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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 6C435C433E0 for ; Wed, 20 May 2020 14:22:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C274207D3 for ; Wed, 20 May 2020 14:22:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727799AbgETOWf (ORCPT ); Wed, 20 May 2020 10:22:35 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:60966 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726829AbgETOWW (ORCPT ); Wed, 20 May 2020 10:22:22 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jbPbu-00035N-UU; Wed, 20 May 2020 15:22:18 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jbPbu-007DPC-9Y; Wed, 20 May 2020 15:22:18 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Herbert Xu" Date: Wed, 20 May 2020 15:13:45 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 17/99] crypto: api - Check spawn->alg under lock in crypto_drop_spawn In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.84-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Herbert Xu commit 7db3b61b6bba4310f454588c2ca6faf2958ad79f upstream. 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: 7ede5a5ba55a ("crypto: api - Fix crypto_drop_spawn crash...") Signed-off-by: Herbert Xu Signed-off-by: Ben Hutchings --- crypto/algapi.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -618,11 +618,9 @@ EXPORT_SYMBOL_GPL(crypto_init_spawn2); 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);