grub-core/loader/multiboot_elfxx.c

   1 /*
   2  *  GRUB  --  GRand Unified Bootloader
   3  *  Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009  Free Software Foundation, Inc.
   4  *
   5  *  GRUB is free software: you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation, either version 3 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  GRUB is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18
  19 #if defined(MULTIBOOT_LOAD_ELF32)
  20 # define XX             32
  21 # define E_MACHINE      MULTIBOOT_ELF32_MACHINE
  22 # define ELFCLASSXX     ELFCLASS32
  23 # define Elf_Ehdr       Elf32_Ehdr
  24 # define Elf_Phdr       Elf32_Phdr
  25 # define Elf_Shdr       Elf32_Shdr
  26 #elif defined(MULTIBOOT_LOAD_ELF64)
  27 # define XX             64
  28 # define E_MACHINE      MULTIBOOT_ELF64_MACHINE
  29 # define ELFCLASSXX     ELFCLASS64
  30 # define Elf_Ehdr       Elf64_Ehdr
  31 # define Elf_Phdr       Elf64_Phdr
  32 # define Elf_Shdr       Elf64_Shdr
  33 #else
  34 #error "I'm confused"
  35 #endif
  36
  37 #include <grub/i386/relocator.h>
  38
  39 #define CONCAT(a,b)     CONCAT_(a, b)
  40 #define CONCAT_(a,b)    a ## b
  41
  42 #pragma GCC diagnostic ignored "-Wcast-align"
  43
  44 /* Check if BUFFER contains ELF32 (or ELF64).  */
  45 static int
  46 CONCAT(grub_multiboot_is_elf, XX) (void *buffer)
  47 {
  48   Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer;
  49
  50   return ehdr->e_ident[EI_CLASS] == ELFCLASSXX;
  51 }
  52
  53 static grub_err_t
  54 CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
  55 {
  56   Elf_Ehdr *ehdr = (Elf_Ehdr *) mld->buffer;
  57   char *phdr_base;
  58   grub_err_t err;
  59   grub_relocator_chunk_t ch;
  60   grub_uint32_t load_offset = 0, load_size;
  61   int i;
  62   void *source = NULL;
  63
  64   if (ehdr->e_ident[EI_MAG0] != ELFMAG0
  65       || ehdr->e_ident[EI_MAG1] != ELFMAG1
  66       || ehdr->e_ident[EI_MAG2] != ELFMAG2
  67       || ehdr->e_ident[EI_MAG3] != ELFMAG3
  68       || ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
  69     return grub_error(GRUB_ERR_UNKNOWN_OS, N_("invalid arch-independent ELF magic"));
  70
  71   if (ehdr->e_ident[EI_CLASS] != ELFCLASSXX || ehdr->e_machine != E_MACHINE
  72       || ehdr->e_version != EV_CURRENT)
  73     return grub_error (GRUB_ERR_UNKNOWN_OS, N_("invalid arch-dependent ELF magic"));
  74
  75   if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
  76     return grub_error (GRUB_ERR_UNKNOWN_OS, N_("this ELF file is not of the right type"));
  77
  78   /* FIXME: Should we support program headers at strange locations?  */
  79   if (ehdr->e_phoff + (grub_uint32_t) ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH)
  80     return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset");
  81
  82   phdr_base = (char *) mld->buffer + ehdr->e_phoff;
  83 #define phdr(i)                 ((Elf_Phdr *) (phdr_base + (i) * ehdr->e_phentsize))
  84
  85   mld->link_base_addr = ~0;
  86
  87   /* Calculate lowest and highest load address.  */
  88   for (i = 0; i < ehdr->e_phnum; i++)
  89     if (phdr(i)->p_type == PT_LOAD)
  90       {
  91         mld->link_base_addr = grub_min (mld->link_base_addr, phdr(i)->p_paddr);
  92         highest_load = grub_max (highest_load, phdr(i)->p_paddr + phdr(i)->p_memsz);
  93       }
  94
  95 #ifdef MULTIBOOT_LOAD_ELF64
  96   if (highest_load >= 0x100000000)
  97     return grub_error (GRUB_ERR_BAD_OS, "segment crosses 4 GiB border");
  98 #endif
  99
 100   if (mld->relocatable)
 101     {
 102       load_size = highest_load - mld->link_base_addr;
 103
 104       grub_dprintf ("multiboot_loader", "align=0x%lx, preference=0x%x, "
 105                     "load_size=0x%x, avoid_efi_boot_services=%d\n",
