grub/grub-core/partmap/msdos.c
Colin Watson e3c78337c3 * include/grub/partition.h (grub_partition_map): Change prototype of
embed to take a maximum value for nsectors.
	* include/grub/emu/hostdisk.h (grub_util_ldm_embed): Likewise.
	* include/grub/fs.h (grub_fs): Likewise.
	* grub-core/partmap/msdos.c (embed_signatures): New array.
	(pc_partition_map_embed): Check for and avoid sectors matching any
	of the signatures in embed_signatures, up to max_nsectors.
	* grub-core/partmap/gpt.c (gpt_partition_map_embed): Restrict
	returned sector map to max_nsectors.
	* grub-core/disk/ldm.c (grub_util_ldm_embed): Likewise.
	* grub-core/fs/btrfs.c (grub_btrfs_embed): Likewise.
	* grub-core/fs/zfs/zfs.c (grub_zfs_embed): Likewise.
	* util/grub-setup.c (setup): Allow for the embedding area being
	split into multiple blocklists.  Tell dest_partmap->embed the
	maximum number of sectors we care about.
2012-02-27 22:25:39 +01:00

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/* pc.c - Read PC style partition tables. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2002,2004,2005,2006,2007,2008,2009 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/>.
*/
#include <grub/partition.h>
#include <grub/msdos_partition.h>
#include <grub/disk.h>
#include <grub/mm.h>
#include <grub/misc.h>
#include <grub/dl.h>
#include <grub/i18n.h>
GRUB_MOD_LICENSE ("GPLv3+");
static struct grub_partition_map grub_msdos_partition_map;
#ifdef GRUB_UTIL
#include <grub/emu/misc.h>
struct embed_signature
{
const char *name;
const char *signature;
int signature_len;
enum { TYPE_SOFTWARE, TYPE_RAID } type;
};
const char message_warn[][200] = {
[TYPE_RAID] = N_("Sector %llu is already in use by %s; avoiding it. "
"Please ask the manufacturer not to store data in MBR gap"),
[TYPE_SOFTWARE] = N_("Sector %llu is already in use by %s; avoiding it. "
"This software may cause boot or other problems in "
"future. Please ask its authors not to store data "
"in the boot track")
};
/* Signatures of other software that may be using sectors in the embedding
area. */
struct embed_signature embed_signatures[] =
{
{
.name = "ZISD",
.signature = "ZISD",
.signature_len = 4,
.type = TYPE_SOFTWARE
},
{
.name = "FlexNet",
.signature = "\xd4\x41\xa0\xf5\x03\x00\x03\x00",
.signature_len = 8,
.type = TYPE_SOFTWARE
},
{
.name = "FlexNet",
.signature = "\xd8\x41\xa0\xf5\x02\x00\x02\x00",
.signature_len = 8,
.type = TYPE_SOFTWARE
},
{
/* from Ryan Perkins */
.name = "HP Backup and Recovery Manager (?)",
.signature = "\x70\x8a\x5d\x46\x35\xc5\x1b\x93"
"\xae\x3d\x86\xfd\xb1\x55\x3e\xe0",
.signature_len = 16,
.type = TYPE_SOFTWARE
},
{
.name = "HighPoint RAID controller",
.signature = "ycgl",
.signature_len = 4,
.type = TYPE_RAID
}
};
#endif
grub_err_t
grub_partition_msdos_iterate (grub_disk_t disk,
int (*hook) (grub_disk_t disk,
const grub_partition_t partition))
{
struct grub_partition p;
struct grub_msdos_partition_mbr mbr;
int labeln = 0;
grub_disk_addr_t lastaddr;
grub_disk_addr_t ext_offset;
grub_disk_addr_t delta = 0;
if (disk->partition && disk->partition->partmap == &grub_msdos_partition_map)
{
if (disk->partition->msdostype == GRUB_PC_PARTITION_TYPE_LINUX_MINIX)
delta = disk->partition->start;
else
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no embedding supported");
}
p.offset = 0;
ext_offset = 0;
p.number = -1;
p.partmap = &grub_msdos_partition_map;
/* Any value different than `p.offset' will satisfy the check during
first loop. */
lastaddr = !p.offset;
while (1)
{
int i;
struct grub_msdos_partition_entry *e;
/* Read the MBR. */
if (grub_disk_read (disk, p.offset, 0, sizeof (mbr), &mbr))
goto finish;
/* This is our loop-detection algorithm. It works the following way:
It saves last position which was a power of two. Then it compares the
saved value with a current one. This way it's guaranteed that the loop
will be broken by at most third walk.
