From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Peter Jones <pjones@redhat.com>

Date: Thu, 9 Jun 2016 12:22:29 -0400

Subject: [PATCH] Re-work some intricacies of PE loading.

The PE spec is not a well written document, and awesomely every place

where there's an ambiguous way to read something, Windows' bootmgfw.efi

takes a different read than either of them.

---

 grub-core/loader/efi/chainloader.c | 156 +++++++++++++++++++++++++++++--------

 include/grub/efi/pe32.h            |  32 +++++++-

 2 files changed, 152 insertions(+), 36 deletions(-)

diff --git a/grub-core/loader/efi/chainloader.c b/grub-core/loader/efi/chainloader.c

index aee8e6becf6..4b77a7d5adb 100644

--- a/grub-core/loader/efi/chainloader.c

+++ b/grub-core/loader/efi/chainloader.c

@@ -301,7 +301,7 @@ image_is_64_bit (grub_pe_header_t *pe_hdr)

   return 0;

 }

-static const grub_uint16_t machine_type =

+static const grub_uint16_t machine_type __attribute__((__unused__)) =

 #if defined(__x86_64__)

   GRUB_PE32_MACHINE_X86_64;

 #elif defined(__aarch64__)

@@ -367,10 +367,10 @@ relocate_coff (pe_coff_loader_image_context_t *context,

   reloc_base = image_address (orig, size, section->raw_data_offset);

   reloc_base_end = image_address (orig, size, section->raw_data_offset

-				  + section->virtual_size - 1);

+				  + section->virtual_size);

-  grub_dprintf ("chain", "reloc_base %p reloc_base_end %p\n", reloc_base,

-		reloc_base_end);

+  grub_dprintf ("chain", "relocate_coff(): reloc_base %p reloc_base_end %p\n",

+		reloc_base, reloc_base_end);

   if (!reloc_base && !reloc_base_end)

     return GRUB_EFI_SUCCESS;

@@ -507,12 +507,13 @@ handle_image (void *data, grub_efi_uint32_t datasize)

   grub_efi_status_t efi_status;

   char *buffer = NULL;

   char *buffer_aligned = NULL;

-  grub_efi_uint32_t i, size;

+  grub_efi_uint32_t i;

   struct grub_pe32_section_table *section;

   char *base, *end;

   pe_coff_loader_image_context_t context;

   grub_uint32_t section_alignment;

   grub_uint32_t buffer_size;

+  int found_entry_point = 0;

   b = grub_efi_system_table->boot_services;

@@ -526,8 +527,28 @@ handle_image (void *data, grub_efi_uint32_t datasize)

       goto error_exit;

     }

+  /*

+   * The spec says, uselessly, of SectionAlignment:

+   * =====

+   * The alignment (in bytes) of sections when they are loaded into

+   * memory. It must be greater than or equal to FileAlignment. The

+   * default is the page size for the architecture.

+   * =====

+   * Which doesn't tell you whose responsibility it is to enforce the

+   * "default", or when.  It implies that the value in the field must

+   * be > FileAlignment (also poorly defined), but it appears visual

+   * studio will happily write 512 for FileAlignment (its default) and

+   * 0 for SectionAlignment, intending to imply PAGE_SIZE.

+   *

+   * We only support one page size, so if it's zero, nerf it to 4096.

+   */

   section_alignment = context.section_alignment;

+  if (section_alignment == 0)

+    section_alignment = 4096;

+

   buffer_size = context.image_size + section_alignment;

+  grub_dprintf ("chain", "image size is %08lx, datasize is %08x\n",

+	       context.image_size, datasize);

   efi_status = efi_call_3 (b->allocate_pool, GRUB_EFI_LOADER_DATA,

 			   buffer_size, &buffer);

@@ -539,7 +560,6 @@ handle_image (void *data, grub_efi_uint32_t datasize)

     }

   buffer_aligned = (char *)ALIGN_UP ((grub_addr_t)buffer, section_alignment);

-

   if (!buffer_aligned)

