From e5d5e5a259a9827e4d6e41e49085f730c773c178 Mon Sep 17 00:00:00 2001
From: Alexey Makhalov <amakhalov@vmware.com>
Date: Tue, 10 Jul 2012 11:58:52 -0400
Subject: [PATCH] Secure Boot support
New commands: linuxefi, initrdefi
If running under secure boot use linuxefi loader only and linux
command is fallback to linuxefi.
Forbid dl file loading (insmod and similar) when secure boot is enabled.
---
grub-core/Makefile.core.def | 8 +
grub-core/kern/dl.c | 21 +++
grub-core/kern/efi/efi.c | 30 +++
grub-core/kern/efi/mm.c | 32 ++++
grub-core/loader/i386/efi/linux.c | 387 ++++++++++++++++++++++++++++++++++++++
grub-core/loader/i386/linux.c | 45 +++++
include/grub/efi/efi.h | 4 +
include/grub/i386/linux.h | 1 +
8 files changed, 528 insertions(+)
create mode 100644 grub-core/loader/i386/efi/linux.c
diff --git a/grub-core/Makefile.core.def b/grub-core/Makefile.core.def
index 2dfa22a..68e47a7 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1734,6 +1734,14 @@ module = {
};
module = {
+ name = linuxefi;
+ efi = loader/i386/efi/linux.c;
+ efi = lib/cmdline.c;
+ enable = i386_efi;
+ enable = x86_64_efi;
+};
+
+module = {
name = chain;
efi = loader/efi/chainloader.c;
i386_pc = loader/i386/pc/chainloader.c;
diff --git a/grub-core/kern/dl.c b/grub-core/kern/dl.c
index e394cd9..04e804d 100644
--- a/grub-core/kern/dl.c
+++ b/grub-core/kern/dl.c
@@ -38,6 +38,14 @@
#define GRUB_MODULES_MACHINE_READONLY
#endif
+#ifdef GRUB_MACHINE_EMU
+#include <sys/mman.h>
+#endif
+
+#ifdef GRUB_MACHINE_EFI
+#include <grub/efi/efi.h>
+#endif
+
#pragma GCC diagnostic ignored "-Wcast-align"
@@ -686,6 +694,19 @@ grub_dl_load_file (const char *filename)
void *core = 0;
grub_dl_t mod = 0;
+#ifdef GRUB_MACHINE_EFI
+ if (grub_efi_secure_boot ())
+ {
+#if 0
+ /* This is an error, but grub2-mkconfig still generates a pile of
+ * insmod commands, so emitting it would be mostly just obnoxious. */
+ grub_error (GRUB_ERR_ACCESS_DENIED,
+ "Secure Boot forbids loading module from %s", filename);
+#endif
+ return 0;
+ }
+#endif
+
grub_boot_time ("Loading module %s", filename);
file = grub_file_open (filename);
diff --git a/grub-core/kern/efi/efi.c b/grub-core/kern/efi/efi.c
index d467785..270eba8 100644
--- a/grub-core/kern/efi/efi.c
+++ b/grub-core/kern/efi/efi.c
@@ -264,6 +264,36 @@ grub_efi_get_variable (const char *var, const grub_efi_guid_t *guid,
return NULL;
}
+grub_efi_boolean_t
+grub_efi_secure_boot (void)
+{
+ grub_efi_guid_t efi_var_guid = GRUB_EFI_GLOBAL_VARIABLE_GUID;
+ grub_size_t datasize;
+ char *secure_boot = NULL;
+ char *setup_mode = NULL;
+ grub_efi_boolean_t ret = 0;
+
+ secure_boot = grub_efi_get_variable("SecureBoot", &efi_var_guid, &datasize);
+
+ if (datasize != 1 || !secure_boot)
+ goto out;
+
+ setup_mode = grub_efi_get_variable("SetupMode", &efi_var_guid, &datasize);
+
+ if (datasize != 1 || !setup_mode)
+ goto out;
+
+ if (*secure_boot && !*setup_mode)
+ ret = 1;
+
+ grub_dprintf ("secureboot", "secure_boot = %d, setup_mode = %d\n",
+ *secure_boot, *setup_mode);
+ out:
+ grub_free (secure_boot);
+ grub_free (setup_mode);
+ return ret;
+}
+
#pragma GCC diagnostic ignored "-Wcast-align"
/* Search the mods section from the PE32/PE32+ image. This code uses
diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index 20a47aa..efb15cc 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -49,6 +49,38 @@ static grub_efi_uintn_t finish_desc_size;
static grub_efi_uint32_t finish_desc_version;
int grub_efi_is_finished = 0;
+/* Allocate pages below a specified address */
+void *
+grub_efi_allocate_pages_max (grub_efi_physical_address_t max,
