Re: security_file_lock cmd argument

Re: security_file_lock cmd argument

[James Morris]

> From: Sten Spans <Sten_Spans@genua.de>

This looks good, but you need to add a signed-off-by line per 
Documentation/SubmittingPatches


> To: linux-kernel@vger.kernel.org
> Subject: security_file_lock cmd argument
> 
> 
> I was playing around with the security_file_lock hook which
> is invoked from fs/locks.c. The desciption in include/linux/security.h
> states the following:
> 
>  * @file_lock:
>  *      Check permission before performing file locking operations.
>  *      Note: this hook mediates both flock and fcntl style locks.
>  *      @file contains the file structure.
>  *      @cmd contains the posix-translated lock operation to perform
>  *      (e.g. F_RDLCK, F_WRLCK).
> 
> However when invoked via sys_flock:
> 
> SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
> {
> ..
>         error = security_file_lock(filp, cmd);
> 
> Which results in passing flock style arguments (LOCK_*) rather
> than fcntl (F_*LCK). This also is inconsistent with the two
> other security_file_lock invocations in the same file.
> This one-liner fixes the issue:
> 
> --- fs/locks.c.orig	2009-07-09 11:26:45.000000000 +0200
> +++ fs/locks.c	2009-07-09 11:27:24.000000000 +0200
> @@ -1590,7 +1590,7 @@
>  	if (can_sleep)
>  		lock->fl_flags |= FL_SLEEP;
>  
> -	error = security_file_lock(filp, cmd);
> +	error = security_file_lock(filp, lock->fl_type);
>  	if (error)
>  		goto out_free;
>  
> -- 
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> 

-- 
James Morris
<jmorris@namei.org>

Re: security_file_lock cmd argument

[Sten Spans]

On Thu, Jul 16, 2009 at 10:05:47AM +1000, James Morris wrote:
> > From: Sten Spans <Sten_Spans@genua.de>
> 
> This looks good, but you need to add a signed-off-by line per 
> Documentation/SubmittingPatches
> 

Makes sense, how about:

Pass posix-translated lock operations to security_file_lock
when invoked via sys_flock.

Signed-off-by: Sten Spans <Sten_Spans@genua.de>

--- fs/locks.c.orig	2009-07-09 11:26:45.000000000 +0200
+++ fs/locks.c	2009-07-09 11:27:24.000000000 +0200
@@ -1590,7 +1590,7 @@
 	if (can_sleep)
 		lock->fl_flags |= FL_SLEEP;
 
-	error = security_file_lock(filp, cmd);
+	error = security_file_lock(filp, lock->fl_type);
 	if (error)
 		goto out_free;
 
-- 
GeNUA Gesellschaft für Netzwerk - und Unix-Administration mbH
Domagkstr. 7, D-85551 Kirchheim. http://www.genua.de
Tel: (089) 99 19 50-0, Fax: (089) 99 19 50 - 999
 
 Geschäftsführer: Dr. Magnus Harlander, Dr. Michaela Harlander,
 Bernhard Schneck. Amtsgericht München HRB 98238

Re: security_file_lock cmd argument

[James Morris]

On Thu, 16 Jul 2009, Sten Spans wrote:

> On Thu, Jul 16, 2009 at 10:05:47AM +1000, James Morris wrote:
> > > From: Sten Spans <Sten_Spans@genua.de>
> > 
> > This looks good, but you need to add a signed-off-by line per 
> > Documentation/SubmittingPatches
> > 
> 
> Makes sense, how about:
> 
> Pass posix-translated lock operations to security_file_lock
> when invoked via sys_flock.
> 
> Signed-off-by: Sten Spans <Sten_Spans@genua.de>

Thanks.

Applied to
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next


-- 
James Morris
<jmorris@namei.org>

security_file_lock cmd argument

[Sten Spans]

I was playing around with the security_file_lock hook which
is invoked from fs/locks.c. The desciption in include/linux/security.h
states the following:

 * @file_lock:
 *      Check permission before performing file locking operations.
 *      Note: this hook mediates both flock and fcntl style locks.
 *      @file contains the file structure.
 *      @cmd contains the posix-translated lock operation to perform
 *      (e.g. F_RDLCK, F_WRLCK).

However when invoked via sys_flock:

SYSCALL_DEFINE2(flock, unsigned int, fd, unsigned int, cmd)
{
..
        error = security_file_lock(filp, cmd);

Which results in passing flock style arguments (LOCK_*) rather
than fcntl (F_*LCK). This also is inconsistent with the two
other security_file_lock invocations in the same file.
This one-liner fixes the issue:

--- fs/locks.c.orig	2009-07-09 11:26:45.000000000 +0200
+++ fs/locks.c	2009-07-09 11:27:24.000000000 +0200
@@ -1590,7 +1590,7 @@
 	if (can_sleep)
 		lock->fl_flags |= FL_SLEEP;
 
-	error = security_file_lock(filp, cmd);
+	error = security_file_lock(filp, lock->fl_type);
 	if (error)
 		goto out_free;
 
-- 
GeNUA Gesellschaft für Netzwerk - und Unix-Administration mbH
Domagkstr. 7, D-85551 Kirchheim. http://www.genua.de
Tel: (089) 99 19 50-0, Fax: (089) 99 19 50 - 999
 
 Geschäftsführer: Dr. Magnus Harlander, Dr. Michaela Harlander,
 Bernhard Schneck. Amtsgericht München HRB 98238