*/
if (labeln && lastaddr == p.offset)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "loop detected");
labeln++;
if ((labeln & (labeln - 1)) == 0)
lastaddr = p.offset;
/* Check if it is valid. */
if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
for (i = 0; i < 4; i++)
if (mbr.entries[i].flag & 0x7f)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "bad boot flag");
/* Analyze DOS partitions. */
for (p.index = 0; p.index < 4; p.index++)
{
e = mbr.entries + p.index;
p.start = p.offset
+ (grub_le_to_cpu32 (e->start)
<< (disk->log_sector_size - GRUB_DISK_SECTOR_BITS)) - delta;
p.len = grub_le_to_cpu32 (e->length)
<< (disk->log_sector_size - GRUB_DISK_SECTOR_BITS);
p.msdostype = e->type;
grub_dprintf ("partition",
"partition %d: flag 0x%x, type 0x%x, start 0x%llx, len 0x%llx\n",
p.index, e->flag, e->type,
(unsigned long long) p.start,
(unsigned long long) p.len);
/* If this is a GPT partition, this MBR is just a dummy. */
if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && p.index == 0)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
/* If this partition is a normal one, call the hook. */
if (! grub_msdos_partition_is_empty (e->type)
&& ! grub_msdos_partition_is_extended (e->type))
{
p.number++;
if (hook (disk, &p))
return grub_errno;
}
else if (p.number < 4)
/* If this partition is a logical one, shouldn't increase the
partition number. */
p.number++;
}
/* Find an extended partition. */
for (i = 0; i < 4; i++)
{
e = mbr.entries + i;
if (grub_msdos_partition_is_extended (e->type))
{
p.offset = ext_offset
+ (grub_le_to_cpu32 (e->start)
<< (disk->log_sector_size - GRUB_DISK_SECTOR_BITS));
if (! ext_offset)
ext_offset = p.offset;
break;
}
}
/* If no extended partition, the end. */
if (i == 4)
break;
}
finish:
return grub_errno;
}
#ifdef GRUB_UTIL
static grub_err_t
pc_partition_map_embed (struct grub_disk *disk, unsigned int *nsectors,
unsigned int max_nsectors,
grub_embed_type_t embed_type,
grub_disk_addr_t **sectors)
{
grub_disk_addr_t end = ~0ULL;
struct grub_msdos_partition_mbr mbr;
int labeln = 0;
/* Any value different than `p.offset' will satisfy the check during
first loop. */
grub_disk_addr_t lastaddr = 1;
grub_disk_addr_t ext_offset = 0;
grub_disk_addr_t offset = 0;
if (embed_type != GRUB_EMBED_PCBIOS)
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
"PC-style partitions curently support "
"only PC-BIOS embedding");
if (disk->partition)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
"Embedding on MSDOS subpartition isn't supported");
while (1)
{
int i;
struct grub_msdos_partition_entry *e;
grub_err_t err;
/* Read the MBR. */
err = grub_disk_read (disk, offset, 0, sizeof (mbr), &mbr);
if (err)
return err;
/* This is our loop-detection algorithm. It works the following way:
It saves last position which was a power of two. Then it compares the
saved value with a current one. This way it's guaranteed that the loop
will be broken by at most third walk.
