From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 21 Oct 2019 13:28:36 -0700 From: Eric Biggers Subject: Re: [PATCH] fscrypt: zeroize fscrypt_info before freeing Message-ID: <20191021202836.GC122863@gmail.com> References: <20191009234442.225847-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191009234442.225847-1-ebiggers@kernel.org> To: linux-fscrypt@vger.kernel.org Cc: "Theodore Y . Ts'o" , Jaegeuk Kim List-ID: On Wed, Oct 09, 2019 at 04:44:42PM -0700, Eric Biggers wrote: > From: Eric Biggers > > memset the struct fscrypt_info to zero before freeing. This isn't > really needed currently, since there's no secret key directly in the > fscrypt_info. But there's a decent chance that someone will add such a > field in the future, e.g. in order to use an API that takes a raw key > such as siphash(). So it's good to do this as a hardening measure. > > Signed-off-by: Eric Biggers > --- > fs/crypto/keysetup.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c > index df3e1c8653884..0ba33e010312f 100644 > --- a/fs/crypto/keysetup.c > +++ b/fs/crypto/keysetup.c > @@ -325,6 +325,7 @@ static void put_crypt_info(struct fscrypt_info *ci) > key_invalidate(key); > key_put(key); > } > + memzero_explicit(ci, sizeof(*ci)); > kmem_cache_free(fscrypt_info_cachep, ci); > } > > -- > 2.23.0.581.g78d2f28ef7-goog > Applied to fscrypt.git for 5.5. - Eric 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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 7944ECA9EAF for ; Mon, 21 Oct 2019 20:28:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41A562086D for ; Mon, 21 Oct 2019 20:28:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571689719; bh=liNerNN4X6Xfh6Ywy8zZWRiH6u0AxwRBvXXp8HOlPHc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=A3qQHg+d/TjfI/pjrQcaqmHPLLE2QFrprNzGaXJ11Xg1u5RZ1AuMzoe6CamIcL0+l DEIW7t8SO0X0QfsiFSwagfJya4RxUCXars/8ojxxk/+bqpj5S4XOJk8NhJ8oEGe4Ko zXt5iS0nn3UeiTE9rNhLINJJViGCr8Cs/ZasXjCY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730238AbfJUU2j (ORCPT ); Mon, 21 Oct 2019 16:28:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:40716 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726672AbfJUU2i (ORCPT ); Mon, 21 Oct 2019 16:28:38 -0400 Received: from gmail.com (unknown [104.132.1.77]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 419AA2067B; Mon, 21 Oct 2019 20:28:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1571689718; bh=liNerNN4X6Xfh6Ywy8zZWRiH6u0AxwRBvXXp8HOlPHc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2rOrzmDOpvfCAOm46BHlwACupM9ivFXgpF0n7xoYgXL7DeUb9IXWe26O5O9WnUSyF aH8hnZjqcZRbq3Lp+aKfQPz9TUoeOz6Lz2zsvQcCb3mtzsjNux059jkcJ132v9bkkA XHZu3tEZ3PucFVHAmQrODjhHt5GhQoqe1nbwH8g4= Date: Mon, 21 Oct 2019 13:28:36 -0700 From: Eric Biggers To: linux-fscrypt@vger.kernel.org Cc: "Theodore Y . Ts'o" , Jaegeuk Kim Subject: Re: [PATCH] fscrypt: zeroize fscrypt_info before freeing Message-ID: <20191021202836.GC122863@gmail.com> Mail-Followup-To: linux-fscrypt@vger.kernel.org, "Theodore Y . Ts'o" , Jaegeuk Kim References: <20191009234442.225847-1-ebiggers@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline In-Reply-To: <20191009234442.225847-1-ebiggers@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-fscrypt-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fscrypt@vger.kernel.org Message-ID: <20191021202836.yA_3g-DgB-pIPL-3DGdihkePiskQTUkJA-ysSNU1Pq8@z> On Wed, Oct 09, 2019 at 04:44:42PM -0700, Eric Biggers wrote: > From: Eric Biggers > > memset the struct fscrypt_info to zero before freeing. This isn't > really needed currently, since there's no secret key directly in the > fscrypt_info. But there's a decent chance that someone will add such a > field in the future, e.g. in order to use an API that takes a raw key > such as siphash(). So it's good to do this as a hardening measure. > > Signed-off-by: Eric Biggers > --- > fs/crypto/keysetup.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c > index df3e1c8653884..0ba33e010312f 100644 > --- a/fs/crypto/keysetup.c > +++ b/fs/crypto/keysetup.c > @@ -325,6 +325,7 @@ static void put_crypt_info(struct fscrypt_info *ci) > key_invalidate(key); > key_put(key); > } > + memzero_explicit(ci, sizeof(*ci)); > kmem_cache_free(fscrypt_info_cachep, ci); > } > > -- > 2.23.0.581.g78d2f28ef7-goog > Applied to fscrypt.git for 5.5. - Eric