linux/fs/hfsplus/wrapper.c
Janne Kalliomäki a6dc8c0421 hfsplus: fix overflow in sector calculations in hfsplus_submit_bio
The variable io_size was unsigned int, which caused the wrong sector number
to be calculated after aligning it. This then caused mount to fail with big
volumes, as backup volume header information was searched from a
wrong sector.

Signed-off-by: Janne Kalliomäki <janne@tuxera.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-06-17 14:39:45 -07:00

281 lines
7.2 KiB
C

/*
* linux/fs/hfsplus/wrapper.c
*
* Copyright (C) 2001
* Brad Boyer (flar@allandria.com)
* (C) 2003 Ardis Technologies <roman@ardistech.com>
*
* Handling of HFS wrappers around HFS+ volumes
*/
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/cdrom.h>
#include <linux/genhd.h>
#include <asm/unaligned.h>
#include "hfsplus_fs.h"
#include "hfsplus_raw.h"
struct hfsplus_wd {
u32 ablk_size;
u16 ablk_start;
u16 embed_start;
u16 embed_count;
};
static void hfsplus_end_io_sync(struct bio *bio, int err)
{
if (err)
clear_bit(BIO_UPTODATE, &bio->bi_flags);
complete(bio->bi_private);
}
/*
* hfsplus_submit_bio - Perfrom block I/O
* @sb: super block of volume for I/O
* @sector: block to read or write, for blocks of HFSPLUS_SECTOR_SIZE bytes
* @buf: buffer for I/O
* @data: output pointer for location of requested data
* @rw: direction of I/O
*
* The unit of I/O is hfsplus_min_io_size(sb), which may be bigger than
* HFSPLUS_SECTOR_SIZE, and @buf must be sized accordingly. On reads
* @data will return a pointer to the start of the requested sector,
* which may not be the same location as @buf.
*
* If @sector is not aligned to the bdev logical block size it will
* be rounded down. For writes this means that @buf should contain data
* that starts at the rounded-down address. As long as the data was
* read using hfsplus_submit_bio() and the same buffer is used things
* will work correctly.
*/
int hfsplus_submit_bio(struct super_block *sb, sector_t sector,
void *buf, void **data, int rw)
{
DECLARE_COMPLETION_ONSTACK(wait);
struct bio *bio;
int ret = 0;
u64 io_size;
loff_t start;
int offset;
/*
* Align sector to hardware sector size and find offset. We
* assume that io_size is a power of two, which _should_
* be true.
*/
io_size = hfsplus_min_io_size(sb);
start = (loff_t)sector << HFSPLUS_SECTOR_SHIFT;
offset = start & (io_size - 1);
sector &= ~((io_size >> HFSPLUS_SECTOR_SHIFT) - 1);
bio = bio_alloc(GFP_NOIO, 1);
bio->bi_sector = sector;
bio->bi_bdev = sb->s_bdev;
bio->bi_end_io = hfsplus_end_io_sync;
bio->bi_private = &wait;
if (!(rw & WRITE) && data)
*data = (u8 *)buf + offset;
while (io_size > 0) {
unsigned int page_offset = offset_in_page(buf);
unsigned int len = min_t(unsigned int, PAGE_SIZE - page_offset,
io_size);
ret = bio_add_page(bio, virt_to_page(buf), len, page_offset);
if (ret != len) {
ret = -EIO;
goto out;
}
io_size -= len;
buf = (u8 *)buf + len;
}
submit_bio(rw, bio);
wait_for_completion(&wait);
if (!bio_flagged(bio, BIO_UPTODATE))
ret = -EIO;
out:
bio_put(bio);
return ret < 0 ? ret : 0;
}
static int hfsplus_read_mdb(void *bufptr, struct hfsplus_wd *wd)
{
u32 extent;
u16 attrib;
__be16 sig;
sig = *(__be16 *)(bufptr + HFSP_WRAPOFF_EMBEDSIG);
if (sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIG) &&
sig != cpu_to_be16(HFSPLUS_VOLHEAD_SIGX))
return 0;
attrib = be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ATTRIB));
if (!(attrib & HFSP_WRAP_ATTRIB_SLOCK) ||
!(attrib & HFSP_WRAP_ATTRIB_SPARED))
return 0;
wd->ablk_size =
be32_to_cpu(*(__be32 *)(bufptr + HFSP_WRAPOFF_ABLKSIZE));
if (wd->ablk_size < HFSPLUS_SECTOR_SIZE)
return 0;
if (wd->ablk_size % HFSPLUS_SECTOR_SIZE)
return 0;
wd->ablk_start =
be16_to_cpu(*(__be16 *)(bufptr + HFSP_WRAPOFF_ABLKSTART));
extent = get_unaligned_be32(bufptr + HFSP_WRAPOFF_EMBEDEXT);
