From patchwork Tue May 26 18:52:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 225421 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 4B70DC433DF for ; Tue, 26 May 2020 18:56:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22FD52084C for ; Tue, 26 May 2020 18:56:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590519386; bh=V/sfiQpCncPkYxfnFXx1t4SCQlwZ//Kxz1si0PlRpq0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=WsSvSLL59+w9UboVQe5xPrdV6aBx29TPUeHSnRGicAlU7HPN3pMDnhjNWmKtwxAj9 mEJF8r3qdo7Qhg9KkXTr2fGhbZszR08I+YzrIWICfGY4ZBh02lRjtYmm7suiaSreo4 m44f5HuD8j988LFbC422PQ+pK6/ccvvor9WZZnhI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389816AbgEZS4Y (ORCPT ); Tue, 26 May 2020 14:56:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:49200 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389806AbgEZS4X (ORCPT ); Tue, 26 May 2020 14:56:23 -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 3F57D208B8; Tue, 26 May 2020 18:56:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1590519382; bh=V/sfiQpCncPkYxfnFXx1t4SCQlwZ//Kxz1si0PlRpq0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0kMsWE0XN0+jJ5OLsEY91PH0a4rrlML3qmGSEFZdPfPsg8N3afr5EErJ7hoOdFcz7 4ohowL2jE3guYVcf/SA/b0DEHd6SBFj8iUcToamU5jRcQE4J4tJSePNZ/nP+9T9MvF l8CT7Z2CqdX40Nmfm7ljjQGmNR4GYd0Aa44TF470= 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 4.4 06/65] evm: Check also if *tfm is an error pointer in init_desc() Date: Tue, 26 May 2020 20:52:25 +0200 Message-Id: <20200526183908.421289701@linuxfoundation.org> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200526183905.988782958@linuxfoundation.org> References: <20200526183905.988782958@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 461f8d891579..44352b0b7510 100644 --- a/security/integrity/evm/evm_crypto.c +++ b/security/integrity/evm/evm_crypto.c @@ -47,7 +47,7 @@ static struct shash_desc *init_desc(char type) algo = evm_hash; } - if (*tfm == NULL) { + if (IS_ERR_OR_NULL(*tfm)) { mutex_lock(&mutex); if (*tfm) goto out;