commit: 78530bf7f2559b317c04991b52217c1608d5a58d From: Artem Bityutskiy <[email protected]> Date: Wed, 13 Apr 2011 10:31:52 +0300 Subject: [PATCH] UBIFS: fix oops when R/O file-system is fsync'ed
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 <[email protected]> for reporting about this issue. Signed-off-by: Artem Bityutskiy <[email protected]> Reported-by: Reuben Dowle <[email protected]> Cc: [email protected] --- fs/ubifs/file.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/fs/ubifs/file.c b/fs/ubifs/file.c index 28be1e6..b286db7 100644 --- a/fs/ubifs/file.c +++ b/fs/ubifs/file.c @@ -1312,6 +1312,9 @@ int ubifs_fsync(struct file *file, int datasync) 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. _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
