464 lines
12 KiB
C
464 lines
12 KiB
C
/* elf.c - load ELF files */
|
||
/*
|
||
* GRUB -- GRand Unified Bootloader
|
||
* Copyright (C) 2003,2004,2005,2006,2007,2008 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/>.
|
||
*/
|
||
|
||
#include <grub/err.h>
|
||
#include <grub/elf.h>
|
||
#include <grub/elfload.h>
|
||
#include <grub/file.h>
|
||
#include <grub/gzio.h>
|
||
#include <grub/misc.h>
|
||
#include <grub/mm.h>
|
||
|
||
/* Check if EHDR is a valid ELF header. */
|
||
static grub_err_t
|
||
grub_elf_check_header (grub_elf_t elf)
|
||
{
|
||
Elf32_Ehdr *e = &elf->ehdr.ehdr32;
|
||
|
||
if (e->e_ident[EI_MAG0] != ELFMAG0
|
||
|| 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)
|
||
return grub_error (GRUB_ERR_BAD_OS, "invalid arch independent ELF magic");
|
||
|
||
return GRUB_ERR_NONE;
|
||
}
|
||
|
||
grub_err_t
|
||
grub_elf_close (grub_elf_t elf)
|
||
{
|
||
grub_file_t file = elf->file;
|
||
|
||
grub_free (elf->phdrs);
|
||
grub_free (elf);
|
||
|
||
if (file)
|
||
grub_file_close (file);
|
||
|
||
return grub_errno;
|
||
}
|
||
|
||
grub_elf_t
|
||
grub_elf_file (grub_file_t file)
|
||
{
|
||
grub_elf_t elf;
|
||
|
||
elf = grub_malloc (sizeof (*elf));
|
||
if (! elf)
|
||
return 0;
|
||
|
||
elf->file = file;
|
||
elf->phdrs = 0;
|
||
|
||
if (grub_file_seek (elf->file, 0) == (grub_off_t) -1)
|
||
goto fail;
|
||
|
||
if (grub_file_read (elf->file, &elf->ehdr, sizeof (elf->ehdr))
|
||
!= sizeof (elf->ehdr))
|
||
{
|
||
grub_error_push ();
|
||
grub_error (GRUB_ERR_READ_ERROR, "Cannot read ELF header.");
|
||
goto fail;
|
||
}
|
||
|
||
if (grub_elf_check_header (elf))
|
||
goto fail;
|
||
|
||
return elf;
|
||
|
||
fail:
|
||
grub_free (elf->phdrs);
|
||
grub_free (elf);
|
||
return 0;
|
||
}
|
||
|
||
grub_elf_t
|
||
grub_elf_open (const char *name)
|
||
{
|
||
grub_file_t file;
|
||
grub_elf_t elf;
|
||
|
||
file = grub_gzfile_open (name, 1);
|
||
if (! file)
|
||
return 0;
|
||
|
||
elf = grub_elf_file (file);
|
||
if (! elf)
|
||
grub_file_close (file);
|
||
|
||
return elf;
|
||
}
|
||
|
||
|
||
/* 32-bit */
|
||
|
||
int
|
||
grub_elf_is_elf32 (grub_elf_t elf)
|
||
{
|
||
return elf->ehdr.ehdr32.e_ident[EI_CLASS] == ELFCLASS32;
|
||
}
|
||
|
||
static grub_err_t
|
||
grub_elf32_load_phdrs (grub_elf_t elf)
|
||
{
|
||
grub_ssize_t phdrs_size;
|
||
|
||
phdrs_size = elf->ehdr.ehdr32.e_phnum * elf->ehdr.ehdr32.e_phentsize;
|
||
|
||
grub_dprintf ("elf", "Loading program headers at 0x%llx, size 0x%lx.\n",
|
||
(unsigned long long) elf->ehdr.ehdr32.e_phoff,
|
||
(unsigned long) phdrs_size);
|
||
|
||
elf->phdrs = grub_malloc (phdrs_size);
|
||
if (! elf->phdrs)
|
||
return grub_errno;
|
||
|
||
if ((grub_file_seek (elf->file, elf->ehdr.ehdr32.e_phoff) == (grub_off_t) -1)
|
||
|| (grub_file_read (elf->file, elf->phdrs, phdrs_size) != phdrs_size))
|
||
{
|
||
grub_error_push ();
|
||
return grub_error (GRUB_ERR_READ_ERROR, "Cannot read program headers");
|
||
}
|
||
|
||
return GRUB_ERR_NONE;
|
||
}
|
||
|
||
static grub_err_t
|
||
