From d441356c924102b43b303520cc1c62a624b014d6 Mon Sep 17 00:00:00 2001
From: Gary Lin <[email protected]>
Date: Thu, 26 Oct 2023 13:18:24 +0800
Subject: [PATCH] Fix the size calculation for the synthesized initrd

When calculating the size of the synthesized initrd in
grub_initrd_component(), the ending "TRAILER!!!" is counted in for every
synthesized initrd. However, in grub_initrd_load(), only one "TRAILER!!!"
will be appended for one group of consecutive synthesized initrds. The
additional size calculation for the ending "TRAILER!!!" could make the
linux kernel to read uninitialized bytes and result in the error message
like this:

Initramfs unpacking failed: invalid magic at start of compressed archive

To fit into the original 'newc' design, the ending "TRAILER!!!" is
removed from grub_initrd_component(). Instead, in grub_initrd_init(),
the 'newc' flag is set when calculating size of the synthesized initrd
to append the ending "TRAILER!!!" later. As for grub_initrd_load(),
since the path to the unsealed key is specified in 'newc_name', it's
unnecessary to set the 'newc' flag while copying the unsealed key
because the flag is already set when parsing the path name.

Signed-off-by: Gary Lin <[email protected]>
---
 grub-core/loader/linux.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

diff --git a/grub-core/loader/linux.c b/grub-core/loader/linux.c
index 4e028f5..9ee8f37 100644
--- a/grub-core/loader/linux.c
+++ b/grub-core/loader/linux.c
@@ -209,13 +209,6 @@ grub_initrd_component (const char *buf, int bufsz, const char *newc_name,
 		&initrd_ctx->size))
     goto overflow;
 
-  initrd_ctx->size = ALIGN_UP (initrd_ctx->size, 4);
-  if (grub_add (initrd_ctx->size,
-		ALIGN_UP (sizeof (struct newc_head)
-			  + sizeof ("TRAILER!!!") - 1, 4),
-		&initrd_ctx->size))
-    goto overflow;
-
   free_dir (root);
   root = 0;
   return GRUB_ERR_NONE;
@@ -312,6 +305,13 @@ grub_initrd_init (int argc, char *argv[],
 	goto overflow;
     }
 
+  FOR_LIST_ELEMENTS (pk, kpuber)
+    if (pk->key && pk->path)
+      {
+	grub_initrd_component (pk->key, pk->key_len, pk->path, initrd_ctx);
+	newc = 1;
+      }
+
   if (newc)
     {
       initrd_ctx->size = ALIGN_UP (initrd_ctx->size, 4);
@@ -324,10 +324,6 @@ grub_initrd_init (int argc, char *argv[],
       root = 0;
     }
 
-  FOR_LIST_ELEMENTS (pk, kpuber)
-    if (pk->key && pk->path)
-      grub_initrd_component (pk->key, pk->key_len, pk->path, initrd_ctx);
-
   return GRUB_ERR_NONE;
 
  overflow:
@@ -404,10 +400,7 @@ grub_initrd_load (struct grub_linux_initrd_context *initrd_ctx,
 
       cursize = initrd_ctx->components[i].size;
       if (initrd_ctx->components[i].buf)
-	{
-	  grub_memcpy (ptr, initrd_ctx->components[i].buf, cursize);
-	  newc = 1;
-	}
+        grub_memcpy (ptr, initrd_ctx->components[i].buf, cursize);
       else if (grub_file_read (initrd_ctx->components[i].file, ptr, cursize)
 	  != cursize)
 	{
-- 
2.35.3