From patchwork Sun Nov 25 15:14:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nayna Jain X-Patchwork-Id: 10696881 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id ED5705A4 for ; Sun, 25 Nov 2018 15:19:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DA2BD29B1D for ; Sun, 25 Nov 2018 15:19:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C708A29B21; Sun, 25 Nov 2018 15:19:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3E58029B1D for ; Sun, 25 Nov 2018 15:19:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726762AbeKZCKO (ORCPT ); Sun, 25 Nov 2018 21:10:14 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:36374 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726746AbeKZCKO (ORCPT ); Sun, 25 Nov 2018 21:10:14 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wAPFEViA106457 for ; Sun, 25 Nov 2018 10:18:57 -0500 Received: from e06smtp05.uk.ibm.com (e06smtp05.uk.ibm.com [195.75.94.101]) by mx0a-001b2d01.pphosted.com with ESMTP id 2nymnc6nvy-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 25 Nov 2018 10:18:56 -0500 Received: from localhost by e06smtp05.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Sun, 25 Nov 2018 15:18:50 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wAPFImGs27918346 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Sun, 25 Nov 2018 15:18:48 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9AED64C04E; Sun, 25 Nov 2018 15:18:48 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1B2E64C052; Sun, 25 Nov 2018 15:18:45 +0000 (GMT) Received: from swastik.ibmuc.com (unknown [9.85.72.131]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Sun, 25 Nov 2018 15:18:44 +0000 (GMT) From: Nayna Jain To: linux-integrity@vger.kernel.org Cc: linux-security-module@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, zohar@linux.ibm.com, dhowells@redhat.com, jforbes@redhat.com, seth.forshee@canonical.com, kexec@lists.infradead.org, keyrings@vger.kernel.org, vgoyal@redhat.com, ebiederm@xmission.com, mpe@ellerman.id.au, Nayna Jain Subject: [PATCH 4/7] efi: Add an EFI signature blob parser Date: Sun, 25 Nov 2018 20:44:57 +0530 X-Mailer: git-send-email 2.13.6 In-Reply-To: <20181125151500.8298-1-nayna@linux.ibm.com> References: <20181125151500.8298-1-nayna@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18112515-0020-0000-0000-000002ED70FA X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18112515-0021-0000-0000-0000213CB9BB Message-Id: <20181125151500.8298-5-nayna@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-11-25_14:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1811250071 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: X-Virus-Scanned: ClamAV using ClamSMTP From: Dave Howells Add a function to parse an EFI signature blob looking for elements of interest. A list is made up of a series of sublists, where all the elements in a sublist are of the same type, but sublists can be of different types. For each sublist encountered, the function pointed to by the get_handler_for_guid argument is called with the type specifier GUID and returns either a pointer to a function to handle elements of that type or NULL if the type is not of interest. If the sublist is of interest, each element is passed to the handler function in turn. Signed-off-by: David Howells Signed-off-by: Nayna Jain --- Changelog: v0: - removed the CONFIG EFI_SIGNATURE_LIST_PARSER - moved efi_parser.c from certs to security/integrity/platform_certs directory include/linux/efi.h | 9 ++ security/integrity/Makefile | 3 +- security/integrity/platform_certs/efi_parser.c | 112 +++++++++++++++++++++++++ 3 files changed, 123 insertions(+), 1 deletion(-) create mode 100644 security/integrity/platform_certs/efi_parser.c diff --git a/include/linux/efi.h b/include/linux/efi.h index 99cba6fe1234..2016145e2d6d 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1138,6 +1138,15 @@ extern int efi_memattr_apply_permissions(struct mm_struct *mm, char * __init efi_md_typeattr_format(char *buf, size_t size, const efi_memory_desc_t *md); + +typedef void (*efi_element_handler_t)(const