     {

       grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));

@@ -548,27 +568,62 @@ handle_image (void *data, grub_efi_uint32_t datasize)

   grub_memcpy (buffer_aligned, data, context.size_of_headers);

+  entry_point = image_address (buffer_aligned, context.image_size,

+			       context.entry_point);

+

+  grub_dprintf ("chain", "entry_point: %p\n", entry_point);

+  if (!entry_point)

+    {

+      grub_error (GRUB_ERR_BAD_ARGUMENT, "invalid entry point");

+      goto error_exit;

+    }

+

   char *reloc_base, *reloc_base_end;

-  reloc_base = image_address (buffer_aligned, datasize,

+  grub_dprintf ("chain", "reloc_dir: %p reloc_size: 0x%08x\n",

+		(void *)(unsigned long long)context.reloc_dir->rva,

+		context.reloc_dir->size);

+  reloc_base = image_address (buffer_aligned, context.image_size,

 			      context.reloc_dir->rva);

   /* RelocBaseEnd here is the address of the last byte of the table */

-  reloc_base_end = image_address (buffer_aligned, datasize,

+  reloc_base_end = image_address (buffer_aligned, context.image_size,

 				  context.reloc_dir->rva

 				  + context.reloc_dir->size - 1);

+  grub_dprintf ("chain", "reloc_base: %p reloc_base_end: %p\n",

+		reloc_base, reloc_base_end);

+

   struct grub_pe32_section_table *reloc_section = NULL;

   section = context.first_section;

   for (i = 0; i < context.number_of_sections; i++, section++)

     {

-      size = section->virtual_size;

-      if (size > section->raw_data_size)

-        size = section->raw_data_size;

+      char name[9];

       base = image_address (buffer_aligned, context.image_size,

 			    section->virtual_address);

       end = image_address (buffer_aligned, context.image_size,

-			   section->virtual_address + size - 1);

+			   section->virtual_address + section->virtual_size -1);

+      grub_strncpy(name, section->name, 9);

+      name[8] = '\0';

+      grub_dprintf ("chain", "Section %d \"%s\" at %p..%p\n", i,

+		   name, base, end);

+

+      if (end < base)

+	{

+	  grub_dprintf ("chain", " base is %p but end is %p... bad.\n",

+		       base, end);

+	  grub_error (GRUB_ERR_BAD_ARGUMENT,

+		      "Image has invalid negative size");

+	  goto error_exit;

+	}

+

+      if (section->virtual_address <= context.entry_point &&

+	  (section->virtual_address + section->raw_data_size - 1)

+	  > context.entry_point)

+	{

+	  found_entry_point++;

+	  grub_dprintf ("chain", " section contains entry point\n");

+	}

       /* We do want to process .reloc, but it's often marked

        * discardable, so we don't want to memcpy it. */

@@ -587,21 +642,46 @@ handle_image (void *data, grub_efi_uint32_t datasize)

 	  if (section->raw_data_size && section->virtual_size &&

 	      base && end && reloc_base == base && reloc_base_end == end)

 	    {

+	      grub_dprintf ("chain", " section is relocation section\n");

 	      reloc_section = section;

 	    }

+	  else

+	    {

+	      grub_dprintf ("chain", " section is not reloc section?\n");

+	      grub_dprintf ("chain", " rds: 0x%08x, vs: %08x\n",

+			    section->raw_data_size, section->virtual_size);

+	      grub_dprintf ("chain", " base: %p end: %p\n", base, end);

+	      grub_dprintf ("chain", " reloc_base: %p reloc_base_end: %p\n",

+			    reloc_base, reloc_base_end);

+	    }

 	}

-      if (section->characteristics && GRUB_PE32_SCN_MEM_DISCARDABLE)

-	continue;

+      grub_dprintf ("chain", " Section characteristics are %08x\n",

+		   section->characteristics);

+      grub_dprintf ("chain", " Section virtual size: %08x\n",

+		   section->virtual_size);

