From patchwork Mon Jan 20 02:36:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Richter X-Patchwork-Id: 1225601 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 481G9X0MXzz9sRQ for ; Mon, 20 Jan 2020 13:40:16 +1100 (AEDT) Authentication-Results: ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 481G9W64fhzDqZk for ; Mon, 20 Jan 2020 13:40:15 +1100 (AEDT) X-Original-To: skiboot@lists.ozlabs.org Delivered-To: skiboot@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.ibm.com (client-ip=148.163.156.1; helo=mx0a-001b2d01.pphosted.com; envelope-from=erichte@linux.ibm.com; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=linux.ibm.com Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 481G674jpmzDqXw for ; Mon, 20 Jan 2020 13:37:19 +1100 (AEDT) Received: from pps.filterd (m0187473.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 00K2Wu2c157863 for ; Sun, 19 Jan 2020 21:37:18 -0500 Received: from e06smtp02.uk.ibm.com (e06smtp02.uk.ibm.com [195.75.94.98]) by mx0a-001b2d01.pphosted.com with ESMTP id 2xkxhwesxv-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Sun, 19 Jan 2020 21:37:17 -0500 Received: from localhost by e06smtp02.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) Mon, 20 Jan 2020 02:37:14 -0000 Received: from d06av22.portsmouth.uk.ibm.com (d06av22.portsmouth.uk.ibm.com [9.149.105.58]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 00K2aMFL50069846 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 20 Jan 2020 02:36:23 GMT Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9D5B04C046; Mon, 20 Jan 2020 02:37:12 +0000 (GMT) Received: from d06av22.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id EA0054C040; Mon, 20 Jan 2020 02:37:11 +0000 (GMT) Received: from ceres.ibmuc.com (unknown [9.80.231.232]) by d06av22.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 20 Jan 2020 02:37:11 +0000 (GMT) From: Eric Richter To: skiboot@lists.ozlabs.org Date: Sun, 19 Jan 2020 20:36:57 -0600 X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200120023700.5373-1-erichte@linux.ibm.com> References: <20200120023700.5373-1-erichte@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 x-cbid: 20012002-0008-0000-0000-0000034AE751 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 20012002-0009-0000-0000-00004A6B486A Message-Id: <20200120023700.5373-10-erichte@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138, 18.0.572 definitions=2020-01-19_08:2020-01-16, 2020-01-19 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 phishscore=0 lowpriorityscore=0 malwarescore=0 suspectscore=0 priorityscore=1501 bulkscore=0 adultscore=0 mlxscore=0 mlxlogscore=999 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-2001200020 Subject: [Skiboot] [PATCH v2 09/12] secvar/backend: add edk2 derived key updates processing X-BeenThere: skiboot@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Mailing list for skiboot development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: nayna@linux.ibm.com Errors-To: skiboot-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Skiboot" From: Nayna Jain As part of secureboot key management, the scheme for handling key updates is derived from tianocore reference implementation[1]. The wrappers for holding the signed update is the Authentication Header and for holding the public key certificate is ESL (EFI Signature List), both derived from tianocore reference implementation[1]. This patch adds the support to process update queue. This involves: 1. Verification of the update signature using the key authorized as per the key hierarchy 2. Handling addition/deletion of the keys 3. Support for dbx(blacklisting of hashes) 4. Validation checks for the updates 5. Supporting multiple ESLs for single variable both for update/verification 6. Timestamp check 7. Allowing only single PK 8. Failure Handling [1] https://github.com/tianocore/edk2-staging.git Signed-off-by: Nayna Jain Signed-off-by: Eric Richter --- V5: - Finalizes the previous version to a complete version taking care of validation, multiple ESLs, single PK, dbx support, timestamp checks and failure handling. doc/secvar/edk2.rst | 49 ++ include/secvar.h | 1 + libstb/secvar/backend/Makefile.inc | 4 +- libstb/secvar/backend/edk2-compat.c | 877 ++++++++++++++++++++++++++++ libstb/secvar/backend/edk2.h | 243 ++++++++ 5 files changed, 1172 insertions(+), 2 deletions(-) create mode 100644 doc/secvar/edk2.rst create mode 100644 libstb/secvar/backend/edk2-compat.c create mode 100644 libstb/secvar/backend/edk2.h diff --git a/doc/secvar/edk2.rst b/doc/secvar/edk2.rst new