dcavalca / rpms / grub2

Forked from rpms/grub2 3 years ago
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Matthew Garrett <mjg59@coreos.com>
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Date: Sun, 9 Aug 2015 16:20:58 -0700
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Subject: [PATCH] Rework linux16 command
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We want a single buffer that contains the entire kernel image in order to
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perform a TPM measurement. Allocate one and copy the entire kernel int it
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before pulling out the individual blocks later on.
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---
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 grub-core/loader/i386/pc/linux.c | 54 +++++++++++++++++++++++-----------------
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 1 file changed, 31 insertions(+), 23 deletions(-)
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diff --git a/grub-core/loader/i386/pc/linux.c b/grub-core/loader/i386/pc/linux.c
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index b19527e8e17..60bb31fbf0d 100644
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--- a/grub-core/loader/i386/pc/linux.c
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+++ b/grub-core/loader/i386/pc/linux.c
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@@ -124,13 +124,14 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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   grub_file_t file = 0;
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   struct linux_kernel_header lh;
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   grub_uint8_t setup_sects;
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-  grub_size_t real_size;
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+  grub_size_t real_size, kernel_offset = 0;
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   grub_ssize_t len;
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   int i;
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   char *grub_linux_prot_chunk;
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   int grub_linux_is_bzimage;
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   grub_addr_t grub_linux_prot_target;
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   grub_err_t err;
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+  grub_uint8_t *kernel = NULL;
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   grub_dl_ref (my_mod);
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@@ -144,7 +145,15 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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   if (! file)
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     goto fail;
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-  if (grub_file_read (file, &lh, sizeof (lh)) != sizeof (lh))
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+  len = grub_file_size (file);
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+  kernel = grub_malloc (len);
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+  if (!kernel)
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+    {
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+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel buffer"));
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+      goto fail;
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+    }
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+
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+  if (grub_file_read (file, kernel, len) != len)
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     {
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       if (!grub_errno)
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 	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
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@@ -152,7 +161,10 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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       goto fail;
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     }
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-  if (lh.boot_flag != grub_cpu_to_le16 (0xaa55))
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+  grub_memcpy (&lh, kernel, sizeof (lh));
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+  kernel_offset = sizeof (lh);
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+
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+  if (lh.boot_flag != grub_cpu_to_le16_compile_time (0xaa55))
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     {
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       grub_error (GRUB_ERR_BAD_OS, "invalid magic number");
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       goto fail;
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@@ -170,7 +182,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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   maximal_cmdline_size = 256;
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-  if (lh.header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
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+  if (lh.header == grub_cpu_to_le32_compile_time (GRUB_LINUX_MAGIC_SIGNATURE)
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       && grub_le_to_cpu16 (lh.version) >= 0x0200)
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     {
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       grub_linux_is_bzimage = (lh.loadflags & GRUB_LINUX_FLAG_BIG_KERNEL);
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@@ -189,7 +201,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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       if (grub_le_to_cpu16 (lh.version) >= 0x0201)
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 	{
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-	  lh.heap_end_ptr = grub_cpu_to_le16 (GRUB_LINUX_HEAP_END_OFFSET);
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+	  lh.heap_end_ptr = grub_cpu_to_le32_compile_time (GRUB_LINUX_HEAP_END_OFFSET);
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 	  lh.loadflags |= GRUB_LINUX_FLAG_CAN_USE_HEAP;
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 	}
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@@ -197,17 +209,17 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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 	lh.cmd_line_ptr = grub_linux_real_target + GRUB_LINUX_CL_OFFSET;
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       else
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 	{
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-	  lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);
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-	  lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);
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-	  lh.setup_move_size = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET
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+	  lh.cl_magic = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_MAGIC);
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+	  lh.cl_offset = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_OFFSET);
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+	  lh.setup_move_size = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_OFFSET
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 						 + maximal_cmdline_size);
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 	}
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     }
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   else
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     {
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       /* Your kernel is quite old...  */
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-      lh.cl_magic = grub_cpu_to_le16 (GRUB_LINUX_CL_MAGIC);
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-      lh.cl_offset = grub_cpu_to_le16 (GRUB_LINUX_CL_OFFSET);
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+      lh.cl_magic = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_MAGIC);
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+      lh.cl_offset = grub_cpu_to_le32_compile_time (GRUB_LINUX_CL_OFFSET);
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       setup_sects = GRUB_LINUX_DEFAULT_SETUP_SECTS;
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@@ -312,15 +324,11 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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   grub_memmove (grub_linux_real_chunk, &lh, sizeof (lh));
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   len = real_size + GRUB_DISK_SECTOR_SIZE - sizeof (lh);
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-  if (grub_file_read (file, grub_linux_real_chunk + sizeof (lh), len) != len)
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-    {
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-      if (!grub_errno)
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-	grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
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-		    argv[0]);
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-      goto fail;
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-    }
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+  grub_memcpy (grub_linux_real_chunk + sizeof (lh), kernel + kernel_offset,
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+	       len);
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+  kernel_offset += len;
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-  if (lh.header != grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
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+  if (lh.header != grub_cpu_to_le32_compile_time (GRUB_LINUX_MAGIC_SIGNATURE)
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       || grub_le_to_cpu16 (lh.version) < 0x0200)
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     /* Clear the heap space.  */
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     grub_memset (grub_linux_real_chunk
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@@ -353,10 +361,8 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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   }
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   len = grub_linux16_prot_size;
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-  if (grub_file_read (file, grub_linux_prot_chunk, grub_linux16_prot_size)
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-      != (grub_ssize_t) grub_linux16_prot_size && !grub_errno)
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-    grub_error (GRUB_ERR_BAD_OS, N_("premature end of file %s"),
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-		argv[0]);
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+  grub_memcpy (grub_linux_prot_chunk, kernel + kernel_offset, len);
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+  kernel_offset += len;
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   if (grub_errno == GRUB_ERR_NONE)
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     {
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@@ -366,6 +372,8 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
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  fail:
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+  grub_free (kernel);
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+
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   if (file)
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     grub_file_close (file);
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@@ -405,7 +413,7 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),
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   lh = (struct linux_kernel_header *) grub_linux_real_chunk;
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-  if (!(lh->header == grub_cpu_to_le32 (GRUB_LINUX_MAGIC_SIGNATURE)
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+  if (!(lh->header == grub_cpu_to_le32_compile_time (GRUB_LINUX_MAGIC_SIGNATURE)
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 	&& grub_le_to_cpu16 (lh->version) >= 0x0200))
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     {
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       grub_error (GRUB_ERR_BAD_OS, "the kernel is too old for initrd");