[PATCH v0 1/2] mkimage: create new ELF Note for SBAT

[Sudhakar Kuppusamy]

we add a new ELF note for SBAT which store the SBAT data.
The name field of shall be the string "Secure-Boot-Advanced-Targeting", 
zero-padded
to 4 byte alignment. The type field shall be 0x41536967 (the ASCII values
for the string "sbat").

Signed-off-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>
Co-authored-by: Daniel Axtens <dja@axtens.net>
---
 include/grub/util/mkimage.h |  4 +--
 util/grub-mkimagexx.c       | 61 ++++++++++++++++++++++++++++++++++---
 2 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/include/grub/util/mkimage.h b/include/grub/util/mkimage.h
index 6f1da89b9..881e3031f 100644
--- a/include/grub/util/mkimage.h
+++ b/include/grub/util/mkimage.h
@@ -51,12 +51,12 @@ grub_mkimage_load_image64 (const char *kernel_path,
                           const struct grub_install_image_target_desc 
*image_target);
 void
 grub_mkimage_generate_elf32 (const struct grub_install_image_target_desc 
*image_target,
-                            int note, size_t appsig_size, char **core_img, 
size_t *core_size,
+                            int note, size_t appsig_size, char *sbat, char 
**core_img, size_t *core_size,
                             Elf32_Addr target_addr,
                             struct grub_mkimage_layout *layout);
 void
 grub_mkimage_generate_elf64 (const struct grub_install_image_target_desc 
*image_target,
-                            int note, size_t appsig_size, char **core_img, 
size_t *core_size,
+                            int note, size_t appsig_size, char *sbat, char 
**core_img, size_t *core_size,
                             Elf64_Addr target_addr,
                             struct grub_mkimage_layout *layout);
 
diff --git a/util/grub-mkimagexx.c b/util/grub-mkimagexx.c
index 9488f0525..2ab90ff8f 100644
--- a/util/grub-mkimagexx.c
+++ b/util/grub-mkimagexx.c
@@ -85,6 +85,14 @@ struct grub_ieee1275_note
   struct grub_ieee1275_note_desc descriptor;
 };
 
+#define GRUB_SBAT_NOTE_NAME "Secure-Boot-Advanced-Targeting"
+#define GRUB_SBAT_NOTE_TYPE 0x73626174 /* "sbat" */
+
+struct grub_sbat_note {
+  Elf32_Nhdr header;
+  char name[ALIGN_UP(sizeof(GRUB_SBAT_NOTE_NAME), 4)];
+};
+
 #define GRUB_APPENDED_SIGNATURE_NOTE_NAME "Appended-Signature"
 #define GRUB_APPENDED_SIGNATURE_NOTE_TYPE 0x41536967 /* "ASig" */
 
@@ -217,7 +225,7 @@ grub_arm_reloc_jump24 (grub_uint32_t *target, Elf32_Addr 
sym_addr)
 
 void
 SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc *image_target,
-                                   int note, size_t appsig_size, char 
**core_img, size_t *core_size,
+                                   int note, size_t appsig_size, char *sbat, 
char **core_img, size_t *core_size,
                                    Elf_Addr target_addr,
                                    struct grub_mkimage_layout *layout)
 {
@@ -226,11 +234,18 @@ SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc
   Elf_Ehdr *ehdr;
   Elf_Phdr *phdr;
   Elf_Shdr *shdr;
-  int header_size, footer_size = 0;
+  int header_size, footer_size = 0, footer_offset = 0;
+  char *footer;
   int phnum = 1;
   int shnum = 4;
   int string_size = sizeof (".text") + sizeof ("mods") + 1;
 
