From patchwork Sat Apr 11 12:09:12 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: 227996 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=unavailable 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 50A2BC2BA2B for ; Sat, 11 Apr 2020 12:27:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1C7B7206A1 for ; Sat, 11 Apr 2020 12:27:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586608064; bh=9c6myMWkd4h7/ocSo5vbM6bKiCYcPp3c6Q2ajw1OyE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KPIX+RDrmj6QJBuiPNZuo8ab73G+FDWffxyp+oNoFvyTknfZhuxZw+0xb6EcBjP+t 2zwelmRtH3Ula8eM6/snSBvREr+6ubRbW5w3T75BNfvrua92ZLASTyHHDhlUNkTqH4 ESPUJMv+qkE6Y5PvErhU0hikI+tXvOzT80UcpDRI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726881AbgDKMNx (ORCPT ); Sat, 11 Apr 2020 08:13:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:47086 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726760AbgDKMNx (ORCPT ); Sat, 11 Apr 2020 08:13:53 -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 A7C2A20787; Sat, 11 Apr 2020 12:13:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586607233; bh=9c6myMWkd4h7/ocSo5vbM6bKiCYcPp3c6Q2ajw1OyE0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Dfafy8LKEb9MNFx4B7qHMBVSe2menaH2y1MIUt2tyJ+V7Kz5XTv1V2S1Vz+giJ6qC jTCUR6Ndpe6Cl8l6Uq9tu55YEA8myK3Ldj1TGmIOeoDrknIQks3k1L9FcmAPWBX9VH hMWvNxVvI+0COisWyDCuv/1pDTzewBTeJl95ajao= 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 4.14 28/38] ceph: canonicalize server path in place Date: Sat, 11 Apr 2020 14:09:12 +0200 Message-Id: <20200411115440.691983233@linuxfoundation.org> X-Mailer: git-send-email 2.26.0 In-Reply-To: <20200411115437.795556138@linuxfoundation.org> References: <20200411115437.795556138@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 | 118 ++++++++++++-------------------------------------------- fs/ceph/super.h | 2 2 files changed, 28 insertions(+), 92 deletions(-) --- a/fs/ceph/super.c +++ b/fs/ceph/super.c @@ -188,6 +188,26 @@ static match_table_t fsopt_tokens = { {-1, NULL} }; +/* + * 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'; +} + static int parse_fsopt_token(char *c, void *private) { struct ceph_mount_options *fsopt = private; @@ -373,73 +393,6 @@ 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) @@ -447,7 +400,6 @@ 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); @@ -457,21 +409,12 @@ 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; @@ -539,6 +482,8 @@ static int parse_mount_options(struct ce err = -ENOMEM; goto out; } + + canonicalize_path(fsopt->server_path); } else { dev_name_end = dev_name + strlen(dev_name); } @@ -938,7 +883,9 @@ 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; @@ -950,16 +897,6 @@ 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); err = ceph_fs_debugfs_init(fsc); @@ -967,7 +904,6 @@ static struct dentry *ceph_real_mount(st goto out; 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 @@ -85,7 +85,7 @@ 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 */ };