From 704890aaa1d5ba485f538cdf20b1030798253c87 Mon Sep 17 00:00:00 2001

From: Matthew Garrett <mjg59@coreos.com>

Date: Sun, 9 Aug 2015 16:20:58 -0700

Subject: [PATCH 223/261] Rework linux16 command

We want a single buffer that contains the entire kernel image in order to

perform a TPM measurement. Allocate one and copy the entire kernel int it

before pulling out the individual blocks later on.

---

 grub-core/loader/i386/pc/linux.c | 54 +++++++++++++++++++++++-----------------

 1 file changed, 31 insertions(+), 23 deletions(-)

diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c

index b19527e8e..60bb31fbf 100644

--- a/grub-core/loader/i386/pc/linux.c

+++ b/grub-core/loader/i386/pc/linux.c

@@ -124,13 +124,14 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   grub_file_t file = 0;

   struct linux_kernel_header lh;

   grub_uint8_t setup_sects;

-  grub_size_t real_size;

+  grub_size_t real_size, kernel_offset = 0;

   grub_ssize_t len;

   int i;

   char *grub_linux_prot_chunk;

   int grub_linux_is_bzimage;

   grub_addr_t grub_linux_prot_target;

   grub_err_t err;

+  grub_uint8_t *kernel = NULL;

   grub_dl_ref (my_mod);

@@ -144,7 +145,15 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   if (! file)

     goto fail;

-  if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))

+  len = grub_file_size (file);

+  kernel = grub_malloc (len);

+  if (!kernel)

+    {

+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel buffer"));

+      goto fail;

+    }

+

+  if (grub_file_read (file, kernel, len) != len)

     {

       if (!grub_errno)

 	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),

@@ -152,7 +161,10 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

       goto fail;

     }

-  if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))

+  grub_memcpy (&lh, kernel, sizeof (lh));

+  kernel_offset = sizeof (lh);

+

+  if (lh.boot_flag != grub_cpu_to_le16_compile_time (0xaa55))

     {

       grub_error (GRUB_ERR_BAD_OS, "invalid magic number");

       goto fail;

@@ -170,7 +182,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   maximal_cmdline_size = 256;

-  if (lh.header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)

+  if (lh.header == grub_cpu_to_le32_compile_time (GRUB_LINUX_MAGIC_SIGNATURE)

       && grub_le_to_cpu16 (lh.version) >= 0x0200)

     {

       grub_linux_is_bzimage = (lh.loadflags & GRUB_LINUX_FLAG_BIG_KERNEL);

@@ -189,7 +201,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

       if (grub_le_to_cpu16 (lh.version) >= 0x0201)

 	{

-	  lh.heap_end_ptr = grub_cpu_to_le16 (GRUB_LINUX_HEAP_END_OFFSET);

+	  lh.heap_end_ptr = grub_cpu_to_le32_compile_time (GRUB_LINUX_HEAP_END_OFFSET);

 	  lh.loadflags |= GRUB_LINUX_FLAG_CAN_USE_HEAP;

 	}

@@ -197,17 +209,17 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

 	lh.cmd_line_ptr = grub_linux_real_target + GRUB_LINUX_CL_OFFSET;

       else

 	{

-	  lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);

-	  lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);

-	  lh.setup_move_size = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET

+	  lh.cl_magic = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_MAGIC);

+	  lh.cl_offset = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_OFFSET);

+	  lh.setup_move_size = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_OFFSET

 						 + maximal_cmdline_size);

 	}

     }

   else

     {

       /* Your kernel is quite old...  */

-      lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);

-      lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);

+      lh.cl_magic = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_MAGIC);

+      lh.cl_offset = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_OFFSET);

       setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;

@@ -312,15 +324,11 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   grub_memmove (grub_linux_real_chunk, &lh, sizeof (lh));

   len = real_size + GRUB_DISK_SECTOR_SIZE - sizeof (lh);

-  if (grub_file_read (file, grub_linux_real_chunk + sizeof (lh), len) != len)

-    {

-      if (!grub_errno)

-	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),

-		    argv[0]);

-      goto fail;

-    }

+  grub_memcpy (grub_linux_real_chunk + sizeof (lh), kernel + kernel_offset,

+	       len);

+  kernel_offset += len;

-  if (lh.header != grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)

+  if (lh.header != grub_cpu_to_le32_compile_time (GRUB_LINUX_MAGIC_SIGNATURE)

       || grub_le_to_cpu16 (lh.version) < 0x0200)

     /* Clear the heap space.  */

     grub_memset (grub_linux_real_chunk

@@ -353,10 +361,8 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   }

   len = grub_linux16_prot_size;

-  if (grub_file_read (file, grub_linux_prot_chunk, grub_linux16_prot_size)

-      != (grub_ssize_t) grub_linux16_prot_size && !grub_errno)

-    grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),

-		argv[0]);

+  grub_memcpy (grub_linux_prot_chunk, kernel + kernel_offset, len);

+  kernel_offset += len;

   if (grub_errno == GRUB_ERR_NONE)

     {

@@ -366,6 +372,8 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

  fail:

+  grub_free (kernel);

+

   if (file)

     grub_file_close (file);

@@ -405,7 +413,7 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

   lh = (struct linux_kernel_header *) grub_linux_real_chunk;

-  if (!(lh->header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)

+  if (!(lh->header == grub_cpu_to_le32_compile_time (GRUB_LINUX_MAGIC_SIGNATURE)

 	&& grub_le_to_cpu16 (lh->version) >= 0x0200))

     {

       grub_error (GRUB_ERR_BAD_OS, "the kernel is too old for initrd");

-- 

2.13.5