From 7a4c13ac72f77cbbaa780c7a53e6bb8d586ff2d9 Mon Sep 17 00:00:00 2001 From: Dan Rosenberg Date: Thu, 24 Jun 2010 12:07:47 +1000 Subject: [PATCH] xfs: prevent swapext from operating on write-only files 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 Reviewed-by: Christoph Hellwig Signed-off-by: Greg Kroah-Hartman --- fs/xfs/xfs_dfrag.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c index 73c22278fdaf..e4ccd9f24829 100644 --- a/fs/xfs/xfs_dfrag.c +++ b/fs/xfs/xfs_dfrag.c @@ -62,7 +62,9 @@ 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; } @@ -74,6 +76,7 @@ xfs_swapext( } if (!(target_file->f_mode & FMODE_WRITE) || + !(target_file->f_mode & FMODE_READ) || (target_file->f_flags & O_APPEND)) { error = XFS_ERROR(EBADF); goto out_put_target_file; -- 2.39.5