+      grub_dprintf ("chain", " Section raw_data size: %08x\n",

+		   section->raw_data_size);

+      if (section->characteristics & GRUB_PE32_SCN_MEM_DISCARDABLE)

+	{

+	  grub_dprintf ("chain", " Discarding section\n");

+	  continue;

+	}

       if (!base || !end)

         {

+	  grub_dprintf ("chain", " section is invalid\n");

           grub_error (GRUB_ERR_BAD_ARGUMENT, "Invalid section size");

           goto error_exit;

         }

-      if (section->virtual_address < context.size_of_headers ||

-	  section->raw_data_offset < context.size_of_headers)

+      if (section->characteristics & GRUB_PE32_SCN_CNT_UNINITIALIZED_DATA)

+	{

+	  if (section->raw_data_size != 0)

+	    grub_dprintf ("chain", " UNINITIALIZED_DATA section has data?\n");

+	}

+      else if (section->virtual_address < context.size_of_headers ||

+	       section->raw_data_offset < context.size_of_headers)

 	{

 	  grub_error (GRUB_ERR_BAD_ARGUMENT,

 		      "Section %d is inside image headers", i);

@@ -609,13 +689,24 @@ handle_image (void *data, grub_efi_uint32_t datasize)

 	}

       if (section->raw_data_size > 0)

-        grub_memcpy (base, (grub_efi_uint8_t*)data + section->raw_data_offset,

-		     size);

+	{

+	  grub_dprintf ("chain", " copying 0x%08x bytes to %p\n",

+			section->raw_data_size, base);

+	  grub_memcpy (base,

+		       (grub_efi_uint8_t*)data + section->raw_data_offset,

+		       section->raw_data_size);

+	}

-      if (size < section->virtual_size)

-        grub_memset (base + size, 0, section->virtual_size - size);

+      if (section->raw_data_size < section->virtual_size)

+	{

+	  grub_dprintf ("chain", " padding with 0x%08x bytes at %p\n",

+			section->virtual_size - section->raw_data_size,

+			base + section->raw_data_size);

+	  grub_memset (base + section->raw_data_size, 0,

+		       section->virtual_size - section->raw_data_size);

+	}

-      grub_dprintf ("chain", "copied section %s\n", section->name);

+      grub_dprintf ("chain", " finished section %s\n", name);

     }

   /* 5 == EFI_IMAGE_DIRECTORY_ENTRY_BASERELOC */

@@ -638,12 +729,15 @@ handle_image (void *data, grub_efi_uint32_t datasize)

 	}

     }

-  entry_point = image_address (buffer_aligned, context.image_size,

-			       context.entry_point);

-

-  if (!entry_point)

+  if (!found_entry_point)

     {

-      grub_error (GRUB_ERR_BAD_ARGUMENT, "invalid entry point");

+      grub_error (GRUB_ERR_BAD_ARGUMENT, "entry point is not within sections");

+      goto error_exit;

+    }

+  if (found_entry_point > 1)

+    {

+      grub_error (GRUB_ERR_BAD_ARGUMENT, "%d sections contain entry point",

+		  found_entry_point);

       goto error_exit;

     }

@@ -661,26 +755,24 @@ handle_image (void *data, grub_efi_uint32_t datasize)

   li->load_options_size = cmdline_len;

   li->file_path = grub_efi_get_media_file_path (file_path);

   li->device_handle = dev_handle;

-  if (li->file_path)

-    {

-      grub_printf ("file path: ");

-      grub_efi_print_device_path (li->file_path);

-    }

-  else

+  if (!li->file_path)

     {

       grub_error (GRUB_ERR_UNKNOWN_DEVICE, "no matching file path found");

       goto error_exit;

     }

+  grub_dprintf ("chain", "booting via entry point\n");

   efi_status = efi_call_2 (entry_point, grub_efi_image_handle,

 			   grub_efi_system_table);

+  grub_dprintf ("chain", "entry_point returned %ld\n", efi_status);

   grub_memcpy (li, &li_bak, sizeof (grub_efi_loaded_image_t));

   efi_status = efi_call_1 (b->free_pool, buffer);

   return 1;

 error_exit:

