From patchwork Wed Dec 12 21:32:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nayna Jain X-Patchwork-Id: 10727133 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 0D3D76C5 for ; Wed, 12 Dec 2018 21:35:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E8D042B7A7 for ; Wed, 12 Dec 2018 21:35:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D95E02B7A8; Wed, 12 Dec 2018 21:35:50 +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=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham 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 059DD2A720 for ; Wed, 12 Dec 2018 21:35:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726297AbeLLVfs (ORCPT ); Wed, 12 Dec 2018 16:35:48 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:37922 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726440AbeLLVfr (ORCPT ); Wed, 12 Dec 2018 16:35:47 -0500 Received: from pps.filterd (m0098396.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBCLYHa7025036 for ; Wed, 12 Dec 2018 16:35:46 -0500 Received: from e06smtp04.uk.ibm.com (e06smtp04.uk.ibm.com [195.75.94.100]) by mx0a-001b2d01.pphosted.com with ESMTP id 2pb9exahgp-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 12 Dec 2018 16:35:46 -0500 Received: from localhost by e06smtp04.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) Wed, 12 Dec 2018 21:35:40 -0000 Received: from d06av24.portsmouth.uk.ibm.com (d06av24.portsmouth.uk.ibm.com [9.149.105.60]) by b06cxnps4074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id wBCLZcsS065980 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 12 Dec 2018 21:35:38 GMT Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B119F4204D; Wed, 12 Dec 2018 21:35:38 +0000 (GMT) Received: from d06av24.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 33BCD4203F; Wed, 12 Dec 2018 21:35:35 +0000 (GMT) Received: from swastik.ibmuc.com (unknown [9.85.69.250]) by d06av24.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 12 Dec 2018 21:35:34 +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, Josh Boyer , Nayna Jain Subject: [PATCH v2a 5/7] efi: Import certificates from UEFI Secure Boot Date: Thu, 13 Dec 2018 03:02:07 +0530 X-Mailer: git-send-email 2.13.6 In-Reply-To: <20181208202705.18673-6-nayna@linux.ibm.com> References: <20181208202705.18673-6-nayna@linux.ibm.com> X-TM-AS-GCONF: 00 x-cbid: 18121221-0016-0000-0000-00000235A344 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18121221-0017-0000-0000-0000328DD927 Message-Id: <20181212213207.12746-1-nayna@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-12-12_04:,, 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-1812120184 Sender: linux-integrity-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Josh Boyer Secure Boot stores a list of allowed certificates in the 'db' variable. This patch imports those certificates into the platform keyring. The shim UEFI bootloader has a similar certificate list stored in the 'MokListRT' variable. We import those as well. Secure Boot also maintains a list of disallowed certificates in the 'dbx' variable. We load those certificates into the system blacklist keyring and forbid any kernel signed with those from loading. [zohar@linux.ibm.com: dropped Josh's original patch description] Signed-off-by: Josh Boyer Signed-off-by: David Howells Signed-off-by: Nayna Jain Acked-by: Serge Hallyn Signed-off-by: Mimi Zohar --- Changelog: v2a: - refactored uefi_blacklist_x509_tbs() and uefi_blacklist_binary() v2: - Fixed the checkpatch.pl warnings v0: - This patch replaces the loading of certificates onto the secondary keyring with platform keyring - removed the CONFIG LOAD_UEFI_KEYS - moved the file load_uefi.o from certs to security/integrity/platform_certs security/integrity/Makefile | 5 +- security/integrity/platform_certs/load_uefi.c | 169 ++++++++++++++++++++++++++ 2 files changed, 173 insertions(+), 1 deletion(-) create mode 100644 security/integrity/platform_certs/load_uefi.c diff --git a/security/integrity/Makefile b/security/integrity/Makefile index 6ee9058866cd..86df9aba8c0f 100644 --- a/security/integrity/Makefile +++ b/security/integrity/Makefile @@ -10,7 +10,10 @@ 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 \ - platform_certs/efi_parser.o + platform_certs/efi_parser.o \ + platform_certs/load_uefi.o +obj-$(CONFIG_LOAD_UEFI_KEYS) += platform_certs/load_uefi.o +$(obj)/load_uefi.o: KBUILD_CFLAGS += -fshort-wchar subdir-$(CONFIG_IMA) += ima obj-$(CONFIG_IMA) += ima/ diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c new file mode 100644 index 000000000000..8ceafa58d98c --- /dev/null +++ b/security/integrity/platform_certs/load_uefi.