From 87562bc5c1a6863009fe244c306b9446b0ceae9c Mon Sep 17 00:00:00 2001 From: Nayna Jain Date: Wed, 16 Sep 2020 11:21:29 -0500 Subject: secvar/backend: add edk2 derived key updates processing 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 9. Resetting keystore if the hardware key hash changes [1] https://github.com/tianocore/edk2-staging.git Signed-off-by: Nayna Jain Signed-off-by: Eric Richter Signed-off-by: Oliver O'Halloran --- libstb/secvar/backend/Makefile.inc | 4 +- libstb/secvar/backend/edk2-compat-process.c | 762 ++++++++++++++++++++++++++++ libstb/secvar/backend/edk2-compat-process.h | 63 +++ libstb/secvar/backend/edk2-compat-reset.c | 115 +++++ libstb/secvar/backend/edk2-compat-reset.h | 24 + libstb/secvar/backend/edk2-compat.c | 282 ++++++++++ libstb/secvar/backend/edk2.h | 251 +++++++++ 7 files changed, 1499 insertions(+), 2 deletions(-) create mode 100644 libstb/secvar/backend/edk2-compat-process.c create mode 100644 libstb/secvar/backend/edk2-compat-process.h create mode 100644 libstb/secvar/backend/edk2-compat-reset.c create mode 100644 libstb/secvar/backend/edk2-compat-reset.h create mode 100644 libstb/secvar/backend/edk2-compat.c create mode 100644 libstb/secvar/backend/edk2.h (limited to 'libstb') diff --git a/libstb/secvar/backend/Makefile.inc b/libstb/secvar/backend/Makefile.inc index 6f491a6..bc987f6 100644 --- a/libstb/secvar/backend/Makefile.inc +++ b/libstb/secvar/backend/Makefile.inc @@ -1,11 +1,11 @@ # SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later # -*-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 edk2-compat-process.c edk2-compat-reset.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-process.c b/libstb/secvar/backend/edk2-compat-process.c new file mode 100644 index 0000000..0129023 --- /dev/null +++ b/libstb/secvar/backend/edk2-compat-process.c @@ -0,0 +1,762 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* Copyright 2020 IBM Corp. */ +#ifndef pr_fmt +#define pr_fmt(fmt) "EDK2_COMPAT: " fmt +#endif + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "libstb/crypto/pkcs7/pkcs7.h" +#include "edk2.h" +#include "../secvar.h" +#include "edk2-compat-process.h" + +bool setup_mode; + +int update_variable_in_bank(struct secvar *update_var, const char *data, + const uint64_t dsize, struct list_head *bank) +{ + struct secvar *var; + + var = find_secvar(update_var->key, update_var->key_len, bank); + if (!var) + return OPAL_EMPTY; + + /* Reallocate the data memory, if there is change in data size */ + if (var->data_size < dsize) + if (realloc_secvar(var, dsize)) + return OPAL_NO_MEM; + + if (dsize && data) + memcpy(var->data, data, dsize); + var->data_size = dsize; + + /* Clear the volatile bit only if updated with positive data size */ + if (dsize) + var->flags &= ~SECVAR_FLAG_VOLATILE; + else + var->flags |= SECVAR_FLAG_VOLATILE; + + if (key_equals(update_var->key, "PK") || key_equals(update_var->key, "HWKH")) + var->flags |= SECVAR_FLAG_PROTECTED; + + return 0; +} + +/* Expand char to wide character size */ +static char *char_to_wchar(const char *key, const size_t keylen) +{ + int i; + char *str; + + str = zalloc(keylen * 2); + if (!str) + return NULL; + + for (i = 0; i < keylen*2; key++) { + str[i++] = *key; + str[i++] = '\0'; + } + + return str; +} + +/* 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; + + if (key_equals(key, "PK")) { + ret[i++] = "PK"; + } else if (key_equals(key, "KEK")) { + ret[i++] = "PK"; + } else if (key_equals(key, "db") || key_equals(key, "dbx")) { + ret[i++] = "KEK"; + ret[i++] = "PK"; + } + + ret[i] = NULL; +} + +static EFI_SIGNATURE_LIST* get_esl_signature_list(const char *buf, size_t buflen) +{ + EFI_SIGNATURE_LIST *list = NULL; + + if (buflen < sizeof(EFI_SIGNATURE_LIST) || !buf) + return NULL; + + list = (EFI_SIGNATURE_LIST *)buf; + + return list; +} + +/* Returns the size of the complete ESL. */ +static int32_t get_esl_signature_list_size(const char *buf, const size_t buflen) +{ + EFI_SIGNATURE_LIST *list = get_esl_signature_list(buf, buflen); + + if (!list) + return OPAL_PARAMETER; + + prlog(PR_DEBUG, "size of signature list size is %u\n", + le32_to_cpu(list->SignatureListSize)); + + return