+  if (sbat)
+    {
+      phnum++;
+      footer_size += ALIGN_UP (sizeof (struct grub_sbat_note) + 
layout->sbat_size, 4);
+    }
+
   if (appsig_size)
     {
       phnum++;
@@ -263,6 +278,7 @@ SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc
   ehdr = (void *) elf_img;
   phdr = (void *) (elf_img + sizeof (*ehdr));
   shdr = (void *) (elf_img + sizeof (*ehdr) + phnum * sizeof (*phdr));
+  footer = elf_img + program_size + header_size;
   memcpy (ehdr->e_ident, ELFMAG, SELFMAG);
   ehdr->e_ident[EI_CLASS] = ELFCLASSXX;
   if (!image_target->bigendian)
@@ -435,6 +451,9 @@ SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc
       phdr->p_filesz = grub_host_to_target32 (XEN_NOTE_SIZE);
       phdr->p_memsz = 0;
       phdr->p_offset = grub_host_to_target32 (header_size + program_size);
+
+      footer = ptr;
+      footer_offset = XEN_NOTE_SIZE;
     }
 
   if (image_target->id == IMAGE_XEN_PVH)
@@ -468,6 +487,9 @@ SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc
       phdr->p_filesz = grub_host_to_target32 (XEN_PVH_NOTE_SIZE);
       phdr->p_memsz = 0;
       phdr->p_offset = grub_host_to_target32 (header_size + program_size);
+
+      footer = ptr;
+      footer_offset = XEN_PVH_NOTE_SIZE;
     }
 
   if (note)
@@ -498,12 +520,39 @@ SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc
       phdr->p_filesz = grub_host_to_target32 (note_size);
       phdr->p_memsz = 0;
       phdr->p_offset = grub_host_to_target32 (header_size + program_size);
+
+      footer = (elf_img + program_size + header_size + note_size);
+      footer_offset += note_size;
     }
 
+  if (sbat) {
+    int note_size = ALIGN_UP(sizeof (struct grub_sbat_note) + 
layout->sbat_size, 4);
+    struct grub_sbat_note *note_ptr = (struct grub_sbat_note *)footer;
+
+    note_ptr->header.n_namesz = grub_host_to_target32 (sizeof 
(GRUB_SBAT_NOTE_NAME));
+    note_ptr->header.n_descsz = grub_host_to_target32 
(ALIGN_UP(layout->sbat_size, 4));
+    note_ptr->header.n_type = grub_host_to_target32 (GRUB_SBAT_NOTE_TYPE);
+    memcpy (note_ptr->name, GRUB_SBAT_NOTE_NAME, sizeof (GRUB_SBAT_NOTE_NAME));
+    memcpy ((char *)(note_ptr + 1), sbat, layout->sbat_size);
+
+    phdr++;
+    phdr->p_type = grub_host_to_target32 (PT_NOTE);
+    phdr->p_flags = grub_host_to_target32 (PF_R);
+    phdr->p_align = grub_host_to_target32 (image_target->voidp_sizeof);
+    phdr->p_vaddr = 0;
+    phdr->p_paddr = 0;
+    phdr->p_filesz = grub_host_to_target32 (note_size);
+    phdr->p_memsz = 0;
+    phdr->p_offset = grub_host_to_target32 (header_size + program_size + 
footer_offset);
+
+    footer += note_size;
+    footer_offset += note_size;
+  }
+
+
   if (appsig_size) {
     int note_size = ALIGN_UP(sizeof (struct grub_appended_signature_note) + 
appsig_size, 4);
-    struct grub_appended_signature_note *note_ptr = (struct 
grub_appended_signature_note *)
-      (elf_img + program_size + header_size + (note ? sizeof (struct 
grub_ieee1275_note) : 0));
+    struct grub_appended_signature_note *note_ptr = (struct 
grub_appended_signature_note *)footer;
 
     note_ptr->header.n_namesz = grub_host_to_target32 (sizeof 
(GRUB_APPENDED_SIGNATURE_NOTE_NAME));
     /* needs to sit at the end, so we round this up and sign some zero padding 
*/
@@ -519,7 +568,9 @@ SUFFIX (grub_mkimage_generate_elf) (const struct 
grub_install_image_target_desc
     phdr->p_paddr = 0;
     phdr->p_filesz = grub_host_to_target32 (note_size);
     phdr->p_memsz = 0;
-    phdr->p_offset = grub_host_to_target32 (header_size + program_size + (note 
? sizeof (struct grub_ieee1275_note) : 0));
+    phdr->p_offset = grub_host_to_target32 (header_size + program_size + 
footer_offset);
+
+    /* do not update footer, this must be last */
   }
 
   {
-- 
2.39.3