*/
if (labeln && lastaddr == offset)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "loop detected");
labeln++;
if ((labeln & (labeln - 1)) == 0)
lastaddr = offset;
/* Check if it is valid. */
if (mbr.signature != grub_cpu_to_le16 (GRUB_PC_PARTITION_SIGNATURE))
return grub_error (GRUB_ERR_BAD_PART_TABLE, "no signature");
for (i = 0; i < 4; i++)
if (mbr.entries[i].flag & 0x7f)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "bad boot flag");
/* Analyze DOS partitions. */
for (i = 0; i < 4; i++)
{
e = mbr.entries + i;
if (!grub_msdos_partition_is_empty (e->type)
&& end > offset
+ (grub_le_to_cpu32 (e->start)
<< (disk->log_sector_size - GRUB_DISK_SECTOR_BITS)))
end = offset + (grub_le_to_cpu32 (e->start)
<< (disk->log_sector_size - GRUB_DISK_SECTOR_BITS));
/* If this is a GPT partition, this MBR is just a dummy. */
if (e->type == GRUB_PC_PARTITION_TYPE_GPT_DISK && i == 0)
return grub_error (GRUB_ERR_BAD_PART_TABLE, "dummy mbr");
}
/* Find an extended partition. */
for (i = 0; i < 4; i++)
{
e = mbr.entries + i;
if (grub_msdos_partition_is_extended (e->type))
{
offset = ext_offset
+ (grub_le_to_cpu32 (e->start)
<< (disk->log_sector_size - GRUB_DISK_SECTOR_BITS));
if (! ext_offset)
ext_offset = offset;
break;
}
}
/* If no extended partition, the end. */
if (i == 4)
break;
}
if (end >= *nsectors + 2)
{
unsigned i, j;
char *embed_signature_check;
unsigned int orig_nsectors, avail_nsectors;
orig_nsectors = *nsectors;
*nsectors = end - 2;
avail_nsectors = *nsectors;
if (*nsectors > max_nsectors)
*nsectors = max_nsectors;
*sectors = grub_malloc (*nsectors * sizeof (**sectors));
if (!*sectors)
return grub_errno;
for (i = 0; i < *nsectors; i++)
(*sectors)[i] = 1 + i;
/* Check for software that is already using parts of the embedding
* area.
*/
embed_signature_check = grub_malloc (GRUB_DISK_SECTOR_SIZE);
for (i = 0; i < *nsectors; i++)
{
if (grub_disk_read (disk, (*sectors)[i], 0, GRUB_DISK_SECTOR_SIZE,
embed_signature_check))
continue;
for (j = 0; j < ARRAY_SIZE (embed_signatures); j++)
if (! grub_memcmp (embed_signatures[j].signature,
embed_signature_check,
embed_signatures[j].signature_len))
break;
if (j == ARRAY_SIZE (embed_signatures))
continue;
grub_util_warn (_(message_warn[embed_signatures[j].type]),
(*sectors)[i], embed_signatures[j].name);
avail_nsectors--;
if (avail_nsectors < *nsectors)
*nsectors = avail_nsectors;
/* Avoid this sector. */
for (j = i; j < *nsectors; j++)
(*sectors)[j]++;
/* Have we run out of space? */
if (avail_nsectors < orig_nsectors)
break;
/* Make sure to check the next sector. */
i--;
}
grub_free (embed_signature_check);
if (*nsectors < orig_nsectors)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("other software is using the embedding area, and "
"there is not enough room for core.img. Such "
"software is often trying to store data in a way "
"that avoids detection. We recommend you "
"investigate"));
return GRUB_ERR_NONE;
}
if (end <= 1)
return grub_error (GRUB_ERR_FILE_NOT_FOUND,
N_("this msdos-style partition label has no "
"post-MBR gap; embedding won't be possible"));
if (*nsectors > 62)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("your core.img is unusually large. "
"It won't fit in the embedding area"));
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("your embedding area is unusually small. "
"core.img won't fit in it."));
}
#endif
/* Partition map type. */
static struct grub_partition_map grub_msdos_partition_map =
{
.name = "msdos",
.iterate = grub_partition_msdos_iterate,
#ifdef GRUB_UTIL
.embed = pc_partition_map_embed
#endif
};
GRUB_MOD_INIT(part_msdos)
{
grub_partition_map_register (&grub_msdos_partition_map);
}
GRUB_MOD_FINI(part_msdos)
{
grub_partition_map_unregister (&grub_msdos_partition_map);
}