le32_to_cpu(list->SignatureListSize); +} + +/* + * Copies the certificate from the ESL into cert buffer and returns the size + * of the certificate + */ +static int get_esl_cert(const char *buf, const size_t buflen, char **cert) +{ + size_t sig_data_offset; + size_t size; + EFI_SIGNATURE_LIST *list = get_esl_signature_list(buf, buflen); + + if (!list) + return OPAL_PARAMETER; + + assert(cert != NULL); + + size = le32_to_cpu(list->SignatureSize) - sizeof(uuid_t); + + 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(EFI_SIGNATURE_LIST) + + le32_to_cpu(list->SignatureHeaderSize) + + 16 * sizeof(uint8_t); + if (sig_data_offset > buflen) + return OPAL_PARAMETER; + + *cert = zalloc(size); + if (!(*cert)) + return OPAL_NO_MEM; + + /* Since buf can have more than one ESL, copy only the size calculated + * to return single ESL */ + 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 size_t get_pkcs7_len(const struct efi_variable_authentication_2 *auth) +{ + uint32_t dw_length; + size_t size; + + assert(auth != NULL); + + dw_length = le32_to_cpu(auth->auth_info.hdr.dw_length); + 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; +} + +int get_auth_descriptor2(const void *buf, const size_t buflen, void **auth_buffer) +{ + const struct efi_variable_authentication_2 *auth = buf; + int auth_buffer_size; + size_t len; + + assert(auth_buffer != NULL); + if (buflen < sizeof(struct efi_variable_authentication_2) + || !buf) + return OPAL_PARAMETER; + + len = get_pkcs7_len(auth); + /* pkcs7 content length cannot be greater than buflen */ + if (len > buflen) + return OPAL_PARAMETER; + + 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; + + /* + * Data = auth descriptor + new ESL data. + * Extracts only the auth descriptor from data. + */ + memcpy(*auth_buffer, buf, auth_buffer_size); + + return auth_buffer_size; +} + +static bool validate_cert(char *signing_cert, int signing_cert_size) +{ + mbedtls_x509_crt x509; + char *x509_buf = NULL; + int rc; + + mbedtls_x509_crt_init(&x509); + rc = mbedtls_x509_crt_parse(&x509, signing_cert, signing_cert_size); + + /* If failure in parsing the certificate, exit */ + if(rc) { + prlog(PR_ERR, "X509 certificate parsing failed %04x\n", rc); + return false; + } + + x509_buf = zalloc(CERT_BUFFER_SIZE); + rc = mbedtls_x509_crt_info(x509_buf, CERT_BUFFER_SIZE, "CRT:", &x509); + + mbedtls_x509_crt_free(&x509); + free(x509_buf); + x509_buf = NULL; + + /* If failure in reading the certificate, exit */ + if (rc < 0) + return false; + + return true; +} + +static bool validate_hash(uuid_t type, int size) +{ + if (uuid_equals(&type, &EFI_CERT_SHA1_GUID) && (size == 20)) + return true; + + if (uuid_equals(&type, &EFI_CERT_SHA224_GUID) && (size == 28)) + return true; + + if (uuid_equals(&type, &EFI_CERT_SHA256_GUID) && (size == 32)) + return true; + + if (uuid_equals(&type, &EFI_CERT_SHA384_GUID) && (size == 48)) + return true; + + if (uuid_equals(&type, &EFI_CERT_SHA512_GUID) && (size == 64)) + return true; + + return false; +} + +int validate_esl_list(const char *key, const char *esl, const size_t size) +{ + int count = 0; + int dsize; + char *data = NULL; + int eslvarsize = size; + int eslsize; + int rc = OPAL_SUCCESS; + int offset = 0; + EFI_SIGNATURE_LIST *list = NULL; + + 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; + + /* Check Supported ESL Type */ + list = get_esl_signature_list(esl, eslvarsize); + + if (!list) + return OPAL_PARAMETER; + + prlog(PR_DEBUG, "size of signature list size is %u\n", + le32_to_cpu(list->SignatureListSize)); + + /* Calculate the size of the ESL */ + eslsize = le32_to_cpu(list->SignatureListSize); + + /* If could not extract the size */ + if (eslsize <= 0) { + prlog(PR_ERR, "Invalid size of the ESL\n"); + rc = OPAL_PARAMETER; + break; + } + + /* Extract the certificate from the ESL */ + dsize = get_esl_cert(esl, eslvarsize, &data); + if (dsize < 0) { + rc = dsize; + break; + } + + if (key_equals(key, "dbx")) { + if (!validate_hash(list->SignatureType, dsize)) { + rc = OPAL_PARAMETER; + break; + } + } else { + if (!uuid_equals(&list->SignatureType, &EFI_CERT_X509_GUID) + || !validate_cert(data, dsize)) { + rc = OPAL_PARAMETER; + break; + } + } + + count++; + + /* Look for the next ESL */ + offset = offset + eslsize; + eslvarsize = eslvarsize - eslsize; + free(data); + /* Since we are going to allocate again in the next iteration */ + data = NULL; + } + + if (rc == OPAL_SUCCESS) { + if (key_equals(key, "PK") && (count > 1)) { + prlog(PR_ERR, "PK can only be one\n"); + rc = OPAL_PARAMETER; + } else { + rc = count; + } + } + + prlog(PR_INFO, "Total ESLs are %d\n", rc); + return rc; +} + +/* Get the timestamp for the last update of the give key */ +static struct efi_time *get_last_timestamp(const char *key, char *last_timestamp) +{ + struct efi_time *timestamp = (struct efi_time*)last_timestamp; + + if (!last_timestamp) + return NULL; + + if (key_equals(key, "PK")) + return ×tamp[0]; + else if (key_equals(key, "KEK")) + return ×tamp[1]; + else if (key_equals(key, "db")) + return ×tamp[2]; + else if (key_equals(key, "dbx")) + return ×tamp[3]; + else + return NULL; +} + +int update_timestamp(const char *key, const struct efi_time *timestamp, char *last_timestamp) +{ + struct efi_time *prev; + + prev = get_last_timestamp(key, last_timestamp); + if (prev == NULL) + return OPAL_INTERNAL_ERROR; + + /* Update with new timestamp */ + memcpy(prev, timestamp, sizeof(struct efi_time)); + + prlog(PR_DEBUG, "updated prev year is %d month %d day %d\n", + le16_to_cpu(prev->year), prev->month, prev->day); + + return OPAL_SUCCESS; +} + +static uint64_t unpack_timestamp(const struct efi_time *timestamp) +{ + uint64_t val = 0; + uint16_t year = le32_to_cpu(timestamp->year); + + /* pad1, nanosecond, timezone, daylight and pad2 are meant to be zero */ + val |= ((uint64_t) timestamp->pad1 & 0xFF) << 0; + val |= ((uint64_t) timestamp->second & 0xFF) << (1*8); + val |= ((uint64_t) timestamp->minute & 0xFF) << (2*8); + val |= ((uint64_t) timestamp->hour & 0xFF) << (3*8); + val |= ((uint64_t) timestamp->day & 0xFF) << (4*8); + val |= ((uint64_t) timestamp->month & 0xFF) << (5*8); + val |= ((uint64_t) year) << (6*8); + + return val; +} + +int check_timestamp(const char *key, const struct efi_time *timestamp, + char *last_timestamp) +{ + struct efi_time *prev; + uint64_t new; + uint64_t last; + + prev = get_last_timestamp(key, last_timestamp); + if (prev == NULL) + return OPAL_INTERNAL_ERROR; + + prlog(PR_DEBUG, "timestamp year is %d month %d day %d\n", + le16_to_cpu(timestamp->year), timestamp->month, + timestamp->day); + prlog(PR_DEBUG, "prev year is %d month %d day %d\n", + le16_to_cpu(prev->year), prev->month, prev->day); + + new = unpack_timestamp(timestamp); + last = unpack_timestamp(prev); + + if (new > last) + return OPAL_SUCCESS; + + return OPAL_PERMISSION; +} + +/* Extract PKCS7 from the authentication header */ +static mbedtls_pkcs7* get_pkcs7(const struct efi_variable_authentication_2 *auth) +{ + char *checkpkcs7cert = NULL; + size_t len; + mbedtls_pkcs7 *pkcs7 = NULL; + int rc; + + len = get_pkcs7_len(auth); + + pkcs7 = malloc(sizeof(struct mbedtls_pkcs7)); + if (!pkcs7) + return NULL; + + mbedtls_pkcs7_init(pkcs7); + rc = mbedtls_pkcs7_parse_der( auth->auth_info.cert_data, len, pkcs7); + if (rc <= 0) { + prlog(PR_ERR, "Parsing pkcs7 failed %04x\n", rc); + goto out; + } + + checkpkcs7cert = zalloc(CERT_BUFFER_SIZE); + if (!checkpkcs7cert) + goto out; + + rc = mbedtls_x509_crt_info(checkpkcs7cert, CERT_BUFFER_SIZE, "CRT:", + &(pkcs7->signed_data.certs)); + if (rc < 0) { + prlog(PR_ERR, "Failed to parse the certificate in PKCS7 structure\n"); + free(checkpkcs7cert); + goto out; + } + + prlog(PR_DEBUG, "%s \n", checkpkcs7cert); + free(checkpkcs7cert); + return pkcs7; + +out: + mbedtls_pkcs7_free(pkcs7); + pkcs7 = NULL; + return pkcs7; +} + +/* Verify the PKCS7 signature on the signed data. */ +static int verify_signature(const struct efi_variable_authentication_2 *auth, + const char *newcert, const size_t new_data_size, + const struct secvar *avar) +{ + mbedtls_pkcs7 *pkcs7 = NULL; + mbedtls_x509_crt x509; + char *signing_cert = NULL; + char *x509_buf = NULL; + int signing_cert_size; + int rc = 0; + char *errbuf; + int eslvarsize; + int eslsize; + int offset = 0; + + if (!auth) + return OPAL_PARAMETER; + + /* Extract the pkcs7 from the auth structure */ + pkcs7 = get_pkcs7(auth); + /* Failure to parse pkcs7 implies bad input. */ + if (!pkcs7) + return OPAL_PARAMETER; + + prlog(PR_INFO, "Load the signing certificate from the keystore"); + + eslvarsize = avar->data_size; + + /* Variable is not empty */ + 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; + + /* Calculate the size of the ESL */ + eslsize = get_esl_signature_list_size(avar->data + offset, + eslvarsize); + /* If could not extract the size */ + if (eslsize <= 0) { + rc = OPAL_PARAMETER; + break; + } + + /* Extract the certificate from the ESL */ + signing_cert_size = get_esl_cert(avar->data + offset, + eslvarsize, &signing_cert); + if (signing_cert_size < 0) { + rc = signing_cert_size; + break; + } + + mbedtls_x509_crt_init(&x509); + rc = mbedtls_x509_crt_parse(&x509, + signing_cert, + signing_cert_size); + + /* This should not happen, unless something corrupted in PNOR */ + if(rc) { + prlog(PR_INFO, "X509 certificate parsing failed %04x\n", rc); + rc = OPAL_INTERNAL_ERROR; + break; + } + + x509_buf = zalloc(CERT_BUFFER_SIZE); + rc = mbedtls_x509_crt_info(x509_buf, + CERT_BUFFER_SIZE, + "CRT:", + &x509); + + /* This should not happen, unless something corrupted in PNOR */ + if (rc < 0) { + free(x509_buf); + rc = OPAL_INTERNAL_ERROR; + break; + } + + prlog(PR_INFO, "%s \n", x509_buf); + free(x509_buf); + x509_buf = NULL; + + rc = mbedtls_pkcs7_signed_hash_verify(pkcs7, &x509, newcert, new_data_size); + + /* If you find a signing certificate, you are done */ + if (rc == 0) { + prlog(PR_INFO, "Signature Verification passed\n"); + mbedtls_x509_crt_free(&x509); + break; + } + + errbuf = zalloc(MBEDTLS_ERR_BUFFER_SIZE); + mbedtls_strerror(rc, errbuf, MBEDTLS_ERR_BUFFER_SIZE); + prlog(PR_INFO, "Signature Verification failed %02x %s\n", + rc, errbuf); + free(errbuf); + + /* Look for the next ESL */ + offset = offset + eslsize; + eslvarsize = eslvarsize - eslsize; + mbedtls_x509_crt_free(&x509); + free(signing_cert); + /* Since we are going to allocate again in the next iteration */ + signing_cert = NULL; + + } + + free(signing_cert); + mbedtls_pkcs7_free(pkcs7); + free(pkcs7); + + return rc; +} + +/* + * Create the hash of the buffer + * name || vendor guid || attributes || timestamp || newcontent + * which is submitted as signed by the user. + * Returns the sha256 hash, else negative error code. + */ +static char *get_hash_to_verify(const char *key, const char *new_data, + const size_t new_data_size, + const struct efi_time *timestamp) +{ + le32 attr = cpu_to_le32(SECVAR_ATTRIBUTES); + size_t varlen; + char *wkey; + uuid_t guid; + unsigned char *hash = NULL; + const mbedtls_md_info_t *md_info; + mbedtls_md_context_t ctx; + int rc; + + md_info = mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 ); + mbedtls_md_init(&ctx); + + rc = mbedtls_md_setup(&ctx, md_info, 0); + if (rc) + goto out; + + rc = mbedtls_md_starts(&ctx); + if (rc) + goto out; + + if (key_equals(key, "PK") + || key_equals(key, "KEK")) + guid = EFI_GLOBAL_VARIABLE_GUID; + else if (key_equals(key, "db") + || key_equals(key, "dbx")) + guid = EFI_IMAGE_SECURITY_DATABASE_GUID; + else + return NULL; + + /* Expand char name to wide character width */ + varlen = strlen(key) * 2; + wkey = char_to_wchar(key, strlen(key)); + rc = mbedtls_md_update(&ctx, wkey, varlen); + free(wkey); + if (rc) + goto out; + + rc = mbedtls_md_update(&ctx, (const unsigned char *)&guid, sizeof(guid)); + if (rc) + goto out; + + rc = mbedtls_md_update(&ctx, (const unsigned char *)&attr, sizeof(attr)); + if (rc) + goto out; + + rc = mbedtls_md_update(&ctx, (const unsigned char *)timestamp, + sizeof(struct efi_time)); + if (rc) + goto out; + + rc = mbedtls_md_update(&ctx, new_data, new_data_size); + if (rc) + goto out; + + hash = zalloc(32); + if (!hash) + return NULL; + rc = mbedtls_md_finish(&ctx, hash); + if (rc) { + free(hash); + hash = NULL; + } + +out: + mbedtls_md_free(&ctx); + return hash; +} + +bool is_pkcs7_sig_format(const void *data) +{ + const struct efi_variable_authentication_2 *auth = data; + uuid_t pkcs7_guid = EFI_CERT_TYPE_PKCS7_GUID; + + return !memcmp(&auth->auth_info.cert_type, &pkcs7_guid, 16); +} + +int process_update(const struct secvar *update, char **newesl, + int *new_data_size, struct efi_time *timestamp, + struct list_head *bank, char *last_timestamp) +{ + struct efi_variable_authentication_2 *auth = NULL; + void *auth_buffer = NULL; + int auth_buffer_size = 0; + const char *key_authority[3]; + char *tbhbuffer = NULL; + size_t tbhbuffersize = 0; + struct secvar *avar = NULL; + int rc = 0; + int i; + + /* We need to split data into authentication descriptor and new ESL */ + auth_buffer_size = get_auth_descriptor2(update->data, + update->data_size, + &auth_buffer); + if ((auth_buffer_size < 0) + || (update->data_size < auth_buffer_size)) { + prlog(PR_ERR, "Invalid auth buffer size\n"); + rc = auth_buffer_size; + goto out; + } + + auth = auth_buffer; + + if (!timestamp) { + rc = OPAL_INTERNAL_ERROR; + goto out; + } + + memcpy(timestamp, auth_buffer, sizeof(struct efi_time)); + + rc = check_timestamp(update->key, timestamp, last_timestamp); + /* Failure implies probably an older command being resubmitted */ + if (rc != OPAL_SUCCESS) { + prlog(PR_INFO, "Timestamp verification failed for key %s\n", update->key); + goto out; + } + + /* Calculate the size of new ESL data */ + *new_data_size = update->data_size - auth_buffer_size; + if (*new_data_size < 0) { + prlog(PR_ERR, "Invalid new ESL (new data content) size\n"); + rc = OPAL_PARAMETER; + goto out; + } + *newesl = zalloc(*new_data_size); + if (!(*newesl)) { + rc = OPAL_NO_MEM; + goto out; + } + memcpy(*newesl, update->data + auth_buffer_size, *new_data_size); + + /* Validate the new ESL is in right format */ + rc = validate_esl_list(update->key, *newesl, *new_data_size); + if (rc < 0) { + prlog(PR_ERR, "ESL validation failed for key %s with error %04x\n", + update->key, rc); + goto out; + } + + if (setup_mode) { + rc = OPAL_SUCCESS; + goto out; + } + + /* Prepare the data to be verified */ + tbhbuffer = get_hash_to_verify(update->key, *newesl, *new_data_size, + timestamp); + if (!tbhbuffer) { + rc = OPAL_INTERNAL_ERROR; + goto out; + } + + /* Get the authority to verify the signature */ + get_key_authority(key_authority, update->key); + + /* + * Try for all the authorities that are allowed to sign. + * For eg. db/dbx can be signed by both PK or KEK + */ + for (i = 0; key_authority[i] != NULL; i++) { + prlog(PR_DEBUG, "key is %s\n", update->key); + prlog(PR_DEBUG, "key authority is %s\n", key_authority[i]); + avar = find_secvar(key_authority[i], + strlen(key_authority[i]) + 1, + bank); + if (!avar || !avar->data_size) + continue; + + /* Verify the signature */ + rc = verify_signature(auth, tbhbuffer, tbhbuffersize, + avar); + + /* Break if signature verification is successful */ + if (rc == OPAL_SUCCESS) + break; + } + +out: + free(auth_buffer); + free(tbhbuffer); + + return rc; +} diff --git a/libstb/secvar/backend/edk2-compat-process.h b/libstb/secvar/backend/edk2-compat-process.h new file mode 100644 index 0000000..737c732 --- /dev/null +++ b/libstb/secvar/backend/edk2-compat-process.h @@ -0,0 +1,63 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* Copyright 2020 IBM Corp. */ + +#ifndef __SECVAR_EDK2_COMPAT_PROCESS__ +#define __SECVAR_EDK2_COMPAT_PROCESS__ + +#ifndef pr_fmt +#define pr_fmt(fmt) "EDK2_COMPAT: " fmt +#endif + +#include +#include +#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" + +#define CERT_BUFFER_SIZE 2048 +#define MBEDTLS_ERR_BUFFER_SIZE 1024 + +#define EDK2_MAX_KEY_LEN SECVAR_MAX_KEY_LEN +#define key_equals(a,b) (!strncmp(a, b, EDK2_MAX_KEY_LEN)) +#define uuid_equals(a,b) (!memcmp(a, b, UUID_SIZE)) + +extern bool setup_mode; +extern struct list_head staging_bank; + +/* Update the variable in the variable bank with the new value. */ +int update_variable_in_bank(struct secvar *update_var, const char *data, + uint64_t dsize, struct list_head *bank); + +/* This function outputs the Authentication 2 Descriptor in the + * auth_buffer and returns the size of the buffer. Please refer to + * edk2.h for details on Authentication 2 Descriptor + */ +int get_auth_descriptor2(const void *buf, const size_t