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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 78368C6778A for ; Thu, 5 Jul 2018 15:22:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2D3932402D for ; Thu, 5 Jul 2018 15:22:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2D3932402D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753778AbeGEPWm (ORCPT ); Thu, 5 Jul 2018 11:22:42 -0400 Received: from mga09.intel.com ([134.134.136.24]:11858 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753259AbeGEPVt (ORCPT ); Thu, 5 Jul 2018 11:21:49 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Jul 2018 08:21:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,312,1526367600"; d="scan'208";a="54666794" Received: from dmorlich-mobl.amr.corp.intel.com (HELO localhost) ([10.252.36.24]) by orsmga008.jf.intel.com with ESMTP; 05 Jul 2018 08:21:44 -0700 Date: Thu, 5 Jul 2018 18:21:43 +0300 From: Jarkko Sakkinen To: "S, Shirish" Cc: Shirish S , linux-integrity@vger.kernel.org, Peter Huewe , Jason Gunthorpe , Arnd Bergmann , Greg Kroah-Hartman , open list Subject: Re: [PATCH] tpm: Fix NULL pointer dereference in tpm_transmit() Message-ID: <20180705152143.GA10001@linux.intel.com> References: <1530695020-21888-1-git-send-email-shirish.s@amd.com> <20180704171357.GB6724@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 05, 2018 at 09:29:34AM +0530, S, Shirish wrote: > > > On 7/4/2018 10:43 PM, Jarkko Sakkinen wrote: > > On Wed, Jul 04, 2018 at 02:33:40PM +0530, Shirish S wrote: > > > During system shutdown, > > > tpm_class_shutdown() when called with TPM_CHIP_FLAG_TPM2 > > > flag set, makes chip->ops NULL. > > > > > > However tpm_chip_unregister() called later in shutdown > > > sequence tries to access chip->ops in tpm_try_transmit() > > > leading the NULL pointer dereference. > > > > > > This patch fixes this issue. > > > Below is the trace for reference: > > > > > > BUG: unable to handle kernel NULL pointer dereference at > > > 0000000000000048 > > > IP: tpm_transmit+0x267/0x565 > > > PGD 0 P4D 0 > > > Oops: 0000 [#1] PREEMPT SMP NOPTI > > > ... > > > task: ffff937c847fe580 task.stack: ffffa79f80b04000 > > > RIP: 0010:tpm_transmit+0x267/0x565 > > > RSP: 0018:ffffa79f80b07c08 EFLAGS: 00010286 > > > RAX: 0000000000000000 RBX: ffff937ca9bc8000 RCX: ffff937c847fe580 > > > RDX: 0000000000000000 RSI: 0000000000000002 RDI: ffffffff98e3cd40 > > > RBP: ffffa79f80b07c88 R08: 000000000001fff4 R09: 0000000000000000 > > > R10: 0000000000000000 R11: 0000000000000000 R12: ffffa79f80b07cd4 > > > R13: 000000000000008c R14: ffffffffffffffc3 R15: 0000000000000000 > > > FS: 00007ef31f747740(0000) GS:ffff937caed00000(0000) > > > knlGS:0000000000000000 > > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > > CR2: 0000000000000048 CR3: 00000001243d2000 CR4: 00000000001406e0 > > > Call Trace: > > > tpm_transmit_cmd+0x25/0x70 > > > tpm2_shutdown+0x69/0xa3 > > > ? __radix_tree_replace+0xd9/0x120 > > > ? idr_replace_ext+0x92/0xb6 > > > tpm_chip_unregister+0xaa/0xdb > > > cr50_i2c_shutdown+0x1e/0x41 > > > device_shutdown+0x157/0x193 > > > kernel_power_off+0x35/0x6e > > > SYSC_reboot+0x120/0x1a3 > > > ? do_writepages+0x36/0x6e > > > ? do_writepages+0x36/0x6e > > > ? sync_inodes_one_sb+0x17/0x17 > > > ? _raw_spin_unlock+0xe/0x20 > > > ? iput+0x87/0x1bd > > > do_syscall_64+0x64/0x72 > > > entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > > > > > > Signed-off-by: Shirish S > > > --- > > > drivers/char/tpm/tpm-interface.c | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c > > > index e32f6e8..b14d196 100644 > > > --- a/drivers/char/tpm/tpm-interface.c > > > +++ b/drivers/char/tpm/tpm-interface.c > > > @@ -411,6 +411,14 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip, > > > unsigned long stop; > > > bool need_locality; > > > + /* chip->ops is made NULL in tpm_class_shutdown() > > > + * This case is hit when tpm_chip_unregister() is called post > > > + * tpm_class_shutdown(), hence exit early and return > > > + * transmit operation not permitted > > > + */ > > > + if (!chip->ops) > > > + return -EPERM; > > > + > > > rc = tpm_validate_command(chip, space, buf, bufsiz); > > > if (rc == -EINVAL) > > > return rc; > > > -- > > > 2.7.4 > > > > > What is cr50 anyway? > Please ignore this patch, i realised the cr50 is not yet upstreamed. > Hence the issue lies in in cr50 and not tpm driver. > Thanks. > Regards, > Shirish S tpm_chip_unregister() in supposed to be called only in removal/detach sequence so the root cause for the NULL pointer deref is the driver, not the existing TPM stack. /Jarkko