+ grub_efi_uintn_t pages)
+{
+ grub_efi_status_t status;
+ grub_efi_boot_services_t *b;
+ grub_efi_physical_address_t address = max;
+
+ if (max > 0xffffffff)
+ return 0;
+
+ b = grub_efi_system_table->boot_services;
+ status = efi_call_4 (b->allocate_pages, GRUB_EFI_ALLOCATE_MAX_ADDRESS, GRUB_EFI_LOADER_DATA, pages, &address);
+
+ if (status != GRUB_EFI_SUCCESS)
+ return 0;
+
+ if (address == 0)
+ {
+ /* Uggh, the address 0 was allocated... This is too annoying,
+ so reallocate another one. */
+ address = max;
+ status = efi_call_4 (b->allocate_pages, GRUB_EFI_ALLOCATE_MAX_ADDRESS, GRUB_EFI_LOADER_DATA, pages, &address);
+ grub_efi_free_pages (0, pages);
+ if (status != GRUB_EFI_SUCCESS)
+ return 0;
+ }
+
+ return (void *) ((grub_addr_t) address);
+}
+
/* Allocate pages. Return the pointer to the first of allocated pages. */
void *
grub_efi_allocate_pages (grub_efi_physical_address_t address,
diff --git a/grub-core/loader/i386/efi/linux.c b/grub-core/loader/i386/efi/linux.c
new file mode 100644
index 0000000..78bc216
--- /dev/null
+++ b/grub-core/loader/i386/efi/linux.c
@@ -0,0 +1,387 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2012 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/loader.h>
+#include <grub/file.h>
+#include <grub/err.h>
+#include <grub/misc.h>
+#include <grub/types.h>
+#include <grub/mm.h>
+#include <grub/cpu/linux.h>
+#include <grub/command.h>
+#include <grub/i18n.h>
+#include <grub/lib/cmdline.h>
+#include <grub/efi/efi.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_dl_t my_mod;
+static int loaded;
+static void *kernel_mem;
+static grub_uint64_t kernel_size;
+static grub_uint8_t *initrd_mem;
+static grub_uint32_t handover_offset;
+struct linux_kernel_params *params;
+static char *linux_cmdline;
+
+#define BYTES_TO_PAGES(bytes) (((bytes) + 0xfff) >> 12)
+
+#define SHIM_LOCK_GUID \
+ { 0x605dab50, 0xe046, 0x4300, {0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23} }
+
+struct grub_efi_shim_lock
+{
+ grub_efi_status_t (*verify) (void *buffer, grub_uint32_t size);
+};
+typedef struct grub_efi_shim_lock grub_efi_shim_lock_t;
+
+static grub_efi_boolean_t
+grub_linuxefi_secure_validate (void *data, grub_uint32_t size)
+{
+ grub_efi_guid_t guid = SHIM_LOCK_GUID;
+ grub_efi_shim_lock_t *shim_lock;
+ grub_efi_status_t status;
+
+ grub_dprintf ("linuxefi", "Locating shim protocol\n");
+ shim_lock = grub_efi_locate_protocol(&guid, NULL);
+
+ if (!shim_lock)
+ {
+ grub_dprintf ("linuxefi", "shim not available\n");
+ return 0;
+ }
+
+ grub_dprintf ("linuxefi", "Asking shim to verify kernel signature\n");
+ status = shim_lock->verify(data, size);
+ if (status == GRUB_EFI_SUCCESS)
+ {
+ grub_dprintf ("linuxefi", "Kernel signature verification passed\n");
+ return 1;
+ }
+
+ grub_dprintf ("linuxefi", "Kernel signature verification failed (0x%lx)\n",
+ (unsigned long) status);
+
+ return 0;
+}
+
+typedef void(*handover_func)(void *, grub_efi_system_table_t *, struct linux_kernel_params *);
+
+static grub_err_t
+grub_linuxefi_boot (void)
+{
+ handover_func hf;
+ int offset = 0;
+
+#ifdef __x86_64__
+ offset = 512;
+#endif
+
+ hf = (handover_func)((char *)kernel_mem + handover_offset + offset);
+
+ asm volatile ("cli");
+
+ hf (grub_efi_image_handle, grub_efi_system_table, params);
+
+ /* Not reached */
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_linuxefi_unload (void)
+{
+ grub_dl_unref (my_mod);
+ loaded = 0;
+ if (initrd_mem)
+ grub_efi_free_pages((grub_efi_physical_address_t)initrd_mem, BYTES_TO_PAGES(params->ramdisk_size));
+ if (linux_cmdline)
