Re: security_file_lock cmd argument

From: James Morris
Date: Wed Jul 15 2009 - 20:06:01 EST


> From: Sten Spans <Sten_Spans@xxxxxxxx>

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


> To: linux-kernel@xxxxxxxxxxxxxxx
> 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@xxxxxxxxx>
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