diff options
Diffstat (limited to 'security/integrity/platform_certs')
| -rw-r--r-- | security/integrity/platform_certs/keyring_handler.c | 48 | ||||
| -rw-r--r-- | security/integrity/platform_certs/keyring_handler.h | 13 | ||||
| -rw-r--r-- | security/integrity/platform_certs/load_uefi.c | 42 | ||||
| -rw-r--r-- | security/integrity/platform_certs/machine_keyring.c | 77 |
4 files changed, 151 insertions, 29 deletions
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c index 5604bd57c990..8a1124e4d769 100644 --- a/security/integrity/platform_certs/keyring_handler.c +++ b/security/integrity/platform_certs/keyring_handler.c @@ -9,6 +9,7 @@ #include <keys/asymmetric-type.h> #include <keys/system_keyring.h> #include "../integrity.h" +#include "keyring_handler.h" static efi_guid_t efi_cert_x509_guid __initdata = EFI_CERT_X509_GUID; static efi_guid_t efi_cert_x509_sha256_guid __initdata = @@ -16,34 +17,12 @@ static efi_guid_t efi_cert_x509_sha256_guid __initdata = static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID; /* - * 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); + mark_hash_blacklisted(data, len, BLACKLIST_HASH_X509_TBS); } /* @@ -52,7 +31,7 @@ static __init void uefi_blacklist_x509_tbs(const char *source, static __init void uefi_blacklist_binary(const char *source, const void *data, size_t len) { - uefi_blacklist_hash(source, data, len, "bin:", 4); + mark_hash_blacklisted(data, len, BLACKLIST_HASH_BINARY); } /* @@ -66,13 +45,28 @@ static __init void uefi_revocation_list_x509(const char *source, /* * Return the appropriate handler for particular signature list types found in - * the UEFI db and MokListRT tables. + * the UEFI db tables. */ __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 NULL; +} + +/* + * Return the appropriate handler for particular signature list types found in + * the MokListRT tables. + */ +__init efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type) +{ + if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) { + if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING) && trust_moklist()) + return add_to_machine_keyring; + else + return add_to_platform_keyring; + } + return NULL; } /* @@ -87,5 +81,5 @@ __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type) return uefi_blacklist_binary; if (efi_guidcmp(*sig_type, efi_cert_x509_guid) == 0) return uefi_revocation_list_x509; - return 0; + return NULL; } diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h index 2462bfa08fe3..212d894a8c0c 100644 --- a/security/integrity/platform_certs/keyring_handler.h +++ b/security/integrity/platform_certs/keyring_handler.h @@ -25,8 +25,21 @@ void blacklist_binary(const char *source, const void *data, size_t len); efi_element_handler_t get_handler_for_db(const efi_guid_t *sig_type); /* + * Return the handler for particular signature list types found in the mok. + */ +efi_element_handler_t get_handler_for_mok(const efi_guid_t *sig_type); + +/* * Return the handler for particular signature list types found in the dbx. */ efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type); #endif + +#ifndef UEFI_QUIRK_SKIP_CERT +#define UEFI_QUIRK_SKIP_CERT(vendor, product) \ + .matches = { \ + DMI_MATCH(DMI_BOARD_VENDOR, vendor), \ + DMI_MATCH(DMI_PRODUCT_NAME, product), \ + }, +#endif diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c index f290f78c3f30..b78753d27d8e 100644 --- a/security/integrity/platform_certs/load_uefi.c +++ b/security/integrity/platform_certs/load_uefi.c @@ -3,15 +3,42 @@ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/cred.h> +#include <linux/dmi.h> #include <linux/err.h> #include <linux/efi.h> #include <linux/slab.h> +#include <linux/ima.h> #include <keys/asymmetric-type.h> #include <keys/system_keyring.h> #include "../integrity.h" #include "keyring_handler.h" /* + * On T2 Macs reading the db and dbx efi variables to load UEFI Secure Boot + * certificates causes occurrence of a page fault in Apple's firmware and + * a crash disabling EFI runtime services. The following quirk skips reading + * these variables. + */ +static const struct dmi_system_id