Re: [PATCH] src/t_attr_corruption: use security.capability instead of security.evm

["Darrick J. Wong" <darrick.wong@oracle.com>]

On Mon, Feb 25, 2019 at 02:47:44PM -0800, Darrick J. Wong wrote:
> On Mon, Feb 25, 2019 at 02:10:52PM -0500, jeffm@suse.com wrote:
> > From: Jeff Mahoney <jeffm@suse.com>
> > 
> > src/t_attr_corruption uses the security.evm extended attribute because
> > it sorts before security.posix_acl_access.  The security.evm attribute
> > is a formatted structure and when passed an uninitialized buffer, it
> > will fail with EPERM.
> > 
> > We see test failures like:
> >     --- tests/generic/529.out2019-02-21 13:22:47.583406922 -0500
> >     +++ /opt/xfstests/results//generic/529.out.bad 2019-02-21 13:57:31.967406922 -0500
> >     @@ -1,2 +1,2 @@
> >      QA output created by 529
> >     -list attr: Numerical result out of range
> >     +set evm: Operation not permitted
> > 
> > This patch uses security.capability which also sorts where it needs to
> > do for the test and also accepts an unformatted buffer.
> > 
> > Signed-off-by: Jeff Mahoney <jeffm@suse.com>
> > ---
> >  src/t_attr_corruption.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/src/t_attr_corruption.c b/src/t_attr_corruption.c
> > index f26611f9..0c229dbc 100644
> > --- a/src/t_attr_corruption.c
> > +++ b/src/t_attr_corruption.c
> > @@ -76,7 +76,7 @@ int main(int argc, char *argv[])
> >  	if (ret)
> >  		die("set posix acl");
> >  
> > -	ret = fsetxattr(fd, "security.evm", buf, 1, 1);
> > +	ret = fsetxattr(fd, "security.capability", buf, 1, 1);
> 
> This fails for me both with and without EVM configured into my kernel:
> 
> fsetxattr(3, "security.capability", "\3", 1, XATTR_CREATE) = -1 EINVAL (Invalid argument)
> 
> Judging from fs/xattr.c it looks as though security.capability also has
> a defined format that's parsed by security/commoncap.c...

And now that I've figured out how to reproduce the xfs bug without a
second attribute, NAK to this and I'll send a more complete fix shortly.

--D

> --D
> 
> >  	if (ret)
> >  		die("set evm");
> >  
> > -- 
> > 2.16.4
> >