diff options
Diffstat (limited to 'MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch')
| -rw-r--r-- | MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch | 246 |
1 files changed, 0 insertions, 246 deletions
diff --git a/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch b/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch deleted file mode 100644 index 08195ff4e..000000000 --- a/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch +++ /dev/null @@ -1,246 +0,0 @@ -From 90dc66270b02981b19a085c6a9184e3452b7b3e8 Mon Sep 17 00:00:00 2001 -From: Josh Boyer <jwboyer@fedoraproject.org> -Date: Fri, 5 May 2017 08:21:59 +0100 -Subject: [PATCH 3/4] MODSIGN: Import certificates from UEFI Secure Boot - -Secure Boot stores a list of allowed certificates in the 'db' variable. -This imports those certificates into the system trusted keyring. This -allows for a third party signing certificate to be used in conjunction -with signed modules. By importing the public certificate into the 'db' -variable, a user can allow a module signed with that certificate to -load. The shim UEFI bootloader has a similar certificate list stored -in the 'MokListRT' variable. We import those as well. - -Secure Boot also maintains a list of disallowed certificates in the 'dbx' -variable. We load those certificates into the newly introduced system -blacklist keyring and forbid any module signed with those from loading and -forbid the use within the kernel of any key with a matching hash. - -This facility is enabled by setting CONFIG_LOAD_UEFI_KEYS. - -Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org> -Signed-off-by: David Howells <dhowells@redhat.com> ---- - certs/Kconfig | 16 ++++++ - certs/Makefile | 4 ++ - certs/load_uefi.c | 168 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ - 3 files changed, 188 insertions(+) - create mode 100644 certs/load_uefi.c - -diff --git a/certs/Kconfig b/certs/Kconfig -index 630ae09..edf9f75 100644 ---- a/certs/Kconfig -+++ b/certs/Kconfig -@@ -90,4 +90,20 @@ config EFI_SIGNATURE_LIST_PARSER - This option provides support for parsing EFI signature lists for - X.509 certificates and turning them into keys. - -+config LOAD_UEFI_KEYS -+ bool "Load certs and blacklist from UEFI db for module checking" -+ depends on SYSTEM_BLACKLIST_KEYRING -+ depends on SECONDARY_TRUSTED_KEYRING -+ depends on EFI -+ depends on EFI_SIGNATURE_LIST_PARSER -+ help -+ If the kernel is booted in secure boot mode, this option will cause -+ the kernel to load the certificates from the UEFI db and MokListRT -+ into the secondary trusted keyring. It will also load any X.509 -+ SHA256 hashes in the dbx list into the blacklist. -+ -+ The effect of this is that, if the kernel is booted in secure boot -+ mode, modules signed with UEFI-stored keys will be permitted to be -+ loaded and keys that match the blacklist will be rejected. -+ - endmenu -diff --git a/certs/Makefile b/certs/Makefile -index 738151a..a5e057a 100644 ---- a/certs/Makefile -+++ b/certs/Makefile -@@ -11,6 +11,10 @@ obj-$(CONFIG_SYSTEM_BLACKLIST_KEYRING) += blacklist_nohashes.o - endif - obj-$(CONFIG_EFI_SIGNATURE_LIST_PARSER) += efi_parser.o - -+obj-$(CONFIG_LOAD_UEFI_KEYS) += load_uefi.o -+$(obj)/load_uefi.o: KBUILD_CFLAGS += -fshort-wchar -+ -+ - ifeq ($(CONFIG_SYSTEM_TRUSTED_KEYRING),y) - - $(eval $(call config_filename,SYSTEM_TRUSTED_KEYS)) -diff --git a/certs/load_uefi.c b/certs/load_uefi.c -new file mode 100644 -index 0000000..b44e464 ---- /dev/null -+++ b/certs/load_uefi.c -@@ -0,0 +1,168 @@ -+#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 "internal.h" -+ -+static __initdata efi_guid_t efi_cert_x509_guid = EFI_CERT_X509_GUID; -+static __initdata efi_guid_t efi_cert_x509_sha256_guid = EFI_CERT_X509_SHA256_GUID; -+static __initdata efi_guid_t efi_cert_sha256_guid = EFI_CERT_SHA256_GUID; -+ -+/* -+ * Get a certificate list blob from the named EFI variable. -+ */ -+static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid, -+ unsigned long *size) -+{ -+ efi_status_t status; -+ unsigned long lsize = 4; -+ unsigned long tmpdb[4]; -+ void *db; -+ -+ status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb); -+ if (status != EFI_BUFFER_TOO_SMALL) { -+ pr_err("Couldn't get size: 0x%lx\n", status); -+ return NULL; -+ } -+ -+ db = kmalloc(lsize, GFP_KERNEL); -+ if (!db) { -+ pr_err("Couldn't allocate memory for uefi cert list\n"); -+ return NULL; -+ } -+ -+ status = efi.get_variable(name, guid, NULL, &lsize, db); -+ if (status != EFI_SUCCESS) { -+ kfree(db); -+ pr_err("Error reading db var: 0x%lx\n", status); -+ return NULL; -+ } -+ -+ *size = lsize; -+ return db; -+} -+ -+/* -+ * Blacklist an X509 TBS hash. -+ */ -+static __init void uefi_blacklist_x509_tbs(const char *source, -+ const void *data, size_t len) -+{ -+ char *hash, *p; -+ -+ hash = kmalloc(4 + len * 2 + 1, GFP_KERNEL); -+ if (!hash) -+ return; -+ p = memcpy(hash, "tbs:", 4); -+ p += 4; -+ bin2hex(p, data, len); -+ p += len * 2; -+ *p = 0; -+ -+ mark_hash_blacklisted(hash); -+ kfree(hash); -+} -+ -+/* -+ * Blacklist the hash of an executable. -+ */ -+static __init void uefi_blacklist_binary(const char *source, -+ const void *data, size_t len) -+{ -+ char *hash, *p; -+ -+ hash = kmalloc(4 + len * 2 + 1, GFP_KERNEL); -+ if (!hash) -+ return; -+ p = memcpy(hash, "bin:", 4); -+ p += 4; -+ bin2hex(p, data, len); -+ p += len * 2; -+ *p = 0; -+ -+ mark_hash_blacklisted(hash); -+ kfree(hash); -+} -+ -+/* -+ * 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_trusted_secondary_key; -+ return 0; -+} -+ -+/* -+ * Return the appropriate handler for particular signature list types found in -+ * the UEFI dbx and MokListXRT tables. -+ */ -+static __init efi_element_handler_t get_handler_for_dbx(const efi_guid_t *sig_type) -+{ -+ if (efi_guidcmp(*sig_type, efi_cert_x509_sha256_guid) == 0) -+ return uefi_blacklist_x509_tbs; -+ if (efi_guidcmp(*sig_type, efi_cert_sha256_guid) == 0) -+ return uefi_blacklist_binary; -+ return 0; -+} -+ -+/* -+ * Load the certs contained in the UEFI databases -+ */ -+static int __init load_uefi_certs(void) -+{ -+ efi_guid_t secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID; -+ efi_guid_t mok_var = EFI_SHIM_LOCK_GUID; -+ void *db = NULL, *dbx = NULL, *mok = NULL; -+ unsigned long dbsize = 0, dbxsize = 0, moksize = 0; -+ int rc = 0; -+ -+ if (!efi.get_variable) -+ return false; -+ -+ /* Get db, MokListRT, and dbx. They might not exist, so it isn't -+ * an error if we can't get them. -+ */ -+ db = get_cert_list(L"db", &secure_var, &dbsize); -+ if (!db) { -+ pr_err("MODSIGN: Couldn't get UEFI db list\n"); -+ } else { -+ rc = parse_efi_signature_list("UEFI:db", -+ db, dbsize, get_handler_for_db); -+ if (rc) -+ pr_err("Couldn't parse db signatures: %d\n", rc); -+ kfree(db); -+ } -+ -+ mok = get_cert_list(L"MokListRT", &mok_var, &moksize); -+ if (!mok) { -+ pr_info("MODSIGN: Couldn't get UEFI MokListRT\n"); -+ } else { -+ rc = parse_efi_signature_list("UEFI:MokListRT", -+ mok, moksize, get_handler_for_db); -+ if (rc) -+ pr_err("Couldn't parse MokListRT signatures: %d\n", rc); -+ kfree(mok); -+ } -+ -+ dbx = get_cert_list(L"dbx", &secure_var, &dbxsize); -+ if (!dbx) { -+ pr_info("MODSIGN: Couldn't get UEFI dbx list\n"); -+ } else { -+ rc = parse_efi_signature_list("UEFI:dbx", -+ dbx, dbxsize, -+ get_handler_for_dbx); -+ if (rc) -+ pr_err("Couldn't parse dbx signatures: %d\n", rc); -+ kfree(dbx); -+ } -+ -+ return rc; -+} -+late_initcall(load_uefi_certs); --- -2.9.3 - |