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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 C4506C433DF for ; Tue, 16 Jun 2020 01:58:11 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 837FB20739 for ; Tue, 16 Jun 2020 01:58:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cmfbCyUD" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 837FB20739 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 31D536B0007; Mon, 15 Jun 2020 21:58:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 2F4656B0008; Mon, 15 Jun 2020 21:58:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1E26B6B000A; Mon, 15 Jun 2020 21:58:11 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0130.hostedemail.com [216.40.44.130]) by kanga.kvack.org (Postfix) with ESMTP id 07FDB6B0007 for ; Mon, 15 Jun 2020 21:58:11 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B494E181AC9CB for ; Tue, 16 Jun 2020 01:58:10 +0000 (UTC) X-FDA: 76933414740.03.tramp14_370398226dfb Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin03.hostedemail.com (Postfix) with ESMTP id 8B18E28A4E8 for ; Tue, 16 Jun 2020 01:58:10 +0000 (UTC) X-HE-Tag: tramp14_370398226dfb X-Filterd-Recvd-Size: 4407 Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [207.211.31.120]) by imf10.hostedemail.com (Postfix) with ESMTP for ; Tue, 16 Jun 2020 01:58:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592272689; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:references:references; bh=w0ZJeQQk3EMaWCq5vRe2fLP4T7LhSgQGKZa9FTUZAA4=; b=cmfbCyUDRGwKjLGBejxtzwXYJZpxYp4m4gTqt1HJSocbaTeByL2ZSn3rJ/ux/7hS8NPcJY pDmzv+GqMhAOF/UyMu9ENB1TqV6U+tP0Mht2YLdiU0vgD5MEO3kgZFDGI5G30nsnTYzl6e 3vAL0jFWUiwI5s0OQXwAYyvRhcKeSIM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-271-siDUOdYEMkuGDz0Coifxdg-1; Mon, 15 Jun 2020 21:58:05 -0400 X-MC-Unique: siDUOdYEMkuGDz0Coifxdg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6856710059B7; Tue, 16 Jun 2020 01:58:00 +0000 (UTC) Received: from llong.com (ovpn-117-41.rdu2.redhat.com [10.10.117.41]) by smtp.corp.redhat.com (Postfix) with ESMTP id 45E126ED96; Tue, 16 Jun 2020 01:57:52 +0000 (UTC) From: Waiman Long To: Andrew Morton , David Howells , Jarkko Sakkinen , James Morris , "Serge E. Hallyn" , Linus Torvalds , Joe Perches , Matthew Wilcox , David Rientjes Cc: Michal Hocko , Johannes Weiner , Dan Carpenter , David Sterba , "Jason A . Donenfeld" , linux-mm@kvack.org, keyrings@vger.kernel.org, linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org, linux-pm@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-amlogic@lists.infradead.org, linux-mediatek@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-ppp@vger.kernel.org, wireguard@lists.zx2c4.com, linux-wireless@vger.kernel.org, devel@driverdev.osuosl.org, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-fscrypt@vger.kernel.org, ecryptfs@vger.kernel.org, kasan-dev@googlegroups.com, linux-bluetooth@vger.kernel.org, linux-wpan@vger.kernel.org, linux-sctp@vger.kernel.org, linux-nfs@vger.kernel.org, tipc-discussion@lists.sourceforge.net, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org, Waiman Long , stable@vger.kernel.org Subject: [PATCH v4 1/3] mm/slab: Use memzero_explicit() in kzfree() Date: Mon, 15 Jun 2020 21:57:16 -0400 Message-Id: <20200616015718.7812-2-longman@redhat.com> In-Reply-To: <20200616015718.7812-1-longman@redhat.com> References: <20200616015718.7812-1-longman@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Rspamd-Queue-Id: 8B18E28A4E8 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The kzfree() function is normally used to clear some sensitive information, like encryption keys, in the buffer before freeing it back to the pool. Memset() is currently used for the buffer clearing. However, it is entirely possible that the compiler may choose to optimize away the memory clearing especially if LTO is being used. To make sure that this optimization will not happen, memzero_explicit(), which is introduced in v3.18, is now used in kzfree() to do the clearing. Fixes: 3ef0e5ba4673 ("slab: introduce kzfree()") Cc: stable@vger.kernel.org Signed-off-by: Waiman Long --- mm/slab_common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/slab_common.c b/mm/slab_common.c index 9e72ba224175..37d48a56431d 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -1726,7 +1726,7 @@ void kzfree(const void *p) if (unlikely(ZERO_OR_NULL_PTR(mem))) return; ks = ksize(mem); - memset(mem, 0, ks); + memzero_explicit(mem, ks); kfree(mem); } EXPORT_SYMBOL(kzfree); -- 2.18.1