[RFC PATCH 3/3] Suport for bi-endianess in elf file

[Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com>]

* grub-core/kern/elf.c: check and switch endianess with grub_{be,le}_to
  cpu functions.
* grub-core/kern/elfXX.c: Likewise.

Also-by: Tomohiro B Berry <tbberry@us.ibm.com>
---
 grub-core/kern/elf.c   | 60 +++++++++++++++++++++++++++++++++++++++--
 grub-core/kern/elfXX.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 131 insertions(+), 2 deletions(-)

diff --git a/grub-core/kern/elf.c b/grub-core/kern/elf.c
index 5f99c43..de90811 100644
--- a/grub-core/kern/elf.c
+++ b/grub-core/kern/elf.c
@@ -28,6 +28,11 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
+void grub_elf32_check_endianess (grub_elf_t elf);
+void grub_elf64_check_endianess (grub_elf_t elf);
+grub_err_t grub_elf32_check_version (grub_elf_t elf);
+grub_err_t grub_elf64_check_version (grub_elf_t elf);
+
 /* Check if EHDR is a valid ELF header.  */
 static grub_err_t
 grub_elf_check_header (grub_elf_t elf)
@@ -38,10 +43,22 @@ grub_elf_check_header (grub_elf_t elf)
       || e->e_ident[EI_MAG1] != ELFMAG1
       || e->e_ident[EI_MAG2] != ELFMAG2
       || e->e_ident[EI_MAG3] != ELFMAG3
-      || e->e_ident[EI_VERSION] != EV_CURRENT
-      || e->e_version != EV_CURRENT)
+      || e->e_ident[EI_VERSION] != EV_CURRENT)
     return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF magic"));
 
+  if (grub_elf_is_elf32 (elf))
+    {
+      grub_elf32_check_endianess (elf);
+      grub_elf32_check_version (elf);
+    }
+  else if (grub_elf_is_elf64 (elf))
+    {
+      grub_elf64_check_endianess (elf);
+      grub_elf64_check_version (elf);
+    }
+  else
+    return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-dependent ELF magic"));
+
   return GRUB_ERR_NONE;
 }
 
@@ -127,7 +144,20 @@ grub_elf_open (const char *name)
 #define grub_elf_is_elfXX grub_elf_is_elf32
 #define grub_elfXX_load_phdrs grub_elf32_load_phdrs
 #define ElfXX_Phdr Elf32_Phdr
+#define ElfXX_Ehdr Elf32_Ehdr
 #define grub_uintXX_t grub_uint32_t
+#define grub_be_to_halfXX grub_be_to_cpu16
+#define grub_be_to_wordXX grub_be_to_cpu32
+#define grub_be_to_addrXX grub_be_to_cpu32
+#define grub_be_to_offXX grub_be_to_cpu32
+#define grub_be_to_XwordXX grub_be_to_wordXX
+#define grub_le_to_halfXX grub_le_to_cpu16
+#define grub_le_to_wordXX grub_le_to_cpu32
+#define grub_le_to_addrXX grub_le_to_cpu32
+#define grub_le_to_offXX grub_le_to_cpu32
+#define grub_le_to_XwordXX grub_le_to_wordXX
+#define grub_elfXX_check_endianess grub_elf32_check_endianess
+#define grub_elfXX_check_version grub_elf32_check_version
 
 #include "elfXX.c"
 
@@ -140,7 +170,20 @@ grub_elf_open (const char *name)
 #undef grub_elf_is_elfXX
 #undef grub_elfXX_load_phdrs
 #undef ElfXX_Phdr
+#undef ElfXX_Ehdr
 #undef grub_uintXX_t
+#undef grub_be_to_halfXX
+#undef grub_be_to_wordXX
+#undef grub_be_to_addrXX
+#undef grub_be_to_offXX
+#undef grub_be_to_XwordXX
+#undef grub_le_to_halfXX
+#undef grub_le_to_wordXX
+#undef grub_le_to_addrXX
+#undef grub_le_to_offXX
+#undef grub_le_to_XwordXX
+#undef grub_elfXX_check_endianess
+#undef grub_elfXX_check_version
 
 \f
 /* 64-bit */
@@ -153,6 +196,19 @@ grub_elf_open (const char *name)
 #define grub_elf_is_elfXX grub_elf_is_elf64
 #define grub_elfXX_load_phdrs grub_elf64_load_phdrs
 #define ElfXX_Phdr Elf64_Phdr
+#define ElfXX_Ehdr Elf64_Ehdr
 #define grub_uintXX_t grub_uint64_t
+#define grub_be_to_halfXX grub_be_to_cpu16
+#define grub_be_to_wordXX grub_be_to_cpu32
+#define grub_be_to_addrXX grub_be_to_cpu64
+#define grub_be_to_offXX grub_be_to_cpu64
+#define grub_be_to_XwordXX grub_be_to_cpu64
+#define grub_le_to_halfXX grub_le_to_cpu16
+#define grub_le_to_wordXX grub_le_to_cpu32
+#define grub_le_to_addrXX grub_le_to_cpu64
+#define grub_le_to_offXX grub_le_to_cpu64
+#define grub_le_to_XwordXX grub_le_to_cpu64
+#define grub_elfXX_check_endianess grub_elf64_check_endianess
+#define grub_elfXX_check_version grub_elf64_check_version
 
