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 922ABEB64DD for ; Sun, 16 Jul 2023 20:27:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232025AbjGPU1p (ORCPT ); Sun, 16 Jul 2023 16:27:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229496AbjGPU1p (ORCPT ); Sun, 16 Jul 2023 16:27:45 -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 49CC2D3 for ; Sun, 16 Jul 2023 13:27:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id C777460EBC for ; Sun, 16 Jul 2023 20:27:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D70E0C433C7; Sun, 16 Jul 2023 20:27:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689539263; bh=e/erS0Qtrc5BnQazcB/s7JaCf9/gvGHjAnjvLvqbeRs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iwvvlMJTDpKU/TM9cQegzSKO/wDO22NhWrjc1GYOB7pAT1Y/YlxLlPGvWhHMTSVBF u37gp2JopPvlEP/aZbtyrGBUppvNGkNXhXBrHGQnhqUPfjsAp/Mvt7w/qXjh4wUH/R UYlDyULkUtNpZQXmqlVfa5sP5dahdGZ6BGqn8yrA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , Christian Brauner Subject: [PATCH 6.4 745/800] fs: avoid empty option when generating legacy mount string Date: Sun, 16 Jul 2023 21:49:58 +0200 Message-ID: <20230716195006.425426842@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230716194949.099592437@linuxfoundation.org> References: <20230716194949.099592437@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: Thomas Weißschuh commit 62176420274db5b5127cd7a0083a9aeb461756ee upstream. As each option string fragment is always prepended with a comma it would happen that the whole string always starts with a comma. This could be interpreted by filesystem drivers as an empty option and may produce errors. For example the NTFS driver from ntfs.ko behaves like this and fails when mounted via the new API. Link: https://github.com/util-linux/util-linux/issues/2298 Signed-off-by: Thomas Weißschuh Fixes: 3e1aeb00e6d1 ("vfs: Implement a filesystem superblock creation/configuration context") Cc: stable@vger.kernel.org Message-Id: <20230607-fs-empty-option-v1-1-20c8dbf4671b@weissschuh.net> Signed-off-by: Christian Brauner Signed-off-by: Greg Kroah-Hartman --- fs/fs_context.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/fs_context.c +++ b/fs/fs_context.c @@ -561,7 +561,8 @@ static int legacy_parse_param(struct fs_ return -ENOMEM; } - ctx->legacy_data[size++] = ','; + if (size) + ctx->legacy_data[size++] = ','; len = strlen(param->key); memcpy(ctx->legacy_data + size, param->key, len); size += len;