grub_elf32_phdr_iterate (grub_elf_t elf,
|
||
int NESTED_FUNC_ATTR (*hook) (grub_elf_t, Elf32_Phdr *, void *),
|
||
void *hook_arg)
|
||
{
|
||
Elf32_Phdr *phdrs;
|
||
unsigned int i;
|
||
|
||
if (! elf->phdrs)
|
||
if (grub_elf32_load_phdrs (elf))
|
||
return grub_errno;
|
||
phdrs = elf->phdrs;
|
||
|
||
for (i = 0; i < elf->ehdr.ehdr32.e_phnum; i++)
|
||
{
|
||
Elf32_Phdr *phdr = phdrs + i;
|
||
grub_dprintf ("elf",
|
||
"Segment %u: type 0x%x paddr 0x%lx memsz 0x%lx "
|
||
"filesz %lx\n",
|
||
i, phdr->p_type,
|
||
(unsigned long) phdr->p_paddr,
|
||
(unsigned long) phdr->p_memsz,
|
||
(unsigned long) phdr->p_filesz);
|
||
if (hook (elf, phdr, hook_arg))
|
||
break;
|
||
}
|
||
|
||
return grub_errno;
|
||
}
|
||
|
||
/* Calculate the amount of memory spanned by the segments. */
|
||
grub_size_t
|
||
grub_elf32_size (grub_elf_t elf)
|
||
{
|
||
Elf32_Addr segments_start = (Elf32_Addr) -1;
|
||
Elf32_Addr segments_end = 0;
|
||
int nr_phdrs = 0;
|
||
|
||
/* Run through the program headers to calculate the total memory size we
|
||
* should claim. */
|
||
auto int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf, Elf32_Phdr *phdr, void *_arg);
|
||
int NESTED_FUNC_ATTR calcsize (grub_elf_t UNUSED _elf, Elf32_Phdr *phdr, void UNUSED *_arg)
|
||
{
|
||
/* Only consider loadable segments. */
|
||
if (phdr->p_type != PT_LOAD)
|
||
return 0;
|
||
nr_phdrs++;
|
||
if (phdr->p_paddr < segments_start)
|
||
segments_start = phdr->p_paddr;
|
||
if (phdr->p_paddr + phdr->p_memsz > segments_end)
|
||
segments_end = phdr->p_paddr + phdr->p_memsz;
|
||
return 0;
|
||
}
|
||
|
||
grub_elf32_phdr_iterate (elf, calcsize, 0);
|
||
|
||
if (nr_phdrs == 0)
|
||
{
|
||
grub_error (GRUB_ERR_BAD_OS, "No program headers present");
|
||
return 0;
|
||
}
|
||
|
||
if (segments_end < segments_start)
|
||
{
|
||
/* Very bad addresses. */
|
||
grub_error (GRUB_ERR_BAD_OS, "Bad program header load addresses");
|
||
return 0;
|
||
}
|
||
|
||
return segments_end - segments_start;
|
||
}
|
||
|
||
|
||
/* Load every loadable segment into memory specified by `_load_hook'. */
|
||
grub_err_t
|
||
grub_elf32_load (grub_elf_t _elf, grub_elf32_load_hook_t _load_hook,
|
||
grub_addr_t *base, grub_size_t *size)
|
||
{
|
||
grub_addr_t load_base = (grub_addr_t) -1ULL;
|
||
grub_size_t load_size = 0;
|
||
grub_err_t err;
|
||
|
||
auto int NESTED_FUNC_ATTR grub_elf32_load_segment (grub_elf_t elf, Elf32_Phdr *phdr, void *hook);
|
||
int NESTED_FUNC_ATTR grub_elf32_load_segment (grub_elf_t elf, Elf32_Phdr *phdr, void *hook)
|
||
{
|
||
grub_elf32_load_hook_t load_hook = (grub_elf32_load_hook_t) hook;
|
||
grub_addr_t load_addr;
|
||
|
||
if (phdr->p_type != PT_LOAD)
|
||
return 0;
|
||
|
||
load_addr = phdr->p_paddr;
|
||
if (load_hook && load_hook (phdr, &load_addr))
|
||
return 1;
|
||
|
||
if (load_addr < load_base)
|
||
load_base = load_addr;
|
||
|
||
grub_dprintf ("elf", "Loading segment at 0x%llx, size 0x%llx\n",
|
||
(unsigned long long) load_addr,
|
||
(unsigned long long) phdr->p_memsz);
|
||
|
||
