From patchwork Sat Apr 11 12:10:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 228067 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, 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 5F89AC2BB85 for ; Sat, 11 Apr 2020 12:20:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 31BD420692 for ; Sat, 11 Apr 2020 12:20:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586607621; bh=eqKyBP6KGSbWlgXN+NoFwfaieYF4KVDs1nuqdXhxW4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=moQyAIdpWUJEbh5ht61Cb28wzoBLWtWBGFA6a1b1PQgIew4rI4L5KMzKq699YC7sQ jfy6bqVGfGa7W8VjqORVOvsCjhLRCSn4PRkddlPsSWXmRKVv463IlFM4xs7extaGc4 uj5Ir8Q/3Px2X1tv7Du6LW00U1Z53liW/flQFP/E= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728940AbgDKMUT (ORCPT ); Sat, 11 Apr 2020 08:20:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:56114 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727091AbgDKMUR (ORCPT ); Sat, 11 Apr 2020 08:20:17 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 9CC532084D; Sat, 11 Apr 2020 12:20:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586607617; bh=eqKyBP6KGSbWlgXN+NoFwfaieYF4KVDs1nuqdXhxW4w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ar+SBzNfpIBp3sXRkGApN22e5dS5Fg61EaXZk0Q+hpoQ0aUi0v+UkHUy2AhKzcBWk +4mZg+uFa2H2vi22uxa5XCXtnQtnvLRhi/m1Gxv4qAGVs2mMoDwI3kxERmHsyq5IAo 3voAWFaaybi4Jh+whm/viCFfcDkTFdm0cEgtzdpU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+98704a51af8e3d9425a9@syzkaller.appspotmail.com, Ilya Dryomov , Jeff Layton , Luis Henriques Subject: [PATCH 5.5 44/44] ceph: canonicalize server path in place Date: Sat, 11 Apr 2020 14:10:04 +0200 Message-Id: <20200411115501.133434100@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200411115456.934174282@linuxfoundation.org> References: <20200411115456.934174282@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ilya Dryomov commit b27a939e8376a3f1ed09b9c33ef44d20f18ec3d0 upstream. syzbot reported that 4fbc0c711b24 ("ceph: remove the extra slashes in the server path") had caused a regression where an allocation could be done under a spinlock -- compare_mount_options() is called by sget_fc() with sb_lock held. We don't really need the supplied server path, so canonicalize it in place and compare it directly. To make this work, the leading slash is kept around and the logic in ceph_real_mount() to skip it is restored. CEPH_MSG_CLIENT_SESSION now reports the same (i.e. canonicalized) path, with the leading slash of course. Fixes: 4fbc0c711b24 ("ceph: remove the extra slashes in the server path") Reported-by: syzbot+98704a51af8e3d9425a9@syzkaller.appspotmail.com Signed-off-by: Ilya Dryomov Reviewed-by: Jeff Layton Signed-off-by: Luis Henriques Signed-off-by: Greg Kroah-Hartman --- fs/ceph/super.c | 121 ++++++++++++-------------------------------------------- fs/ceph/super.h | 2 2 files changed, 29 insertions(+), 94 deletions(-) --- a/fs/ceph/super.c +++ b/fs/ceph/super.c @@ -209,6 +209,26 @@ struct ceph_parse_opts_ctx { }; /* + * Remove adjacent slashes and then the trailing slash, unless it is + * the only remaining character. + * + * E.g. "//dir1////dir2///" --> "/dir1/dir2", "///" --> "/". + */ +static void canonicalize_path(char *path) +{ + int i, j = 0; + + for (i = 0; path[i] != '\0'; i++) { + if (path[i] != '/' || j < 1 || path[j - 1] != '/') + path[j++] = path[i]; + } + + if (j > 1 && path[j - 1] == '/') + j--; + path[j] = '\0'; +} + +/* * Parse the source parameter. Distinguish the server list from the path. * * The source will look like: @@ -230,15 +250,16 @@ static int ceph_parse_source(struct fs_p dev_name_end = strchr(dev_name, '/'); if (dev_name_end) { - kfree(fsopt->server_path); - /* * The server_path will include the whole chars from userland * including the leading '/'. */ + kfree(fsopt->server_path); fsopt->server_path = kstrdup(dev_name_end, GFP_KERNEL); if (!fsopt->server_path) return -ENOMEM; + + canonicalize_path(fsopt->server_path); } else { dev_name_end = dev_name + strlen(dev_name); } @@ -462,73 +483,6 @@ static int strcmp_null(const char *s1, c return strcmp(s1, s2); } -/** - * path_remove_extra_slash - Remove the extra slashes in the server path - * @server_path: the server path and could be NULL - * - * Return NULL if the path is NULL or only consists of "/", or a string - * without any extra slashes including the leading slash(es) and the - * slash(es) at the end of the server path, such as: - * "//dir1////dir2///" --> "dir1/dir2" - */ -static char *path_remove_extra_slash(const char *server_path) -{ - const char *path = server_path; - const char *cur, *end; - char *buf, *p; - int len; - - /* if the server path is omitted */ - if (!path) - return NULL; - - /* remove all the leading slashes */ - while (*path == '/') - path++; - - /* if the server path only consists of slashes */ - if (*path == '\0') - return NULL; - - len = strlen(path); - - buf = kmalloc(len + 1, GFP_KERNEL); - if (!buf) - return ERR_PTR(-ENOMEM); - - end = path + len; - p = buf; - do { - cur = strchr(path, '/'); - if (!cur) - cur = end; - - len = cur - path; - - /* including one '/' */ - if (cur != end) - len += 1; - - memcpy(p, path, len); - p += len; - - while (cur <= end && *cur == '/') - cur++; - path = cur; - } while (path < end); - - *p = '\0'; - - /* - * remove the last slash if there has and just to make sure that - * we will get something like "dir1/dir2" - */ - if (*(--p) == '/') - *p = '\0'; - - return buf; -} - static int compare_mount_options(struct ceph_mount_options *new_fsopt, struct ceph_options *new_opt, struct ceph_fs_client *fsc) @@ -536,7 +490,6 @@ static int compare_mount_options(struct struct ceph_mount_options *fsopt1 = new_fsopt; struct ceph_mount_options *fsopt2 = fsc->mount_options; int ofs = offsetof(struct ceph_mount_options, snapdir_name); - char *p1, *p2; int ret; ret = memcmp(fsopt1, fsopt2, ofs); @@ -546,21 +499,12 @@ static int compare_mount_options(struct ret = strcmp_null(fsopt1->snapdir_name, fsopt2->snapdir_name); if (ret) return ret; + ret = strcmp_null(fsopt1->mds_namespace, fsopt2->mds_namespace); if (ret) return ret; - p1 = path_remove_extra_slash(fsopt1->server_path); - if (IS_ERR(p1)) - return PTR_ERR(p1); - p2 = path_remove_extra_slash(fsopt2->server_path); - if (IS_ERR(p2)) { - kfree(p1); - return PTR_ERR(p2); - } - ret = strcmp_null(p1, p2); - kfree(p1); - kfree(p2); + ret = strcmp_null(fsopt1->server_path, fsopt2->server_path); if (ret) return ret; @@ -962,7 +906,9 @@ static struct dentry *ceph_real_mount(st mutex_lock(&fsc->client->mount_mutex); if (!fsc->sb->s_root) { - const char *path, *p; + const char *path = fsc->mount_options->server_path ? + fsc->mount_options->server_path + 1 : ""; + err = __ceph_open_session(fsc->client, started); if (err < 0) goto out; @@ -974,22 +920,11 @@ static struct dentry *ceph_real_mount(st goto out; } - p = path_remove_extra_slash(fsc->mount_options->server_path); - if (IS_ERR(p)) { - err = PTR_ERR(p); - goto out; - } - /* if the server path is omitted or just consists of '/' */ - if (!p) - path = ""; - else - path = p; dout("mount opening path '%s'\n", path); ceph_fs_debugfs_init(fsc); root = open_root_dentry(fsc, path, started); - kfree(p); if (IS_ERR(root)) { err = PTR_ERR(root); goto out; --- a/fs/ceph/super.h +++ b/fs/ceph/super.h @@ -91,7 +91,7 @@ struct ceph_mount_options { char *snapdir_name; /* default ".snap" */ char *mds_namespace; /* default NULL */ - char *server_path; /* default "/" */ + char *server_path; /* default NULL (means "/") */ char *fscache_uniq; /* default NULL */ };