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linux-next/block/partitions/atari.c
Gabriel Krisman Bertazi 9c8747167e block: atari: Return early for unsupported sector size
For 4K LBA or very large disks, atari_partition can easily get tricked
into thinking it has found an Atari partition table.  Depending on the
data in the disk, it ends up creating partitions with awkward lengths.

We saw logs like this while playing with fio.

[5.625867] nvme2n1: AHDI p2
[5.625872] nvme2n1: p2 size 2910030523 extends beyond EOD, truncated

People has had issues with misinterpreted AHDI partition tables for a long
time, see this BSD thread from 1995, for example.

https://mail-index.netbsd.org/port-atari/1995/11/19/0001.html

Since the atari partition, according to the spec, doesn't even support
sector sizes with more than 512, a quick sanity check is reasonable to
just bail out early, before even attempting to read sector 0.

Signed-off-by: Gabriel Krisman Bertazi <krisman@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-07-13 09:31:44 -07:00

157 lines
4.1 KiB
C

/*
* fs/partitions/atari.c
*
* Code extracted from drivers/block/genhd.c
*
* Copyright (C) 1991-1998 Linus Torvalds
* Re-organised Feb 1998 Russell King
*/
#include <linux/ctype.h>
#include "check.h"
#include "atari.h"
/* ++guenther: this should be settable by the user ("make config")?.
*/
#define ICD_PARTS
/* check if a partition entry looks valid -- Atari format is assumed if at
least one of the primary entries is ok this way */
#define VALID_PARTITION(pi,hdsiz) \
(((pi)->flg & 1) && \
isalnum((pi)->id[0]) && isalnum((pi)->id[1]) && isalnum((pi)->id[2]) && \
be32_to_cpu((pi)->st) <= (hdsiz) && \
be32_to_cpu((pi)->st) + be32_to_cpu((pi)->siz) <= (hdsiz))
static inline int OK_id(char *s)
{
return memcmp (s, "GEM", 3) == 0 || memcmp (s, "BGM", 3) == 0 ||
memcmp (s, "LNX", 3) == 0 || memcmp (s, "SWP", 3) == 0 ||
memcmp (s, "RAW", 3) == 0 ;
}
int atari_partition(struct parsed_partitions *state)
{
Sector sect;
struct rootsector *rs;
struct partition_info *pi;
u32 extensect;
u32 hd_size;
int slot;
#ifdef ICD_PARTS
int part_fmt = 0; /* 0:unknown, 1:AHDI, 2:ICD/Supra */
#endif
/*
* ATARI partition scheme supports 512 lba only. If this is not
* the case, bail early to avoid miscalculating hd_size.
*/
if (bdev_logical_block_size(state->bdev) != 512)
return 0;
rs = read_part_sector(state, 0, &sect);
if (!rs)
return -1;
/* Verify this is an Atari rootsector: */
hd_size = state->bdev->bd_inode->i_size >> 9;
if (!VALID_PARTITION(&rs->part[0], hd_size) &&
!VALID_PARTITION(&rs->part[1], hd_size) &&
!VALID_PARTITION(&rs->part[2], hd_size) &&
!VALID_PARTITION(&rs->part[3], hd_size)) {
/*
* if there's no valid primary partition, assume that no Atari
* format partition table (there's no reliable magic or the like
* :-()
*/
put_dev_sector(sect);
return 0;
}
pi = &rs->part[0];
strlcat(state->pp_buf, " AHDI", PAGE_SIZE);
for (slot = 1; pi < &rs->part[4] && slot < state->limit; slot++, pi++) {
struct rootsector *xrs;
Sector sect2;
ulong partsect;
if ( !(pi->flg & 1) )
continue;
/* active partition */
if (memcmp (pi->id, "XGM", 3) != 0) {
/* we don't care about other id's */
put_partition (state, slot, be32_to_cpu(pi->st),
be32_to_cpu(pi->siz));
continue;
}
/* extension partition */
#ifdef ICD_PARTS
part_fmt = 1;
#endif
strlcat(state->pp_buf, " XGM<", PAGE_SIZE);
partsect = extensect = be32_to_cpu(pi->st);
while (1) {
xrs = read_part_sector(state, partsect, &sect2);
if (!xrs) {
printk (" block %ld read failed\n", partsect);
put_dev_sector(sect);
return -1;
}
/* ++roman: sanity check: bit 0 of flg field must be set */
if (!(xrs->part[0].flg & 1)) {
printk( "\nFirst sub-partition in extended partition is not valid!\n" );
put_dev_sector(sect2);
break;
}
put_partition(state, slot,
partsect + be32_to_cpu(xrs->part[0].st),
be32_to_cpu(xrs->part[0].siz));
if (!(xrs->part[1].flg & 1)) {
/* end of linked partition list */
put_dev_sector(sect2);
break;
}
if (memcmp( xrs->part[1].id, "XGM", 3 ) != 0) {
printk("\nID of extended partition is not XGM!\n");
put_dev_sector(sect2);
break;
}
partsect = be32_to_cpu(xrs->part[1].st) + extensect;
put_dev_sector(sect2);
if (++slot == state->limit) {
printk( "\nMaximum number of partitions reached!\n" );
break;
}
}
strlcat(state->pp_buf, " >", PAGE_SIZE);
}
#ifdef ICD_PARTS
if ( part_fmt!=1 ) { /* no extended partitions -> test ICD-format */
pi = &rs->icdpart[0];
/* sanity check: no ICD format if first partition invalid */
if (OK_id(pi->id)) {
strlcat(state->pp_buf, " ICD<", PAGE_SIZE);
for (; pi < &rs->icdpart[8] && slot < state->limit; slot++, pi++) {
/* accept only GEM,BGM,RAW,LNX,SWP partitions */
if (!((pi->flg & 1) && OK_id(pi->id)))
continue;
part_fmt = 2;
put_partition (state, slot,
be32_to_cpu(pi->st),
be32_to_cpu(pi->siz));
}
strlcat(state->pp_buf, " >", PAGE_SIZE);
}
}
#endif
put_dev_sector(sect);
strlcat(state->pp_buf, "\n", PAGE_SIZE);
return 1;
}