path: root/debian/patches/linuxefi.patch

From fc550c31c25dcf9eb58ca1e987f3ce2be8ebac28 Mon Sep 17 00:00:00 2001
From: Matthew Garrett <mjg@redhat.com>
Date: Mon, 13 Jan 2014 12:13:15 +0000
Subject: Add "linuxefi" loader which avoids ExitBootServices

Origin: vendor, http://pkgs.fedoraproject.org/cgit/grub2.git/tree/grub2-linuxefi.patch
Author: Colin Watson <cjwatson@ubuntu.com>
Author: Steve Langasek <steve.langasek@canonical.com>
Author: Linn Crosetto <linn@hpe.com>
Forwarded: no
Last-Update: 2021-09-24

Patch-Name: linuxefi.patch
---
 grub-core/Makefile.core.def       |   7 +
 grub-core/kern/efi/mm.c           |  32 +++
 grub-core/loader/i386/efi/linux.c | 383 ++++++++++++++++++++++++++++++
 grub-core/loader/i386/linux.c     |  41 ++++
 include/grub/efi/efi.h            |   3 +
 5 files changed, 466 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 8022e1c0a..e5b3d27f5 100644
--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1874,6 +1874,13 @@ module = {
   enable = x86_64_efi;
 };
 
+module = {
+  name = linuxefi;
+  efi = loader/i386/efi/linux.c;
+  enable = i386_efi;
+  enable = x86_64_efi;
+};
+
 module = {
   name = chain;
   efi = loader/efi/chainloader.c;
diff --git a/grub-core/kern/efi/mm.c b/grub-core/kern/efi/mm.c
index 9838fb2f5..f6aef0ef6 100644
--- a/grub-core/kern/efi/mm.c
+++ b/grub-core/kern/efi/mm.c
@@ -113,6 +113,38 @@ grub_efi_drop_alloc (grub_efi_physical_address_t address,
     }
 }
 
+/* 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_real (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 000000000..45b68c05a
--- /dev/null
+++ b/grub-core/loader/i386/efi/linux.c
@@ -0,0 +1,383 @@
+/*
+ *  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/linux.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/sb.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;
+
+  if (grub_efi_get_secureboot () != GRUB_EFI_SECUREBOOT_MODE_ENABLED)
+    {
+      grub_dprintf ("linuxefi", "secure boot not enabled, not validating");
+      return 1;
+    }
+
+  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)(grub_addr_t)initrd_mem, BYTES_TO_PAGES(params->ramdisk_size));
+  if (linux_cmdline)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_t)linux_cmdline, BYTES_TO_PAGES(params->cmdline_size + 1));
+  if (kernel_mem)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_t)kernel_mem, BYTES_TO_PAGES(kernel_size));
+  if (params)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_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_size_t size = 0;
+  struct grub_linux_initrd_context initrd_ctx;
+
+  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;
+    }
+
+  if (grub_initrd_init (argc, argv, &initrd_ctx))
+    goto fail;
+
+  size = grub_get_initrd_size (&initrd_ctx);
+
+  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;
+    }
+
+  grub_dprintf ("linuxefi", "initrd_mem = %lx\n", (unsigned long) initrd_mem);
+
+  params->ramdisk_size = size;
+  params->ramdisk_image = (grub_uint32_t)(grub_addr_t) initrd_mem;
+
+  if (grub_initrd_load (&initrd_ctx, argv, initrd_mem))
+    goto fail;
+
+  params->ramdisk_size = size;
+
+ fail:
+  grub_initrd_close (&initrd_ctx);
+
+  if (initrd_mem && grub_errno)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_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_i386_kernel_header lh;
+  grub_ssize_t len, start, filelen;
+  void *kernel;
+
+  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], GRUB_FILE_TYPE_LINUX_KERNEL);
+  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]);
+      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;
+    }
+
+  grub_dprintf ("linuxefi", "params = %lx\n", (unsigned long) params);
+
+  grub_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_dprintf ("linuxefi", "linux_cmdline = %lx\n",
+		(unsigned long) linux_cmdline);
+
+  grub_memcpy (linux_cmdline, LINUX_IMAGE, sizeof (LINUX_IMAGE));
+  {
+    grub_err_t err;
+    err = grub_create_loader_cmdline (argc, argv,
+				      linux_cmdline
+				      + sizeof (LINUX_IMAGE) - 1,
+				      lh.cmdline_size
+				      - (sizeof (LINUX_IMAGE) - 1),
+				      GRUB_VERIFY_KERNEL_CMDLINE);
+    if (err)
+      goto fail;
+  }
+
+  lh.cmd_line_ptr = (grub_uint32_t)(grub_addr_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_fixed(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;
+    }
+  grub_errno = GRUB_ERR_NONE;
+
+  grub_dprintf ("linuxefi", "kernel_mem = %lx\n", (unsigned long) kernel_mem);
+
+  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_addr_t) kernel_mem;
+    }
+
+  grub_memcpy (params, &lh, 2 * 512);
+
+  params->type_of_loader = 0x21;
+
+ fail:
+
+  if (file)
+    grub_file_close (file);
+
+  if (grub_errno != GRUB_ERR_NONE)
+    {
+      grub_dl_unref (my_mod);
+      loaded = 0;
+    }
+
+  if (linux_cmdline && !loaded)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_t)linux_cmdline, BYTES_TO_PAGES(lh.cmdline_size + 1));
+
+  if (kernel_mem && !loaded)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_t)kernel_mem, BYTES_TO_PAGES(kernel_size));
+
+  if (params && !loaded)
+    grub_efi_free_pages((grub_efi_physical_address_t)(grub_addr_t)params, BYTES_TO_PAGES(16384));
+
+  return grub_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 9f74a96b1..be37a1640 100644
--- a/grub-core/loader/i386/linux.c
+++ b/grub-core/loader/i386/linux.c
@@ -78,6 +78,8 @@ 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;
@@ -659,6 +661,39 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
 
   grub_dl_ref (my_mod);
 
+#ifdef GRUB_MACHINE_EFI
+  using_linuxefi = 0;
+  if (grub_efi_get_secureboot () == GRUB_EFI_SECUREBOOT_MODE_ENABLED)
+    {
+      /* linuxefi requires a successful signature check and then hand over
+	 to the kernel without calling ExitBootServices. */
+      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);
+	      goto fail;
+	    }
+	}
+    }
+#endif
+
   if (argc == 0)
     {
       grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
@@ -1042,6 +1077,12 @@ 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 83d958f99..08f6ee00a 100644
--- a/include/grub/efi/efi.h
+++ b/include/grub/efi/efi.h
@@ -47,6 +47,9 @@ EXPORT_FUNC(grub_efi_allocate_fixed) (grub_efi_physical_address_t address,
 				      grub_efi_uintn_t pages);
 void *
 EXPORT_FUNC(grub_efi_allocate_any_pages) (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);
 grub_efi_uintn_t EXPORT_FUNC(grub_efi_find_mmap_size) (void);