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 08CB2C43603 for ; Wed, 11 Dec 2019 03:36:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BDB1A2073B for ; Wed, 11 Dec 2019 03:36:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576035380; bh=SkVfA6xgJAbS059jIkmd/O2ESqZPtM5+P7Tsfh7xNHI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=DBLJJYSfamA1rAxH8pX/YQuOzfYu5iSS7FKhAomzIDbLWPQzAGEVjn442g7M5XYiw 7NATi1kTO2rhGeWvvetl8xJ5+gSw7StupzxwJzJG3QDM0wMxZgqYGF4vrR8u+YP5Ju /k/L2FuZPCOg5dA6tP//KeljMB73Oi30coT4z72c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726687AbfLKDgU (ORCPT ); Tue, 10 Dec 2019 22:36:20 -0500 Received: from mail.kernel.org ([198.145.29.99]:34750 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726642AbfLKDgU (ORCPT ); Tue, 10 Dec 2019 22:36:20 -0500 Received: from sol.localdomain (c-24-5-143-220.hsd1.ca.comcast.net [24.5.143.220]) (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 ABDC720718; Wed, 11 Dec 2019 03:36:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576035379; bh=SkVfA6xgJAbS059jIkmd/O2ESqZPtM5+P7Tsfh7xNHI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HXgH5NOpv7dtdabPUStdREksXfiM6EBnlOAFlTfX55k1+aQTa5qGni/Mu+vXGymtL TJqZUMsexRZmWBywPGL/+tNEvXVN+ZFmsovJGiA81602MEHyG+siTFiiFDaOuKNJq6 hMqDxoGMJ54idwxLQRqbSGosB1vTAszc7hw2r+hw= Date: Tue, 10 Dec 2019 19:36:18 -0800 From: Eric Biggers To: Herbert Xu Cc: Linux Crypto Mailing List Subject: Re: [PATCH] crypto: api - Check spawn->alg under lock in crypto_drop_spawn Message-ID: <20191211033618.GG732@sol.localdomain> References: <20191206055517.53o7xtpxdo2bx6qe@gondor.apana.org.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191206055517.53o7xtpxdo2bx6qe@gondor.apana.org.au> Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org On Fri, Dec 06, 2019 at 01:55:17PM +0800, Herbert Xu wrote: > We need to check whether spawn->alg is NULL under lock as otherwise > the algorithm could be removed from under us after we have checked > it and found it to be non-NULL. This could cause us to remove the > spawn from a non-existent list. > > Fixes: 6bfd48096ff8 ("[CRYPTO] api: Added spawns") > Cc: > Signed-off-by: Herbert Xu > > diff --git a/crypto/algapi.c b/crypto/algapi.c > index 783006f4d339..6869feb31c99 100644 > --- a/crypto/algapi.c > +++ b/crypto/algapi.c > @@ -668,11 +668,9 @@ EXPORT_SYMBOL_GPL(crypto_grab_spawn); > > void crypto_drop_spawn(struct crypto_spawn *spawn) > { > - if (!spawn->alg) > - return; > - > down_write(&crypto_alg_sem); > - list_del(&spawn->list); > + if (spawn->alg) > + list_del(&spawn->list); > up_write(&crypto_alg_sem); > } > EXPORT_SYMBOL_GPL(crypto_drop_spawn); Seems the Fixes tag is wrong. It should be: Fixes: 7ede5a5ba55a ("crypto: api - Fix crypto_drop_spawn crash on blank spawns") - Eric