+  grub_dprintf ("chain", "error_exit: grub_errno: %d\n", grub_errno);

   if (buffer)

       efi_call_1 (b->free_pool, buffer);

diff --git a/include/grub/efi/pe32.h b/include/grub/efi/pe32.h

index f79782e1bde..8396bde4917 100644

--- a/include/grub/efi/pe32.h

+++ b/include/grub/efi/pe32.h

@@ -227,12 +227,18 @@ struct grub_pe32_section_table

   grub_uint32_t characteristics;

 };

+#define GRUB_PE32_SCN_TYPE_NO_PAD		0x00000008

 #define GRUB_PE32_SCN_CNT_CODE			0x00000020

 #define GRUB_PE32_SCN_CNT_INITIALIZED_DATA	0x00000040

-#define GRUB_PE32_SCN_MEM_DISCARDABLE		0x02000000

-#define GRUB_PE32_SCN_MEM_EXECUTE		0x20000000

-#define GRUB_PE32_SCN_MEM_READ			0x40000000

-#define GRUB_PE32_SCN_MEM_WRITE			0x80000000

+#define GRUB_PE32_SCN_CNT_UNINITIALIZED_DATA	0x00000080

+#define GRUB_PE32_SCN_LNK_OTHER			0x00000100

+#define GRUB_PE32_SCN_LNK_INFO			0x00000200

+#define GRUB_PE32_SCN_LNK_REMOVE		0x00000800

+#define GRUB_PE32_SCN_LNK_COMDAT		0x00001000

+#define GRUB_PE32_SCN_GPREL			0x00008000

+#define GRUB_PE32_SCN_MEM_16BIT			0x00020000

+#define GRUB_PE32_SCN_MEM_LOCKED		0x00040000

+#define GRUB_PE32_SCN_MEM_PRELOAD		0x00080000

 #define GRUB_PE32_SCN_ALIGN_1BYTES		0x00100000

 #define GRUB_PE32_SCN_ALIGN_2BYTES		0x00200000

@@ -241,10 +247,28 @@ struct grub_pe32_section_table

 #define GRUB_PE32_SCN_ALIGN_16BYTES		0x00500000

 #define GRUB_PE32_SCN_ALIGN_32BYTES		0x00600000

 #define GRUB_PE32_SCN_ALIGN_64BYTES		0x00700000

+#define GRUB_PE32_SCN_ALIGN_128BYTES		0x00800000

+#define GRUB_PE32_SCN_ALIGN_256BYTES		0x00900000

+#define GRUB_PE32_SCN_ALIGN_512BYTES		0x00A00000

+#define GRUB_PE32_SCN_ALIGN_1024BYTES		0x00B00000

+#define GRUB_PE32_SCN_ALIGN_2048BYTES		0x00C00000

+#define GRUB_PE32_SCN_ALIGN_4096BYTES		0x00D00000

+#define GRUB_PE32_SCN_ALIGN_8192BYTES		0x00E00000

 #define GRUB_PE32_SCN_ALIGN_SHIFT		20

 #define GRUB_PE32_SCN_ALIGN_MASK		7

+#define GRUB_PE32_SCN_LNK_NRELOC_OVFL		0x01000000

+#define GRUB_PE32_SCN_MEM_DISCARDABLE		0x02000000

+#define GRUB_PE32_SCN_MEM_NOT_CACHED		0x04000000

+#define GRUB_PE32_SCN_MEM_NOT_PAGED		0x08000000

+#define GRUB_PE32_SCN_MEM_SHARED		0x10000000

+#define GRUB_PE32_SCN_MEM_EXECUTE		0x20000000

+#define GRUB_PE32_SCN_MEM_READ			0x40000000

+#define GRUB_PE32_SCN_MEM_WRITE			0x80000000

+

+

+

 #define GRUB_PE32_SIGNATURE_SIZE 4

 struct grub_pe32_header