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grub/util/grub-mkstandalone.c
Andrei Borzenkov 478b567520 grub-mkstandalone: out of bound access to tar header magic 
Magic size is 6 bytes and we copied 7 bytes in it.

CID: 73587, 73888
Closes bug 43690
2014-11-28 20:39:22 +03:00

360 lines
8.3 KiB
C
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/*
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013 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 <config.h>
#include <grub/util/install.h>
#include <grub/util/misc.h>
#include <grub/emu/config.h>
#include <string.h>
#pragma GCC diagnostic ignored "-Wmissing-prototypes"
#pragma GCC diagnostic ignored "-Wmissing-declarations"
#include <argp.h>
#pragma GCC diagnostic error "-Wmissing-prototypes"
#pragma GCC diagnostic error "-Wmissing-declarations"
static char *output_image;
static char **files;
static int nfiles;
const struct grub_install_image_target_desc *format;
static FILE *memdisk;
enum
{
OPTION_OUTPUT = 'o',
OPTION_FORMAT = 'O'
};
static struct argp_option options[] = {
GRUB_INSTALL_OPTIONS,
{"output", 'o', N_("FILE"),
0, N_("save output in FILE [required]"), 2},
{"format", 'O', N_("FILE"), 0, 0, 2},
{"compression", 'C', "xz|none|auto", OPTION_HIDDEN, 0, 2},
{0, 0, 0, 0, 0, 0}
};
static char *
help_filter (int key, const char *text, void *input __attribute__ ((unused)))
{
switch (key)
{
case 'O':
{
char *formats = grub_install_get_image_targets_string (), *ret;
ret = xasprintf ("%s\n%s %s", _("generate an image in FORMAT"),
_("available formats:"), formats);
free (formats);
return ret;
}
default:
return grub_install_help_filter (key, text, input);
}
}
static error_t
argp_parser (int key, char *arg, struct argp_state *state)
{
if (key == 'C')
key = GRUB_INSTALL_OPTIONS_INSTALL_CORE_COMPRESS;
if (grub_install_parse (key, arg))
return 0;
switch (key)
{
case 'o':
if (output_image)
free (output_image);
output_image = xstrdup (arg);
break;
case 'O':
{
format = grub_install_get_image_target (arg);
if (!format)
{
printf (_("unknown target format %s\n"), arg);
argp_usage (state);
exit (1);
}
break;
}
case ARGP_KEY_ARG:
files[nfiles++] = xstrdup (arg);
break;
default:
return ARGP_ERR_UNKNOWN;
}
return 0;
}
struct argp argp = {
options, argp_parser, N_("[OPTION] SOURCE..."),
N_("Generate a standalone image (containing all modules) in the selected format")"\v"N_("Graft point syntax (E.g. /boot/grub/grub.cfg=./grub.cfg) is accepted"),
NULL, help_filter, NULL
};
/* tar support */
#define MAGIC "ustar"
struct head
{
char name[100];
char mode[8];
char uid[8];
char gid[8];
char size[12];
char mtime[12];
char chksum[8];
char typeflag;
char linkname[100];
char magic[6];
char version[2];
char uname[32];
char gname[32];
char devmajor[8];
char devminor[8];
char prefix[155];
char pad[12];
} GRUB_PACKED;
static void
write_zeros (unsigned rsz)
{
char buf[512];
memset (buf, 0, 512);
fwrite (buf, 1, rsz, memdisk);
}
static void
write_pad (unsigned sz)
{
write_zeros ((~sz + 1) & 511);
}
static void
set_tar_value (char *field, grub_uint32_t val,
unsigned len)
{
unsigned i;
for (i = 0; i < len - 1; i++)
field[len - 2 - i] = '0' + ((val >> (3 * i)) & 7);
}
static void
compute_checksum (struct head *hd)
{
unsigned int chk = 0;
unsigned char *ptr;
memset (hd->chksum, ' ', 8);
for (ptr = (unsigned char *) hd; ptr < (unsigned char *) (hd + 1); ptr++)
chk += *ptr;
set_tar_value (hd->chksum, chk, 8);
}
static void
add_tar_file (const char *from,
const char *to)
{
char *tcn;
const char *iptr;
char *optr;
struct head hd;
grub_util_fd_t in;
ssize_t r;
grub_uint32_t mtime = 0;
grub_uint32_t size;
COMPILE_TIME_ASSERT (sizeof (hd) == 512);
if (grub_util_is_special_file (from))
return;
mtime = grub_util_get_mtime (from);