buflen, + void **auth_buffer); + +/* Check the format of the ESL */ +int validate_esl_list(const char *key, const char *esl, const size_t size); + +/* Update the TS variable with the new timestamp */ +int update_timestamp(const char *key, const struct efi_time *timestamp, char *last_timestamp); + +/* Check the new timestamp against the timestamp last update was done */ +int check_timestamp(const char *key, const struct efi_time *timestamp, char *last_timestamp); + +/* Check the GUID of the data type */ +bool is_pkcs7_sig_format(const void *data); + +/* Process the update */ +int process_update(const struct secvar *update, char **newesl, + int *neweslsize, struct efi_time *timestamp, + struct list_head *bank, char *last_timestamp); + +#endif diff --git a/libstb/secvar/backend/edk2-compat-reset.c b/libstb/secvar/backend/edk2-compat-reset.c new file mode 100644 index 0000000..cc3c6d0 --- /dev/null +++ b/libstb/secvar/backend/edk2-compat-reset.c @@ -0,0 +1,115 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* Copyright 2020 IBM Corp. */ +#include +#include +#include "edk2-compat-process.h" +#include "edk2-compat-reset.h" +#include "../secvar.h" + +int reset_keystore(struct list_head *bank) +{ + struct secvar *var; + int rc = 0; + + var = find_secvar("PK", 3, bank); + if (var) + rc = update_variable_in_bank(var, NULL, 0, bank); + if (rc) + return rc; + + var = find_secvar("KEK", 4, bank); + if (var) + rc = update_variable_in_bank(var, NULL, 0, bank); + if (rc) + return rc; + + var = find_secvar("db", 3, bank); + if (var) + rc = update_variable_in_bank(var, NULL, 0, bank); + if (rc) + return rc; + + var = find_secvar("dbx", 4, bank); + if (var) + rc = update_variable_in_bank(var, NULL, 0, bank); + if (rc) + return rc; + + var = find_secvar("TS", 3, bank); + if (var) + rc = update_variable_in_bank(var, NULL, 0, bank); + if (rc) + return rc; + + var = find_secvar("HWKH", 5, bank); + if (var) + rc = update_variable_in_bank(var, NULL, 0, bank); + + return rc; +} + + +int add_hw_key_hash(struct list_head *bank) +{ + struct secvar *var; + uint32_t hw_key_hash_size; + const char *hw_key_hash; + struct dt_node *secureboot; + + secureboot = dt_find_by_path(dt_root, "ibm,secureboot"); + if (!secureboot) + return false; + + hw_key_hash_size = dt_prop_get_u32(secureboot, "hw-key-hash-size"); + + hw_key_hash = dt_prop_get(secureboot, "hw-key-hash"); + + if (!hw_key_hash) + return OPAL_PERMISSION; + + var = new_secvar("HWKH", 5, hw_key_hash, + hw_key_hash_size, SECVAR_FLAG_PROTECTED); + list_add_tail(bank, &var->link); + + return OPAL_SUCCESS; +} + +int delete_hw_key_hash(struct list_head *bank) +{ + struct secvar *var; + int rc; + + var = find_secvar("HWKH", 5, bank); + if (!var) + return OPAL_SUCCESS; + + rc = update_variable_in_bank(var, NULL, 0, bank); + return rc; +} + +int verify_hw_key_hash(void) +{ + const char *hw_key_hash; + struct dt_node *secureboot; + struct secvar *var; + + secureboot = dt_find_by_path(dt_root, "ibm,secureboot"); + if (!secureboot) + return OPAL_INTERNAL_ERROR; + + hw_key_hash = dt_prop_get(secureboot, "hw-key-hash"); + + if (!hw_key_hash) + return OPAL_INTERNAL_ERROR; + + /* This value is from the protected storage */ + var = find_secvar("HWKH", 5, &variable_bank); + if (!var) + return OPAL_PERMISSION; + + if (memcmp(hw_key_hash, var->data, var->data_size) != 0) + return OPAL_PERMISSION; + + return OPAL_SUCCESS; +} + diff --git a/libstb/secvar/backend/edk2-compat-reset.h b/libstb/secvar/backend/edk2-compat-reset.h new file mode 100644 index 0000000..bede9c9 --- /dev/null +++ b/libstb/secvar/backend/edk2-compat-reset.h @@ -0,0 +1,24 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* Copyright 2020 IBM Corp. */ + +#ifndef __SECVAR_EDK2_COMPAT_CLEAR_KEYS__ +#define __SECVAR_EDK2_COMPAT_CLEAR_KEYS__ + +#ifndef pr_fmt +#define pr_fmt(fmt) "EDK2_COMPAT: " fmt +#endif + +/* clear all os keys and the timestamp*/ +int reset_keystore(struct list_head *bank); + +/* Compares the hw-key-hash from device tree to the value stored in + * the protected storage to ensure it is not modified */ +int verify_hw_key_hash(void); + +/* Adds hw-key-hash */ +int add_hw_key_hash(struct list_head *bank); + +/* Delete hw-key-hash */ +int delete_hw_key_hash(struct list_head *bank); + +#endif diff --git a/libstb/secvar/backend/edk2-compat.c b/libstb/secvar/backend/edk2-compat.c new file mode 100644 index 0000000..52631c0 --- /dev/null +++ b/libstb/secvar/backend/edk2-compat.