From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Jeremy Linton <jeremy.linton@arm.com>

Date: Tue, 6 Sep 2022 15:33:03 -0500

Subject: [PATCH] Correct BSS zeroing on aarch64

The aarch64 loader doesn't use efi bootservices, and

therefor it has a very minimal loader which makes a lot

of assumptions about the kernel layout. With the ZBOOT

changes, the layout has changed a bit and we not should

really be parsing the PE sections to determine how much

data to copy, otherwise the BSS won't be setup properly.

This code still makes a lot of assumptions about the

the kernel layout, so its far from ideal, but it works.

Resolves: rhbz#2125069

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>

---

 grub-core/loader/arm64/linux.c | 27 ++++++++++++++++++++++-----

 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/grub-core/loader/arm64/linux.c b/grub-core/loader/arm64/linux.c

index 489d0c7173..419f2201df 100644

--- a/grub-core/loader/arm64/linux.c

+++ b/grub-core/loader/arm64/linux.c

@@ -316,10 +316,12 @@ grub_cmd_initrd (grub_command_t cmd __attribute__ ((unused)),

 static grub_err_t

 parse_pe_header (void *kernel, grub_uint64_t *total_size,

 		 grub_uint32_t *entry_offset,

-		 grub_uint32_t *alignment)

+		 grub_uint32_t *alignment,grub_uint32_t *code_size)

 {

   struct linux_arch_kernel_header *lh = kernel;

   struct grub_armxx_linux_pe_header *pe;

+  grub_uint16_t i;

+  struct grub_pe32_section_table *sections;

   pe = (void *)((unsigned long)kernel + lh->hdr_offset);

@@ -329,6 +331,19 @@ parse_pe_header (void *kernel, grub_uint64_t *total_size,

   *total_size   = pe->opt.image_size;

   *entry_offset = pe->opt.entry_addr;

   *alignment    = pe->opt.section_alignment;

+  *code_size    = pe->opt.section_alignment;

+

+  sections = (struct grub_pe32_section_table *) ((char *)&pe->opt +

+						 pe->coff.optional_header_size);

+  grub_dprintf ("linux", "num_sections     : %d\n",  pe->coff.num_sections );

+  for (i = 0 ; i < pe->coff.num_sections; i++)

+    {

+      grub_dprintf ("linux", "raw_size   : %lld\n",

+		    (long long) sections[i].raw_data_size);

+      grub_dprintf ("linux", "virt_size  : %lld\n",

+		    (long long) sections[i].virtual_size);

+      *code_size += sections[i].raw_data_size;

+    }

   return GRUB_ERR_NONE;

 }

@@ -341,6 +356,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   grub_err_t err;

   grub_off_t filelen;

   grub_uint32_t align;

+  grub_uint32_t code_size;

   void *kernel = NULL;

   int nx_supported = 1;

@@ -373,11 +389,12 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   if (grub_arch_efi_linux_check_image (kernel) != GRUB_ERR_NONE)

     goto fail;

-  if (parse_pe_header (kernel, &kernel_size, &handover_offset, &align) != GRUB_ERR_NONE)

+  if (parse_pe_header (kernel, &kernel_size, &handover_offset, &align, &code_size) != GRUB_ERR_NONE)

     goto fail;

   grub_dprintf ("linux", "kernel mem size     : %lld\n", (long long) kernel_size);

   grub_dprintf ("linux", "kernel entry offset : %d\n", handover_offset);

   grub_dprintf ("linux", "kernel alignment    : 0x%x\n", align);

+  grub_dprintf ("linux", "kernel size         : 0x%x\n", code_size);

   err = grub_efi_check_nx_image_support((grub_addr_t)kernel, filelen, &nx_supported);

   if (err != GRUB_ERR_NONE)

@@ -396,9 +413,9 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),

   kernel_addr = (void *)ALIGN_UP((grub_uint64_t)kernel_alloc_addr, align);

   grub_dprintf ("linux", "kernel @ %p\n", kernel_addr);

-  grub_memcpy (kernel_addr, kernel, grub_min(filelen, kernel_size));

-  if (kernel_size > filelen)

-    grub_memset ((char *)kernel_addr + filelen, 0, kernel_size - filelen);

+  grub_memcpy (kernel_addr, kernel, grub_min(code_size, kernel_size));

+  if (kernel_size > code_size)

+    grub_memset ((char *)kernel_addr + code_size, 0, kernel_size - code_size);

   grub_free(kernel);

   kernel = NULL;