linux-kernel - Re: [PATCH v3 03/57] locking: Introduce _

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <202306131244.E8DF4CA166@keescook>
Date:   Tue, 13 Jun 2023 12:46:29 -0700
From:   Kees Cook <keescook@...omium.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     torvalds@...ux-foundation.org, gregkh@...uxfoundation.org,
        pbonzini@...hat.com, masahiroy@...nel.org, nathan@...nel.org,
        ndesaulniers@...gle.com, nicolas@...sle.eu,
        catalin.marinas@....com, will@...nel.org, vkoul@...nel.org,
        trix@...hat.com, ojeda@...nel.org, mingo@...hat.com,
        longman@...hat.com, boqun.feng@...il.com, dennis@...nel.org,
        tj@...nel.org, cl@...ux.com, acme@...nel.org, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
        namhyung@...nel.org, irogers@...gle.com, adrian.hunter@...el.com,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de, bristot@...hat.com, vschneid@...hat.com,
        paulmck@...nel.org, frederic@...nel.org, quic_neeraju@...cinc.com,
        joel@...lfernandes.org, josh@...htriplett.org,
        mathieu.desnoyers@...icios.com, jiangshanlai@...il.com,
        rientjes@...gle.com, vbabka@...e.cz, roman.gushchin@...ux.dev,
        42.hyeyoo@...il.com, apw@...onical.com, joe@...ches.com,
        dwaipayanray1@...il.com, lukas.bulwahn@...il.com,
        john.johansen@...onical.com, paul@...l-moore.com,
        jmorris@...ei.org, serge@...lyn.com, linux-kbuild@...r.kernel.org,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org,
        llvm@...ts.linux.dev, linux-perf-users@...r.kernel.org,
        rcu@...r.kernel.org, linux-security-module@...r.kernel.org,
        tglx@...utronix.de, ravi.bangoria@....com, error27@...il.com,
        luc.vanoostenryck@...il.com
Subject: Re: [PATCH v3 03/57] locking: Introduce __cleanup() based
 infrastructure

On Tue, Jun 13, 2023 at 12:55:22PM +0200, Peter Zijlstra wrote:
> On Mon, Jun 12, 2023 at 11:07:16AM +0200, Peter Zijlstra wrote:
> 
> > --- /dev/null
> > +++ b/include/linux/cleanup.h
> > @@ -0,0 +1,167 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +#ifndef __LINUX_GUARDS_H
> > +#define __LINUX_GUARDS_H
> > +
> > +#include <linux/compiler.h>
> > +
> > +/*
> > + * DEFINE_FREE(name, type, free):
> > + *	simple helper macro that defines the required wrapper for a __free()
> > + *	based cleanup function. @free is an expression using '_T' to access
> > + *	the variable.
> > + *
> > + * __free(name):
> > + *	variable attribute to add a scoped based cleanup to the variable.
> > + *
> 
> 	no_free_ptr(var):
> 	  like a non-atomic xchg(var, NULL), such that the cleanup
> 	  function will be inhibited -- provided it sanely deals with a
> 	  NULL value.
> 
> > + * return_ptr(p):
> > + *	returns p while inhibiting the __free().
> > + *
> > + * Ex.
> > + *
> > + * DEFINE_FREE(kfree, void *, if (_T) kfree(_T))
> > + *
> > + *	struct obj *p = kmalloc(...);
> 
> That should obviously have been:
> 
> 	struct obj *p __free(kfree) = kmalloc(...);

Okay, good. I noticed that too. :)

I also didn't see any users of the kfree helpers (maybe I missed them?)
Maybe add at least one conversion just to have an example conversion for
it too?

-Kees

-- 
Kees Cook