 106                     (long) mld->align, mld->preference, load_size,
 107                     mld->avoid_efi_boot_services);
 108
 109       if (load_size > mld->max_addr || mld->min_addr > mld->max_addr - load_size)
 110         return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
 111
 112       err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
 113                                               mld->min_addr, mld->max_addr - load_size,
 114                                               load_size, mld->align ? mld->align : 1,
 115                                               mld->preference, mld->avoid_efi_boot_services);
 116
 117       if (err)
 118         {
 119           grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n");
 120           return err;
 121         }
 122
 123       mld->load_base_addr = get_physical_target_address (ch);
 124       source = get_virtual_current_address (ch);
 125     }
 126   else
 127     mld->load_base_addr = mld->link_base_addr;
 128
 129   grub_dprintf ("multiboot_loader", "relocatable=%d, link_base_addr=0x%x, "
 130                 "load_base_addr=0x%x\n", mld->relocatable,
 131                 mld->link_base_addr, mld->load_base_addr);
 132
 133   /* Load every loadable segment in memory.  */
 134   for (i = 0; i < ehdr->e_phnum; i++)
 135     {
 136       if (phdr(i)->p_type == PT_LOAD)
 137         {
 138
 139           grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx\n",
 140                         i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr);
 141
 142           if (mld->relocatable)
 143             {
 144               load_offset = phdr(i)->p_paddr - mld->link_base_addr;
 145               grub_dprintf ("multiboot_loader", "segment %d: load_offset=0x%x\n", i, load_offset);
 146             }
 147           else
 148             {
 149               err = grub_relocator_alloc_chunk_addr (GRUB_MULTIBOOT (relocator), &ch,
 150                                                      phdr(i)->p_paddr, phdr(i)->p_memsz);
 151
 152               if (err)
 153                 {
 154                   grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n");
 155                   return err;
 156                 }
 157
 158               source = get_virtual_current_address (ch);
 159             }
 160
 161           if (phdr(i)->p_filesz != 0)
 162             {
 163               if (grub_file_seek (mld->file, (grub_off_t) phdr(i)->p_offset)
 164                   == (grub_off_t) -1)
 165                 return grub_errno;
 166
 167               if (grub_file_read (mld->file, (grub_uint8_t *) source + load_offset, phdr(i)->p_filesz)
 168                   != (grub_ssize_t) phdr(i)->p_filesz)
 169                 {
 170                   if (!grub_errno)
 171                     grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
 172                                 mld->filename);
 173                   return grub_errno;
 174                 }
 175             }
 176
 177           if (phdr(i)->p_filesz < phdr(i)->p_memsz)
 178             grub_memset ((grub_uint8_t *) source + load_offset + phdr(i)->p_filesz, 0,
 179                          phdr(i)->p_memsz - phdr(i)->p_filesz);
 180         }
 181     }
 182
 183   for (i = 0; i < ehdr->e_phnum; i++)
 184     if (phdr(i)->p_vaddr <= ehdr->e_entry
 185         && phdr(i)->p_vaddr + phdr(i)->p_memsz > ehdr->e_entry)
 186       {
 187         GRUB_MULTIBOOT (payload_eip) = (ehdr->e_entry - phdr(i)->p_vaddr)
 188           + phdr(i)->p_paddr;
 189 #ifdef MULTIBOOT_LOAD_ELF64
 190 # ifdef __mips
 191   /* We still in 32-bit mode.  */
 192   if ((ehdr->e_entry - phdr(i)->p_vaddr)
 193       + phdr(i)->p_paddr < 0xffffffff80000000ULL)
