From db4da8095b5ba722d22502c8d090e66816a5577d Mon Sep 17 00:00:00 2001
From: Matthew Garrett <mjg@redhat.com>
Date: Fri, 6 Nov 2020 08:36:36 +0000
Subject: [PATCH 1/9] Add support for Linux EFI stub loading on aarch64.

Add support for Linux EFI stub loading on aarch64.

v1:
Make efi handoff the default loader for arm64 platform.

v2:
The efi shim_lock verifier has been moved to grub core so local
shim_lock protocol is no longer needed here for aarch64 efi to verify
the loaded kernel image. From now on the framework will take care the
verificaion, consolidating the integration of various security verifiers
like secure boot, gpg and tpm.

---
 grub-core/Makefile.core.def        |   4 +-
 grub-core/loader/arm64/efi/linux.c | 443 +++++++++++++++++++++++++++++
 include/grub/arm/linux.h           |   9 +
 include/grub/arm64/linux.h         |  10 +
 4 files changed, 465 insertions(+), 1 deletion(-)
 create mode 100644 grub-core/loader/arm64/efi/linux.c

--- a/grub-core/Makefile.core.def
+++ b/grub-core/Makefile.core.def
@@ -1854,7 +1854,7 @@
   arm_coreboot = loader/arm/linux.c;
   arm_efi = loader/efi/linux.c;
   arm_uboot = loader/arm/linux.c;
-  arm64 = loader/efi/linux.c;
+  arm64 = loader/arm64/efi/linux.c;
   loongarch64 = loader/efi/linux.c;
   riscv32 = loader/efi/linux.c;
   riscv64 = loader/efi/linux.c;
@@ -1922,7 +1922,7 @@
 