file mode 100644 index 00000000..e0c29457 --- /dev/null +++ b/doc/secvar/edk2.rst @@ -0,0 +1,49 @@ +.. _secvar/edk2: + +Skiboot edk2-compatible Secure Variable Backend +=============================================== + +Overview +-------- + +The edk2 secure variable backend for skiboot borrows from edk2 concepts +such as the three key hierarchy (PK, KEK, and db), and a similar +structure. In general, variable updates must be signed with a key +of a higher level. So, updates to the db must be signed with a key stored +in the KEK; updates to the KEK must be signed with the PK. Updates to the +PK must be signed with the previous PK (if any). + +Variables are stored in the efi signature list format, and updates are a +signed variant that includes an authentication header. + +If no PK is currently enrolled, the system is considered to be in "Setup +Mode". Any key can be enrolled without signature checks. However, once a +PK is enrolled, the system switches to "User Mode", and each update must +now be signed according to the hierarchy. Furthermore, when in "User +Mode", the backend initialized the ``os-secure-mode`` device tree flag, +signaling to the kernel that we are in secure mode. + +Updates are processed sequentially, in the order that they were provided +in the update queue. If any update fails to validate, appears to be +malformed, or any other error occurs, NO updates will not be applied. +This includes updates that may have successfully applied prior to the +error. The system will continue in an error state, reporting the error +reason via the ``update-status`` device tree property. + +P9 Special Case for the Platform Key +------------------------------------ + +Due to the powerful nature of the platform key and the lack of lockable +flash, the edk2 backend will store the PK in TPM NV rather than PNOR on +P9 systems. (TODO expand on this) + +Update Status Return Codes +-------------------------- + +TODO, edk2 driver needs to actually return these properly first + + +Device Tree Bindings +-------------------- + +TODO diff --git a/include/secvar.h b/include/secvar.h index 2875c700..8b701e00 100644 --- a/include/secvar.h +++ b/include/secvar.h @@ -24,6 +24,7 @@ struct secvar_backend_driver { }; extern struct secvar_storage_driver secboot_tpm_driver; +extern struct secvar_backend_driver edk2_compatible_v1; int secvar_main(struct secvar_storage_driver, struct secvar_backend_driver); diff --git a/libstb/secvar/backend/Makefile.inc b/libstb/secvar/backend/Makefile.inc index cc1a49fa..1c1896ab 100644 --- a/libstb/secvar/backend/Makefile.inc +++ b/libstb/secvar/backend/Makefile.inc @@ -1,11 +1,11 @@ # SPDX-License-Identifier: Apache-2.0 # -*-Makefile-*- -SECVAR_BACKEND_DIR = libstb/secvar/backend +SECVAR_BACKEND_DIR = $(SRC)/libstb/secvar/backend SUBDIRS += $(SECVAR_BACKEND_DIR) -SECVAR_BACKEND_SRCS = +SECVAR_BACKEND_SRCS = edk2-compat.c SECVAR_BACKEND_OBJS = $(SECVAR_BACKEND_SRCS:%.c=%.o) SECVAR_BACKEND = $(SECVAR_BACKEND_DIR)/built-in.a diff --git a/libstb/secvar/backend/edk2-compat.c b/libstb/secvar/backend/edk2-compat.c new file mode 100644 index 00000000..b99738b1 --- /dev/null +++ b/libstb/secvar/backend/edk2-compat.c @@ -0,0 +1,877 @@ +// SPDX-License-Identifier: Apache-2.0 +/* Copyright 2019 IBM Corp. */ +#ifndef pr_fmt +#define pr_fmt(fmt) "EDK2_COMPAT: " fmt +#endif + +#include +#include +#include +#include +#include +#include +#include "libstb/crypto/pkcs7/pkcs7.h" +#include "edk2.h" +#include "opal-api.h" +#include "../secvar.h" +#include "../secvar_devtree.h" +#include "../secvar_tpmnv.h" +#include + +#define TPMNV_ID_EDK2_PK 0x4532504b // E2PK + +static bool setup_mode; + +//struct efi_time *timestamp_list; + +/* + * Converts utf8 string to ucs2 + */ +static char *utf8_to_ucs2(const char *key, const char keylen) +{ + int i; + char *str; + str = zalloc(keylen * 2); + + for (i = 0; i < keylen*2; key++) { + str[i++] = *key; + str[i++] = '\0'; + } + return str; +} + +/* + * Returns true if key1 = key2 + */ +static bool key_equals(const char *key1, const char *key2) +{ + if (memcmp(key1, key2, strlen(key2)+1) == 0) + return true; + + return false; +} + +/** + * Returns the authority that can sign the given key update + */ +static void get_key_authority(const char *ret[3], const char *key) +{ + int i = 0; + + memset(ret, 0, sizeof(char *) * 3); + if (key_equals(key, "PK")) + ret[i++] = "PK"; + if (key_equals(key, "KEK")) + ret[i++] = "PK"; + if (key_equals(key, "db") || key_equals(key, "dbx")) { + ret[i++] = "KEK"; + ret[i++] = "PK"; + } + ret[i] = NULL; +} + +/* + * PK needs to be