if (grub_file_seek (elf->file, phdr->p_offset) == (grub_off_t) -1)
|
||
{
|
||
grub_error_push ();
|
||
return grub_error (GRUB_ERR_BAD_OS,
|
||
"Invalid offset in program header.");
|
||
}
|
||
|
||
if (phdr->p_filesz)
|
||
{
|
||
grub_ssize_t read;
|
||
read = grub_file_read (elf->file, (void *) load_addr, phdr->p_filesz);
|
||
if (read != (grub_ssize_t) phdr->p_filesz)
|
||
{
|
||
/* XXX How can we free memory from `load_hook'? */
|
||
grub_error_push ();
|
||
return grub_error (GRUB_ERR_BAD_OS,
|
||
"Couldn't read segment from file: "
|
||
"wanted 0x%lx bytes; read 0x%lx bytes.",
|
||
phdr->p_filesz, read);
|
||
}
|
||
}
|
||
|
||
if (phdr->p_filesz < phdr->p_memsz)
|
||
grub_memset ((void *) (long) (load_addr + phdr->p_filesz),
|
||
0, phdr->p_memsz - phdr->p_filesz);
|
||
|
||
load_size += phdr->p_memsz;
|
||
|
||
return 0;
|
||
}
|
||
|
||
err = grub_elf32_phdr_iterate (_elf, grub_elf32_load_segment, _load_hook);
|
||
|
||
if (base)
|
||
*base = load_base;
|
||
if (size)
|
||
*size = load_size;
|
||
|
||
return err;
|
||
}
|
||
|
||
|
||
|
||
/* 64-bit */
|
||
|
||
int
|
||
grub_elf_is_elf64 (grub_elf_t elf)
|
||
{
|
||
return elf->ehdr.ehdr64.e_ident[EI_CLASS] == ELFCLASS64;
|
||
}
|
||
|
||
static grub_err_t
|
||
grub_elf64_load_phdrs (grub_elf_t elf)
|
||
{
|
||
grub_ssize_t phdrs_size;
|
||
|
||
phdrs_size = elf->ehdr.ehdr64.e_phnum * elf->ehdr.ehdr64.e_phentsize;
|
||
|
||
grub_dprintf ("elf", "Loading program headers at 0x%llx, size 0x%lx.\n",
|
||
(unsigned long long) elf->ehdr.ehdr64.e_phoff,
|
||
(unsigned long) phdrs_size);
|
||
|
||
elf->phdrs = grub_malloc (phdrs_size);
|
||
if (! elf->phdrs)
|
||
return grub_errno;
|
||
|
||
if ((grub_file_seek (elf->file, elf->ehdr.ehdr64.e_phoff) == (grub_off_t) -1)
|
||
|| (grub_file_read (elf->file, elf->phdrs, phdrs_size) != phdrs_size))
|
||
{
|
||
grub_error_push ();
|
||
return grub_error (GRUB_ERR_READ_ERROR, "Cannot read program headers");
|
||
}
|
||
|
||
return GRUB_ERR_NONE;
|
||
}
|
||
|
||
static grub_err_t
|
||
grub_elf64_phdr_iterate (grub_elf_t elf,
|
||
int NESTED_FUNC_ATTR (*hook) (grub_elf_t, Elf64_Phdr *, void *),
|
||
void *hook_arg)
|
||
{
|
||
Elf64_Phdr *phdrs;
|
||
unsigned int i;
|
||
|
||
if (! elf->phdrs)
|
||
if (grub_elf64_load_phdrs (elf))
|
||
return grub_errno;
|
||
phdrs = elf->phdrs;
|
||
|
||
for (i = 0; i < elf->ehdr.ehdr64.e_phnum; i++)
|
||
{
|
||
Elf64_Phdr *phdr = phdrs + i;
|
||
grub_dprintf ("elf",
|
||
"Segment %u: type 0x%x paddr 0x%lx memsz 0x%lx "
|
||
"filesz %lx\n",
|
||
i, phdr->p_type,
|
||
(unsigned long) phdr->p_paddr,
|
||
(unsigned long) phdr->p_memsz,
|
||
(unsigned long) phdr->p_filesz);
|
||
if (hook (elf, phdr, hook_arg))
|
||
break;
|
||
}
|
||
|
||
return grub_errno;
|
||
}
|
||
|
||
/* Calculate the amount of memory spanned by the segments. */
|
||
grub_size_t
|
||
grub_elf64_size (grub_elf_t elf)
|
||
{
|
||
Elf64_Addr segments_start = (Elf64_Addr) -1;
|
||
Elf64_Addr segments_end = 0;
|
||
int nr_phdrs = 0;
|
||
|
||
/* Run through the program headers to calculate the total memory size we
