From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932392Ab1DYUdp (ORCPT ); Mon, 25 Apr 2011 16:33:45 -0400 Received: from 1wt.eu ([62.212.114.60]:34568 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932432Ab1DYUZV (ORCPT ); Mon, 25 Apr 2011 16:25:21 -0400 Message-Id: <20110425200240.251979898@pcw.home.local> User-Agent: quilt/0.48-1 Date: Mon, 25 Apr 2011 22:05:19 +0200 From: Willy Tarreau To: linux-kernel@vger.kernel.org, stable@kernel.org, stable-review@kernel.org Cc: Artem Bityutskiy , Greg Kroah-Hartman Subject: [PATCH 167/173] UBIFS: fix oops when R/O file-system is fsynced In-Reply-To: <46075c3a3ef08be6d70339617d6afc98@local> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.27.59-stable review patch. If anyone has any objections, please let us know. ------------------ From: Artem Bityutskiy commit 78530bf7f2559b317c04991b52217c1608d5a58d upstream. This patch fixes severe UBIFS bug: UBIFS oopses when we 'fsync()' an file on R/O-mounter file-system. We (the UBIFS authors) incorrectly thought that VFS would not propagate 'fsync()' down to the file-system if it is read-only, but this is not the case. It is easy to exploit this bug using the following simple perl script: use strict; use File::Sync qw(fsync sync); die "File path is not specified" if not defined $ARGV[0]; my $path = $ARGV[0]; open FILE, "<", "$path" or die "Cannot open $path: $!"; fsync(\*FILE) or die "cannot fsync $path: $!"; close FILE or die "Cannot close $path: $!"; Thanks to Reuben Dowle for reporting about this issue. Signed-off-by: Artem Bityutskiy Reported-by: Reuben Dowle Signed-off-by: Greg Kroah-Hartman --- fs/ubifs/file.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1311,6 +1311,9 @@ int ubifs_fsync(struct file *file, struc dbg_gen("syncing inode %lu", inode->i_ino); + if (inode->i_sb->s_flags & MS_RDONLY) + return 0; + /* * VFS has already synchronized dirty pages for this inode. Synchronize * the inode unless this is a 'datasync()' call.