char *source, + const void *element_data, + size_t element_size); +extern int __init parse_efi_signature_list( + const char *source, + const void *data, size_t size, + efi_element_handler_t (*get_handler_for_guid)(const efi_guid_t *)); + /** * efi_range_is_wc - check the WC bit on an address range * @start: starting kvirt address diff --git a/security/integrity/Makefile b/security/integrity/Makefile index 046ffc1bb42d..6ee9058866cd 100644 --- a/security/integrity/Makefile +++ b/security/integrity/Makefile @@ -9,7 +9,8 @@ integrity-y := iint.o integrity-$(CONFIG_INTEGRITY_AUDIT) += integrity_audit.o integrity-$(CONFIG_INTEGRITY_SIGNATURE) += digsig.o integrity-$(CONFIG_INTEGRITY_ASYMMETRIC_KEYS) += digsig_asymmetric.o -integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o +integrity-$(CONFIG_INTEGRITY_PLATFORM_KEYRING) += platform_certs/platform_keyring.o \ + platform_certs/efi_parser.o subdir-$(CONFIG_IMA) += ima obj-$(CONFIG_IMA) += ima/ diff --git a/security/integrity/platform_certs/efi_parser.c b/security/integrity/platform_certs/efi_parser.c new file mode 100644 index 000000000000..4e396f98f5c7 --- /dev/null +++ b/security/integrity/platform_certs/efi_parser.c @@ -0,0 +1,112 @@ +/* EFI signature/key/certificate list parser + * + * Copyright (C) 2012, 2016 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#define pr_fmt(fmt) "EFI: "fmt +#include +#include +#include +#include + +/** + * parse_efi_signature_list - Parse an EFI signature list for certificates + * @source: The source of the key + * @data: The data blob to parse + * @size: The size of the data blob + * @get_handler_for_guid: Get the handler func for the sig type (or NULL) + * + * Parse an EFI signature list looking for elements of interest. A list is + * made up of a series of sublists, where all the elements in a sublist are of + * the same type, but sublists can be of different types. + * + * For each sublist encountered, the @get_handler_for_guid function is called + * with the type specifier GUID and returns either a pointer to a function to + * handle elements of that type or NULL if the type is not of interest. + * + * If the sublist is of interest, each element is passed to the handler + * function in turn. + * + * Error EBADMSG is returned if the list doesn't parse correctly and 0 is + * returned if the list was parsed correctly. No error can be returned from + * the @get_handler_for_guid function or the element handler function it + * returns. + */ +int __init parse_efi_signature_list( + const char *source, + const void *data, size_t size, + efi_element_handler_t (*get_handler_for_guid)(const efi_guid_t *)) +{ + efi_element_handler_t handler; + unsigned offs = 0; + + pr_devel("-->%s(,%zu)\n", __func__, size); + + while (size > 0) { + const efi_signature_data_t *elem; + efi_signature_list_t list; + size_t lsize, esize, hsize, elsize; + + if (size < sizeof(list)) + return -EBADMSG; + + memcpy(&list, data, sizeof(list)); + pr_devel("LIST[%04x] guid=%pUl ls=%x hs=%x ss=%x\n", + offs, + list.signature_type.b, list.signature_list_size, + list.signature_header_size, list.signature_size); + + lsize = list.signature_list_size; + hsize = list.signature_header_size; + esize = list.signature_size; + elsize = lsize - sizeof(list) - hsize; + + if (lsize > size) { + pr_devel("<--%s() = -EBADMSG [overrun @%x]\n", + __func__, offs); + return -EBADMSG; + } + + if (lsize < sizeof(list) || + lsize - sizeof(list) < hsize || + esize < sizeof(*elem) || + elsize < esize || + elsize % esize != 0) { + pr_devel("- bad size combo @%x\n", offs); + return -EBADMSG; + } + + handler = get_handler_for_guid(&list.signature_type); + if (!handler) { + data += lsize; + size -= lsize; + offs += lsize; + continue; + } + + data += sizeof(list) + hsize; + size -= sizeof(list) + hsize; + offs += sizeof(list) + hsize; + + for (; elsize > 0; elsize -= esize) { + elem = data; + + pr_devel("ELEM[%04x]\n", offs); + handler(source, + &elem->signature_data, + esize - sizeof(*elem)); + + data += esize; + size -= esize; + offs += esize; + } + } + + return 0; +}