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include +#include +#include +#include +#include +#include +#include +#include "../integrity.h" + +static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID; +static efi_guid_t efi_cert_x509_sha256_guid __initdata = + EFI_CERT_X509_SHA256_GUID; +static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID; + +/* + * Get a certificate list blob from the named EFI variable. + */ +static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid, + unsigned long *size) +{ + efi_status_t status; + unsigned long lsize = 4; + unsigned long tmpdb[4]; + void *db; + + status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb); + if (status != EFI_BUFFER_TOO_SMALL) { + pr_err("Couldn't get size: 0x%lx\n", status); + return NULL; + } + + db = kmalloc(lsize, GFP_KERNEL); + if (!db) + return NULL; + + status = efi.get_variable(name, guid, NULL, &lsize, db); + if (status != EFI_SUCCESS) { + kfree(db); + pr_err("Error reading db var: 0x%lx\n", status); + return NULL; + } + + *size = lsize; + return db; +} + +/* + * Blacklist a hash. + */ +static __init void uefi_blacklist_hash(const char *source, const void *data, + size_t len, const char *type, + size_t type_len) +{ + char *hash, *p; + + hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL); + if (!hash) + return; + p = memcpy(hash, type, type_len); + p += type_len; + bin2hex(p, data, len); + p += len * 2; + *p = 0; + + mark_hash_blacklisted(hash); + kfree(hash); +} + +/* + * Blacklist an X509 TBS hash. + */ +static __init void uefi_blacklist_x509_tbs(const char *source, + const void *data, size_t len) +{ + uefi_blacklist_hash(source, data, len, "tbs:", 4); +} + +/* + * Blacklist the hash of an executable. + */ +static __init void uefi_blacklist_binary(const char *source, + const void *data, size_t len) +{ + uefi_blacklist_hash(source, data, len, "bin:", 4); +} + +/* + * Return the appropriate handler for particular signature list types found in + * the UEFI db and MokListRT tables. + */ +static __init efi_element_handler_t get_handler_for_db(const efi_guid_t * + sig_type) +{ + if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) + return add_to_platform_keyring; + return 0; +} + +/* + * Return the appropriate handler for particular signature list types found in + * the UEFI dbx and MokListXRT tables. + */ +static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t * + sig_type) +{ + if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0) + return uefi_blacklist_x509_tbs; + if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0) + return uefi_blacklist_binary; + return 0; +} + +/* + * Load the certs contained in the UEFI databases + */ +static int __init load_uefi_certs(void) +{ + efi_guid_t secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID; + efi_guid_t mok_var = EFI_SHIM_LOCK_GUID; + void *db = NULL, *dbx = NULL, *mok = NULL; + unsigned long dbsize = 0, dbxsize = 0, moksize = 0; + int rc = 0; + + if (!efi.get_variable) + return false; + + /* Get db, MokListRT, and dbx. They might not exist, so it isn't + * an error if we can't get them. + */ + db = get_cert_list(L"db", &secure_var, &dbsize); + if (!db) { + pr_err("Couldn't get UEFI db list\n"); + } else { + rc = parse_efi_signature_list("UEFI:db", + db, dbsize, get_handler_for_db); + if (rc) + pr_err("Couldn't parse db signatures: %d\n", rc); + kfree(db); + } + + mok = get_cert_list(L"MokListRT", &mok_var, &moksize); + if (!mok) { + pr_info("Couldn't get UEFI MokListRT\n"); + } else { + rc = parse_efi_signature_list("UEFI:MokListRT", + mok, moksize, get_handler_for_db); + if (rc) + pr_err("Couldn't parse MokListRT signatures: %d\n", rc); + kfree(mok); + } + + dbx = get_cert_list(L"dbx", &secure_var, &dbxsize); + if (!dbx) { + pr_info("Couldn't get UEFI dbx list\n"); + } else { + rc = parse_efi_signature_list("UEFI:dbx", + dbx, dbxsize, + get_handler_for_dbx); + if (rc) + pr_err("Couldn't parse dbx signatures: %d\n", rc); + kfree(dbx); + } + + return rc; +} +late_initcall(load_uefi_certs);