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later +/* Copyright 2020 IBM Corp. */ +#ifndef pr_fmt +#define pr_fmt(fmt) "EDK2_COMPAT: " fmt +#endif + +#include +#include +#include +#include +#include +#include +#include +#include +#include "libstb/crypto/pkcs7/pkcs7.h" +#include "edk2.h" +#include "../secvar.h" +#include "edk2-compat-process.h" +#include "edk2-compat-reset.h" + +struct list_head staging_bank; + +/* + * Initializes supported variables as empty if not loaded from + * storage. Variables are initialized as volatile if not found. + * Updates should clear this flag. + * Returns OPAL Error if anything fails in initialization + */ +static int edk2_compat_pre_process(struct list_head *variable_bank, + struct list_head *update_bank __unused) +{ + struct secvar *pkvar; + struct secvar *kekvar; + struct secvar *dbvar; + struct secvar *dbxvar; + struct secvar *tsvar; + + pkvar = find_secvar("PK", 3, variable_bank); + if (!pkvar) { + pkvar = new_secvar("PK", 3, NULL, 0, SECVAR_FLAG_VOLATILE + | SECVAR_FLAG_PROTECTED); + if (!pkvar) + return OPAL_NO_MEM; + + list_add_tail(variable_bank, &pkvar->link); + } + if (pkvar->data_size == 0) + setup_mode = true; + else + setup_mode = false; + + kekvar = find_secvar("KEK", 4, variable_bank); + if (!kekvar) { + kekvar = new_secvar("KEK", 4, NULL, 0, SECVAR_FLAG_VOLATILE); + if (!kekvar) + return OPAL_NO_MEM; + + list_add_tail(variable_bank, &kekvar->link); + } + + dbvar = find_secvar("db", 3, variable_bank); + if (!dbvar) { + dbvar = new_secvar("db", 3, NULL, 0, SECVAR_FLAG_VOLATILE); + if (!dbvar) + return OPAL_NO_MEM; + + list_add_tail(variable_bank, &dbvar->link); + } + + dbxvar = find_secvar("dbx", 4, variable_bank); + if (!dbxvar) { + dbxvar = new_secvar("dbx", 4, NULL, 0, SECVAR_FLAG_VOLATILE); + if (!dbxvar) + return OPAL_NO_MEM; + + list_add_tail(variable_bank, &dbxvar->link); + } + + /* + * Should only ever happen on first boot. Timestamp is + * initialized with all zeroes. + */ + tsvar = find_secvar("TS", 3, variable_bank); + if (!tsvar) { + tsvar = alloc_secvar(3, sizeof(struct efi_time) * 4); + if (!tsvar) + return OPAL_NO_MEM; + + memcpy(tsvar->key, "TS", 3); + tsvar->key_len = 3; + tsvar->data_size = sizeof(struct efi_time) * 4; + memset(tsvar->data, 0, tsvar->data_size); + list_add_tail(variable_bank, &tsvar->link); + } + + return OPAL_SUCCESS; +}; + +static int edk2_compat_process(struct list_head *variable_bank, + struct list_head *update_bank) +{ + struct secvar *var = NULL; + struct secvar *tsvar = NULL; + struct efi_time timestamp; + char *newesl = NULL; + int neweslsize; + int rc = 0; + + prlog(PR_INFO, "Setup mode = %d\n", setup_mode); + + /* Check HW-KEY-HASH */ + if (!setup_mode) { + rc = verify_hw_key_hash(); + if (rc != OPAL_SUCCESS) { + prlog(PR_ERR, "Hardware key hash verification mismatch\n"); + rc = reset_keystore(variable_bank); + if (rc) + goto cleanup; + setup_mode = true; + goto cleanup; + } + } + + /* Return early if we have no updates to process */ + if (list_empty(update_bank)) { + return OPAL_EMPTY; + } + + /* + * Make a working copy of variable bank that is updated + * during process + */ + list_head_init(&staging_bank); + copy_bank_list(&staging_bank, variable_bank); + + /* + * 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. + */ + + /* Read the TS variable first time and then keep updating it in-memory */ + tsvar = find_secvar("TS", 3, &staging_bank); + + /* + * We cannot find timestamp variable, did someone tamper it ?, return + * OPAL_PERMISSION + */ + if (!tsvar) + return OPAL_PERMISSION; + + list_for_each(update_bank, var, link) { + + /* + * Submitted data is auth_2 descriptor + new ESL data + * Extract the auth_2 2 descriptor + */ + prlog(PR_INFO, "Update for %s\n", var->key); + + rc = process_update(var, &newesl, + &neweslsize, ×tamp, + &staging_bank, + tsvar->data); + if (rc) { + prlog(PR_ERR, "Update processing failed with rc %04x\n", rc); + break; + } + + /* + * If reached here means, signature is verified so update the + * value in the variable bank + */ + rc = update_variable_in_bank(var, + newesl, + neweslsize, + &staging_bank); + if (rc) { + prlog(PR_ERR, "Updating the variable data failed %04x\n", rc); + break; + } + + free(newesl); + newesl = NULL; + /* Update the TS variable with the new timestamp */ + rc = update_timestamp(var->key, + ×tamp, + tsvar->data); + if (rc) { + prlog (PR_ERR, "Variable updated, but timestamp updated failed %04x\n", rc); + break; + } + + /* + * If the PK is updated, update the secure boot state of the + * system at the end of processing + */ + if (key_equals(var->key, "PK")) { + /* + * PK is tied to a particular firmware image by mapping it with + * hw-key-hash of that firmware. When PK is updated, hw-key-hash + * is updated. And when PK is deleted, delete hw-key-hash as well + */ + if(neweslsize == 0) { + setup_mode = true; + delete_hw_key_hash(&staging_bank); + } else { + setup_mode = false; + add_hw_key_hash(&staging_bank); + } + prlog(PR_DEBUG, "setup mode is %d\n", setup_mode); + } + } + + if (rc == 0) { + /* Update the variable bank with updated working copy */ + clear_bank_list(variable_bank); + copy_bank_list(variable_bank, &staging_bank); + } + +cleanup: + /* + * For any failure in processing update queue, we clear the update bank + * and return failure + */ + free(newesl); + clear_bank_list(&staging_bank); + clear_bank_list(update_bank); + + return rc; +} + +static int edk2_compat_post_process(struct list_head *variable_bank, + struct list_head *update_bank __unused) +{ + struct secvar *hwvar; + if (!setup_mode) { + secvar_set_secure_mode(); + prlog(PR_INFO, "Enforcing OS secure mode\n"); + /* + * HW KEY HASH is no more needed after this point. It is already + * visible to userspace via device-tree, so exposing via sysfs is + * just a duplication. Remove it from in-memory copy. + */ + hwvar = find_secvar("HWKH", 5, variable_bank); + if (!hwvar) { + prlog(PR_ERR, "cannot find hw-key-hash, should not happen\n"); + return OPAL_INTERNAL_ERROR; + } + list_del(&hwvar->link); + dealloc_secvar(hwvar); + } + + return OPAL_SUCCESS; +} + +static int edk2_compat_validate(struct secvar *var) +{ + + /* + * Checks if the update is for supported + * Non-volatile secure variables + */ + if (!key_equals(var->key, "PK") + && !key_equals(var->key, "KEK") + && !key_equals(var->key, "db") + && !key_equals(var->key, "dbx")) + return OPAL_PARAMETER; + + /* Check that signature type is PKCS7 */ + if (!is_pkcs7_sig_format(var->data)) + return OPAL_PARAMETER; + + return OPAL_SUCCESS; +}; + +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 0000000..1ed9a11 --- /dev/null +++ b/libstb/secvar/backend/edk2.h @@ -0,0 +1,251 @@ +/* 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 2020 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. +/// + +static const uuid_t EFI_CERT_TYPE_PKCS7_GUID = {{0x9d, 0xd2, 0xaf, 0x4a, 0xdf, 0x68, 0xee, 0x49, 0x8a, 0xa9, 0x34, 0x7d, 0x37, 0x56, 0x65, 0xa7}}; + +static const uuid_t EFI_CERT_X509_GUID = {{ 0xa1, 0x59, 0xc0, 0xa5, 0xe4, 0x94, 0xa7, 0x4a, 0x87, 0xb5, 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72 }}; + +static const uuid_t EFI_CERT_SHA1_GUID = {{ 0x12, 0xa5, 0x6c, 0x82, 0x10, 0xcf, 0xc9, 0x4a, 0xb1, 0x87, 0xbe, 0x01, 0x49, 0x66, 0x31, 0xbd }}; + +static const uuid_t EFI_CERT_SHA224_GUID = {{ 0x33, 0x52, 0x6e, 0x0b, 0x5c, 0xa6, 0xc9, 0x44, 0x94, 0x07, 0xd9, 0xab, 0x83, 0xbf, 0xc8, 0xbd }}; + +static const uuid_t EFI_CERT_SHA256_GUID = {{ 0x26, 0x16, 0xc4, 0xc1, 0x4c, 0x50, 0x92, 0x40, 0xac, 0xa9, 0x41, 0xf9, 0x36, 0x93, 0x43, 0x28 }}; + +static const uuid_t EFI_CERT_SHA384_GUID = {{ 0x07, 0x53, 0x3e, 0xff, 0xd0, 0x9f, 0xc9, 0x48, 0x85, 0xf1, 0x8a, 0xd5, 0x6c, 0x70, 0x1e, 0x01 }}; + +static const uuid_t EFI_CERT_SHA512_GUID = {{ 0xae, 0x0f, 0x3e, 0x09, 0xc4, 0xa6, 0x50, 0x4f, 0x9f, 0x1b, 0xd4, 0x1e, 0x2b, 0x89, 0xc1, 0x9a }}; + +#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[]; +}; +/* + * 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 -- cgit v1.1