Re: [PATCH] eCryptfs: Fix directory open regression in linux-stable

[Henry Jensen <hjensen@gmx.de>]

Hello,

it seems, that none of the suggested patches will be included in
4.4.15? GKH doesn't mention one in his mail "4.4.15-stable review" on
the stable list.

Regards,

Henry



On Tue, 5 Jul 2016 17:14:20 -0400
Jeff Mahoney <jeffm@suse.com> wrote:

> On 6/28/16 11:39 PM, Tyler Hicks wrote:
> > Cherry-picking mainline commit 2f36db71009304b3f0b95afacd8eba1f9f046b87
> > introduces a regression in eCryptfs when mainline commit
> > 6a480a7842545ec520a91730209ec0bae41694c1 (4.6+) is not present. The
> > regression causes all attempts at opening directory files to fail with
> > EMEDIUMTYPE when the lower filesystem's file_operations for directory
> > files do not implement mmap.
> > 
> > This is a simple fix that allows the check for the lower file's mmap
> > implementation to be ignored if the lower file is a directory.  
> 
> I have a different fix that I believe is more correct for this.  I would
> have posted it in response to the original fix if it were ever actually
> posted for public discussion.
> 
> Denying open is the wrong place to fix this.  It's too heavy a hammer
> and, as we see here, a bit fragile.
> 
> The right fix is to deny the mmap call instead.
> 
> -Jeff
> 
> > Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
> > Tested-by: Tyler Hicks <tyhicks@canonical.com> # 4.4.y, 3.18.y
> > Cc: <stable@vger.kernel.org> # 4.5-
> > ---
> >  fs/ecryptfs/kthread.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/fs/ecryptfs/kthread.c b/fs/ecryptfs/kthread.c
> > index e818f5a..b9faeab 100644
> > --- a/fs/ecryptfs/kthread.c
> > +++ b/fs/ecryptfs/kthread.c
> > @@ -171,7 +171,7 @@ int ecryptfs_privileged_open(struct file **lower_file,
> >  		goto out;
> >  	}
> >  have_file:
> > -	if ((*lower_file)->f_op->mmap == NULL) {
> > +	if ((*lower_file)->f_op->mmap == NULL && !d_is_dir(lower_dentry)) {
> >  		fput(*lower_file);
> >  		*lower_file = NULL;
> >  		rc = -EMEDIUMTYPE;
> >   
> 
> 
> -- 
> Jeff Mahoney
> SUSE Labs
>