 194     return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
 195 # else
 196   /* We still in 32-bit mode.  */
 197   if ((ehdr->e_entry - phdr(i)->p_vaddr)
 198       + phdr(i)->p_paddr > 0xffffffff)
 199     return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
 200 # endif
 201 #endif
 202         break;
 203       }
 204
 205   if (i == ehdr->e_phnum)
 206     return grub_error (GRUB_ERR_BAD_OS, "entry point isn't in a segment");
 207
 208 #if defined (__i386__) || defined (__x86_64__)
 209
 210 #elif defined (__mips)
 211   GRUB_MULTIBOOT (payload_eip) |= 0x80000000;
 212 #else
 213 #error Please complete this
 214 #endif
 215
 216   if (ehdr->e_shnum)
 217     {
 218       grub_uint8_t *shdr, *shdrptr;
 219
 220       shdr = grub_malloc ((grub_uint32_t) ehdr->e_shnum * ehdr->e_shentsize);
 221       if (!shdr)
 222         return grub_errno;
 223
 224       if (grub_file_seek (mld->file, ehdr->e_shoff) == (grub_off_t) -1)
 225         {
 226           grub_free (shdr);
 227           return grub_errno;
 228         }
 229
 230       if (grub_file_read (mld->file, shdr, (grub_uint32_t) ehdr->e_shnum * ehdr->e_shentsize)
 231               != (grub_ssize_t) ehdr->e_shnum * ehdr->e_shentsize)
 232         {
 233           if (!grub_errno)
 234             grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
 235                         mld->filename);
 236           return grub_errno;
 237         }
 238
 239       for (shdrptr = shdr, i = 0; i < ehdr->e_shnum;
 240            shdrptr += ehdr->e_shentsize, i++)
 241         {
 242           Elf_Shdr *sh = (Elf_Shdr *) shdrptr;
 243           void *src;
 244           grub_addr_t target;
 245
 246           if (mld->mbi_ver >= 2 && (sh->sh_type == SHT_REL || sh->sh_type == SHT_RELA))
 247             return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "ELF files with relocs are not supported yet");
 248
 249           /* This section is a loaded section,
 250              so we don't care.  */
 251           if (sh->sh_addr != 0)
 252             continue;
 253
 254           /* This section is empty, so we don't care.  */
 255           if (sh->sh_size == 0)
 256             continue;
 257
 258           err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch, 0,
 259                                                   (0xffffffff - sh->sh_size) + 1,
 260                                                   sh->sh_size, sh->sh_addralign,
 261                                                   GRUB_RELOCATOR_PREFERENCE_NONE,
 262                                                   mld->avoid_efi_boot_services);
 263           if (err)
 264             {
 265               grub_dprintf ("multiboot_loader", "Error loading shdr %d\n", i);
 266               return err;
 267             }
 268           src = get_virtual_current_address (ch);
 269           target = get_physical_target_address (ch);
 270
 271           if (grub_file_seek (mld->file, sh->sh_offset) == (grub_off_t) -1)
 272             return grub_errno;
 273
 274           if (grub_file_read (mld->file, src, sh->sh_size)
 275               != (grub_ssize_t) sh->sh_size)
 276             {
 277               if (!grub_errno)
 278                 grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
 279                             mld->filename);
 280               return grub_errno;
 281             }
 282           sh->sh_addr = target;
 283         }
 284       GRUB_MULTIBOOT (add_elfsyms) (ehdr->e_shnum, ehdr->e_shentsize,
 285                                     ehdr->e_shstrndx, shdr);
 286     }
 287
 288 #undef phdr
 289
 290   return grub_errno;
 291 }
 292
 293 #undef XX
 294 #undef E_MACHINE
 295 #undef ELFCLASSXX
 296 #undef Elf_Ehdr
 297 #undef Elf_Phdr
 298 #undef Elf_Shdr