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=-10.1 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,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 1CC69C433DF for ; Tue, 9 Jun 2020 00:37:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EB441206C3 for ; Tue, 9 Jun 2020 00:37:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591663024; bh=iBUom3UexuJtoL9Ox33IMnAZayXMsAmGh1AfuUlcV8s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=KtboRj1QBdAgw2QavzxZYZcKhWPJRo51RRCTvRNk9yyXZAszwsWIZHkhIODpUuKx9 Jr1BewHuR1fS6QtfWromyMetZUzAJW2xqgvSVSavZ8euLiNb0YT0dqgnIJsyCmSbNT DTakBvdSv5hsTXb0gXk01GPVr0euAyAieBfO7+nU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729634AbgFIAhC (ORCPT ); Mon, 8 Jun 2020 20:37:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:33812 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729633AbgFHXNw (ORCPT ); Mon, 8 Jun 2020 19:13:52 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 934D6212CC; Mon, 8 Jun 2020 23:13:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1591658032; bh=iBUom3UexuJtoL9Ox33IMnAZayXMsAmGh1AfuUlcV8s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=d0eL5QqP8ei447D5afqv2l8GxkeH0hRjTbXsuTBo8hNRWhZOQ/0TMNh+8UEqOXG/j HAbV9zm/3zV08DTc+C0eAKCu3kPi8SDoGSySu2aa5lZSXjIp2aTTfiI34Kv0jUZrLb GHZNcoh36qrUTd6wS0qdbPS9Fd9fXyXxUv3OO6sg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Roberto Sassu , Krzysztof Struczynski , Mimi Zohar , Sasha Levin , linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH AUTOSEL 5.6 083/606] evm: Check also if *tfm is an error pointer in init_desc() Date: Mon, 8 Jun 2020 19:03:28 -0400 Message-Id: <20200608231211.3363633-83-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200608231211.3363633-1-sashal@kernel.org> References: <20200608231211.3363633-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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; -- 2.25.1