 #include "elfXX.c"
diff --git a/grub-core/kern/elfXX.c b/grub-core/kern/elfXX.c
index 1d09971..ecf9df6 100644
--- a/grub-core/kern/elfXX.c
+++ b/grub-core/kern/elfXX.c
@@ -154,3 +154,76 @@ grub_elfXX_load (grub_elf_t elf, const char *filename,
 
   return grub_errno;
 }
+
+void
+grub_elfXX_check_endianess (grub_elf_t elf)
+{
+  ElfXX_Ehdr *e = &(elf->ehdr.ehdrXX);
+  ElfXX_Phdr *phdr;
+
+  if (e->e_ident[EI_DATA] == ELFDATA2MSB)
+    {
+      e->e_type = grub_be_to_halfXX (e->e_type);
+      e->e_machine = grub_be_to_halfXX (e->e_machine);
+      e->e_version = grub_be_to_wordXX (e->e_version);
+      e->e_entry = grub_be_to_addrXX (e->e_entry);
+      e->e_phoff = grub_be_to_offXX (e->e_phoff);
+      e->e_shoff = grub_be_to_offXX (e->e_shoff);
+      e->e_flags = grub_be_to_wordXX (e->e_flags);
+      e->e_ehsize = grub_be_to_halfXX (e->e_ehsize);
+      e->e_phentsize = grub_be_to_halfXX (e->e_phentsize);
+      e->e_phnum = grub_be_to_halfXX (e->e_phnum);
+      e->e_shentsize = grub_be_to_halfXX (e->e_shentsize);
+      e->e_shnum = grub_be_to_halfXX (e->e_shnum);
+      e->e_shstrndx = grub_be_to_halfXX (e->e_shstrndx);
+
+      FOR_ELFXX_PHDRS (elf,phdr)
+        {
+          phdr->p_type = grub_be_to_wordXX (phdr->p_type);
+          phdr->p_flags = grub_be_to_wordXX (phdr->p_flags);
+          phdr->p_offset = grub_be_to_offXX (phdr->p_offset);
+          phdr->p_vaddr = grub_be_to_addrXX (phdr->p_vaddr);
+          phdr->p_paddr = grub_be_to_addrXX (phdr->p_paddr);
+          phdr->p_filesz = grub_be_to_XwordXX (phdr->p_filesz);
+          phdr->p_memsz = grub_be_to_XwordXX (phdr->p_memsz);
+          phdr->p_align = grub_be_to_XwordXX (phdr->p_align);
+        }
+    }
+  else if (e->e_ident[EI_DATA] == ELFDATA2LSB)
+    {
+      e->e_type = grub_le_to_halfXX (e->e_type);
+      e->e_machine = grub_le_to_halfXX (e->e_machine);
+      e->e_version = grub_le_to_wordXX (e->e_version);
+      e->e_entry = grub_le_to_addrXX (e->e_entry);
+      e->e_phoff = grub_le_to_offXX (e->e_phoff);
+      e->e_shoff = grub_le_to_offXX (e->e_shoff);
+      e->e_flags = grub_le_to_wordXX (e->e_flags);
+      e->e_ehsize = grub_le_to_halfXX (e->e_ehsize);
+      e->e_phentsize = grub_le_to_halfXX (e->e_phentsize);
+      e->e_phnum = grub_le_to_halfXX (e->e_phnum);
+      e->e_shentsize = grub_le_to_halfXX (e->e_shentsize);
+      e->e_shnum = grub_le_to_halfXX (e->e_shnum);
+      e->e_shstrndx = grub_le_to_halfXX (e->e_shstrndx);
+
+      FOR_ELFXX_PHDRS (elf,phdr)
+        {
+          phdr->p_type = grub_le_to_wordXX (phdr->p_type);
+          phdr->p_flags = grub_le_to_wordXX (phdr->p_flags);
+          phdr->p_offset = grub_le_to_offXX (phdr->p_offset);
+          phdr->p_vaddr = grub_le_to_addrXX (phdr->p_vaddr);
+          phdr->p_paddr = grub_le_to_addrXX (phdr->p_paddr);
+          phdr->p_filesz = grub_le_to_XwordXX (phdr->p_filesz);
+          phdr->p_memsz = grub_le_to_XwordXX (phdr->p_memsz);
+          phdr->p_align = grub_le_to_XwordXX (phdr->p_align);
+        }
+    }
+}
+
+grub_err_t
+grub_elfXX_check_version (grub_elf_t elf)
+{
+  if (elf->ehdr.ehdrXX.e_version != EV_CURRENT)
+    return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF magic"));
+
+  return GRUB_ERR_NONE;
+}
-- 
1.8.1.4