optr = tcn = xmalloc (strlen (to) + 1);
for (iptr = to; *iptr == '/'; iptr++);
for (; *iptr; iptr++)
if (!(iptr[0] == '/' && iptr[1] == '/'))
*optr++ = *iptr;
*optr = '\0';
if (grub_util_is_directory (from))
{
grub_util_fd_dir_t d;
grub_util_fd_dirent_t de;
d = grub_util_fd_opendir (from);
while ((de = grub_util_fd_readdir (d)))
{
char *fp, *tfp;
if (strcmp (de->d_name, ".") == 0)
continue;
if (strcmp (de->d_name, "..") == 0)
continue;
fp = grub_util_path_concat (2, from, de->d_name);
tfp = xasprintf ("%s/%s", to, de->d_name);
add_tar_file (fp, tfp);
free (fp);
}
grub_util_fd_closedir (d);
free (tcn);
return;
}
if (optr - tcn > 99)
{
memset (&hd, 0, sizeof (hd));
memcpy (hd.name, tcn, 99);
memcpy (hd.mode, "0000600", 7);
memcpy (hd.uid, "0001750", 7);
memcpy (hd.gid, "0001750", 7);
set_tar_value (hd.size, optr - tcn, 12);
set_tar_value (hd.mtime, mtime, 12);
hd.typeflag = 'L';
memcpy (hd.magic, MAGIC, sizeof (hd.magic));
memcpy (hd.uname, "grub", 4);
memcpy (hd.gname, "grub", 4);
compute_checksum (&hd);
fwrite (&hd, 1, sizeof (hd), memdisk);
fwrite (tcn, 1, optr - tcn, memdisk);
write_pad (optr - tcn);
}
in = grub_util_fd_open (from, GRUB_UTIL_FD_O_RDONLY);
if (!GRUB_UTIL_FD_IS_VALID (in))
grub_util_error (_("cannot open `%s': %s"), from, grub_util_fd_strerror ());
if (!grub_install_copy_buffer)
grub_install_copy_buffer = xmalloc (GRUB_INSTALL_COPY_BUFFER_SIZE);
size = grub_util_get_fd_size (in, from, NULL);
memset (&hd, 0, sizeof (hd));
memcpy (hd.name, tcn, optr - tcn < 99 ? optr - tcn : 99);
memcpy (hd.mode, "0000600", 7);
memcpy (hd.uid, "0001750", 7);
memcpy (hd.gid, "0001750", 7);
set_tar_value (hd.size, size, 12);
set_tar_value (hd.mtime, mtime, 12);
hd.typeflag = '0';
memcpy (hd.magic, MAGIC, sizeof (hd.magic));
memcpy (hd.uname, "grub", 4);
memcpy (hd.gname, "grub", 4);
compute_checksum (&hd);
fwrite (&hd, 1, sizeof (hd), memdisk);
while (1)
{
r = grub_util_fd_read (in, grub_install_copy_buffer, GRUB_INSTALL_COPY_BUFFER_SIZE);
if (r <= 0)
break;
fwrite (grub_install_copy_buffer, 1, r, memdisk);
}
grub_util_fd_close (in);
write_pad (size);
}
int
main (int argc, char *argv[])
{
const char *pkglibdir;
int i;
grub_util_host_init (&argc, &argv);
grub_util_disable_fd_syncs ();
files = xmalloc ((argc + 1) * sizeof (files[0]));
argp_parse (&argp, argc, argv, 0, 0, 0);
pkglibdir = grub_util_get_pkglibdir ();
if (!output_image)
grub_util_error ("%s", _("output file must be specified"));
if (!format)
grub_util_error ("%s", _("Target format not specified (use the -O option)."));
if (!grub_install_source_directory)
grub_install_source_directory = grub_util_path_concat (2, pkglibdir, grub_util_get_target_dirname (format));
enum grub_install_plat plat = grub_install_get_target (grub_install_source_directory);
char *memdisk_dir = grub_util_make_temporary_dir ();
char *boot_grub = grub_util_path_concat (3, memdisk_dir, "boot", "grub");
grub_install_copy_files (grub_install_source_directory,
boot_grub, plat);
char *memdisk_img = grub_util_make_temporary_file ();
memdisk = grub_util_fopen (memdisk_img, "wb");
add_tar_file (memdisk_dir, "");
for (i = 0; i < nfiles; i++)
{
char *eq = grub_strchr (files[i], '=');
char *from, *to;
if (!eq)
{
from = files[i];
to = files[i];
}
else
{
*eq = '\0';
to = files[i];
from = eq + 1;
}
while (*to == '/')
to++;
add_tar_file (from, to);
}
write_zeros (512);
fclose (memdisk);
grub_util_unlink_recursive (memdisk_dir);
grub_install_push_module ("memdisk");
grub_install_push_module ("tar");
grub_install_make_image_wrap (grub_install_source_directory,
"(memdisk)/boot/grub", output_image,
memdisk_img, NULL,
grub_util_get_target_name (format), 0);
grub_util_unlink (memdisk_img);
return 0;
}
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