+ grub_efi_free_pages((grub_efi_physical_address_t)linux_cmdline, BYTES_TO_PAGES(params->cmdline_size + 1));
+ if (kernel_mem)
+ grub_efi_free_pages((grub_efi_physical_address_t)kernel_mem, BYTES_TO_PAGES(kernel_size));
+ if (params)
+ grub_efi_free_pages((grub_efi_physical_address_t)params, BYTES_TO_PAGES(16384));
+ return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
+ int argc, char *argv[])
+{
+ grub_file_t *files = 0;
+ int i, nfiles = 0;
+ grub_size_t size = 0;
+ grub_uint8_t *ptr;
+
+ if (argc == 0)
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
+ goto fail;
+ }
+
+ if (!loaded)
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, N_("you need to load the kernel first"));
+ goto fail;
+ }
+
+ files = grub_zalloc (argc * sizeof (files[0]));
+ if (!files)
+ goto fail;
+
+ for (i = 0; i < argc; i++)
+ {
+ grub_file_filter_disable_compression ();
+ files[i] = grub_file_open (argv[i]);
+ if (! files[i])
+ goto fail;
+ nfiles++;
+ size += ALIGN_UP (grub_file_size (files[i]), 4);
+ }
+
+ initrd_mem = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(size));
+
+ if (!initrd_mem)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate initrd"));
+ goto fail;
+ }
+
+ params->ramdisk_size = size;
+ params->ramdisk_image = (grub_uint32_t)(grub_uint64_t) initrd_mem;
+
+ ptr = initrd_mem;
+
+ for (i = 0; i < nfiles; i++)
+ {
+ grub_ssize_t cursize = grub_file_size (files[i]);
+ if (grub_file_read (files[i], ptr, cursize) != cursize)
+ {
+ if (!grub_errno)
+ grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
+ argv[i]);
+ goto fail;
+ }
+ ptr += cursize;
+ grub_memset (ptr, 0, ALIGN_UP_OVERHEAD (cursize, 4));
+ ptr += ALIGN_UP_OVERHEAD (cursize, 4);
+ }
+
+ params->ramdisk_size = size;
+
+ fail:
+ for (i = 0; i < nfiles; i++)
+ grub_file_close (files[i]);
+ grub_free (files);
+
+ if (initrd_mem && grub_errno)
+ grub_efi_free_pages((grub_efi_physical_address_t)initrd_mem, BYTES_TO_PAGES(size));
+
+ return grub_errno;
+}
+
+static grub_err_t
+grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
+ int argc, char *argv[])
+{
+ grub_file_t file = 0;
+ struct linux_kernel_header lh;
+ grub_ssize_t len, start, filelen;
+ void *kernel;
+ grub_err_t fail_errno;
+
+ grub_dl_ref (my_mod);
+
+ if (argc == 0)
+ {
+ grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
+ goto fail;
+ }
+
+ file = grub_file_open (argv[0]);
+ if (! file)
+ goto fail;
+
+ filelen = grub_file_size (file);
+
+ kernel = grub_malloc(filelen);
+
+ if (!kernel)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel buffer"));
+ goto fail;
+ }
+
+ if (grub_file_read (file, kernel, filelen) != filelen)
+ {
+ grub_error (GRUB_ERR_FILE_READ_ERROR, N_("Can't read kernel %s"), argv[0]);
+ grub_free (kernel);
+ goto fail;
+ }
+
+ if (! grub_linuxefi_secure_validate (kernel, filelen))
+ {
+ grub_error (GRUB_ERR_ACCESS_DENIED, N_("%s has invalid signature"), argv[0]);
+ grub_free (kernel);
+ goto fail;
+ }
+
+ grub_file_seek (file, 0);
+
+ grub_free(kernel);
+
+ params = grub_efi_allocate_pages_max (0x3fffffff, BYTES_TO_PAGES(16384));
+
+ if (! params)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, "cannot allocate kernel parameters");
+ goto fail;
+ }
+
+ memset (params, 0, 16384);
+
+ if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))
+ {
+ if (!grub_errno)
+ grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
+ argv[0]);
+ goto fail;
+ }
+
+ if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))
+ {
+ grub_error (GRUB_ERR_BAD_OS, N_("invalid magic number"));
+ goto fail;
+ }
+
+ if (lh.setup_sects > GRUB_LINUX_MAX_SETUP_SECTS)
