From nobody Fri Apr 26 13:45:12 2024 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 7C703C433F5 for ; Tue, 24 May 2022 05:51:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234594AbiEXFvS (ORCPT ); Tue, 24 May 2022 01:51:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41776 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233200AbiEXFvO (ORCPT ); Tue, 24 May 2022 01:51:14 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB01C26CF; Mon, 23 May 2022 22:51:12 -0700 (PDT) Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 24O4BxAq030449; Tue, 24 May 2022 05:50:56 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=Q/r7+WPBf0nCRCN57fl/w6PxCRan20knpAY9VVDjYCk=; b=oWzh6xeVHnesy/BHmCwzroYoj7ikvq3EgGnDr3kAHoHZkBJoQ96paGs6c0PjHXERpvUq mMnKuadUCx8ArJT2/73RcF7M+yhZzR8+bwLmfGU7r5E2bYAUQ3Lw4OSQuuHx27XialL8 VHyaf9P3MbmIdGwDIGSZLH0n6FVTXCgqBpUlrkEFuaK9/IOgUS+Mfgg1cW+uUW+MkCsI JmJnAa83pOAjIsxWQaTQgWZE3/0W/Fm74qriSaRMbyTEGu3BtxlJ9cx9Uuebz+znNqMQ w4D4X1Kn+njpv5fCX+ZNOamRnTT3d3wgL+Y3OwBgSceIqBHhZo793kIPVuwC8RF5h819 OQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3g8r4d1m8p-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 24 May 2022 05:50:55 +0000 Received: from m0098394.ppops.net (m0098394.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 24O5otqn029920; Tue, 24 May 2022 05:50:55 GMT Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3g8r4d1m7y-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 24 May 2022 05:50:55 +0000 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 24O5meD1031445; Tue, 24 May 2022 05:50:52 GMT Received: from b06avi18878370.portsmouth.uk.ibm.com (b06avi18878370.portsmouth.uk.ibm.com [9.149.26.194]) by ppma06ams.nl.ibm.com with ESMTP id 3g6qbjbtgy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 24 May 2022 05:50:52 +0000 Received: from d06av24.portsmouth.uk.ibm.com (mk.ibm.com [9.149.105.60]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 24O5o1ZU21954982 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 24 May 2022 05:50:01 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8D76F42045; Tue, 24 May 2022 05:50:49 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C132D42047; Tue, 24 May 2022 05:50:44 +0000 (GMT) Received: from vajain21.in.ibm.com (unknown [9.43.16.48]) by d06av24.portsmouth.uk.ibm.com (Postfix) with SMTP; Tue, 24 May 2022 05:50:44 +0000 (GMT) Received: by vajain21.in.ibm.com (sSMTP sendmail emulation); Tue, 24 May 2022 11:20:43 +0530 From: Vaibhav Jain To: linuxppc-dev@lists.ozlabs.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Vaibhav Jain , "Aneesh Kumar K . V" , Michael Ellerman , Frank Rowand , Prakhar Srivastava , Lakshmi Ramasubramanian , Thiago Jung Bauermann , Rob Herring Subject: [PATCH v2] of: check previous kernel's ima-kexec-buffer against memory bounds Date: Tue, 24 May 2022 11:20:42 +0530 Message-Id: <20220524055042.1527968-1-vaibhav@linux.ibm.com> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-GUID: TKQZRSPZy-aQC937xyit7SfhoITYr0hx X-Proofpoint-ORIG-GUID: hBgWtJdM4BJLssmHlMOqECZR-rmZxLLy X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-24_01,2022-05-23_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 spamscore=0 mlxscore=0 priorityscore=1501 adultscore=0 malwarescore=0 bulkscore=0 impostorscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=999 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205240033 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Presently ima_get_kexec_buffer() doesn't check if the previous kernel's ima-kexec-buffer lies outside the addressable memory range. This can result in a kernel panic if the new kernel is booted with 'mem=3DX' arg and the ima-kexec-buffer was allocated beyond that range by the previous kernel. The panic is usually of the form below: $ sudo kexec --initrd initrd vmlinux --append=3D'mem=3D16G' BUG: Unable to handle kernel data access on read at 0xc000c01fff7f0000 Faulting instruction address: 0xc000000000837974 Oops: Kernel access of bad area, sig: 11 [#1] NIP [c000000000837974] ima_restore_measurement_list+0x94/0x6c0 LR [c00000000083b55c] ima_load_kexec_buffer+0xac/0x160 Call Trace: [c00000000371fa80] [c00000000083b55c] ima_load_kexec_buffer+0xac/0x160 [c00000000371fb00] [c0000000020512c4] ima_init+0x80/0x108 [c00000000371fb70] [c0000000020514dc] init_ima+0x4c/0x120 [c00000000371fbf0] [c000000000012240] do_one_initcall+0x60/0x2c0 [c00000000371fcc0] [c000000002004ad0] kernel_init_freeable+0x344/0x3ec [c00000000371fda0] [c0000000000128a4] kernel_init+0x34/0x1b0 [c00000000371fe10] [c00000000000ce64] ret_from_kernel_thread+0x5c/0x64 Instruction dump: f92100b8 f92100c0 90e10090 910100a0 4182050c 282a0017 3bc00000 40810330 7c0802a6 fb610198 7c9b2378 f80101d0 2c090001 40820614 e9240010 ---[ end trace 0000000000000000 ]--- Fix this issue by checking returned PFN range of previous kernel's ima-kexec-buffer with pfn_valid to ensure correct memory bounds. Fixes: 467d27824920 ("powerpc: ima: get the kexec buffer passed by the prev= ious kernel") Cc: Frank Rowand Cc: Prakhar Srivastava Cc: Lakshmi Ramasubramanian Cc: Thiago Jung Bauermann Cc: Rob Herring Signed-off-by: Vaibhav Jain --- Changelog =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D v2: * Instead of using memblock to determine the valid bounds use pfn_valid() t= o do so since memblock may not be available late after the kernel init. [ Mpe ] * Changed the patch prefix from 'powerpc' to 'of' [ Mpe ] * Updated the 'Fixes' tag to point to correct commit that introduced this function. [ Rob ] * Fixed some whitespace/tab issues in the patch description [ Rob ] * Added another check for checking ig 'tmp_size' for ima-kexec-buffer is > 0 --- drivers/of/kexec.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c index 8d374cc552be..879e984fe901 100644 --- a/drivers/of/kexec.c +++ b/drivers/of/kexec.c @@ -126,6 +126,7 @@ int ima_get_kexec_buffer(void **addr, size_t *size) { int ret, len; unsigned long tmp_addr; + unsigned int start_pfn, end_pfn; size_t tmp_size; const void *prop; =20 @@ -140,6 +141,22 @@ int ima_get_kexec_buffer(void **addr, size_t *size) if (ret) return ret; =20 + /* Do some sanity on the returned size for the ima-kexec buffer */ + if (!tmp_size) + return -ENOENT; + + /* + * Calculate the PFNs for the buffer and ensure + * they are with in addressable memory. + */ + start_pfn =3D PHYS_PFN(tmp_addr); + end_pfn =3D PHYS_PFN(tmp_addr + tmp_size - 1); + if (!pfn_valid(start_pfn) || !pfn_valid(end_pfn)) { + pr_warn("IMA buffer at 0x%lx, size =3D 0x%zx beyond memory\n", + tmp_addr, tmp_size); + return -EINVAL; + } + *addr =3D __va(tmp_addr); *size =3D tmp_size; =20 --=20 2.35.1