lkml.org 
[lkml]   [2011]   [Apr]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[10/26] UBIFS: fix oops when R/O file-system is fsynced
2.6.33-longterm review patch.  If anyone has any objections, please let us know.

------------------
From: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>

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 <Reuben.Dowle@navico.com> for reporting about this
issue.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reported-by: Reuben Dowle <Reuben.Dowle@navico.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
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.



\
 
 \ /
  Last update: 2011-04-19 23:07    [from the cache]
©2003-2011 Jasper Spaans