 module = {
   name = linuxefi;
-  efi = lib/fake_module.c;
+  x86 = lib/fake_module.c;
   enable = i386_efi;
   enable = x86_64_efi;
 };
--- /dev/null
+++ b/grub-core/loader/arm64/efi/linux.c
@@ -0,0 +1,411 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013  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/charset.h>
+#include <grub/command.h>
+#include <grub/err.h>
+#include <grub/file.h>
+#include <grub/fdt.h>
+#include <grub/linux.h>
+#include <grub/loader.h>
+#include <grub/mm.h>
+#include <grub/types.h>
+#include <grub/cpu/linux.h>
+#include <grub/efi/efi.h>
+#include <grub/efi/fdtload.h>
+#include <grub/efi/memory.h>
+#include <grub/efi/pe32.h>
+#include <grub/i18n.h>
+#include <grub/lib/cmdline.h>
+#include <grub/verify.h>
+
+GRUB_MOD_LICENSE ("GPLv3+");
+
+static grub_dl_t my_mod;
+static int loaded;
+
+static void *kernel_addr;
+static grub_uint64_t kernel_size;
+static grub_uint32_t handover_offset;
+
+static char *linux_args;
+static grub_uint32_t cmdline_size;
+
+static grub_addr_t initrd_start;
+static grub_addr_t initrd_end;
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wcast-align"
+
+typedef void (*handover_func) (void *, grub_efi_system_table_t *, void *);
+
+static grub_err_t
+grub_efi_linux_boot (void *kernel_address, grub_off_t offset,
+		     void *kernel_params)
+{
+  handover_func hf;
+
+  hf = (handover_func)((char *)kernel_address + offset);
+  hf (grub_efi_image_handle, grub_efi_system_table, kernel_params);
+
+  return GRUB_ERR_BUG;
+}
+
+#pragma GCC diagnostic pop
+
+static grub_err_t
+grub_arch_efi_linux_check_image (struct linux_arch_kernel_header * lh)
+{
+  if (lh->magic != GRUB_LINUX_ARMXX_MAGIC_SIGNATURE)
+    return grub_error(GRUB_ERR_BAD_OS, "invalid magic number");
+
+  if ((lh->code0 & 0xffff) != GRUB_PE32_MAGIC)
+    return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
+		       N_("plain image kernel not supported - rebuild with CONFIG_(U)EFI_STUB enabled"));
+
+  grub_dprintf ("linux", "UEFI stub kernel:\n");
+  grub_dprintf ("linux", "PE/COFF header @ %08x\n", lh->hdr_offset);
+
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+finalize_params_linux (void)
+{
+  grub_efi_loaded_image_t *loaded_image = NULL;
+  int node, retval, len;
+
+  void *fdt;
+
+  fdt = grub_fdt_load (GRUB_EFI_LINUX_FDT_EXTRA_SPACE);
+
+  if (!fdt)
+    goto failure;
+
+  node = grub_fdt_find_subnode (fdt, 0, "chosen");
+  if (node < 0)
+    node = grub_fdt_add_subnode (fdt, 0, "chosen");
+
+  if (node < 1)
+    goto failure;
+
+  /* Set initrd info */
+  if (initrd_start && initrd_end > initrd_start)
+    {
+      grub_dprintf ("linux", "Initrd @ %p-%p\n",
+		    (void *) initrd_start, (void *) initrd_end);
+
+      retval = grub_fdt_set_prop64 (fdt, node, "linux,initrd-start",
+				    initrd_start);
+      if (retval)
+	goto failure;
+      retval = grub_fdt_set_prop64 (fdt, node, "linux,initrd-end",
+				    initrd_end);
+      if (retval)
+	goto failure;
+    }
+
+  if (grub_fdt_install() != GRUB_ERR_NONE)
+    goto failure;
+
+  grub_dprintf ("linux", "Installed/updated FDT configuration table @ %p\n",
+		fdt);
+
+  /* Convert command line to UCS-2 */
+  loaded_image = grub_efi_get_loaded_image (grub_efi_image_handle);
+  if (!loaded_image)
+    goto failure;
+
+  loaded_image->load_options_size = len =
+    (grub_strlen (linux_args) + 1) * sizeof (grub_efi_char16_t);
+  loaded_image->load_options =
+    grub_efi_allocate_any_pages (GRUB_EFI_BYTES_TO_PAGES (loaded_image->load_options_size));
+  if (!loaded_image->load_options)
+    return grub_error(GRUB_ERR_BAD_OS, "failed to create kernel parameters");
+
+  loaded_image->load_options_size =
+    2 * grub_utf8_to_utf16 (loaded_image->load_options, len,
+			    (grub_uint8_t *) linux_args, len, NULL);
+
+  return GRUB_ERR_NONE;
+
+failure:
+  grub_fdt_unload();
+  return grub_error(GRUB_ERR_BAD_OS, "failed to install/update FDT");
+}
+
+static void
+free_params (void)
+{
+  grub_efi_loaded_image_t *loaded_image = NULL;
+
+  loaded_image = grub_efi_get_loaded_image (grub_efi_image_handle);
+  if (loaded_image)
+    {
+      if (loaded_image->load_options)
+	grub_efi_free_pages ((grub_efi_physical_address_t)(grub_efi_uintn_t)loaded_image->load_options,
+			     GRUB_EFI_BYTES_TO_PAGES (loaded_image->load_options_size));
+      loaded_image->load_options = NULL;
+      loaded_image->load_options_size = 0;
+    }
+}
+
+grub_err_t
+grub_arch_efi_linux_boot_image (grub_addr_t addr,
+			        grub_size_t size __attribute__ ((unused)),
+			        char *args)
+{
+  grub_err_t retval;
+
+  retval = finalize_params_linux ();
+  if (retval != GRUB_ERR_NONE)
+    return grub_errno;
+
+  grub_dprintf ("linux", "linux command line: '%s'\n", args);
+
+  retval = grub_efi_linux_boot ((char *)addr, handover_offset, (void *)addr);
+
+  /* Never reached... */
+  free_params();
+  return retval;
+}
+
+static grub_err_t
+grub_linux_boot (void)
+{
+  return (grub_arch_efi_linux_boot_image ((grub_addr_t)kernel_addr, kernel_size, linux_args));
+}
+
+static grub_err_t
+grub_linux_unload (void)
+{
+  grub_dl_unref (my_mod);
+  loaded = 0;
+  if (initrd_start)
+    grub_efi_free_pages ((grub_efi_physical_address_t) initrd_start,