stored in the TPMNV space if on p9 + * We store it using the form , the + * extra secvar headers are unnecessary + */ +static int edk2_p9_load_pk(void) +{ + struct secvar_node *pkvar; + uint64_t size; + int rc; + + // Ensure it exists + rc = secvar_tpmnv_alloc(TPMNV_ID_EDK2_PK, -1); + + // Peek to get the size + rc = secvar_tpmnv_read(TPMNV_ID_EDK2_PK, &size, sizeof(size), 0); + if (rc == OPAL_EMPTY) + return 0; + else if (rc) + return -1; + + if (size > secvar_storage.max_var_size) + return OPAL_RESOURCE; + + pkvar = alloc_secvar(size); + memcpy(pkvar->var->key, "PK", 3); + pkvar->var->key_len = 3; + pkvar->var->data_size = size; + pkvar->flags |= SECVAR_FLAG_VOLATILE; + + rc = secvar_tpmnv_read(TPMNV_ID_EDK2_PK, pkvar->var->data, pkvar->var->data_size, sizeof(pkvar->var->data_size)); + if (rc) + return rc; + + list_add_tail(&variable_bank, &pkvar->link); + + return OPAL_SUCCESS; +} + +/* + * Writes the PK to the TPM. + */ +static int edk2_p9_write_pk(void) +{ + char *tmp; + int32_t tmpsize; + struct secvar_node *pkvar; + int rc; + + pkvar = find_secvar("PK", 3, &variable_bank); + + // Should not happen + if (!pkvar) + return OPAL_INTERNAL_ERROR; + + // Reset the pk flag to volatile on p9 + pkvar->flags |= SECVAR_FLAG_VOLATILE; + + tmpsize = secvar_tpmnv_size(TPMNV_ID_EDK2_PK); + if (tmpsize < 0) { + prlog(PR_ERR, "TPMNV space for PK was not allocated properly\n"); + return OPAL_RESOURCE; + } + if (tmpsize < pkvar->var->data_size + sizeof(pkvar->var->data_size)) { + prlog(PR_ERR, "TPMNV PK space is insufficient, %d < %llu\n", tmpsize, + // Cast needed because x86 compiler complains building the test + (long long unsigned) pkvar->var->data_size + sizeof(pkvar->var->data_size)); + return OPAL_RESOURCE; + } + + tmp = zalloc(tmpsize); + if (!tmp) + return OPAL_NO_MEM; + + memcpy(tmp, &pkvar->var->data_size, sizeof(pkvar->var->data_size)); + memcpy(tmp + sizeof(pkvar->var->data_size), + pkvar->var->data, + pkvar->var->data_size); + + tmpsize = pkvar->var->data_size + sizeof(pkvar->var->data_size); + + rc = secvar_tpmnv_write(TPMNV_ID_EDK2_PK, tmp, tmpsize, 0); + + free(tmp); + + return rc; +} + +/* + * Returns the size of the ESL. + */ +static int get_esl_signature_list_size(char *buf) +{ + EFI_SIGNATURE_LIST list; + + memcpy(&list, buf, sizeof(EFI_SIGNATURE_LIST)); + + prlog(PR_DEBUG, "size of signature list size is %u\n", le32_to_cpu(list.SignatureListSize)); + + return le32_to_cpu(list.SignatureListSize); +} + +/* + * Returns the size of the certificate contained in the ESL. + */ +static int get_esl_cert_size(char *buf) +{ + EFI_SIGNATURE_LIST list; + uint32_t sigsize; + + memcpy(&list, buf, sizeof(EFI_SIGNATURE_LIST)); + + sigsize = le32_to_cpu(list.SignatureListSize) - sizeof(list) + - le32_to_cpu(list.SignatureHeaderSize) - sizeof(uuid_t); + + prlog(PR_DEBUG, "sig size is %u\n", sigsize); + return sigsize; +} + +/* + * Copies the certificate from the ESL into cert buffer. + */ +static int get_esl_cert(char *buf, char **cert) +{ + int sig_data_offset; + int size; + EFI_SIGNATURE_LIST list; + + memset(&list, 0, sizeof(EFI_SIGNATURE_LIST)); + memcpy(&list, buf, sizeof(EFI_SIGNATURE_LIST)); + + prlog(PR_DEBUG,"size of signature list size is %u\n", le32_to_cpu(list.SignatureListSize)); + prlog(PR_DEBUG, "size of signature header size is %u\n", le32_to_cpu(list.SignatureHeaderSize)); + prlog(PR_DEBUG, "size of signature size is %u\n", le32_to_cpu(list.SignatureSize)); + sig_data_offset = sizeof(list.SignatureType) + + sizeof(list.SignatureListSize) + + sizeof(list.SignatureHeaderSize) + + sizeof(list.SignatureSize) + + le32_to_cpu(list.SignatureHeaderSize) + + 16 * sizeof(uint8_t); + + size = le32_to_cpu(list.SignatureSize) - sizeof(uuid_t); + + memcpy(*cert, buf + sig_data_offset, size); + + return size; +} + +/* + * Extracts size of the PKCS7 signed data embedded in the + * struct Authentication 2 Descriptor Header. + */ +static int get_pkcs7_len(struct efi_variable_authentication_2 *auth) +{ + uint32_t dw_length = le32_to_cpu(auth->auth_info.hdr.dw_length); + int size; + + size = dw_length - (sizeof(auth->auth_info.hdr.dw_length) + + sizeof(auth->auth_info.hdr.w_revision) + + sizeof(auth->auth_info.hdr.w_certificate_type) + + sizeof(auth->auth_info.cert_type)); + + return size; +} + +/* + * Return the timestamp from the Authentication 2 Descriptor. + */ +static int get_timestamp_from_auth(char *data, struct efi_time **timestamp) +{ + *timestamp = (struct efi_time *) data; + + return 0; +} + +/* + * This function outputs the Authentication 2 Descriptor in the + * auth_buffer and returns the size of the buffer. + */ +static int get_auth_descriptor2(void *data, char **auth_buffer) +{ + struct efi_variable_authentication_2 *auth = data; + uint64_t auth_buffer_size; + int len; + + if (!auth_buffer) + return OPAL_PARAMETER; + + len = get_pkcs7_len(auth); + if (len < 0) + return OPAL_NO_MEM; + + auth_buffer_size = sizeof(auth->timestamp) + sizeof(auth->auth_info.hdr) + + sizeof(auth->auth_info.cert_type) + len; + + *auth_buffer = zalloc(auth_buffer_size); + if (!