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grub/grub-core/loader/multiboot_elfxx.c
Vladimir Serbinenko ec4630c2b5 multiboot: disentangle multiboot and multiboot2. 
Previously we had multiboot and multiboot2 declaring the same symbols.
This can potentially lead to aliasing and strange behaviours when e.g.
module instead of module2 is used with multiboot2.

Bug: #51137
2020-09-21 12:02:37 -04:00

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8.6 KiB
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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2007,2008,2009 Free Software Foundation, Inc.
*
* GRUB is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#if defined(MULTIBOOT_LOAD_ELF32)
# define XX 32
# define E_MACHINE MULTIBOOT_ELF32_MACHINE
# define ELFCLASSXX ELFCLASS32
# define Elf_Ehdr Elf32_Ehdr
# define Elf_Phdr Elf32_Phdr
# define Elf_Shdr Elf32_Shdr
#elif defined(MULTIBOOT_LOAD_ELF64)
# define XX 64
# define E_MACHINE MULTIBOOT_ELF64_MACHINE
# define ELFCLASSXX ELFCLASS64
# define Elf_Ehdr Elf64_Ehdr
# define Elf_Phdr Elf64_Phdr
# define Elf_Shdr Elf64_Shdr
#else
#error "I'm confused"
#endif
#include <grub/i386/relocator.h>
#define CONCAT(a,b) CONCAT_(a, b)
#define CONCAT_(a,b) a ## b
#pragma GCC diagnostic ignored "-Wcast-align"
/* Check if BUFFER contains ELF32 (or ELF64). */
static int
CONCAT(grub_multiboot_is_elf, XX) (void *buffer)
{
Elf_Ehdr *ehdr = (Elf_Ehdr *) buffer;
return ehdr->e_ident[EI_CLASS] == ELFCLASSXX;
}
static grub_err_t
CONCAT(grub_multiboot_load_elf, XX) (mbi_load_data_t *mld)
{
Elf_Ehdr *ehdr = (Elf_Ehdr *) mld->buffer;
char *phdr_base;
grub_err_t err;
grub_relocator_chunk_t ch;
grub_uint32_t load_offset, load_size;
int i;
void *source;
if (ehdr->e_ident[EI_MAG0] != ELFMAG0
|| ehdr->e_ident[EI_MAG1] != ELFMAG1
|| ehdr->e_ident[EI_MAG2] != ELFMAG2
|| ehdr->e_ident[EI_MAG3] != ELFMAG3
|| ehdr->e_ident[EI_DATA] != ELFDATA2LSB)
return grub_error(GRUB_ERR_UNKNOWN_OS, N_("invalid arch-independent ELF magic"));
if (ehdr->e_ident[EI_CLASS] != ELFCLASSXX || ehdr->e_machine != E_MACHINE
|| ehdr->e_version != EV_CURRENT)
return grub_error (GRUB_ERR_UNKNOWN_OS, N_("invalid arch-dependent ELF magic"));
if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
return grub_error (GRUB_ERR_UNKNOWN_OS, N_("this ELF file is not of the right type"));
/* FIXME: Should we support program headers at strange locations? */
if (ehdr->e_phoff + (grub_uint32_t) ehdr->e_phnum * ehdr->e_phentsize > MULTIBOOT_SEARCH)
return grub_error (GRUB_ERR_BAD_OS, "program header at a too high offset");
phdr_base = (char *) mld->buffer + ehdr->e_phoff;
#define phdr(i) ((Elf_Phdr *) (phdr_base + (i) * ehdr->e_phentsize))
mld->link_base_addr = ~0;
/* Calculate lowest and highest load address. */
for (i = 0; i < ehdr->e_phnum; i++)
if (phdr(i)->p_type == PT_LOAD)
{
mld->link_base_addr = grub_min (mld->link_base_addr, phdr(i)->p_paddr);
highest_load = grub_max (highest_load, phdr(i)->p_paddr + phdr(i)->p_memsz);
}
#ifdef MULTIBOOT_LOAD_ELF64
if (highest_load >= 0x100000000)
return grub_error (GRUB_ERR_BAD_OS, "segment crosses 4 GiB border");
#endif
load_size = highest_load - mld->link_base_addr;
if (mld->relocatable)
{
if (load_size > mld->max_addr || mld->min_addr > mld->max_addr - load_size)
return grub_error (GRUB_ERR_BAD_OS, "invalid min/max address and/or load size");
err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch,
mld->min_addr, mld->max_addr - load_size,
load_size, mld->align ? mld->align : 1,
mld->preference, mld->avoid_efi_boot_services);
}
else
err = grub_relocator_alloc_chunk_addr (GRUB_MULTIBOOT (relocator), &ch,
mld->link_base_addr, load_size);
if (err)
{
grub_dprintf ("multiboot_loader", "Cannot allocate memory for OS image\n");
return err;
}
mld->load_base_addr = get_physical_target_address (ch);
source = get_virtual_current_address (ch);
grub_dprintf ("multiboot_loader", "link_base_addr=0x%x, load_base_addr=0x%x, "
"load_size=0x%x, relocatable=%d\n", mld->link_base_addr,
