diff options
Diffstat (limited to 'MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch')
| -rw-r--r-- | MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch | 182 |
1 files changed, 182 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..b136acaf0 --- /dev/null +++ b/MODSIGN-Import-certificates-from-UEFI-Secure-Boot.patch @@ -0,0 +1,182 @@ +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 706b16fa6de8..470e8dfcb517 100644 +--- a/include/linux/efi.h ++++ b/include/linux/efi.h +@@ -595,6 +595,12 @@ 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 eca8ab59ae7f..9a782b02e4d5 100644 +--- a/init/Kconfig ++++ b/init/Kconfig +@@ -1888,6 +1888,15 @@ 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 1408b3353a3c..8a3be67a3a15 100644 +--- a/kernel/Makefile ++++ b/kernel/Makefile +@@ -46,6 +46,7 @@ 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); |