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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 79BEAC433E0 for ; Fri, 5 Jun 2020 06:16:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 495AC2081A for ; Fri, 5 Jun 2020 06:16:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591337809; bh=lQj9XObAGDgR1ex1yeP32vok/302Xza6LfEFxKwA3LI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=HCeJ3pbR/bmx89kcWmoLZKdG1RgA7H/sMVkdtf7Y3J9JQ4UNqP1YW3mR6Gl5E3ASe +U4FdsTiDje+PgcY7a5O+BDG+3yqFKPVUnt8uhwj9bcHqP3xVsBTxd9cuxIIWyjlXN kjB4Yc1vH/ydrBeSdcM8LI2AzI0QVDEiIUsZN5DI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726084AbgFEGQs (ORCPT ); Fri, 5 Jun 2020 02:16:48 -0400 Received: from mail.kernel.org ([198.145.29.99]:35846 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725280AbgFEGQs (ORCPT ); Fri, 5 Jun 2020 02:16:48 -0400 Received: from sol.localdomain (c-107-3-166-239.hsd1.ca.comcast.net [107.3.166.239]) (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 AB4B7207ED; Fri, 5 Jun 2020 06:16:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591337807; bh=lQj9XObAGDgR1ex1yeP32vok/302Xza6LfEFxKwA3LI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Fq3qaSGbW3ebeiK+npkJTIjeQNSxvCOwtVxIlsaX+unoX65dJdXUIjnF6u+O1MvgP fHw+vOI/XQcSNNWQ8fCQUpBBsFaZrEIJk8AmAz4KPe7O6h2EGCblkQS5/TEwcwHosF g11J8O2dEvi0AwLETbplGhiM+fWNbPgCvsySMjvM= Date: Thu, 4 Jun 2020 23:16:46 -0700 From: Eric Biggers To: Stephan Mueller Cc: Dan Carpenter , davem@davemloft.net, herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, syzbot Subject: Re: [PATCH v2] crypto: DRBG - always try to free Jitter RNG instance Message-ID: <20200605061646.GA107328@sol.localdomain> References: <0000000000002a280b05a725cd93@google.com> <2551009.mvXUDI8C0e@positron.chronox.de> <20200605004336.GC148196@sol.localdomain> <5789529.snvNDI1NMy@tauon.chronox.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5789529.snvNDI1NMy@tauon.chronox.de> Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Fri, Jun 05, 2020 at 07:58:15AM +0200, Stephan Mueller wrote: > Am Freitag, 5. Juni 2020, 02:43:36 CEST schrieb Eric Biggers: > > Hi Eric, > > > On Thu, Jun 04, 2020 at 08:41:00AM +0200, Stephan Müller wrote: > > > The Jitter RNG is unconditionally allocated as a seed source follwoing > > > the patch 97f2650e5040. Thus, the instance must always be deallocated. > > > > > > Reported-by: syzbot+2e635807decef724a1fa@syzkaller.appspotmail.com > > > Fixes: 97f2650e5040 ("crypto: drbg - always seeded with SP800-90B ...") > > > Signed-off-by: Stephan Mueller > > > --- > > > > > > crypto/drbg.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/crypto/drbg.c b/crypto/drbg.c > > > index 37526eb8c5d5..8a0f16950144 100644 > > > --- a/crypto/drbg.c > > > +++ b/crypto/drbg.c > > > @@ -1631,6 +1631,9 @@ static int drbg_uninstantiate(struct drbg_state > > > *drbg)> > > > if (drbg->random_ready.func) { > > > > > > del_random_ready_callback(&drbg->random_ready); > > > cancel_work_sync(&drbg->seed_work); > > > > > > + } > > > + > > > + if (!IS_ERR_OR_NULL(drbg->jent)) { > > > > > > crypto_free_rng(drbg->jent); > > > drbg->jent = NULL; > > > > > > } > > > > It it okay that ->jent can be left as an ERR_PTR() value? > > > > Perhaps it should always be set to NULL? > > The error value is used in the drbg_instantiate function. There it is checked > whether -ENOENT (i.e. the cipher is not available) or any other error is > present. I am not sure we should move that check. > > Thanks for the review. > > drbg_seed() and drbg_async_seed() check for drbg->jent being NULL. Will that now break due it drbg->jent possibly being an ERR_PTR()? Hence why I'm asking whether drbg_uninstantiate() should set it to NULL. - Eric