From: Casey Schaufler <casey@schaufler-ca.com>
To: Jiri Slaby <jirislaby@gmail.com>, casey@schaufler-ca.com
Cc: akpm@osdl.org, torvalds@osdl.org, linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH] (2.6.24-rc3-mm2) -mm Smack mutex cleanup
Date: Mon, 3 Dec 2007 21:04:34 -0800 (PST) [thread overview]
Message-ID: <267816.97172.qm@web36601.mail.mud.yahoo.com> (raw)
In-Reply-To: <47548F40.8090309@gmail.com>
--- Jiri Slaby <jirislaby@gmail.com> wrote:
> On 12/03/2007 07:39 PM, Casey Schaufler wrote:
> > From: Casey Schaufler <casey@schaufler-ca.com>
> >
> > Clean out unnecessary mutex initializations for Smack list locks.
> > Once this is done, there is no need for them to be shared among
> > multiple files, so pull them out of the header file and put them
> > in the files where they belong.
>
> Then it might be static.
Doh. Right you are.
> > Pull unnecessary locking from smack_inode_setsecurity, it used
> > to be required when the assignment was not guaranteed to be a
> > scalar value but isn't now.
> >
> > Change uses of __capable(current,...) to capable(...).
> > Take out an inappropriate cast. Use container_of() instead
> > of doing the same calculation by hand.
> > Fix comment spelling errors.
>
> Too many different changes according to the name of the patch.
OK, that's fair.
> > Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
> >
> > ---
> >
> > Tested with stamp-2007-11-30-16-39
> >
> > security/smack/smack.h | 3 --
> > security/smack/smack_access.c | 3 ++
> > security/smack/smack_lsm.c | 34 +++++++++-----------------------
> > security/smack/smackfs.c | 6 +++++
> > 4 files changed, 19 insertions(+), 27 deletions(-)
> >
> > diff -uprN -X linux-2.6.24-rc3-mm2-base/Documentation/dontdiff
> linux-2.6.24-rc3-mm2-base/security/smack/smack_lsm.c
> linux-2.6.24-rc3-mm2-smack/security/smack/smack_lsm.c
> > --- linux-2.6.24-rc3-mm2-base/security/smack/smack_lsm.c 2007-11-27
> 16:47:05.000000000 -0800
> > +++ linux-2.6.24-rc3-mm2-smack/security/smack/smack_lsm.c 2007-11-28
> 11:46:13.000000000 -0800
> [...]
> > @@ -748,9 +746,7 @@ static int smack_inode_setsecurity(struc
> > return -EINVAL;
> >
> > if (strcmp(name, XATTR_SMACK_SUFFIX) == 0) {
> > - mutex_lock(&nsp->smk_lock);
> > nsp->smk_inode = sp;
> > - mutex_unlock(&nsp->smk_lock);
> > return 0;
> > }
> > /*
>
> Ok, it still might be atomic as a variable change, but it will break
> scenarios
> such as
>
> mutex_lock(&nsp->smk_lock);
> create(nsp->smk_inode);
> cook_a_dinner();
> get_info(nsp->smk_inode);
> mutex_unlock(&nsp->smk_lock);
>
> While cook_a_dinner(), smack_inode_setsecurity() is called and the attribute
> changed...
>
> Doesn't this matter?
The only place dinner can get cooked is during d_instantiate, and
you can't call inode_security until after that's finished. No,
it doesn't matter.
Casey Schaufler
casey@schaufler-ca.com
prev parent reply other threads:[~2007-12-04 5:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-12-03 18:39 [PATCH] (2.6.24-rc3-mm2) -mm Smack mutex cleanup Casey Schaufler
2007-12-03 23:20 ` Jiri Slaby
2007-12-04 5:04 ` Casey Schaufler [this message]
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