->srv_lock); kfree(server->leaf_fullpath); server->leaf_fullpath = npath; + spin_unlock(&server->srv_lock); mutex_unlock(&server->refpath_lock); - server->current_fullpath = server->leaf_fullpath; } return rc; } @@ -474,7 +476,7 @@ static int __tree_connect_dfs_target(con share = prefix = NULL; /* Check if share matches with tcp ses */ - rc = dfs_cache_get_tgt_share(server->current_fullpath + 1, tit, &share, &prefix); + rc = dfs_cache_get_tgt_share(server->leaf_fullpath + 1, tit, &share, &prefix); if (rc) { cifs_dbg(VFS, "%s: failed to parse target share: %d\n", __func__, rc); break; @@ -488,7 +490,7 @@ static int __tree_connect_dfs_target(con continue; } - dfs_cache_noreq_update_tgthint(server->current_fullpath + 1, tit); + dfs_cache_noreq_update_tgthint(server->leaf_fullpath + 1, tit); tree_connect_ipc(xid, tree, cifs_sb, tcon); scnprintf(tree, MAX_TREE_SIZE, "\\%s", share); @@ -602,8 +604,8 @@ int cifs_tree_connect(const unsigned int cifs_sb = CIFS_SB(sb); /* If it is not dfs or there was no cached dfs referral, then reconnect to same share */ - if (!server->current_fullpath || - dfs_cache_noreq_find(server->current_fullpath + 1, &ref, &tl)) { + if (!server->leaf_fullpath || + dfs_cache_noreq_find(server->leaf_fullpath + 1, &ref, &tl)) { rc = ops->tree_connect(xid, tcon->ses, tcon->tree_name, tcon, cifs_sb->local_nls); goto out; } --- a/fs/cifs/dfs.h +++ b/fs/cifs/dfs.h @@ -43,8 +43,12 @@ static inline char *dfs_get_automount_de size_t len; char *s; - if (unlikely(!server->origin_fullpath)) + spin_lock(&server->srv_lock); + if (unlikely(!server->origin_fullpath)) { + spin_unlock(&server->srv_lock); return ERR_PTR(-EREMOTE); + } + spin_unlock(&server->srv_lock); s = dentry_path_raw(dentry, page, PATH_MAX); if (IS_ERR(s)) @@ -53,13 +57,18 @@ static inline char *dfs_get_automount_de if (!s[1]) s++; + spin_lock(&server->srv_lock); len = strlen(server->origin_fullpath); - if (s < (char *)page + len) + if (s < (char *)page + len) { + spin_unlock(&server->srv_lock); return ERR_PTR(-ENAMETOOLONG); + } s -= len; memcpy(s, server->origin_fullpath, len); + spin_unlock(&server->srv_lock); convert_delimiter(s, '/'); + return s; } --- a/fs/cifs/dfs_cache.c +++ b/fs/cifs/dfs_cache.c @@ -1278,8 +1278,12 @@ static void refresh_cache_worker(struct spin_lock(&cifs_tcp_ses_lock); list_for_each_entry(server, &cifs_tcp_ses_list, tcp_ses_list) { - if (!server->leaf_fullpath) + spin_lock(&server->srv_lock); + if (!server->leaf_fullpath) { + spin_unlock(&server->srv_lock); continue; + } + spin_unlock(&server->srv_lock); list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) { if (ses->tcon_ipc) {