From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Leo Sandoval <lsandova@redhat.com>
Date: Wed, 29 May 2024 17:35:35 -0600
Subject: [PATCH] loader/efi/linux.c: read the kernel image before header

Signed-off-by: Leo Sandoval <lsandova@redhat.com>
---
 grub-core/loader/efi/linux.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/grub-core/loader/efi/linux.c b/grub-core/loader/efi/linux.c
index d9ded7c4f12..3ada50ed969 100644
--- a/grub-core/loader/efi/linux.c
+++ b/grub-core/loader/efi/linux.c
@@ -559,6 +559,7 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   grub_file_t file = 0;
   struct linux_arch_kernel_header lh;
   grub_off_t filelen;
+  grub_off_t filereadlen;
   grub_uint32_t align;
   grub_uint32_t code_size;
   void *kernel = NULL;
@@ -592,6 +593,25 @@ grub_cmd_linux (grub_command_t cmd __attribute__ ((unused)),
   if (!file)
     goto fail;
 
+  filelen = grub_file_size (file);
+  kernel = grub_malloc(filelen);
+  if (!kernel)
+    {
+      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel load buffer"));
+      goto fail;
+    }
+
+  filereadlen = grub_file_read (file, kernel, filelen);
+  grub_dprintf ("linux", "filelen     : %lld\n", (long long) filelen);
+  grub_dprintf ("linux", "filereadlen : %lld\n", (long long) filereadlen);
+
+  if (filereadlen < filelen)
+    {
+      grub_error (GRUB_ERR_FILE_READ_ERROR, N_("Can't read kernel %s"),
+		  argv[0]);
+      goto fail;
+    }
+
   if (grub_arch_efi_linux_load_image_header (file, &lh) != GRUB_ERR_NONE)
 #if !defined(__i386__) && !defined(__x86_64__)
     goto fail;
@@ -612,20 +632,6 @@ fallback:
     }
 #endif
 
-  filelen = grub_file_size (file);
-  kernel = grub_malloc(filelen);
-  if (!kernel)
-    {
-      grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("cannot allocate kernel load buffer"));
-      goto fail;
-    }
-
-  if (grub_file_read (file, kernel, filelen) < (grub_ssize_t)filelen)
-    {
-      grub_error (GRUB_ERR_FILE_READ_ERROR, N_("Can't read kernel %s"),
-		  argv[0]);
-      goto fail;
-    }
 
 #if !defined(__i386__) && !defined(__x86_64__)
   if (parse_pe_header (kernel, &kernel_size, &handover_offset, &align, &code_size) != GRUB_ERR_NONE)