+			 GRUB_EFI_BYTES_TO_PAGES (initrd_end - initrd_start));
+  initrd_start = initrd_end = 0;
+  grub_free (linux_args);
+  if (kernel_addr)
+    grub_efi_free_pages ((grub_addr_t) kernel_addr,
+			 GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+  grub_fdt_unload ();
+  return GRUB_ERR_NONE;
+}
+
+/*
+ * As per linux/Documentation/arm/Booting
+ * ARM initrd needs to be covered by kernel linear mapping,
+ * so place it in the first 512MB of DRAM.
+ *
+ * As per linux/Documentation/arm64/booting.txt
+ * ARM64 initrd needs to be contained entirely within a 1GB aligned window
+ * of up to 32GB of size that covers the kernel image as well.
+ * Since the EFI stub loader will attempt to load the kernel near start of
+ * RAM, place the buffer in the first 32GB of RAM.
+ */
+#ifdef __arm__
+#define INITRD_MAX_ADDRESS_OFFSET (512U * 1024 * 1024)
+#else /* __aarch64__ */
+#define INITRD_MAX_ADDRESS_OFFSET (32ULL * 1024 * 1024 * 1024)
+#endif
+
+/*
+ * This function returns a pointer to a legally allocated initrd buffer,
+ * or NULL if unsuccessful
+ */
+static void *
+allocate_initrd_mem (int initrd_pages)
+{
+  grub_addr_t max_addr;
+
+  if (grub_efi_get_ram_base (&max_addr) != GRUB_ERR_NONE)
+    return NULL;
+
+  max_addr += INITRD_MAX_ADDRESS_OFFSET - 1;
+
+  return grub_efi_allocate_pages_real (max_addr, initrd_pages,
+				       GRUB_EFI_ALLOCATE_MAX_ADDRESS,
+				       GRUB_EFI_LOADER_DATA);
+}
+
+static grub_err_t
+grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
+		 int argc, char *argv[])
+{
+  struct grub_linux_initrd_context initrd_ctx = { 0, 0, 0 };
+  int initrd_size, initrd_pages;
+  void *initrd_mem = NULL;
+
+  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;
+
+  initrd_size = grub_get_initrd_size (&initrd_ctx);
+  grub_dprintf ("linux", "Loading initrd\n");
+
+  initrd_pages = (GRUB_EFI_BYTES_TO_PAGES (initrd_size));
+  initrd_mem = allocate_initrd_mem (initrd_pages);
+
+  if (!initrd_mem)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+      goto fail;
+    }
+
+  if (grub_initrd_load (&initrd_ctx, initrd_mem))
+    goto fail;
+
+  initrd_start = (grub_addr_t) initrd_mem;
+  initrd_end = initrd_start + initrd_size;
+  grub_dprintf ("linux", "[addr=%p, size=0x%x]\n",
+		(void *) initrd_start, initrd_size);
+
+ fail:
+  grub_initrd_close (&initrd_ctx);
+  if (initrd_mem && !initrd_start)
+    grub_efi_free_pages ((grub_addr_t) initrd_mem, initrd_pages);
+
+  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_arch_kernel_header lh;
+  struct grub_armxx_linux_pe_header *pe;
+  grub_err_t err;
+
+  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;
+
+  kernel_size = grub_file_size (file);
+
+  if (grub_file_read (file, &lh, sizeof (lh)) < (long) sizeof (lh))
+    return grub_errno;
+
+  if (grub_arch_efi_linux_check_image (&lh) != GRUB_ERR_NONE)
+    goto fail;
+
+  grub_loader_unset();
+
+  grub_dprintf ("linux", "kernel file size: %lld\n", (long long) kernel_size);
+  kernel_addr = grub_efi_allocate_any_pages (GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+  grub_dprintf ("linux", "kernel numpages: %lld\n",
+		(long long) GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+  if (!kernel_addr)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+      goto fail;
+    }
+
+  grub_file_seek (file, 0);
+  if (grub_file_read (file, kernel_addr, kernel_size)
+      < (grub_int64_t) kernel_size)
+    {
+      if (!grub_errno)
+	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"), argv[0]);
+      goto fail;
+    }
+
+  grub_dprintf ("linux", "kernel @ %p\n", kernel_addr);
+
+  pe = (void *)((unsigned long)kernel_addr + lh.hdr_offset);
+  handover_offset = pe->opt.entry_addr;
+
+  cmdline_size = grub_loader_cmdline_size (argc, argv) + sizeof (LINUX_IMAGE);
+  linux_args = grub_malloc (cmdline_size);
+  if (!linux_args)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
+      goto fail;
+    }
+  grub_memcpy (linux_args, LINUX_IMAGE, sizeof (LINUX_IMAGE));
+  err = grub_create_loader_cmdline (argc, argv,
+				    linux_args + sizeof (LINUX_IMAGE) - 1,
+				    cmdline_size,
+				    GRUB_VERIFY_KERNEL_CMDLINE);
+  if (err)
+    goto fail;
+
+  if (grub_errno == GRUB_ERR_NONE)
+    {
+      grub_loader_set (grub_linux_boot, grub_linux_unload, 0);
+      loaded = 1;
+    }
+
+fail:
+  if (file)
+    grub_file_close (file);
+
+  if (grub_errno != GRUB_ERR_NONE)
+    {
+      grub_dl_unref (my_mod);
+      loaded = 0;
+    }
+
+  if (linux_args && !loaded)
+    grub_free (linux_args);
+
+  if (kernel_addr && !loaded)
+    grub_efi_free_pages ((grub_addr_t) kernel_addr,
+			 GRUB_EFI_BYTES_TO_PAGES (kernel_size));
+
+  return grub_errno;
+}
+
+
+static grub_command_t cmd_linux, cmd_initrd;
+
+GRUB_MOD_INIT (linux)
+{
+  cmd_linux = grub_register_command ("linux", grub_cmd_linux, 0,
+				     N_("Load Linux."));
+  cmd_initrd = grub_register_command ("initrd", grub_cmd_initrd, 0,
+				      N_("Load initrd."));
+  my_mod = mod;
+}
+
+GRUB_MOD_FINI (linux)
+{
+  grub_unregister_command (cmd_linux);
+  grub_unregister_command (cmd_initrd);
+}
--- a/include/grub/arm/linux.h
+++ b/include/grub/arm/linux.h
@@ -20,10 +20,22 @@
 #ifndef GRUB_ARM_LINUX_HEADER
 #define GRUB_ARM_LINUX_HEADER 1
 
