From patchwork Fri Jun 19 14:32:59 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: 223815 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=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 40DA7C433E1 for ; Fri, 19 Jun 2020 16:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1627D2168B for ; Fri, 19 Jun 2020 16:20:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592583629; bh=AWo+FzPtuscLoyhgxZsRwU07bUkaec074OF380jB8Z0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=uXUq3w9hKIIQjwPGHL5y/8ILFMxT/gNb1TCvyMnuayTFRTFkeKIy6NBxIIbI56MP0 yN98Ze416p3YK8Cws2HxBo9HwFXdeu+njruNeUv9/w+BnGdhrXsd3B+ZQtRfdKDSrP 0bbkX9xFbhtCGr5p//4beq8UltuTRM+HFwUoj+X4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2394509AbgFSQU1 (ORCPT ); Fri, 19 Jun 2020 12:20:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:57800 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390410AbgFSPBY (ORCPT ); Fri, 19 Jun 2020 11:01:24 -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 12A3720776; Fri, 19 Jun 2020 15:01:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592578884; bh=AWo+FzPtuscLoyhgxZsRwU07bUkaec074OF380jB8Z0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WrS+LSY+I5YdsRWXaiZOK+NfktKr2omYsFrmHPiC6tywGfIUrzbCrENqQN2VdI4qV VZfhwAMmK14zkdNlW4hjObErXi2AcOSVpVtH1XTi58yP6sx0zT4HV/uH1c8JmULIRB FkZeeX5oLg3usO/rav0clcizFRrR6Sc8B3QQc2Mw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Takashi Iwai , Roberto Sassu , Mimi Zohar Subject: [PATCH 4.19 194/267] ima: Directly assign the ima_default_policy pointer to ima_rules Date: Fri, 19 Jun 2020 16:32:59 +0200 Message-Id: <20200619141658.058225592@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141648.840376470@linuxfoundation.org> References: <20200619141648.840376470@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 commit 067a436b1b0aafa593344fddd711a755a58afb3b upstream. This patch prevents the following oops: [ 10.771813] BUG: kernel NULL pointer dereference, address: 0000000000000 [...] [ 10.779790] RIP: 0010:ima_match_policy+0xf7/0xb80 [...] [ 10.798576] Call Trace: [ 10.798993] ? ima_lsm_policy_change+0x2b0/0x2b0 [ 10.799753] ? inode_init_owner+0x1a0/0x1a0 [ 10.800484] ? _raw_spin_lock+0x7a/0xd0 [ 10.801592] ima_must_appraise.part.0+0xb6/0xf0 [ 10.802313] ? ima_fix_xattr.isra.0+0xd0/0xd0 [ 10.803167] ima_must_appraise+0x4f/0x70 [ 10.804004] ima_post_path_mknod+0x2e/0x80 [ 10.804800] do_mknodat+0x396/0x3c0 It occurs when there is a failure during IMA initialization, and ima_init_policy() is not called. IMA hooks still call ima_match_policy() but ima_rules is NULL. This patch prevents the crash by directly assigning the ima_default_policy pointer to ima_rules when ima_rules is defined. This wouldn't alter the existing behavior, as ima_rules is always set at the end of ima_init_policy(). Cc: stable@vger.kernel.org # 3.7.x Fixes: 07f6a79415d7d ("ima: add appraise action keywords and default rules") Reported-by: Takashi Iwai Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar Signed-off-by: Greg Kroah-Hartman --- security/integrity/ima/ima_policy.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/security/integrity/ima/ima_policy.c +++ b/security/integrity/ima/ima_policy.c @@ -196,7 +196,7 @@ static struct ima_rule_entry secure_boot static LIST_HEAD(ima_default_rules); static LIST_HEAD(ima_policy_rules); static LIST_HEAD(ima_temp_rules); -static struct list_head *ima_rules; +static struct list_head *ima_rules = &ima_default_rules; static int ima_policy __initdata; @@ -544,7 +544,6 @@ void __init ima_init_policy(void) temp_ima_appraise |= IMA_APPRAISE_POLICY; } - ima_rules = &ima_default_rules; ima_update_policy_flag(); }