On Wed, May 29, 2019 at 08:43:11PM +0300, Amir Goldstein wrote:
> Note that by using the helper, the order of calling file_remove_privs()
> after file_update_mtime() in xfs_file_aio_write_checks() has changed.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
> ---
> fs/xfs/xfs_file.c | 15 +--------------
> 1 file changed, 1 insertion(+), 14 deletions(-)
>
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 76748255f843..916a35cae5e9 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -367,20 +367,7 @@ xfs_file_aio_write_checks(
> * lock above. Eventually we should look into a way to avoid
> * the pointless lock roundtrip.
> */
> - if (likely(!(file->f_mode & FMODE_NOCMTIME))) {
...especially since here we think NOCMTIME is likely /not/ to be set.
> - error = file_update_time(file);
> - if (error)
> - return error;
> - }
> -
> - /*
> - * If we're writing the file then make sure to clear the setuid and
> - * setgid bits if the process is not being run by root. This keeps
> - * people from modifying setuid and setgid binaries.
> - */
> - if (!IS_NOSEC(inode))
> - return file_remove_privs(file);
Hm, file_modified doesn't have the !IS_NOSEC check guarding
file_remove_privs, are you sure it's ok to remove the suid bits
unconditionally? Even if SB_NOSEC (and therefore S_NOSEC) are set?
--D
> - return 0;
> + return file_modified(file);
> }
>
> static int
> --
> 2.17.1
>
