From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.1 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_IN_DEF_DKIM_WL autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BA55FC4727E for ; Wed, 30 Sep 2020 12:51:31 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id B470120674 for ; Wed, 30 Sep 2020 12:51:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="L7X6TOpx" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B470120674 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-20067-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 20104 invoked by uid 550); 30 Sep 2020 12:51:23 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 20084 invoked from network); 30 Sep 2020 12:51:22 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=061+j+6egSPgQBxcQTsTW5phFlVIKpu1EERfRNYFm3I=; b=L7X6TOpxVSA1+/tKoz+lBrre35i6hykvaIsiSKRHazC1OEzRn8KvgpXAhkiiZiVegY hdXFas3bd8RElezjRN1Xeo7xyo7N2TkVLXtqU3NGt5Q8cVO3mr5kv+TEr1CYFZCRj4Z/ NW5e/35SOVX/7oaogpcsuZY+pT2bwreoZd2XwBqQnwrCKrSePcNpSqJb0uFF/Id6AfFs KOYk8XjmATWuR/1g8kLMRJOhm10DPe9hbErIsERzBQXL30eRmJc/Lg9yUE0wgl2QU6er RnRvuI5XvMS9yKOd/4XI7PcEwBEw2l3rf/ujZ4+IWPrfSKuDeZm1cQ/nKtWd1HwBDjMP EdIA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=061+j+6egSPgQBxcQTsTW5phFlVIKpu1EERfRNYFm3I=; b=ISSX3jUhmjbMPKe3+E8+giDC5BDb9fvU6BmR08Sk5EazVrvojPbRVoIPp2vervqP/U 2MTSnwyQuQ7tjQ47Bf26dS+BZePKuBTvMV76bCWPT8/Lvs0J1l5YeqIOjVk9XusW+7K/ 4iK+4RoTiFtvj8tEZzDtypPfk4UZFDNSjnoOMWsigb97tbEpu+VuV/H/TtKIq06iDRk8 xgCB9tZz/ICFyAxpUYNlXsGmtbdJm8AKWpnloptO9Tj52xkGO3BL/VsD5t/ldFMPWTZO h/GQNctdps4IEBuJNu4VHQ0kSajA0cFV/S2aey25oYkkjcGCSLpvl691JHIO2cC2Iyh5 uhMA== X-Gm-Message-State: AOAM530KxfY3Qv4I7gcXWcQqdNyl2rXcii4WpxlWgut0Tdw8Y8mIlM6L acp3LN7yKg+5uQTsovN6itRy7nXxzT5VFhhY9EIIkA== X-Google-Smtp-Source: ABdhPJzmy6011bRCaz/kYoxOSxfcZV6R3wEOIH1+eORfD6559vOkDZuINzOB4rqg9WTL3BgoD4kKzA3W5h9iSh2kySo= X-Received: by 2002:a7b:cd93:: with SMTP id y19mr2785473wmj.112.1601470270876; Wed, 30 Sep 2020 05:51:10 -0700 (PDT) MIME-Version: 1.0 References: <20200929183513.380760-1-alex.popov@linux.com> <20200929183513.380760-3-alex.popov@linux.com> In-Reply-To: <20200929183513.380760-3-alex.popov@linux.com> From: Alexander Potapenko Date: Wed, 30 Sep 2020 14:50:59 +0200 Message-ID: Subject: Re: [PATCH RFC v2 2/6] mm/slab: Perform init_on_free earlier To: Alexander Popov Cc: Kees Cook , Jann Horn , Will Deacon , Andrey Ryabinin , Dmitry Vyukov , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Masahiro Yamada , Masami Hiramatsu , Steven Rostedt , Peter Zijlstra , Krzysztof Kozlowski , Patrick Bellasi , David Howells , Eric Biederman , Johannes Weiner , Laura Abbott , Arnd Bergmann , Greg Kroah-Hartman , Daniel Micay , Andrey Konovalov , Matthew Wilcox , Pavel Machek , Valentin Schneider , kasan-dev , Linux Memory Management List , Kernel Hardening , LKML , notify@kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Sep 29, 2020 at 8:35 PM Alexander Popov wrot= e: > > Currently in CONFIG_SLAB init_on_free happens too late, and heap > objects go to the heap quarantine being dirty. Lets move memory > clearing before calling kasan_slab_free() to fix that. > > Signed-off-by: Alexander Popov Reviewed-by: Alexander Potapenko > --- > mm/slab.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/mm/slab.c b/mm/slab.c > index 3160dff6fd76..5140203c5b76 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -3414,6 +3414,9 @@ static void cache_flusharray(struct kmem_cache *cac= hep, struct array_cache *ac) > static __always_inline void __cache_free(struct kmem_cache *cachep, void= *objp, > unsigned long caller) > { > + if (unlikely(slab_want_init_on_free(cachep))) > + memset(objp, 0, cachep->object_size); > + > /* Put the object into the quarantine, don't touch it for now. */ > if (kasan_slab_free(cachep, objp, _RET_IP_)) > return; > @@ -3432,8 +3435,6 @@ void ___cache_free(struct kmem_cache *cachep, void = *objp, > struct array_cache *ac =3D cpu_cache_get(cachep); > > check_irq_off(); > - if (unlikely(slab_want_init_on_free(cachep))) > - memset(objp, 0, cachep->object_size); > kmemleak_free_recursive(objp, cachep->flags); > objp =3D cache_free_debugcheck(cachep, objp, caller); > memcg_slab_free_hook(cachep, virt_to_head_page(objp), objp); > -- > 2.26.2 > --=20 Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Stra=C3=9Fe, 33 80636 M=C3=BCnchen Gesch=C3=A4ftsf=C3=BChrer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg