Implement cross-endian ELF load for powerpc

diff --git a/grub-core/kern/elf.c b/grub-core/kern/elf.c
index 5f99c43cc81a1b5458343f68ebbf9303e79bbd7b..00de36984f3bd376385c632b5cbb25f8a6eedacb 100644 (file)
--- a/grub-core/kern/elf.c
+++ b/grub-core/kern/elf.c
@@ -28,6 +28,23 @@
 
 GRUB_MOD_LICENSE ("GPLv3+");
 
+#if defined(__powerpc__) && defined(GRUB_MACHINE_IEEE1275)
+#define GRUB_ELF_ENABLE_BI_ENDIAN 1
+#else
+#define GRUB_ELF_ENABLE_BI_ENDIAN 0
+#endif
+
+#if defined(GRUB_CPU_WORDS_BIGENDIAN)
+#define GRUB_ELF_NATIVE_ENDIANNESS ELFDATA2MSB
+#define GRUB_ELF_OPPOSITE_ENDIANNESS ELFDATA2LSB
+#else
+#define GRUB_ELF_NATIVE_ENDIANNESS ELFDATA2LSB
+#define GRUB_ELF_OPPOSITE_ENDIANNESS ELFDATA2MSB
+#endif
+
+static int grub_elf32_check_endianess_and_bswap_ehdr (grub_elf_t elf);
+static int grub_elf64_check_endianess_and_bswap_ehdr (grub_elf_t elf);
+
 /* Check if EHDR is a valid ELF header.  */
 static grub_err_t
 grub_elf_check_header (grub_elf_t elf)
@@ -38,8 +55,25 @@ 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))
+    {
+      if (!grub_elf32_check_endianess_and_bswap_ehdr (elf)) {
+       return grub_error (GRUB_ERR_BAD_OS, "invalid ELF endianness magic");
+      }
+    }
+  else if (grub_elf_is_elf64 (elf))
+    {
+      if (!grub_elf64_check_endianess_and_bswap_ehdr (elf)) {
+       return grub_error (GRUB_ERR_BAD_OS, "invalid ELF endianness magic");
+      }
+    }
+  else
+    return grub_error (GRUB_ERR_BAD_OS, "unknown ELF class");
+
+  if (e->e_version != EV_CURRENT)
     return grub_error (GRUB_ERR_BAD_OS, N_("invalid arch-independent ELF magic"));
 
   return GRUB_ERR_NONE;
@@ -117,6 +151,9 @@ grub_elf_open (const char *name)
 }
 
 \f
+#define grub_swap_bytes_halfXX grub_swap_bytes16
+#define grub_swap_bytes_wordXX grub_swap_bytes32
+
 /* 32-bit */
 #define ehdrXX ehdr32
 #define ELFCLASSXX ELFCLASS32
@@ -127,7 +164,12 @@ 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_swap_bytes_addrXX grub_swap_bytes32
+#define grub_swap_bytes_offXX grub_swap_bytes32
+#define grub_swap_bytes_XwordXX grub_swap_bytes32
+#define grub_elfXX_check_endianess_and_bswap_ehdr grub_elf32_check_endianess_and_bswap_ehdr
 
 #include "elfXX.c"
 
@@ -140,7 +182,12 @@ 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_swap_bytes_addrXX
+#undef grub_swap_bytes_offXX
+#undef grub_swap_bytes_XwordXX
+#undef grub_elfXX_check_endianess_and_bswap_ehdr
 
 \f
 /* 64-bit */
@@ -153,6 +200,11 @@ 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_swap_bytes_addrXX grub_swap_bytes64
+#define grub_swap_bytes_offXX grub_swap_bytes64
+#define grub_swap_bytes_XwordXX grub_swap_bytes64
+#define grub_elfXX_check_endianess_and_bswap_ehdr grub_elf64_check_endianess_and_bswap_ehdr
 
 #include "elfXX.c"

diff --git a/grub-core/kern/elfXX.c b/grub-core/kern/elfXX.c
index 1d0997186f7f8c10090f75d24ffa39eb4414d7d7..b91c39d9e8bd74a43760cd29a51fe8a7fb228adf 100644 (file)
--- a/grub-core/kern/elfXX.c
+++ b/grub-core/kern/elfXX.c
@@ -31,6 +31,25 @@ grub_elfXX_load_phdrs (grub_elf_t elf)
       return grub_errno;
     }
 
+#if GRUB_ELF_ENABLE_BI_ENDIAN
+  if (elf->ehdr.ehdrXX.e_ident[EI_DATA] == GRUB_ELF_OPPOSITE_ENDIANNESS)
+    {
+      ElfXX_Phdr *phdr;
+      for (phdr = elf->phdrs; (char *) phdr < (char *) elf->phdrs + phdrs_size;
+          phdr = (ElfXX_Phdr *) ((char *) phdr + elf->ehdr.ehdrXX.e_phentsize))
+       {
+         phdr->p_type = grub_swap_bytes_wordXX (phdr->p_type);
+         phdr->p_flags = grub_swap_bytes_wordXX (phdr->p_flags);
+          phdr->p_offset = grub_swap_bytes_offXX (phdr->p_offset);
+          phdr->p_vaddr = grub_swap_bytes_addrXX (phdr->p_vaddr);
+          phdr->p_paddr = grub_swap_bytes_addrXX (phdr->p_paddr);
+          phdr->p_filesz = grub_swap_bytes_XwordXX (phdr->p_filesz);
+          phdr->p_memsz = grub_swap_bytes_XwordXX (phdr->p_memsz);
+          phdr->p_align = grub_swap_bytes_XwordXX (phdr->p_align);
+        }
+    }
+#endif /* GRUB_ELF_ENABLE_BI_ENDIAN */
+
   return GRUB_ERR_NONE;
 }
 
@@ -154,3 +173,35 @@ grub_elfXX_load (grub_elf_t elf, const char *filename,
 
   return grub_errno;
 }
+
+static int
+grub_elfXX_check_endianess_and_bswap_ehdr (grub_elf_t elf)
+{
+  ElfXX_Ehdr *e = &(elf->ehdr.ehdrXX);
+  if (e->e_ident[EI_DATA] == GRUB_ELF_NATIVE_ENDIANNESS)
+    {
+      return 1;
+    }
+
+#if GRUB_ELF_ENABLE_BI_ENDIAN
+  if (e->e_ident[EI_DATA] == GRUB_ELF_OPPOSITE_ENDIANNESS)
+    {
+      e->e_type = grub_swap_bytes_halfXX (e->e_type);
+      e->e_machine = grub_swap_bytes_halfXX (e->e_machine);
+      e->e_version = grub_swap_bytes_wordXX (e->e_version);
+      e->e_entry = grub_swap_bytes_addrXX (e->e_entry);
+      e->e_phoff = grub_swap_bytes_offXX (e->e_phoff);
+      e->e_shoff = grub_swap_bytes_offXX (e->e_shoff);
+      e->e_flags = grub_swap_bytes_wordXX (e->e_flags);
+      e->e_ehsize = grub_swap_bytes_halfXX (e->e_ehsize);
+      e->e_phentsize = grub_swap_bytes_halfXX (e->e_phentsize);
+      e->e_phnum = grub_swap_bytes_halfXX (e->e_phnum);
+      e->e_shentsize = grub_swap_bytes_halfXX (e->e_shentsize);
+      e->e_shnum = grub_swap_bytes_halfXX (e->e_shnum);
+      e->e_shstrndx = grub_swap_bytes_halfXX (e->e_shstrndx);
+      return 1;
+    }
+#endif /* GRUB_ELF_ENABLE_BI_ENDIAN */
+
+  return 0;
+}