From patchwork Sun Dec 12 01:28:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Berger X-Patchwork-Id: 12672113 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2178C433EF for ; Sun, 12 Dec 2021 01:28:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230024AbhLLB2Q (ORCPT ); Sat, 11 Dec 2021 20:28:16 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:28336 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230038AbhLLB2P (ORCPT ); Sat, 11 Dec 2021 20:28:15 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 1BC0vaQe022711; Sun, 12 Dec 2021 01:28:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=YZDQ1dVmJSObr2QC5ds1YJSFNcrnTSy0Dpv1KV7by7M=; b=NzNAwTGfeotavIYcra89xn1xTyNs23Pyt2HBdTIgWdV7B7ao1UvZmpl+UjdiVukBfdUH eiAVRmA1WB9o3od30Yjx0OwY+U2wkAcBS2c/dlSt8UfDFKGq18zSoFh6D84pzVPAV1yy gCz0c6izzq7oUAKF2foyH+WJg5g/Gb7csoyL1RxEXm51Da83nEGYT/2tLYm5Zc/tRTV6 BX6kQHWYeZMXbrnNjHbRFq33BWeeIumyx+qttn4OLLLF5OJdZiziXRvtEbQhHhFmg4cp pxaZVB8Cbe+A0qZvCLLTR+mhM7miVG2IVA6yxoW3Das3vx/+kSlYvjTFhnjj3GeDOfJ8 zA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 3cw70f89rr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 12 Dec 2021 01:28:10 +0000 Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 1BC1S96w018427; Sun, 12 Dec 2021 01:28:09 GMT Received: from ppma01wdc.us.ibm.com (fd.55.37a9.ip4.static.sl-reverse.com [169.55.85.253]) by mx0a-001b2d01.pphosted.com with ESMTP id 3cw70f89rf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 12 Dec 2021 01:28:09 +0000 Received: from pps.filterd (ppma01wdc.us.ibm.com [127.0.0.1]) by ppma01wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 1BC1J37h030766; Sun, 12 Dec 2021 01:28:08 GMT Received: from b01cxnp22034.gho.pok.ibm.com (b01cxnp22034.gho.pok.ibm.com [9.57.198.24]) by ppma01wdc.us.ibm.com with ESMTP id 3cvkm91xkt-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 12 Dec 2021 01:28:08 +0000 Received: from b01ledav002.gho.pok.ibm.com (b01ledav002.gho.pok.ibm.com [9.57.199.107]) by b01cxnp22034.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 1BC1S6qa11338076 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sun, 12 Dec 2021 01:28:06 GMT Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F0EF912405C; Sun, 12 Dec 2021 01:28:05 +0000 (GMT) Received: from b01ledav002.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D7600124054; Sun, 12 Dec 2021 01:28:05 +0000 (GMT) Received: from sbct-3.pok.ibm.com (unknown [9.47.158.153]) by b01ledav002.gho.pok.ibm.com (Postfix) with ESMTP; Sun, 12 Dec 2021 01:28:05 +0000 (GMT) From: Stefan Berger To: jarkko@kernel.org, peterhuewe@gmx.de, linux-integrity@vger.kernel.org Cc: jgg@ziepe.ca, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, pavrampu@in.ibm.com, Korrapati.Likhitha@ibm.com, gcwilson@us.ibm.com, Stefan Berger Subject: [PATCH] tpm: Fix kexec crash due to access to ops NULL pointer (powerpc) Date: Sat, 11 Dec 2021 20:28:04 -0500 Message-Id: <20211212012804.1555661-1-stefanb@linux.ibm.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: GxgV9UOK6OpX3GkMwldcJNfNFy16amgT X-Proofpoint-GUID: Wc47lRA6TO1_spWYa5gsKtc-wxTsIIDq X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2021-12-11_10,2021-12-10_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 phishscore=0 bulkscore=0 priorityscore=1501 mlxlogscore=782 clxscore=1011 suspectscore=0 mlxscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2112120004 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Fix the following crash on kexec by checking chip->ops for a NULL pointer in tpm_chip_start() and returning an error code if this is the case. BUG: Kernel NULL pointer dereference on read at 0x00000060 Faulting instruction address: 0xc00000000099a06c Oops: Kernel access of bad area, sig: 11 [#1] ... NIP [c00000000099a06c] tpm_chip_start+0x2c/0x140 LR [c00000000099a808] tpm_chip_unregister+0x108/0x170 Call Trace: [c0000000188bfa00] [c000000002b03930] fw_devlink_strict+0x0/0x8 (unreliable) [c0000000188bfa30] [c00000000099a808] tpm_chip_unregister+0x108/0x170 [c0000000188bfa70] [c0000000009a3874] tpm_ibmvtpm_remove+0x34/0x130 [c0000000188bfae0] [c000000000110dbc] vio_bus_remove+0x5c/0xb0 [c0000000188bfb20] [c0000000009bc154] device_shutdown+0x1d4/0x3a8 [c0000000188bfbc0] [c000000000196e14] kernel_restart_prepare+0x54/0x70 The referenced patch below introduced a function to shut down the VIO bus. The bus shutdown now calls tpm_del_char_device (via tpm_chip_unregister) after a call to tpm_class_shutdown, which already set chip->ops to NULL. The crash occurrs when tpm_del_char_device calls tpm_chip_start with the chip->ops NULL pointer. Fixes: 39d0099f9439 ("powerpc/pseries: Add shutdown() to vio_driver and vio_bus") Signed-off-by: Stefan Berger Tested-by: Sachin Sant --- drivers/char/tpm/tpm-chip.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index ddaeceb7e109..cca1bde296ee 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -101,6 +101,9 @@ int tpm_chip_start(struct tpm_chip *chip) { int ret; + if (!chip->ops) + return -EINVAL; + tpm_clk_enable(chip); if (chip->locality == -1) {