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author | Michael Ellerman <mpe@ellerman.id.au> | 2019-11-13 08:52:25 +0300 |
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committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-11-13 08:55:50 +0300 |
commit | d34a5709be85e88a8bb7537cd38b8eca8085047a (patch) | |
tree | 0371b60368b91eb954138f77d8be8704f09df44f /security/integrity/platform_certs | |
parent | ea458effa88e4f4739551d76fe3f702daf607995 (diff) | |
parent | 8220e22d11a05049aab9693839ab82e5e177ccde (diff) | |
download | linux-d34a5709be85e88a8bb7537cd38b8eca8085047a.tar.xz |
Merge branch 'topic/secureboot' into next
Merge the secureboot support, as well as the IMA changes needed to
support it.
From Nayna's cover letter:
In order to verify the OS kernel on PowerNV systems, secure boot
requires X.509 certificates trusted by the platform. These are
stored in secure variables controlled by OPAL, called OPAL secure
variables. In order to enable users to manage the keys, the secure
variables need to be exposed to userspace.
OPAL provides the runtime services for the kernel to be able to
access the secure variables. This patchset defines the kernel
interface for the OPAL APIs. These APIs are used by the hooks, which
load these variables to the keyring and expose them to the userspace
for reading/writing.
Overall, this patchset adds the following support:
* expose secure variables to the kernel via OPAL Runtime API interface
* expose secure variables to the userspace via kernel sysfs interface
* load kernel verification and revocation keys to .platform and
.blacklist keyring respectively.
The secure variables can be read/written using simple linux
utilities cat/hexdump.
For example:
Path to the secure variables is: /sys/firmware/secvar/vars
Each secure variable is listed as directory.
$ ls -l
total 0
drwxr-xr-x. 2 root root 0 Aug 20 21:20 db
drwxr-xr-x. 2 root root 0 Aug 20 21:20 KEK
drwxr-xr-x. 2 root root 0 Aug 20 21:20 PK
The attributes of each of the secure variables are (for example: PK):
$ ls -l
total 0
-r--r--r--. 1 root root 4096 Oct 1 15:10 data
-r--r--r--. 1 root root 65536 Oct 1 15:10 size
--w-------. 1 root root 4096 Oct 1 15:12 update
The "data" is used to read the existing variable value using
hexdump. The data is stored in ESL format. The "update" is used to
write a new value using cat. The update is to be submitted as AUTH
file.
Diffstat (limited to 'security/integrity/platform_certs')
-rw-r--r-- | security/integrity/platform_certs/keyring_handler.c | 80 | ||||
-rw-r--r-- | security/integrity/platform_certs/keyring_handler.h | 32 | ||||
-rw-r--r-- | security/integrity/platform_certs/load_powerpc.c | 96 | ||||
-rw-r--r-- | security/integrity/platform_certs/load_uefi.c | 67 |
4 files changed, 209 insertions, 66 deletions
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c new file mode 100644 index 000000000000..c5ba695c10e3 --- /dev/null +++ b/security/integrity/platform_certs/keyring_handler.c @@ -0,0 +1,80 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/cred.h> +#include <linux/err.h> +#include <linux/efi.h> +#include <linux/slab.h> +#include <keys/asymmetric-type.h> +#include <keys/system_keyring.h> +#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; + +/* + * 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. + */ +__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. + */ +__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; +} diff --git a/security/integrity/platform_certs/keyring_handler.h b/security/integrity/platform_certs/keyring_handler.h new file mode 100644 index 000000000000..2462bfa08fe3 --- /dev/null +++ b/security/integrity/platform_certs/keyring_handler.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef PLATFORM_CERTS_INTERNAL_H +#define PLATFORM_CERTS_INTERNAL_H + +#include <linux/efi.h> + +void blacklist_hash(const char *source, const void *data, + size_t len, const char *type, + size_t type_len); + +/* + * Blacklist an X509 TBS hash. + */ +void blacklist_x509_tbs(const char *source, const void *data, size_t len); + +/* + * Blacklist the hash of an executable. + */ +void blacklist_binary(const char *source, const void *data, size_t len); + +/* + * Return the handler for particular signature list types found in the db. + */ +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 dbx. + */ +efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type); + +#endif diff --git a/security/integrity/platform_certs/load_powerpc.c b/security/integrity/platform_certs/load_powerpc.c new file mode 100644 index 000000000000..a2900cb85357 --- /dev/null +++ b/security/integrity/platform_certs/load_powerpc.c @@ -0,0 +1,96 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2019 IBM Corporation + * Author: Nayna Jain + * + * - loads keys and hashes stored and controlled by the firmware. + */ +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/cred.h> +#include <linux/err.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <asm/secure_boot.h> +#include <asm/secvar.h> +#include "keyring_handler.h" + +/* + * Get a certificate list blob from the named secure variable. + */ +static __init void *get_cert_list(u8 *key, unsigned long keylen, uint64_t *size) +{ + int rc; + void *db; + + rc = secvar_ops->get(key, keylen, NULL, size); + if (rc) { + pr_err("Couldn't get size: %d\n", rc); + return NULL; + } + + db = kmalloc(*size, GFP_KERNEL); + if (!db) + return NULL; + + rc = secvar_ops->get(key, keylen, db, size); + if (rc) { + kfree(db); + pr_err("Error reading %s var: %d\n", key, rc); + return NULL; + } + + return db; +} + +/* + * Load the certs contained in the keys databases into the platform trusted + * keyring and the blacklisted X.509 cert SHA256 hashes into the blacklist + * keyring. + */ +static int __init load_powerpc_certs(void) +{ + void *db = NULL, *dbx = NULL; + uint64_t dbsize = 0, dbxsize = 0; + int rc = 0; + struct device_node *node; + + if (!secvar_ops) + return -ENODEV; + + /* The following only applies for the edk2-compat backend. */ + node = of_find_compatible_node(NULL, NULL, "ibm,edk2-compat-v1"); + if (!node) + return -ENODEV; + + /* + * Get db, and dbx. They might not exist, so it isn't an error if we + * can't get them. + */ + db = get_cert_list("db", 3, &dbsize); + if (!db) { + pr_err("Couldn't get db list from firmware\n"); + } else { + rc = parse_efi_signature_list("powerpc:db", db, dbsize, + get_handler_for_db); + if (rc) + pr_err("Couldn't parse db signatures: %d\n", rc); + kfree(db); + } + + dbx = get_cert_list("dbx", 4, &dbxsize); + if (!dbx) { + pr_info("Couldn't get dbx list from firmware\n"); + } else { + rc = parse_efi_signature_list("powerpc:dbx", dbx, dbxsize, + get_handler_for_dbx); + if (rc) + pr_err("Couldn't parse dbx signatures: %d\n", rc); + kfree(dbx); + } + + of_node_put(node); + + return rc; +} +late_initcall(load_powerpc_certs); diff --git a/security/integrity/platform_certs/load_uefi.c b/security/integrity/platform_certs/load_uefi.c index 81b19c52832b..4369204a19cd 100644 --- a/security/integrity/platform_certs/load_uefi.c +++ b/security/integrity/platform_certs/load_uefi.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 = @@ -68,72 +69,6 @@ static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *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); -} - -/* - * 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 into the platform trusted * keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist * keyring. |