uefi_skip_cert[] = { + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,2") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,3") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,4") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,2") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,3") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,4") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,2") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir9,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "Macmini8,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacPro7,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,1") }, + { UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,2") }, + { } +}; + +/* * Look to see if a UEFI variable called MokIgnoreDB exists and return true if * it does. * @@ -94,7 +121,7 @@ static int __init load_moklist_certs(void) rc = parse_efi_signature_list("UEFI:MokListRT (MOKvar table)", mokvar_entry->data, mokvar_entry->data_size, - get_handler_for_db); + get_handler_for_mok); /* All done if that worked. */ if (!rc) return rc; @@ -109,7 +136,7 @@ static int __init load_moklist_certs(void) mok = get_cert_list(L"MokListRT", &mok_var, &moksize, &status); if (mok) { rc = parse_efi_signature_list("UEFI:MokListRT", - mok, moksize, get_handler_for_db); + mok, moksize, get_handler_for_mok); kfree(mok); if (rc) pr_err("Couldn't parse MokListRT signatures: %d\n", rc); @@ -137,6 +164,13 @@ static int __init load_uefi_certs(void) unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0; efi_status_t status; int rc = 0; + const struct dmi_system_id *dmi_id; + + dmi_id = dmi_first_match(uefi_skip_cert); + if (dmi_id) { + pr_err("Reading UEFI Secure Boot Certs is not supported on T2 Macs.\n"); + return false; + } if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE)) return false; @@ -176,6 +210,10 @@ static int __init load_uefi_certs(void) kfree(dbx); } + /* the MOK/MOKx can not be trusted when secure boot is disabled */ + if (!arch_ima_get_secureboot()) + return 0; + mokx = get_cert_list(L"MokListXRT", &mok_var, &mokxsize, &status); if (!mokx) { if (status == EFI_NOT_FOUND) diff --git a/security/integrity/platform_certs/machine_keyring.c b/security/integrity/platform_certs/machine_keyring.c new file mode 100644 index 000000000000..7aaed7950b6e --- /dev/null +++ b/security/integrity/platform_certs/machine_keyring.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Machine keyring routines. + * + * Copyright (c) 2021, Oracle and/or its affiliates. + */ + +#include <linux/efi.h> +#include "../integrity.h" + +static bool trust_mok; + +static __init int machine_keyring_init(void) +{ + int rc; + + rc = integrity_init_keyring(INTEGRITY_KEYRING_MACHINE); + if (rc) + return rc; + + pr_notice("Machine keyring initialized\n"); + return 0; +} +device_initcall(machine_keyring_init); + +void __init add_to_machine_keyring(const char *source, const void *data, size_t len) +{ + key_perm_t perm; + int rc; + + perm = (KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW; + rc = integrity_load_cert(INTEGRITY_KEYRING_MACHINE, source, data, len, perm); + + /* + * Some MOKList keys may not pass the machine keyring restrictions. + * If the restriction check does not pass and the platform keyring + * is configured, try to add it into that keyring instead. + */ + if (rc && IS_ENABLED(CONFIG_INTEGRITY_PLATFORM_KEYRING)) + rc = integrity_load_cert(INTEGRITY_KEYRING_PLATFORM, source, + data, len, perm); + + if (rc) + pr_info("Error adding keys to machine keyring %s\n", source); +} + +/* + * Try to load the MokListTrustedRT MOK variable to see if we should trust + * the MOK keys within the kernel. It is not an error if this variable + * does not exist. If it does not exist, MOK keys should not be trusted + * within the machine keyring. + */ +static __init bool uefi_check_trust_mok_keys(void) +{ + struct efi_mokvar_table_entry *mokvar_entry; + + mokvar_entry = efi_mokvar_entry_find("MokListTrustedRT"); + + if (mokvar_entry) + return true; + + return false; +} + +bool __init trust_moklist(void) +{ + static bool initialized; + + if (!initialized) { + initialized = true; + + if (uefi_check_trust_mok_keys()) + trust_mok = true; + } + + return trust_mok; +} |