summaryrefslogtreecommitdiffstats
path: root/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch
diff options
context:
space:
mode:
Diffstat (limited to 'MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch')
-rw-r--r--MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch186
1 files changed, 186 insertions, 0 deletions
diff --git a/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch b/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch
new file mode 100644
index 000000000..e65958a30
--- /dev/null
+++ b/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch
@@ -0,0 +1,186 @@
+From f06dd05414175619d0083fe4236705755f4692bd Mon Sep 17 00:00:00 2001
+From: Josh Boyer <jwboyer@fedoraproject.org>
+Date: Fri, 26 Oct 2012 12:42:16 -0400
+Subject: [PATCH] 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.
+
+In the opposite case, Secure Boot 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.
+
+Signed-off-by: Josh Boyer <jwboyer@fedoraproject.org>
+---
+ include/linux/efi.h | 6 ++++
+ init/Kconfig | 9 +++++
+ kernel/Makefile | 3 ++
+ kernel/modsign_uefi.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++
+ 4 files changed, 110 insertions(+)
+ create mode 100644 kernel/modsign_uefi.c
+
+diff --git a/include/linux/efi.h b/include/linux/efi.h
+index 41359e548bcb..db9e6118575e 100644
+--- a/include/linux/efi.h
++++ b/include/linux/efi.h
+@@ -587,6 +587,12 @@ void efi_native_runtime_setup(void);
+ #define EFI_CERT_X509_GUID \
+ EFI_GUID( 0xa5c059a1, 0x94e4, 0x4aa7, 0x87, 0xb5, 0xab, 0x15, 0x5c, 0x2b, 0xf0, 0x72 )
+
++#define EFI_IMAGE_SECURITY_DATABASE_GUID \
++ EFI_GUID( 0xd719b2cb, 0x3d3a, 0x4596, 0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f )
++
++#define EFI_SHIM_LOCK_GUID \
++ EFI_GUID( 0x605dab50, 0xe046, 0x4300, 0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23 )
++
+ typedef struct {
+ efi_guid_t guid;
+ u64 table;
+diff --git a/init/Kconfig b/init/Kconfig
+index 223b1a32bbcb..3bad458f1c68 100644
+--- a/init/Kconfig
++++ b/init/Kconfig
+@@ -1874,6 +1874,15 @@ config MODULE_SIG_ALL
+ comment "Do not forget to sign required modules with scripts/sign-file"
+ depends on MODULE_SIG_FORCE && !MODULE_SIG_ALL
+
++config MODULE_SIG_UEFI
++ bool "Allow modules signed with certs stored in UEFI"
++ depends on MODULE_SIG && SYSTEM_BLACKLIST_KEYRING && EFI
++ select EFI_SIGNATURE_LIST_PARSER
++ help
++ This will import certificates stored in UEFI and allow modules
++ signed with those to be loaded. It will also disallow loading
++ of modules stored in the UEFI dbx variable.
++
+ choice
+ prompt "Which hash algorithm should modules be signed with?"
+ depends on MODULE_SIG
+diff --git a/kernel/Makefile b/kernel/Makefile
+index dc5c77544fd6..95bdf3398880 100644
+--- a/kernel/Makefile
++++ b/kernel/Makefile
+@@ -45,6 +45,7 @@ obj-$(CONFIG_UID16) += uid16.o
+ obj-$(CONFIG_SYSTEM_TRUSTED_KEYRING) += system_keyring.o system_certificates.o
+ obj-$(CONFIG_MODULES) += module.o
+ obj-$(CONFIG_MODULE_SIG) += module_signing.o
++obj-$(CONFIG_MODULE_SIG_UEFI) += modsign_uefi.o
+ obj-$(CONFIG_KALLSYMS) += kallsyms.o
+ obj-$(CONFIG_BSD_PROCESS_ACCT) += acct.o
+ obj-$(CONFIG_KEXEC) += kexec.o
+@@ -99,6 +100,8 @@ obj-$(CONFIG_TORTURE_TEST) += torture.o
+
+ $(obj)/configs.o: $(obj)/config_data.h
+
++$(obj)/modsign_uefi.o: KBUILD_CFLAGS += -fshort-wchar
++
+ # config_data.h contains the same information as ikconfig.h but gzipped.
+ # Info from config_data can be extracted from /proc/config*
+ targets += config_data.gz
+diff --git a/kernel/modsign_uefi.c b/kernel/modsign_uefi.c
+new file mode 100644
+index 000000000000..94b0eb38a284
+--- /dev/null
++++ b/kernel/modsign_uefi.c
+@@ -0,0 +1,92 @@
++#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 "module-internal.h"
++
++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 = NULL;
++
++ 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");
++ goto out;
++ }
++
++ status = efi.get_variable(name, guid, NULL, &lsize, db);
++ if (status != EFI_SUCCESS) {
++ kfree(db);
++ db = NULL;
++ pr_err("Error reading db var: 0x%lx\n", status);
++ }
++out:
++ *size = lsize;
++ return db;
++}
++
++/*
++ * * 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;
++
++ /* Check if SB is enabled and just return if not */
++ if (!efi_enabled(EFI_SECURE_BOOT))
++ return 0;
++
++ /* 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(db, dbsize, system_trusted_keyring);
++ 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(mok, moksize, system_trusted_keyring);
++ 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(dbx, dbxsize,
++ system_blacklist_keyring);
++ if (rc)
++ pr_err("Couldn't parse dbx signatures: %d\n", rc);
++ kfree(dbx);
++ }
++
++ return rc;
++}
++late_initcall(load_uefi_certs);
+--
+1.9.3
+