[v3,07/13] xfs: use file_modified() helper
diff mbox series

Message ID 20190529174318.22424-8-amir73il@gmail.com
State New
Headers show
Series
  • Fixes for major copy_file_range() issues
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Commit Message

Amir Goldstein May 29, 2019, 5:43 p.m. UTC
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@gmail.com>
---
 fs/xfs/xfs_file.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

Comments

Darrick J. Wong May 29, 2019, 6:31 p.m. UTC | #1
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@gmail.com>
> ---
>  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
>
Amir Goldstein May 29, 2019, 7:10 p.m. UTC | #2
On Wed, May 29, 2019 at 9:31 PM Darrick J. Wong <darrick.wong@oracle.com> wrote:
>
> 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@gmail.com>
> > ---
> >  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?
>

file_remove_privs() has its own IS_NOSEC() check.

Thanks,
Amir.
Darrick J. Wong May 29, 2019, 7:13 p.m. UTC | #3
On Wed, May 29, 2019 at 10:10:37PM +0300, Amir Goldstein wrote:
> On Wed, May 29, 2019 at 9:31 PM Darrick J. Wong <darrick.wong@oracle.com> wrote:
> >
> > 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@gmail.com>
> > > ---
> > >  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?
> >
> 
> file_remove_privs() has its own IS_NOSEC() check.

Ah, ok,
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>

--D

> Thanks,
> Amir.

Patch
diff mbox series

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))) {
-		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);
-	return 0;
+	return file_modified(file);
 }
 
 static int