(*auth_buffer)) + return OPAL_NO_MEM; + + memcpy(*auth_buffer, data, auth_buffer_size); + + return auth_buffer_size; +} + +/* Check that PK has single ESL */ +static bool is_single_pk(char *data, uint64_t data_size) +{ + char *auth_buffer = NULL; + uint64_t auth_buffer_size = 0; + char *newesl = NULL; + uint64_t new_data_size = 0; + int esllistsize; + + auth_buffer_size = get_auth_descriptor2(data, &auth_buffer); + printf("auth buffer size is %d\n", (int)auth_buffer_size); + free(auth_buffer); + if (auth_buffer_size <= 0) + return false; + + /* Calculate the size of new ESL data */ + new_data_size = data_size - auth_buffer_size; + printf("new data size is %d\n", (int)new_data_size); + + if (!new_data_size) + return true; + + newesl = zalloc(new_data_size); + memcpy(newesl, data + auth_buffer_size, new_data_size); + + esllistsize = get_esl_signature_list_size(newesl); + printf("esl list size is %d\n", esllistsize); + free(newesl); + if (new_data_size > esllistsize) + return false; + + return true; +} + +/* + * Initializes supported variables as empty if not loaded from + * storage. Variables are initialized as volatile if not found. + * Updates should clear this flag. +ec* + * Returns OPAL Error if anything fails in initialization + */ +static int edk2_compat_pre_process(void) +{ + struct secvar_node *pkvar; + struct secvar_node *kekvar; + struct secvar_node *dbvar; + struct secvar_node *dbxvar; + struct secvar_node *tsvar; + + // If we are on p9, we need to store the PK in write-lockable + // TPMNV space, as we determine our secure mode based on if this + // variable exists. + // NOTE: Activation of this behavior is subject to change in a later + // patch version, ideally the platform should be able to configure + // whether it wants this extra protection, or to instead store + // everything via the storage driver. + if (proc_gen == proc_gen_p9) + edk2_p9_load_pk(); + + pkvar = find_secvar("PK", 3, &variable_bank); + if (!pkvar) { + pkvar = alloc_secvar(0); + if (!pkvar) + return OPAL_NO_MEM; + + memcpy(pkvar->var->key, "PK", 3); + pkvar->var->key_len = 3; + pkvar->flags |= SECVAR_FLAG_VOLATILE; + list_add_tail(&variable_bank, &pkvar->link); + } + if (pkvar->var->data_size == 0) + setup_mode = true; + else + setup_mode = false; + + kekvar = find_secvar("KEK", 4, &variable_bank); + if (!kekvar) { + kekvar = alloc_secvar(0); + if (!kekvar) + return OPAL_NO_MEM; + + memcpy(kekvar->var->key, "KEK", 4); + kekvar->var->key_len = 4; + kekvar->flags |= SECVAR_FLAG_VOLATILE; + list_add_tail(&variable_bank, &kekvar->link); + } + + dbvar = find_secvar("db", 3, &variable_bank); + if (!dbvar) { + dbvar = alloc_secvar(0); + if (!dbvar) + return OPAL_NO_MEM; + + memcpy(dbvar->var->key, "db", 3); + dbvar->var->key_len = 3; + dbvar->flags |= SECVAR_FLAG_VOLATILE; + list_add_tail(&variable_bank, &dbvar->link); + } + + dbxvar = find_secvar("dbx", 4, &variable_bank); + if (!dbxvar) { + dbxvar = alloc_secvar(0); + if (!dbxvar) + return OPAL_NO_MEM; + + memcpy(dbxvar->var->key, "dbx", 4); + dbxvar->var->key_len = 4; + dbxvar->flags |= SECVAR_FLAG_VOLATILE; + list_add_tail(&variable_bank, &dbxvar->link); + } + + tsvar = find_secvar("TS", 3, &variable_bank); + // Should only ever happen on first boot + if (!tsvar) { + tsvar = alloc_secvar(sizeof(struct efi_time) * 4); + if (!tsvar) + return OPAL_NO_MEM; + + memcpy(tsvar->var->key, "TS", 3); + tsvar->var->key_len = 3; + tsvar->var->data_size = sizeof(struct efi_time) * 4; + memset(tsvar->var->data, 0, tsvar->var->data_size); + //tsvar->flags |= SECVAR_FLAG_VOLATILE; + list_add_tail(&variable_bank, &tsvar->link); + } + + return OPAL_SUCCESS; +}; + +/** + * Returns true if we are in Setup Mode + * + * Setup Mode is active if we have no PK. + * Otherwise, we are in user mode. + */ +/** +static int is_setup_mode(void) +{ + struct secvar_node *setup; + + setup = find_secvar((char *)"PK", 3, &variable_bank); + + // Not sure why this wouldn't exist + if (!setup) + return 1; + + return !setup->var->data_size; +} +**/ + +/** + * Update the variable with the new value. + */ +static int add_to_variable_bank(struct