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,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 B657DC2BA83 for ; Thu, 13 Feb 2020 16:10:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8540C206ED for ; Thu, 13 Feb 2020 16:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581610240; bh=ZYhu1oglyVabZJCIqMih7PEUtRywOI7/sk/iy065ffc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=O1aa6v9ULpBFXX4oi7AJSIRxLKH69GU5yQ6N3BJU1wNQh/R/97logJdJc+GKTcz2j PJIbglMOPdlkTt7Q5Q6EfBqKwSjz8UiWSgho6OdDpDkLAw9qBdvgDlGIsU79HWl8oS 91IRiTJWCaA073uP1kzd53uy4pYRjX1A88nnKio4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730186AbgBMQKj (ORCPT ); Thu, 13 Feb 2020 11:10:39 -0500 Received: from mail.kernel.org ([198.145.29.99]:60274 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727987AbgBMPWf (ORCPT ); Thu, 13 Feb 2020 10:22:35 -0500 Received: from localhost (unknown [104.132.1.104]) (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 302B624699; Thu, 13 Feb 2020 15:22:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581607355; bh=ZYhu1oglyVabZJCIqMih7PEUtRywOI7/sk/iy065ffc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y9+rzGx7WCymVyH3c5Z36Dtv5TFi4EaRGCV1w2FKI7CyhV0KayeRvuOn36V0jkJWL YMMG6JYyZT7AvpBZPimnttEXSuRXb3LX4D5Ex4NidXUFI2UJdC8lfbzlN6KmwkxJNw 95gCkzcbx9X9nhdcKIAe9u1QUz31d7uoW1e3YgSo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Herbert Xu Subject: [PATCH 4.4 21/91] crypto: api - Check spawn->alg under lock in crypto_drop_spawn Date: Thu, 13 Feb 2020 07:19:38 -0800 Message-Id: <20200213151829.841711176@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200213151821.384445454@linuxfoundation.org> References: <20200213151821.384445454@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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...") Cc: Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/algapi.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) --- a/crypto/algapi.c +++ b/crypto/algapi.c @@ -653,11 +653,9 @@ 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);