| | Date | Fri, 30 Jul 2010 10:53:16 -0700 | | From | Greg KH <> | | Subject | [179/205] xfs: prevent swapext from operating on write-only files |
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2.6.34-stable review patch. If anyone has any objections, please let us know.
------------------ From: Dan Rosenberg <dan.j.rosenberg@gmail.com>
commit 1817176a86352f65210139d4c794ad2d19fc6b63 upstream.
This patch prevents user "foo" from using the SWAPEXT ioctl to swap a write-only file owned by user "bar" into a file owned by "foo" and subsequently reading it. It does so by checking that the file descriptors passed to the ioctl are also opened for reading.
Signed-off-by: Dan Rosenberg <dan.j.rosenberg@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- fs/xfs/xfs_dfrag.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/fs/xfs/xfs_dfrag.c +++ b/fs/xfs/xfs_dfrag.c @@ -69,7 +69,9 @@ xfs_swapext( goto out; } - if (!(file->f_mode & FMODE_WRITE) || (file->f_flags & O_APPEND)) { + if (!(file->f_mode & FMODE_WRITE) || + !(file->f_mode & FMODE_READ) || + (file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_file; } @@ -81,6 +83,7 @@ xfs_swapext( } if (!(tmp_file->f_mode & FMODE_WRITE) || + !(tmp_file->f_mode & FMODE_READ) || (tmp_file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_tmp_file;
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