|
||
* should claim. */
|
||
auto int NESTED_FUNC_ATTR calcsize (grub_elf_t _elf, Elf64_Phdr *phdr, void *_arg);
|
||
int NESTED_FUNC_ATTR calcsize (grub_elf_t UNUSED _elf, Elf64_Phdr *phdr, void UNUSED *_arg)
|
||
{
|
||
/* Only consider loadable segments. */
|
||
if (phdr->p_type != PT_LOAD)
|
||
return 0;
|
||
nr_phdrs++;
|
||
if (phdr->p_paddr < segments_start)
|
||
segments_start = phdr->p_paddr;
|
||
if (phdr->p_paddr + phdr->p_memsz > segments_end)
|
||
segments_end = phdr->p_paddr + phdr->p_memsz;
|
||
return 0;
|
||
}
|
||
|
||
grub_elf64_phdr_iterate (elf, calcsize, 0);
|
||
|
||
if (nr_phdrs == 0)
|
||
{
|
||
grub_error (GRUB_ERR_BAD_OS, "No program headers present");
|
||
return 0;
|
||
}
|
||
|
||
if (segments_end < segments_start)
|
||
{
|
||
/* Very bad addresses. */
|
||
grub_error (GRUB_ERR_BAD_OS, "Bad program header load addresses");
|
||
return 0;
|
||
}
|
||
|
||
return segments_end - segments_start;
|
||
}
|
||
|
||
|
||
/* Load every loadable segment into memory specified by `_load_hook'. */
|
||
grub_err_t
|
||
grub_elf64_load (grub_elf_t _elf, grub_elf64_load_hook_t _load_hook,
|
||
grub_addr_t *base, grub_size_t *size)
|
||
{
|
||
grub_addr_t load_base = (grub_addr_t) -1ULL;
|
||
grub_size_t load_size = 0;
|
||
grub_err_t err;
|
||
|
||
auto int NESTED_FUNC_ATTR grub_elf64_load_segment (grub_elf_t elf, Elf64_Phdr *phdr,
|
||
void *hook);
|
||
int NESTED_FUNC_ATTR grub_elf64_load_segment (grub_elf_t elf, Elf64_Phdr *phdr, void *hook)
|
||
{
|
||
grub_elf64_load_hook_t load_hook = (grub_elf64_load_hook_t) hook;
|
||
grub_addr_t load_addr;
|
||
|
||
if (phdr->p_type != PT_LOAD)
|
||
return 0;
|
||
|
||
load_addr = phdr->p_paddr;
|
||
if (load_hook && load_hook (phdr, &load_addr))
|
||
return 1;
|
||
|
||
if (load_addr < load_base)
|
||
load_base = load_addr;
|
||
|
||
grub_dprintf ("elf", "Loading segment at 0x%llx, size 0x%llx\n",
|
||
(unsigned long long) load_addr,
|
||
(unsigned long long) phdr->p_memsz);
|
||
|
||
if (grub_file_seek (elf->file, phdr->p_offset) == (grub_off_t) -1)
|
||
{
|
||
grub_error_push ();
|
||
return grub_error (GRUB_ERR_BAD_OS,
|
||
"Invalid offset in program header.");
|
||
}
|
||
|
||
if (phdr->p_filesz)
|
||
{
|
||
grub_ssize_t read;
|
||
read = grub_file_read (elf->file, (void *) load_addr, phdr->p_filesz);
|
||
if (read != (grub_ssize_t) phdr->p_filesz)
|
||
{
|
||
/* XXX How can we free memory from `load_hook'? */
|
||
grub_error_push ();
|
||
return grub_error (GRUB_ERR_BAD_OS,
|
||
"Couldn't read segment from file: "
|
||
"wanted 0x%lx bytes; read 0x%lx bytes.",
|
||
phdr->p_filesz, read);
|
||
}
|
||
}
|
||
|
||
if (phdr->p_filesz < phdr->p_memsz)
|
||
grub_memset ((void *) (long) (load_addr + phdr->p_filesz),
|
||
0, phdr->p_memsz - phdr->p_filesz);
|
||
|
||
load_size += phdr->p_memsz;
|
||
|
||
return 0;
|
||
}
|
||
|
||
err = grub_elf64_phdr_iterate (_elf, grub_elf64_load_segment, _load_hook);
|
||
|
||
if (base)
|
||
*base = load_base;
|
||
if (size)
|
||
*size = load_size;
|
||
|
||
return err;
|
||
}
|