From patchwork Tue May 26 18:52:22 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 225369 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 E26EDC433DF for ; Tue, 26 May 2020 19:07:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0E04208B8 for ; Tue, 26 May 2020 19:07:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590520028; bh=iBUom3UexuJtoL9Ox33IMnAZayXMsAmGh1AfuUlcV8s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=p3DSD8iubwZENdeYgt5Z3MFn9XkLvRkOki476akO+YMwtdayeeH/NAQxEFv1I36Pi N9Z6ceNBsqyC6N1FjhEC3fJERqgwVTOJoWtBnAAXFES5+5VXkbCGnhKfHJXFEmTdzL 595lqIyHnc2+E1qGYON/DK3lTZwneU24cV9P1Wzo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391694AbgEZTHI (ORCPT ); Tue, 26 May 2020 15:07:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:35664 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391236AbgEZTHG (ORCPT ); Tue, 26 May 2020 15:07:06 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 E6679208A7; Tue, 26 May 2020 19:07:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590520026; bh=iBUom3UexuJtoL9Ox33IMnAZayXMsAmGh1AfuUlcV8s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=jMTdhEFiiHtwiqLSnfq/8mHUOgHZH6ei8flpRRemL52mLvJ+/PMXDf5gyvSUl68jA b3hvnmRtKylEN4jcpRf8EpWPzX027gFXVPFJok3hGDT7fsx43d4vQORgIAzoPvv8Jl Ln5uTwzeFWN9x4/vyZGiUYOMxhZp2/FV0M+MOJoE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Krzysztof Struczynski , Roberto Sassu , Mimi Zohar , Sasha Levin Subject: [PATCH 5.4 004/111] evm: Check also if *tfm is an error pointer in init_desc() Date: Tue, 26 May 2020 20:52:22 +0200 Message-Id: <20200526183932.856574380@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200526183932.245016380@linuxfoundation.org> References: <20200526183932.245016380@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Roberto Sassu [ Upstream commit 53de3b080d5eae31d0de219617155dcc34e7d698 ] This patch avoids a kernel panic due to accessing an error pointer set by crypto_alloc_shash(). It occurs especially when there are many files that require an unsupported algorithm, as it would increase the likelihood of the following race condition: Task A: *tfm = crypto_alloc_shash() <= error pointer Task B: if (*tfm == NULL) <= *tfm is not NULL, use it Task B: rc = crypto_shash_init(desc) <= panic Task A: *tfm = NULL This patch uses the IS_ERR_OR_NULL macro to determine whether or not a new crypto context must be created. Cc: stable@vger.kernel.org Fixes: d46eb3699502b ("evm: crypto hash replaced by shash") Co-developed-by: Krzysztof Struczynski Signed-off-by: Krzysztof Struczynski Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Sasha Levin --- security/integrity/evm/evm_crypto.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/security/integrity/evm/evm_crypto.c b/security/integrity/evm/evm_crypto.c index d485f6fc908e..302adeb2d37b 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -93,7 +93,7 @@ static struct shash_desc *init_desc(char type, uint8_t hash_algo) algo = hash_algo_name[hash_algo]; } - if (*tfm == NULL) { + if (IS_ERR_OR_NULL(*tfm)) { mutex_lock(&mutex); if (*tfm) goto out;