0043-util-mkimage-avoid-adding-section-table-entry-outsid.patch

From 45468642affc3d641b5d73c5d6e63e1578bf9150 Mon Sep 17 00:00:00 2001
From: Markus Boehme <markubo@amazon.com>
Date: Fri, 28 Oct 2022 16:09:05 +0000
Subject: [PATCH] util/mkimage: avoid adding section table entry outside PE EFI
 header

The number of sections in a PE EFI image can vary depending on the
options passed to mkimage, but their maximum number must be known at
compile time. Potentially adding a new section to a PE EFI image
therefore requires changes in at least two places of the code.

The prior commit fixed a situation where the maximum number of sections
was not bumped while implementing support for an new section. Catch
these situations at runtime rather than silently relying on sufficient
padding being available for the new section table entry or overwriting
part of the image.

Signed-off-by: Markus Boehme <markubo@amazon.com>
---
 util/mkimage.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/util/mkimage.c b/util/mkimage.c
index 2db1045..1455c94 100644
--- a/util/mkimage.c
+++ b/util/mkimage.c
@@ -821,6 +821,7 @@ grub_install_get_image_targets_string (void)
  */
 static struct grub_pe32_section_table *
 init_pe_section(const struct grub_install_image_target_desc *image_target,
+		const char *pe_img,
 		struct grub_pe32_section_table *section,
 		const char * const name,
 		grub_uint32_t *vma, grub_uint32_t vsz, grub_uint32_t valign,
@@ -828,6 +829,15 @@ init_pe_section(const struct grub_install_image_target_desc *image_target,
 		grub_uint32_t characteristics)
 {
   size_t len = strlen (name);
+  const char *pe_header_end;
+
+  if (image_target->voidp_sizeof == 4)
+    pe_header_end = pe_img + EFI32_HEADER_SIZE;
+  else
+    pe_header_end = pe_img + EFI64_HEADER_SIZE;
+
+  if ((char *) section >= pe_header_end)
+    grub_util_error (_("section table space exhausted trying to add %s"), name);
 
   if (len > sizeof (section->name))
     grub_util_error (_("section name %s length is bigger than %lu"),
@@ -1438,7 +1448,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 	/* The sections.  */
 	PE_OHDR (o32, o64, code_base) = grub_host_to_target32 (vma);
 	PE_OHDR (o32, o64, code_size) = grub_host_to_target32 (layout.exec_size);
-	section = init_pe_section (image_target, section, ".text",
+	section = init_pe_section (image_target, pe_img, section, ".text",
 				   &vma, layout.exec_size,
 				   image_target->section_align,
 				   &raw_data, layout.exec_size,
@@ -1452,7 +1462,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 							       ALIGN_UP (total_module_size,
 									 GRUB_PE32_FILE_ALIGNMENT));
 
-	section = init_pe_section (image_target, section, ".data",
+	section = init_pe_section (image_target, pe_img, section, ".data",
 				   &vma, scn_size, image_target->section_align,
 				   &raw_data, scn_size,
 				   GRUB_PE32_SCN_CNT_INITIALIZED_DATA |
@@ -1460,7 +1470,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 				   GRUB_PE32_SCN_MEM_WRITE);
 
 	scn_size = pe_size - layout.reloc_size - sbat_size - raw_data;
-	section = init_pe_section (image_target, section, "mods",
+	section = init_pe_section (image_target, pe_img, section, "mods",
 				   &vma, scn_size, image_target->section_align,
 				   &raw_data, scn_size,
 				   GRUB_PE32_SCN_CNT_INITIALIZED_DATA |
@@ -1472,7 +1482,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 	    pe_sbat = pe_img + raw_data;
 	    grub_util_load_image (sbat_path, pe_sbat);
 
-	    section = init_pe_section (image_target, section, ".sbat",
+	    section = init_pe_section (image_target, pe_img, section, ".sbat",
 				       &vma, sbat_size,
 				       image_target->section_align,
 				       &raw_data, sbat_size,
@@ -1484,7 +1494,7 @@ grub_install_generate_image (const char *dir, const char *prefix,
 	PE_OHDR (o32, o64, base_relocation_table.rva) = grub_host_to_target32 (vma);
 	PE_OHDR (o32, o64, base_relocation_table.size) = grub_host_to_target32 (scn_size);
 	memcpy (pe_img + raw_data, layout.reloc_section, scn_size);
-	init_pe_section (image_target, section, ".reloc",
+	init_pe_section (image_target, pe_img, section, ".reloc",
 			 &vma, scn_size, image_target->section_align,
 			 &raw_data, scn_size,
 			 GRUB_PE32_SCN_CNT_INITIALIZED_DATA |
-- 
2.39.0