+ {
+ grub_error (GRUB_ERR_BAD_OS, N_("too many setup sectors"));
+ goto fail;
+ }
+
+ if (lh.version < grub_cpu_to_le16 (0x020b))
+ {
+ grub_error (GRUB_ERR_BAD_OS, N_("kernel too old"));
+ goto fail;
+ }
+
+ if (!lh.handover_offset)
+ {
+ grub_error (GRUB_ERR_BAD_OS, N_("kernel doesn't support EFI handover"));
+ goto fail;
+ }
+
+ linux_cmdline = grub_efi_allocate_pages_max(0x3fffffff,
+ BYTES_TO_PAGES(lh.cmdline_size + 1));
+
+ if (!linux_cmdline)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate cmdline"));
+ goto fail;
+ }
+
+ grub_memcpy (linux_cmdline, LINUX_IMAGE, sizeof (LINUX_IMAGE));
+ grub_create_loader_cmdline (argc, argv,
+ linux_cmdline + sizeof (LINUX_IMAGE) - 1,
+ lh.cmdline_size - (sizeof (LINUX_IMAGE) - 1));
+
+ lh.cmd_line_ptr = (grub_uint32_t)(grub_uint64_t)linux_cmdline;
+
+ handover_offset = lh.handover_offset;
+
+ start = (lh.setup_sects + 1) * 512;
+ len = grub_file_size(file) - start;
+
+ kernel_mem = grub_efi_allocate_pages(lh.pref_address,
+ BYTES_TO_PAGES(lh.init_size));
+
+ if (!kernel_mem)
+ kernel_mem = grub_efi_allocate_pages_max(0x3fffffff,
+ BYTES_TO_PAGES(lh.init_size));
+
+ if (!kernel_mem)
+ {
+ grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate kernel"));
+ goto fail;
+ }
+
+ if (grub_file_seek (file, start) == (grub_off_t) -1)
+ {
+ grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
+ argv[0]);
+ goto fail;
+ }
+
+ if (grub_file_read (file, kernel_mem, len) != len && !grub_errno)
+ {
+ grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
+ argv[0]);
+ }
+
+ if (grub_errno == GRUB_ERR_NONE)
+ {
+ grub_loader_set (grub_linuxefi_boot, grub_linuxefi_unload, 0);
+ loaded = 1;
+ lh.code32_start = (grub_uint32_t)(grub_uint64_t) kernel_mem;
+ }
+
+ memcpy(params, &lh, 2 * 512);
+
+ params->type_of_loader = 0x21;
+
+ fail:
+ fail_errno = grub_errno;
+ if (file)
+ grub_file_close (file);
+
+ if (fail_errno != GRUB_ERR_NONE)
+ {
+ grub_dl_unref (my_mod);
+ loaded = 0;
+ }
+
+ if (linux_cmdline && !loaded)
+ grub_efi_free_pages((grub_efi_physical_address_t)linux_cmdline, BYTES_TO_PAGES(lh.cmdline_size + 1));
+
+ if (kernel_mem && !loaded)
+ grub_efi_free_pages((grub_efi_physical_address_t)kernel_mem, BYTES_TO_PAGES(kernel_size));
+
+ if (params && !loaded)
+ grub_efi_free_pages((grub_efi_physical_address_t)params, BYTES_TO_PAGES(16384));
+
+ return fail_errno;
+}
+
+static grub_command_t cmd_linux, cmd_initrd;
+
+GRUB_MOD_INIT(linuxefi)
+{
+ cmd_linux =
+ grub_register_command ("linuxefi", grub_cmd_linux,
+ 0, N_("Load Linux."));
+ cmd_initrd =
+ grub_register_command ("initrdefi", grub_cmd_initrd,
+ 0, N_("Load initrd."));
+ my_mod = mod;
+}
+
+GRUB_MOD_FINI(linuxefi)
+{
+ grub_unregister_command (cmd_linux);
+ grub_unregister_command (cmd_initrd);
+}
diff --git a/grub-core/loader/i386/linux.c b/grub-core/loader/i386/linux.c
index b15b8cc..fce1b45 100644
--- a/grub-core/loader/i386/linux.c
+++ b/grub-core/loader/i386/linux.c
@@ -75,6 +75,8 @@ static grub_size_t maximal_cmdline_size;
static struct linux_kernel_params linux_params;
static char *linux_cmdline;
#ifdef GRUB_MACHINE_EFI
+static int using_linuxefi;
+static grub_command_t initrdefi_cmd;
static grub_efi_uintn_t efi_mmap_size;
#else
static const grub_size_t efi_mmap_size = 0;
@@ -689,6 +691,43 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
grub_dl_ref (my_mod);
+#ifdef GRUB_MACHINE_EFI
+ using_linuxefi = 0;
+ if (grub_efi_secure_boot ())
+ {
+ /* Use linuxefi if SB is enabled, which will require a successful
+ signature check and then hand over to the kernel without calling
+ ExitBootServices.