+#include <grub/efi/pe32.h>
 #include "system.h"
 
 #include <grub/efi/pe32.h>
 
+struct grub_arm_linux_pe_header
+{
+  grub_uint32_t magic;
+  struct grub_pe32_coff_header coff;
+  struct grub_pe32_optional_header opt;
+};
+
+#if defined(__arm__)
+# define grub_armxx_linux_pe_header grub_arm_linux_pe_header
+#endif
+
 #if defined GRUB_MACHINE_UBOOT
 # include <grub/uboot/uboot.h>
 # define LINUX_ADDRESS        (start_of_ram + 0x8000)
--- /dev/null
+++ b/include/grub/arm64/linux.h
@@ -0,0 +1,39 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013  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/>.
+ */
+
+#ifndef GRUB_ARM64_LINUX_HEADER
+#define GRUB_ARM64_LINUX_HEADER 1
+
+#include <grub/types.h>
+#include <grub/efi/pe32.h>
+
+#define GRUB_LINUX_ARM64_MAGIC_SIGNATURE 0x644d5241 /* 'ARM\x64' */
+
+struct grub_arm64_linux_pe_header
+{
+  grub_uint32_t magic;
+  struct grub_pe32_coff_header coff;
+  struct grub_pe64_optional_header opt;
+};
+
+#if defined(__aarch64__)
+# define GRUB_LINUX_ARMXX_MAGIC_SIGNATURE GRUB_LINUX_ARM64_MAGIC_SIGNATURE
+# define grub_armxx_linux_pe_header grub_arm64_linux_pe_header
+#endif
+
+#endif /* ! GRUB_ARM64_LINUX_HEADER */