mld->load_base_addr, load_size, mld->relocatable);
if (mld->relocatable)
grub_dprintf ("multiboot_loader", "align=0x%lx, preference=0x%x, avoid_efi_boot_services=%d\n",
(long) mld->align, mld->preference, mld->avoid_efi_boot_services);
/* Load every loadable segment in memory. */
for (i = 0; i < ehdr->e_phnum; i++)
{
if (phdr(i)->p_type == PT_LOAD)
{
grub_dprintf ("multiboot_loader", "segment %d: paddr=0x%lx, memsz=0x%lx, vaddr=0x%lx\n",
i, (long) phdr(i)->p_paddr, (long) phdr(i)->p_memsz, (long) phdr(i)->p_vaddr);
load_offset = phdr(i)->p_paddr - mld->link_base_addr;
if (phdr(i)->p_filesz != 0)
{
if (grub_file_seek (mld->file, (grub_off_t) phdr(i)->p_offset)
== (grub_off_t) -1)
return grub_errno;
if (grub_file_read (mld->file, (grub_uint8_t *) source + load_offset, phdr(i)->p_filesz)
!= (grub_ssize_t) phdr(i)->p_filesz)
{
if (!grub_errno)
grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
mld->filename);
return grub_errno;
}
}
if (phdr(i)->p_filesz < phdr(i)->p_memsz)
grub_memset ((grub_uint8_t *) source + load_offset + phdr(i)->p_filesz, 0,
phdr(i)->p_memsz - phdr(i)->p_filesz);
}
}
for (i = 0; i < ehdr->e_phnum; i++)
if (phdr(i)->p_vaddr <= ehdr->e_entry
&& phdr(i)->p_vaddr + phdr(i)->p_memsz > ehdr->e_entry)
{
GRUB_MULTIBOOT (payload_eip) = (ehdr->e_entry - phdr(i)->p_vaddr)
+ phdr(i)->p_paddr;
#ifdef MULTIBOOT_LOAD_ELF64
# ifdef __mips
/* We still in 32-bit mode. */
if ((ehdr->e_entry - phdr(i)->p_vaddr)
+ phdr(i)->p_paddr < 0xffffffff80000000ULL)
return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
# else
/* We still in 32-bit mode. */
if ((ehdr->e_entry - phdr(i)->p_vaddr)
+ phdr(i)->p_paddr > 0xffffffff)
return grub_error (GRUB_ERR_BAD_OS, "invalid entry point for ELF64");
# endif
#endif
break;
}
if (i == ehdr->e_phnum)
return grub_error (GRUB_ERR_BAD_OS, "entry point isn't in a segment");
#if defined (__i386__) || defined (__x86_64__)
#elif defined (__mips)
GRUB_MULTIBOOT (payload_eip) |= 0x80000000;
#else
#error Please complete this
#endif
if (ehdr->e_shnum)
{
grub_uint8_t *shdr, *shdrptr;
shdr = grub_malloc ((grub_uint32_t) ehdr->e_shnum * ehdr->e_shentsize);
if (!shdr)
return grub_errno;
if (grub_file_seek (mld->file, ehdr->e_shoff) == (grub_off_t) -1)
{
grub_free (shdr);
return grub_errno;
}
if (grub_file_read (mld->file, shdr, (grub_uint32_t) ehdr->e_shnum * ehdr->e_shentsize)
!= (grub_ssize_t) ehdr->e_shnum * ehdr->e_shentsize)
{
if (!grub_errno)
grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
mld->filename);
return grub_errno;
}
for (shdrptr = shdr, i = 0; i < ehdr->e_shnum;
shdrptr += ehdr->e_shentsize, i++)
{
Elf_Shdr *sh = (Elf_Shdr *) shdrptr;
void *src;
grub_addr_t target;
if (mld->mbi_ver >= 2 && (sh->sh_type == SHT_REL || sh->sh_type == SHT_RELA))
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET, "ELF files with relocs are not supported yet");
/* This section is a loaded section,
so we don't care. */
if (sh->sh_addr != 0)
continue;
/* This section is empty, so we don't care. */
if (sh->sh_size == 0)
continue;
err = grub_relocator_alloc_chunk_align (GRUB_MULTIBOOT (relocator), &ch, 0,
(0xffffffff - sh->sh_size) + 1,
sh->sh_size, sh->sh_addralign,
GRUB_RELOCATOR_PREFERENCE_NONE,
mld->avoid_efi_boot_services);
if (err)
{
grub_dprintf ("multiboot_loader", "Error loading shdr %d\n", i);
return err;
}
src = get_virtual_current_address (ch);
target = get_physical_target_address (ch);
if (grub_file_seek (mld->file, sh->sh_offset) == (grub_off_t) -1)
return grub_errno;
if (grub_file_read (mld->file, src, sh->sh_size)
!= (grub_ssize_t) sh->sh_size)
{
if (!grub_errno)
grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
mld->filename);
return grub_errno;
}
sh->sh_addr = target;
}
GRUB_MULTIBOOT (add_elfsyms) (ehdr->e_shnum, ehdr->e_shentsize,
ehdr->e_shstrndx, shdr);
}
#undef phdr
return grub_errno;
}
#undef XX
#undef E_MACHINE
#undef ELFCLASSXX
#undef Elf_Ehdr
#undef Elf_Phdr
#undef Elf_Shdr
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