+ If that fails, however, DO NOT fall back to original 'linux'
+ command which boots an unsigned kernel. */
+ grub_dl_t mod;
+ grub_command_t linuxefi_cmd;
+
+ grub_dprintf ("linux", "Secure Boot enabled: trying linuxefi\n");
+
+ mod = grub_dl_load ("linuxefi");
+ if (mod)
+ {
+ grub_dl_ref (mod);
+ linuxefi_cmd = grub_command_find ("linuxefi");
+ initrdefi_cmd = grub_command_find ("initrdefi");
+ if (linuxefi_cmd && initrdefi_cmd)
+ {
+ (linuxefi_cmd->func) (linuxefi_cmd, argc, argv);
+ if (grub_errno == GRUB_ERR_NONE)
+ {
+ grub_dprintf ("linux", "Handing off to linuxefi\n");
+ using_linuxefi = 1;
+ return GRUB_ERR_NONE;
+ }
+ grub_dprintf ("linux", "linuxefi failed (%d)\n", grub_errno);
+ grub_errno = GRUB_ERR_ACCESS_DENIED;
+ }
+ }
+ goto fail;
+ }
+#endif
+
if (argc == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
@@ -1051,6 +1090,12 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
grub_err_t err;
struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 };
+#ifdef GRUB_MACHINE_EFI
+ /* If we're using linuxefi, just forward to initrdefi. */
+ if (using_linuxefi && initrdefi_cmd)
+ return (initrdefi_cmd->func) (initrdefi_cmd, argc, argv);
+#endif
+
if (argc == 0)
{
grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
diff --git a/include/grub/efi/efi.h b/include/grub/efi/efi.h
index e9c601f..62a3d97 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -40,6 +40,9 @@ void EXPORT_FUNC(grub_efi_stall) (grub_efi_uintn_t microseconds);
void *
EXPORT_FUNC(grub_efi_allocate_pages) (grub_efi_physical_address_t address,
grub_efi_uintn_t pages);
+void *
+EXPORT_FUNC(grub_efi_allocate_pages_max) (grub_efi_physical_address_t max,
+ grub_efi_uintn_t pages);
void EXPORT_FUNC(grub_efi_free_pages) (grub_efi_physical_address_t address,
grub_efi_uintn_t pages);
int
@@ -73,6 +76,7 @@ EXPORT_FUNC (grub_efi_set_variable) (const char *var,
const grub_efi_guid_t *guid,
void *data,
grub_size_t datasize);
+grub_efi_boolean_t EXPORT_FUNC (grub_efi_secure_boot) (void);
int
EXPORT_FUNC (grub_efi_compare_device_paths) (const grub_efi_device_path_t *dp1,
const grub_efi_device_path_t *dp2);
diff --git a/include/grub/i386/linux.h b/include/grub/i386/linux.h
index da0ca3b..fc36bda 100644
--- a/include/grub/i386/linux.h
+++ b/include/grub/i386/linux.h
@@ -139,6 +139,7 @@ struct linux_kernel_header
grub_uint64_t setup_data;
grub_uint64_t pref_address;
grub_uint32_t init_size;
+ grub_uint32_t handover_offset;
} GRUB_PACKED;
/* Boot parameters for Linux based on 2.6.12. This is used by the setup
--
2.8.1