wd->embed_start = (extent >> 16) & 0xFFFF;
wd->embed_count = extent & 0xFFFF;
return 1;
}
static int hfsplus_get_last_session(struct super_block *sb,
sector_t *start, sector_t *size)
{
struct cdrom_multisession ms_info;
struct cdrom_tocentry te;
int res;
/* default values */
*start = 0;
*size = sb->s_bdev->bd_inode->i_size >> 9;
if (HFSPLUS_SB(sb)->session >= 0) {
te.cdte_track = HFSPLUS_SB(sb)->session;
te.cdte_format = CDROM_LBA;
res = ioctl_by_bdev(sb->s_bdev,
CDROMREADTOCENTRY, (unsigned long)&te);
if (!res && (te.cdte_ctrl & CDROM_DATA_TRACK) == 4) {
*start = (sector_t)te.cdte_addr.lba << 2;
return 0;
}
printk(KERN_ERR "hfs: invalid session number or type of track\n");
return -EINVAL;
}
ms_info.addr_format = CDROM_LBA;
res = ioctl_by_bdev(sb->s_bdev, CDROMMULTISESSION,
(unsigned long)&ms_info);
if (!res && ms_info.xa_flag)
*start = (sector_t)ms_info.addr.lba << 2;
return 0;
}
/* Find the volume header and fill in some minimum bits in superblock */
/* Takes in super block, returns true if good data read */
int hfsplus_read_wrapper(struct super_block *sb)
{
struct hfsplus_sb_info *sbi = HFSPLUS_SB(sb);
struct hfsplus_wd wd;
sector_t part_start, part_size;
u32 blocksize;
int error = 0;
error = -EINVAL;
blocksize = sb_min_blocksize(sb, HFSPLUS_SECTOR_SIZE);
if (!blocksize)
goto out;
if (hfsplus_get_last_session(sb, &part_start, &part_size))
goto out;
error = -ENOMEM;
sbi->s_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
if (!sbi->s_vhdr_buf)
goto out;
sbi->s_backup_vhdr_buf = kmalloc(hfsplus_min_io_size(sb), GFP_KERNEL);
if (!sbi->s_backup_vhdr_buf)
goto out_free_vhdr;
reread:
error = hfsplus_submit_bio(sb, part_start + HFSPLUS_VOLHEAD_SECTOR,
sbi->s_vhdr_buf, (void **)&sbi->s_vhdr,
READ);
if (error)
goto out_free_backup_vhdr;
error = -EINVAL;
switch (sbi->s_vhdr->signature) {
case cpu_to_be16(HFSPLUS_VOLHEAD_SIGX):
set_bit(HFSPLUS_SB_HFSX, &sbi->flags);
/*FALLTHRU*/
case cpu_to_be16(HFSPLUS_VOLHEAD_SIG):
break;
case cpu_to_be16(HFSP_WRAP_MAGIC):
if (!hfsplus_read_mdb(sbi->s_vhdr, &wd))
goto out_free_backup_vhdr;
wd.ablk_size >>= HFSPLUS_SECTOR_SHIFT;
part_start += (sector_t)wd.ablk_start +
(sector_t)wd.embed_start * wd.ablk_size;
part_size = (sector_t)wd.embed_count * wd.ablk_size;
goto reread;
default:
/*
* Check for a partition block.
*
* (should do this only for cdrom/loop though)
*/
if (hfs_part_find(sb, &part_start, &part_size))
goto out_free_backup_vhdr;
goto reread;
}
error = hfsplus_submit_bio(sb, part_start + part_size - 2,
sbi->s_backup_vhdr_buf,
(void **)&sbi->s_backup_vhdr, READ);
if (error)
goto out_free_backup_vhdr;
error = -EINVAL;
if (sbi->s_backup_vhdr->signature != sbi->s_vhdr->signature) {
printk(KERN_WARNING
"hfs: invalid secondary volume header\n");
goto out_free_backup_vhdr;
}
blocksize = be32_to_cpu(sbi->s_vhdr->blocksize);
/*
* Block size must be at least as large as a sector and a multiple of 2.
*/
if (blocksize < HFSPLUS_SECTOR_SIZE || ((blocksize - 1) & blocksize))
goto out_free_backup_vhdr;
sbi->alloc_blksz = blocksize;
sbi->alloc_blksz_shift = 0;
while ((blocksize >>= 1) != 0)
sbi->alloc_blksz_shift++;
blocksize = min(sbi->alloc_blksz, (u32)PAGE_SIZE);
/*
* Align block size to block offset.
*/
while (part_start & ((blocksize >> HFSPLUS_SECTOR_SHIFT) - 1))
blocksize >>= 1;
if (sb_set_blocksize(sb, blocksize) != blocksize) {
printk(KERN_ERR "hfs: unable to set blocksize to %u!\n",
blocksize);
goto out_free_backup_vhdr;
}
sbi->blockoffset =
part_start >> (sb->s_blocksize_bits - HFSPLUS_SECTOR_SHIFT);
sbi->part_start = part_start;
sbi->sect_count = part_size;
sbi->fs_shift = sbi->alloc_blksz_shift - sb->s_blocksize_bits;
return 0;
out_free_backup_vhdr:
kfree(sbi->s_backup_vhdr_buf);
out_free_vhdr:
kfree(sbi->s_vhdr_buf);
out:
return error;
}