From patchwork Fri Jun 19 14:33:14 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 224016 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 5E40FC433E1 for ; Fri, 19 Jun 2020 15:37:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3C85020786 for ; Fri, 19 Jun 2020 15:37:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592581049; bh=YU3kO4xL3qaPihHEix2qNmzom9gZ1iPwN0l/h3Y3dOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=02tYW2EijLGF2Ik8/t2FdU/6CZ7eFvWOUHBb3FZq4I1ZPqV+U0CEfiQQER5YqTGN1 C94teZtjhHIRegaUDirjvgl39ZQ9xFeV1dNiWHZJYy5zCcIFHfXAZQK9vlmZKR5jlm xDuiBwRXvqsRWApgd2+5n/l3BuQR6OBF8pD4WCxI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404375AbgFSPhV (ORCPT ); Fri, 19 Jun 2020 11:37:21 -0400 Received: from mail.kernel.org ([198.145.29.99]:34032 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2393565AbgFSPaO (ORCPT ); Fri, 19 Jun 2020 11:30:14 -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 895FC21974; Fri, 19 Jun 2020 15:30:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592580614; bh=YU3kO4xL3qaPihHEix2qNmzom9gZ1iPwN0l/h3Y3dOY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kc9y7ABLqLWZ8EcfQ1o6qDNldvjhHg0beTtnmTNthJUCoAE+FcQ41PiBMreWCDNw+ RDl6ek/6+WymIYIHIKWaP++CGRGQAxRs5je86zjcj6hINdQfa8fNpHO3tcOlat1Qwo IJWZ4kTPyZrwptg7+O3bBHCDsebFgQoD9JTyjPF0= 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 5.7 276/376] ima: Directly assign the ima_default_policy pointer to ima_rules Date: Fri, 19 Jun 2020 16:33:14 +0200 Message-Id: <20200619141723.400024064@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141710.350494719@linuxfoundation.org> References: <20200619141710.350494719@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 @@ -204,7 +204,7 @@ static struct ima_rule_entry *arch_polic 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; /* Pre-allocated buffer used for matching keyrings. */ static char *ima_keyrings; @@ -765,7 +765,6 @@ void __init ima_init_policy(void) ARRAY_SIZE(default_appraise_rules), IMA_DEFAULT_POLICY); - ima_rules = &ima_default_rules; ima_update_policy_flag(); }