From patchwork Tue Apr 17 16:53:37 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zheng Liu X-Patchwork-Id: 153250 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id DB77EB704A for ; Wed, 18 Apr 2012 02:48:10 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754764Ab2DQQru (ORCPT ); Tue, 17 Apr 2012 12:47:50 -0400 Received: from mail-pz0-f66.google.com ([209.85.210.66]:64735 "EHLO mail-pz0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753824Ab2DQQrZ (ORCPT ); Tue, 17 Apr 2012 12:47:25 -0400 Received: by dade7 with SMTP id e7so3181879dad.1 for ; Tue, 17 Apr 2012 09:47:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=fM7CidqFqECH/aWsPJvZKQGKL9zJ9aJkpvd3prLgqHE=; b=DIMGkKHAb/Pe2FX6zC4Gg6YFLI6x6hXKOID2x0hF+YLwWgz7k7OdGkLVWpWGgsRt8v /Cgzrc9uUSsn0uqga76Ab0pYpTmNoYr0+DkvPaQxK10eBqvi+/WkyxtAWmyQdfGj3iif sv062+GhlAQh3ZLAJFhVO/wJ6kYactxRkHyQcwRK0DjTgwjevmKBeWb02gYEltqyLpBy uQ+lm6ntfjQmHQUUIgd7v0o8yxvomvufliJ/NC3/nbS/WTtxNe443SUOk4Zmu1Lin0rY 832AYv5O2g1BxGI1RNqnYY5EBCRISay5Xgjr4QFN2ZVHzr2QEBgKJubd4JBu/QYssmIX sB4A== Received: by 10.68.221.1 with SMTP id qa1mr9161526pbc.41.1334681245266; Tue, 17 Apr 2012 09:47:25 -0700 (PDT) Received: from localhost.localdomain ([182.92.247.2]) by mx.google.com with ESMTPS id i1sm16620234pbv.49.2012.04.17.09.47.23 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 17 Apr 2012 09:47:25 -0700 (PDT) From: Zheng Liu To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org Cc: Zheng Liu Subject: [RFC][PATCH 2/3] vfs: add security check for _NO_HIDE_STALE flag Date: Wed, 18 Apr 2012 00:53:37 +0800 Message-Id: <1334681618-9452-3-git-send-email-wenqing.lz@taobao.com> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1334681618-9452-1-git-send-email-wenqing.lz@taobao.com> References: <1334681618-9452-1-git-send-email-wenqing.lz@taobao.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Zheng Liu A new variable is added to enable/disable _NO_HIDE_STALE flag becuase this flag is possible to be abused. Signed-off-by: Zheng Liu --- fs/open.c | 10 ++++++++++ include/linux/sysctl.h | 1 + kernel/sysctl.c | 10 ++++++++++ 3 files changed, 21 insertions(+), 0 deletions(-) diff --git a/fs/open.c b/fs/open.c index 1d3117f..43fd39c 100644 --- a/fs/open.c +++ b/fs/open.c @@ -213,6 +213,11 @@ SYSCALL_ALIAS(sys_ftruncate64, SyS_ftruncate64); #endif #endif /* BITS_PER_LONG == 32 */ +/* + * enable/disable FALLOC_FL_NO_HIDE_STALE flag + * 0: disable (default), 1: enable + */ +int sysctl_enable_falloc_no_hide_stale = 0; int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) { @@ -249,6 +254,11 @@ int do_fallocate(struct file *file, int mode, loff_t offset, loff_t len) if (ret) return ret; + /* Check for enabling _NO_HIDE_STALE flag */ + if (mode & FALLOC_FL_NO_HIDE_STALE && + !sysctl_enable_falloc_no_hide_stale) + return -EPERM; + if (S_ISFIFO(inode->i_mode)) return -ESPIPE; diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index c34b4c8..484e5dc 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -820,6 +820,7 @@ enum FS_AIO_NR=18, /* current system-wide number of aio requests */ FS_AIO_MAX_NR=19, /* system-wide maximum number of aio requests */ FS_INOTIFY=20, /* inotify submenu */ + FS_FALLOC_STALE=21, /* enable fallocate _NO_HIDE_STALE flag */ FS_OCFS2=988, /* ocfs2 */ }; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 4ab1187..37de7c2 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -108,6 +108,7 @@ extern int percpu_pagelist_fraction; extern int compat_log; extern int latencytop_enabled; extern int sysctl_nr_open_min, sysctl_nr_open_max; +extern int sysctl_enable_falloc_no_hide_stale; #ifndef CONFIG_MMU extern int sysctl_nr_trim_pages; #endif @@ -1517,6 +1518,15 @@ static struct ctl_table fs_table[] = { .proc_handler = &pipe_proc_fn, .extra1 = &pipe_min_size, }, + { + .procname = "falloc_no_hide_stale", + .data = &sysctl_enable_falloc_no_hide_stale, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &zero, + .extra2 = &one, + }, { } };