secvar *secvar, void *data, uint64_t dsize) +{ + struct secvar_node *node; + + node = find_secvar(secvar->key, secvar->key_len, &variable_bank); + if (!node) + return OPAL_INTERNAL_ERROR; + + // Expand the secvar allocated memory if needed + if (node->size < dsize) + if (realloc_secvar(node, dsize)) + return OPAL_NO_MEM; + + node->var->data_size = dsize; + memcpy(node->var->data, data, dsize); + node->flags &= ~SECVAR_FLAG_VOLATILE; // Clear the volatile bit when updated + + return 0; +} + +static struct efi_time *get_last_timestamp(char *key) +{ + struct secvar_node *node; + struct efi_time *prev; + char *timestamp_list; + u8 off; + + node = find_secvar("TS", 3, &variable_bank); + if (!strncmp(key, "PK", 3)) + off = 0; + else if (!strncmp(key, "KEK", 4)) + off = 1; + else if (!strncmp(key, "db", 3)) + off = 2; + else if (!strncmp(key, "dbx", 4)) + off = 3; + else + return NULL; // unexpected variable name? + + timestamp_list = node->var->data; + if (!timestamp_list) + return NULL; + + prev = (struct efi_time *) (timestamp_list + (off * sizeof(struct efi_time))); + + return prev; +} + +// Update the TS variable with the new timestamp +static int update_timestamp(char *key, struct efi_time *timestamp) +{ + struct efi_time *prev; + + prev = get_last_timestamp(key); + if (prev == NULL) + return OPAL_PARAMETER; + + memcpy(prev, timestamp, sizeof(struct efi_time)); + + printf("updated prev year is %d month %d day %d\n", le16_to_cpu(prev->year), prev->month, prev->day); +// add_to_variable_bank(node->var, timestamp_list, node->var->data_size); + + return OPAL_SUCCESS; +} + +static int check_timestamp(char *key, struct efi_time *timestamp) +{ + struct efi_time *prev; + char *current = NULL; + char *last =NULL; + int s1 = 0; + + prev = get_last_timestamp(key); + if (prev == NULL) + return OPAL_PARAMETER; + + printf("timestamp year is %d month %d day %d\n", le16_to_cpu(timestamp->year), timestamp->month, timestamp->day); + printf("prev year is %d month %d day %d\n", le16_to_cpu(prev->year), prev->month, prev->day); + if (le16_to_cpu(timestamp->year) > le16_to_cpu(prev->year)) + return OPAL_SUCCESS; + if (le16_to_cpu(timestamp->year) < le16_to_cpu(prev->year)) + return OPAL_PERMISSION; + + current = &(timestamp->month); + last = &(prev->month); + + s1 = memcmp(current, last, 5); + if (s1 <= 0) { + printf("s1 is %d\n", s1); + return OPAL_PERMISSION; + } + + return OPAL_SUCCESS; +} + +/* + * Verify the PKCS7 signature on the signed data. + */ +static int verify_signature(void *auth_buffer, char *newcert, + uint64_t new_data_size, struct secvar *avar) +{ + struct efi_variable_authentication_2 *auth; + mbedtls_pkcs7 *pkcs7; + mbedtls_x509_crt x509; + char *checkpkcs7cert; + char *signing_cert = NULL; + char *x509_buf; + int len; + int signing_cert_size; + int rc; + char *errbuf; + int eslvarsize; + int offset = 0; + + auth = auth_buffer; + len = get_pkcs7_len(auth); + pkcs7 = malloc(sizeof(struct mbedtls_pkcs7)); + mbedtls_pkcs7_init(pkcs7); + + rc = mbedtls_pkcs7_parse_der( + (const unsigned char *)auth->auth_info.cert_data, + (const unsigned int)len, pkcs7); + if (rc) { + prlog(PR_ERR, "Parsing pkcs7 failed %04x\n", rc); + goto pkcs7out; + } + + checkpkcs7cert = zalloc(2048); + mbedtls_x509_crt_info(checkpkcs7cert, 2048, "CRT:", &(pkcs7->signed_data.certs)); + prlog(PR_DEBUG, "%s \n", checkpkcs7cert); + free(checkpkcs7cert); + + prlog(PR_INFO, "Load the signing certificate from the keystore"); + + eslvarsize = avar->data_size; + + while (eslvarsize > 0) { + prlog(PR_DEBUG, "esl var size size is %d offset is %d\n", eslvarsize, offset); + if (eslvarsize < sizeof(EFI_SIGNATURE_LIST)) + break; + + signing_cert_size = get_esl_cert_size(avar->data + offset); + if (!signing_cert_size) { + rc = OPAL_PERMISSION; + break; + } + + signing_cert = zalloc(signing_cert_size); + get_esl_cert(avar->data + offset, &signing_cert); + + mbedtls_x509_crt_init(&x509); + rc = mbedtls_x509_crt_parse(&x509, signing_cert, signing_cert_size); + + /* If failure in parsing the certificate, try next */ + if(rc) { + prlog(PR_INFO, "X509 certificate parsing failed %04x\n", rc); + goto next; + } + + x509_buf = zalloc(2048); + mbedtls_x509_crt_info(x509_buf, 2048, "CRT:", &x509); + prlog(PR_INFO, "%s \n", x509_buf); + free(x509_buf); + rc = mbedtls_pkcs7_signed_data_verify(pkcs7, &x509, newcert, new_data_size); + + /* If find a signing certificate, you are done */ + if (rc == 0) { + if (signing_cert) + free(signing_cert); + mbedtls_x509_crt_free(&x509); + prlog(PR_INFO, "Signature Verification passed\n"); + break; + } + + errbuf = zalloc(1024); + mbedtls_strerror(rc, errbuf, 1024); + prlog(PR_INFO, "Signature Verification failed %02x %s\n", rc, errbuf); + free(errbuf); + +next: + offset += get_esl_signature_list_size(avar->data + offset); + eslvarsize = eslvarsize - offset; + mbedtls_x509_crt_free(&x509); + if (signing_cert) + free(signing_cert); + + } + +pkcs7out: + mbedtls_pkcs7_free(pkcs7); + free(pkcs7); + + return rc; +} + + +/** + * Create the single buffer + * name || vendor guid || attributes || timestamp || newcontent + * which is submitted as signed by the user. + */ +static int get_data_to_verify(char *key, char *new_data, + uint64_t new_data_size, + char **buffer, + uint64_t *buffer_size, struct efi_time *timestamp) +{ + le32 attr = cpu_to_le32(SECVAR_ATTRIBUTES); + int size = 0; + int varlen; + char *wkey; + uuid_t guid; + + if (key_equals(key, "PK") + || key_equals(key, "KEK")) + guid = EFI_GLOBAL_VARIABLE_GUID; + + if (key_equals(key, "db") + || key_equals(key, "dbx")) + guid = EFI_IMAGE_SECURITY_DATABASE_GUID; + + // Convert utf8 name to ucs2 width + varlen = strlen(key) * 2; + wkey = utf8_to_ucs2(key, strlen(key)); + + // Prepare the single buffer + *buffer_size = varlen + UUID_SIZE + sizeof(attr) + + sizeof(struct efi_time) + new_data_size; + *buffer = zalloc(*buffer_size); + + memcpy(*buffer + size, wkey, varlen); + size = size + varlen; + memcpy(*buffer + size, &guid, sizeof(guid)); + size = size + sizeof(guid); + memcpy(*buffer + size, &attr, sizeof(attr)); + size = size + sizeof(attr); + memcpy(*buffer + size, timestamp , sizeof(struct efi_time)); + size = size + sizeof(struct efi_time); + + memcpy(*buffer + size, new_data, new_data_size); + size = size + new_data_size; + + free(wkey); + + return 0; +} + +static int edk2_compat_process(void) +{ + char *auth_buffer = NULL; + uint64_t auth_buffer_size = 0; + struct efi_time *timestamp = NULL; + const char *key_authority[3]; + char *newesl = NULL; + uint64_t new_data_size = 0; + char *tbhbuffer = NULL; + uint64_t tbhbuffersize = 0; + struct secvar_node *anode = NULL; + struct secvar_node *node = NULL; + int rc = 0; + int pk_updated = 0; + int i; + + //setup_mode = is_setup_mode(); + prlog(PR_INFO, "Setup mode = %d\n", setup_mode); + + /* Loop through each command in the update bank. + * If any command fails, it just loops out of the update bank. + * It should also clear the update bank. + */ + list_for_each(&update_bank, node, link) { + + /* Submitted data is auth_2 descriptor + new ESL data + * Extract the auth_2 2 descriptor + */ + printf("setup mode is %d\n", setup_mode); + prlog(PR_INFO, "update for %s\n", node->var->key); + auth_buffer_size = get_auth_descriptor2(node->var->data, &auth_buffer); + if (auth_buffer_size <= 0) + return OPAL_PARAMETER; + + if (node->var->data_size < auth_buffer_size) { + rc = OPAL_PARAMETER; + goto out; + } + + rc = get_timestamp_from_auth(auth_buffer, ×tamp); + if (rc < 0) + goto out; + + rc = check_timestamp(node->var->key, timestamp); + if (rc) + goto out; + + /* Calculate the size of new ESL data */ + new_data_size = node->var->data_size - auth_buffer_size; + newesl = zalloc(new_data_size); + memcpy(newesl, node->var->data + auth_buffer_size, new_data_size); + + if (!setup_mode) { + /* Prepare the data to be verified */ + rc = get_data_to_verify(node->var->key, newesl, + new_data_size, &tbhbuffer, + &tbhbuffersize, timestamp); + + /* Get the authority to verify the signature */ + get_key_authority(key_authority, node->var->key); + i = 0; + + /* Try for all the authorities that are allowed to sign. + * For eg. db/dbx can be signed by both PK or KEK + */ + while (key_authority[i] != NULL) { + prlog(PR_DEBUG, "key is %s\n", node->var->key); + prlog(PR_DEBUG, "key authority is %s\n", key_authority[i]); + anode = find_secvar(key_authority[i], strlen(key_authority[i]) + 1, + &variable_bank); + if (!anode) { + rc = OPAL_PERMISSION; + goto out; + } + if (anode->var->data_size == 0) { + rc = OPAL_PERMISSION; + goto out; + } + + /* Verify the signature */ + rc = verify_signature(auth_buffer, tbhbuffer, + tbhbuffersize, anode->var); + + /* Break if signature verification is successful */ + if (!rc) + break; + i++; + } + } + + if (rc) + goto out; + + /* + * If reached here means, signature is verified so update the + * value in the variable bank + */ + add_to_variable_bank(node->var, newesl, new_data_size); + // Update the TS variable with the new timestamp + update_timestamp(node->var->key, timestamp); + + /* If the PK is updated, update the secure boot state of the + * system at the end of processing */ + if (key_equals(node->var->key, "PK")) { + pk_updated = 1; + if(new_data_size == 0) + setup_mode = true; + else + setup_mode = false; + printf("setup mode is %d\n", setup_mode); + } + } + + if (pk_updated) { + // Store the updated pk in TPMNV on p9 + if (proc_gen == proc_gen_p9) { + rc = edk2_p9_write_pk(); + prlog(PR_INFO, "edk2_p9_write rc=%d\n", rc); + } + } + +out: + if (auth_buffer) + free(auth_buffer); + if (newesl) + free(newesl); + if (tbhbuffer) + free(tbhbuffer); + + clear_bank_list(&update_bank); + + return rc; +} + +static int edk2_compat_post_process(void) +{ + printf("setup mode is %d\n", setup_mode); + if (!setup_mode) { + secvar_set_secure_mode(); + prlog(PR_INFO, "Enforcing OS secure mode\n"); + } + + return 0; +} + +static bool is_pkcs7_sig_format(void *data) +{ + struct efi_variable_authentication_2 *auth = data; + uuid_t pkcs7_guid = EFI_CERT_TYPE_PKCS7_GUID; + + if(!(memcmp(&auth->auth_info.cert_type, &pkcs7_guid, 16) == 0)) + return false; + + return true; +} + +static int edk2_compat_validate(struct secvar *var) +{ + + /* + * Checks if the update is for supported + * Non-volatile secure variales + */ + if (!key_equals(var->key, "PK") + && !key_equals(var->key, "KEK") + && !key_equals(var->key, "db") + && !key_equals(var->key, "dbx")) + return -1; + + /* + * PK update should contain single ESL. + */ + //Not sure if we need to restrict it but, am adding as of now. + //Feel free to remove it if you don't it as good idea + if (key_equals(var->key, "PK")) { + printf("check if single PK\n"); + if (!is_single_pk(var->data, var->data_size)) { + printf("not single pk\n"); + return -1; + } + } + + /* + * Check that signature type is PKCS7 + */ + if (!is_pkcs7_sig_format(var->data)) + return -1; + //Some more checks needs to be added: + // - check guid + // - check auth struct + // - possibly check signature? can't add but can validate + + return 0; +}; + +struct secvar_backend_driver edk2_compatible_v1 = { + .pre_process = edk2_compat_pre_process, + .process = edk2_compat_process, + .post_process = edk2_compat_post_process, + .validate = edk2_compat_validate, + .compatible = "ibm,edk2-compat-v1", +}; diff --git a/libstb/secvar/backend/edk2.h b/libstb/secvar/backend/edk2.h new file mode 100644 index 00000000..29874ef7 --- /dev/null +++ b/libstb/secvar/backend/edk2.h @@ -0,0 +1,243 @@ +/* Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved. This + * program and the accompanying materials are licensed and made available + * under the terms and conditions of the 2-Clause BSD License which + * accompanies this distribution. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * This file is derived from the following files referred from edk2-staging[1] repo + * of tianocore + * + * MdePkg/Include/Guid/GlobalVariable.h + * MdePkg/Include/Guid/WinCertificate.h + * MdePkg/Include/Uefi/UefiMultiPhase.h + * MdePkg/Include/Uefi/UefiBaseType.h + * MdePkg/Include/Guid/ImageAuthentication.h + * + * [1] https://github.com/tianocore/edk2-staging + * + * Copyright 2019 IBM Corp. + */ + +#ifndef __EDK2_H__ +#define __EDK2_H__ + +#define UUID_SIZE 16 + +typedef struct { + u8 b[UUID_SIZE]; +} uuid_t; + +#define EFI_GLOBAL_VARIABLE_GUID (uuid_t){{0x61, 0xDF, 0xe4, 0x8b, 0xca, 0x93, 0xd2, 0x11, 0xaa, \ + 0x0d, 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c}} + +#define EFI_IMAGE_SECURITY_DATABASE_GUID (uuid_t){{0xcb, 0xb2, 0x19, 0xd7, 0x3a, 0x3d, 0x96, 0x45, \ + 0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f}} + +#define SECVAR_ATTRIBUTES 39 + +/// +/// This identifies a signature based on an X.509 certificate. If the signature is an X.509 +/// certificate then verification of the signature of an image should validate the public +/// key certificate in the image using certificate path verification, up to this X.509 +/// certificate as a trusted root. The SignatureHeader size shall always be 0. The +/// SignatureSize may vary but shall always be 16 (size of the SignatureOwner component) + +/// the size of the certificate itself. +/// Note: This means that each certificate will normally be in a separate EFI_SIGNATURE_LIST. +/// + +#define EFI_CERT_RSA2048_GUID \ + (UUID_INIT) (0x3c5766e8, 0x269c, 0x4e34, 0xaa, 0x14, 0xed, 0x77, 0x6e, 0x85, 0xb3, 0xb6) + +#define EFI_CERT_TYPE_PKCS7_GUID (uuid_t){{0x9d, 0xd2, 0xaf, 0x4a, 0xdf, 0x68, 0xee, 0x49, \ + 0x8a, 0xa9, 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7}} + +#define EFI_VARIABLE_NON_VOLATILE 0x00000001 +#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x00000002 +#define EFI_VARIABLE_RUNTIME_ACCESS 0x00000004 + +/* + * Attributes of Authenticated Variable + */ +#define EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS 0x00000020 +#define EFI_VARIABLE_APPEND_WRITE 0x00000040 +/* + * NOTE: EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS is deprecated and should be + * considered reserved. + */ +#define EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS 0x00000010 + +/* + * win_certificate.w_certificate_type + */ +#define WIN_CERT_TYPE_PKCS_SIGNED_DATA 0x0002 + +#define SECURE_BOOT_MODE_ENABLE 1 +#define SECURE_BOOT_MODE_DISABLE 0 +/// +/// Depricated value definition for SetupMode variable +/// +#define SETUP_MODE 1 +#define USER_MODE 0 + +/* + * EFI Time Abstraction: + * Year: 1900 - 9999 + * Month: 1 - 12 + * Day: 1 - 31 + * Hour: 0 - 23 + * Minute: 0 - 59 + * Second: 0 - 59 + * Nanosecond: 0 - 999,999,999 + * TimeZone: -1440 to 1440 or 2047 + */ +struct efi_time { + u16 year; + u8 month; + u8 day; + u8 hour; + u8 minute; + u8 second; + u8 pad1; + u32 nanosecond; + s16 timezone; + u8 daylight; + u8 pad2; +}; +//*********************************************************************** +// Signature Database +//*********************************************************************** +/// +/// The format of a signature database. +/// +#pragma pack(1) + +typedef struct { + /// + /// An identifier which identifies the agent which added the signature to the list. + /// + uuid_t SignatureOwner; + /// + /// The format of the signature is defined by the SignatureType. + /// + unsigned char SignatureData[0]; +} EFI_SIGNATURE_DATA; + +typedef struct { + /// + /// Type of the signature. GUID signature types are defined in below. + /// + uuid_t SignatureType; + /// + /// Total size of the signature list, including this header. + /// + uint32_t SignatureListSize; + /// + /// Size of the signature header which precedes the array of signatures. + /// + uint32_t SignatureHeaderSize; + /// + /// Size of each signature. + /// + uint32_t SignatureSize; + /// + /// Header before the array of signatures. The format of this header is specified + /// by the SignatureType. + /// UINT8 SignatureHeader[SignatureHeaderSize]; + /// + /// An array of signatures. Each signature is SignatureSize bytes in length. + /// EFI_SIGNATURE_DATA Signatures[][SignatureSize]; + /// +} EFI_SIGNATURE_LIST; + + +/* + * The win_certificate structure is part of the PE/COFF specification. + */ +struct win_certificate { + /* + * The length of the entire certificate, including the length of the + * header, in bytes. + */ + u32 dw_length; + /* + * The revision level of the WIN_CERTIFICATE structure. The current + * revision level is 0x0200. + */ + u16 w_revision; + /* + * The certificate type. See WIN_CERT_TYPE_xxx for the UEFI certificate + * types. The UEFI specification reserves the range of certificate type + * values from 0x0EF0 to 0x0EFF. + */ + u16 w_certificate_type; + /* + * The following is the actual certificate. The format of + * the certificate depends on wCertificateType. + */ + /// UINT8 bCertificate[ANYSIZE_ARRAY]; +}; + +/* + * Certificate which encapsulates a GUID-specific digital signature + */ +struct win_certificate_uefi_guid { + /* + * This is the standard win_certificate header, where w_certificate_type + * is set to WIN_CERT_TYPE_EFI_GUID. + */ + struct win_certificate hdr; + /* + * This is the unique id which determines the format of the cert_data. + */ + uuid_t cert_type; + /* + * The following is the certificate data. The format of the data is + * determined by the @cert_type. If @cert_type is + * EFI_CERT_TYPE_RSA2048_SHA256_GUID, the @cert_data will be + * EFI_CERT_BLOCK_RSA_2048_SHA256 structure. + */ + u8 cert_data[1]; +}; +/* + * When the attribute EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS is set, + * then the Data buffer shall begin with an instance of a complete (and + * serialized) EFI_VARIABLE_AUTHENTICATION_2 descriptor. The descriptor shall be + * followed by the new variable value and DataSize shall reflect the combined + * size of the descriptor and the new variable value. The authentication + * descriptor is not part of the variable data and is not returned by subsequent + * calls to GetVariable(). + */ +struct efi_variable_authentication_2 { + /* + * For the TimeStamp value, components Pad1, Nanosecond, TimeZone, Daylight and + * Pad2 shall be set to 0. This means that the time shall always be expressed in GMT. + */ + struct efi_time timestamp; + /* + * Only a CertType of EFI_CERT_TYPE_PKCS7_GUID is accepted. + */ + struct win_certificate_uefi_guid auth_info; +}; + +#endif