From fe519348967c7096e4b9466fc39bd393cd58319a Mon Sep 17 00:00:00 2001
From: Vladimir Serbinenko <phco...@gmail.com>
Date: Mon, 10 Jul 2023 17:17:35 +0200
Subject: [PATCH 01/01] loader/bsd: Fix loading after unaligned module

Current code implicitly assumes that aligning chunk_size + *kern_end is
the same as aligning on curload which is not the case because
chunk_size starts at zero even if *kern_end is unaligned and ALIGN_PAGE
moved curload to an aligned position but not *kern_end + chunk_size

Signed-off-by: Vladimir Serbinenko <phco...@gmail.com>
---
 grub-core/loader/i386/bsdXX.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/grub-core/loader/i386/bsdXX.c b/grub-core/loader/i386/bsdXX.c
index 09d909f1b..d3de8a29b 100644
--- a/grub-core/loader/i386/bsdXX.c
+++ b/grub-core/loader/i386/bsdXX.c
@@ -88,10 +88,9 @@ SUFFIX (grub_freebsd_load_elfmodule_obj) (struct grub_relocator *relocator,
   Elf_Shnum shnum;
   grub_addr_t curload, module;
   grub_err_t err;
-  grub_size_t chunk_size = 0;
   void *chunk_src;
 
-  curload = module = ALIGN_PAGE (*kern_end);
+  module = ALIGN_PAGE (*kern_end);
 
   err = read_headers (file, argv[0], &e, &shdr);
   if (err != GRUB_ERR_NONE)
@@ -101,6 +100,8 @@ SUFFIX (grub_freebsd_load_elfmodule_obj) (struct grub_relocator *relocator,
   if (err != GRUB_ERR_NONE)
     goto out;
 
+  curload = module;
+
   for (s = shdr; s < (Elf_Shdr *) ((grub_uint8_t *) shdr + shnum * e.e_shentsize);
        s = (Elf_Shdr *) ((grub_uint8_t *) s + e.e_shentsize))
     {
@@ -108,21 +109,24 @@ SUFFIX (grub_freebsd_load_elfmodule_obj) (struct grub_relocator *relocator,
 	continue;
 
       if (s->sh_addralign)
-	chunk_size = ALIGN_UP (chunk_size + *kern_end, s->sh_addralign)
-	  - *kern_end;
+	curload = ALIGN_UP (curload, s->sh_addralign);
 
-      chunk_size += s->sh_size;
+      curload += s->sh_size;
     }
 
+  *kern_end = ALIGN_PAGE (curload);
+
   {
     grub_relocator_chunk_t ch;
     err = grub_relocator_alloc_chunk_addr (relocator, &ch,
-					   module, chunk_size);
+					   module, curload - module);
     if (err != GRUB_ERR_NONE)
       goto out;
     chunk_src = get_virtual_current_address (ch);
   }
 
+  curload = module;
+
   for (s = shdr; s < (Elf_Shdr *) ((grub_uint8_t *) shdr + shnum * e.e_shentsize);
        s = (Elf_Shdr *) ((grub_uint8_t *) s + e.e_shentsize))
     {
@@ -141,13 +145,13 @@ SUFFIX (grub_freebsd_load_elfmodule_obj) (struct grub_relocator *relocator,
 	{
 	default:
 	case SHT_PROGBITS:
-	  err = load (file, argv[0], (grub_uint8_t *) chunk_src + curload - *kern_end,
+	  err = load (file, argv[0], (grub_uint8_t *) chunk_src + curload - module,
 		      s->sh_offset, s->sh_size);
 	  if (err != GRUB_ERR_NONE)
 	    goto out;
 	  break;
 	case SHT_NOBITS:
-	  grub_memset ((grub_uint8_t *) chunk_src + curload - *kern_end, 0,
+	  grub_memset ((grub_uint8_t *) chunk_src + curload - module, 0,
 		       s->sh_size);
 	  break;
 	}
-- 
2.42.0

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