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linux/fs/udf/truncate.c
Steve Magnani b490bdd630 udf: Fix 64-bit sign extension issues affecting blocks > 0x7FFFFFFF 
Large (> 1 TiB) UDF filesystems appear subject to several problems when
mounted on 64-bit systems:

* readdir() can fail on a directory containing File Identifiers residing
  above 0x7FFFFFFF. This manifests as a 'ls' command failing with EIO.

* FIBMAP on a file block located above 0x7FFFFFFF can return a negative
  value. The low 32 bits are correct, but applications that don't mask the
  high 32 bits of the result can perform incorrectly.

Per suggestion by Jan Kara, introduce a udf_pblk_t type for representation
of UDF block addresses. Ultimately, all driver functions that manipulate
UDF block addresses should use this type; for now, deployment is limited
to functions with actual or potential sign extension issues.

Changes to udf_readdir() and udf_block_map() address the issues noted
above; other changes address potential similar issues uncovered during
audit of the driver code.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2017-10-17 11:56:45 +02:00

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/*
* truncate.c
*
* PURPOSE
* Truncate handling routines for the OSTA-UDF(tm) filesystem.
*
* COPYRIGHT
* This file is distributed under the terms of the GNU General Public
* License (GPL). Copies of the GPL can be obtained from:
* ftp://prep.ai.mit.edu/pub/gnu/GPL
* Each contributing author retains all rights to their own work.
*
* (C) 1999-2004 Ben Fennema
* (C) 1999 Stelias Computing Inc
*
* HISTORY
*
* 02/24/99 blf Created.
*
*/
#include "udfdecl.h"
#include <linux/fs.h>
#include <linux/mm.h>
#include "udf_i.h"
#include "udf_sb.h"
static void extent_trunc(struct inode *inode, struct extent_position *epos,
struct kernel_lb_addr *eloc, int8_t etype, uint32_t elen,
uint32_t nelen)
{
struct kernel_lb_addr neloc = {};
int last_block = (elen + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
int first_block = (nelen + inode->i_sb->s_blocksize - 1) >>
inode->i_sb->s_blocksize_bits;
if (nelen) {
if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
udf_free_blocks(inode->i_sb, inode, eloc, 0,
last_block);
etype = (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30);
} else
neloc = *eloc;
nelen = (etype << 30) | nelen;
}
if (elen != nelen) {
udf_write_aext(inode, epos, &neloc, nelen, 0);
if (last_block > first_block) {
if (etype == (EXT_RECORDED_ALLOCATED >> 30))
mark_inode_dirty(inode);
if (etype != (EXT_NOT_RECORDED_NOT_ALLOCATED >> 30))
udf_free_blocks(inode->i_sb, inode, eloc,
first_block,
last_block - first_block);
}
}
}
/*
* Truncate the last extent to match i_size. This function assumes
* that preallocation extent is already truncated.
*/
void udf_truncate_tail_extent(struct inode *inode)
{
struct extent_position epos = {};
struct kernel_lb_addr eloc;
uint32_t elen, nelen;
uint64_t lbcount = 0;
int8_t etype = -1, netype;
int adsize;
struct udf_inode_info *iinfo = UDF_I(inode);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
inode->i_size == iinfo->i_lenExtents)
return;
/* Are we going to delete the file anyway? */
if (inode->i_nlink == 0)
return;
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
adsize = sizeof(struct short_ad);
else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
adsize = sizeof(struct long_ad);
else
BUG();
/* Find the last extent in the file */
while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
etype = netype;
lbcount += elen;
if (lbcount > inode->i_size) {
if (lbcount - inode->i_size >= inode->i_sb->s_blocksize)
udf_warn(inode->i_sb,
"Too long extent after EOF in inode %u: i_size: %lld lbcount: %lld extent %u+%u\n",
(unsigned)inode->i_ino,
(long long)inode->i_size,
(long long)lbcount,
(unsigned)eloc.logicalBlockNum,
(unsigned)elen);
nelen = elen - (lbcount - inode->i_size);
epos.offset -= adsize;
extent_trunc(inode, &epos, &eloc, etype, elen, nelen);
epos.offset += adsize;
if (udf_next_aext(inode, &epos, &eloc, &elen, 1) != -1)
udf_err(inode->i_sb,
"Extent after EOF in inode %u\n",
(unsigned)inode->i_ino);
break;
}
}
/* This inode entry is in-memory only and thus we don't have to mark
* the inode dirty */
iinfo->i_lenExtents = inode->i_size;
brelse(epos.bh);
}
void udf_discard_prealloc(struct inode *inode)
{
struct extent_position epos = { NULL, 0, {0, 0} };
struct kernel_lb_addr eloc;
uint32_t elen;
uint64_t lbcount = 0;
int8_t etype = -1, netype;
int adsize;
struct udf_inode_info *iinfo = UDF_I(inode);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB ||
inode->i_size == iinfo->i_lenExtents)
return;
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
adsize = sizeof(struct short_ad);
else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
adsize = sizeof(struct long_ad);
else
adsize = 0;
epos.block = iinfo->i_location;
/* Find the last extent in the file */
while ((netype = udf_next_aext(inode, &epos, &eloc, &elen, 1)) != -1) {
etype = netype;
lbcount += elen;
}
if (etype == (EXT_NOT_RECORDED_ALLOCATED >> 30)) {
epos.offset -= adsize;
lbcount -= elen;
extent_trunc(inode, &epos, &eloc, etype, elen, 0);
if (!epos.bh) {
iinfo->i_lenAlloc =
epos.offset -
udf_file_entry_alloc_offset(inode);
mark_inode_dirty(inode);
} else {
struct allocExtDesc *aed =
(struct allocExtDesc *)(epos.bh->b_data);
aed->lengthAllocDescs =
cpu_to_le32(epos.offset -
sizeof(struct allocExtDesc));
if (!UDF_QUERY_FLAG(inode->i_sb, UDF_FLAG_STRICT) ||
UDF_SB(inode->i_sb)->s_udfrev >= 0x0201)
udf_update_tag(epos.bh->b_data, epos.offset);
else
udf_update_tag(epos.bh->b_data,
sizeof(struct allocExtDesc));
mark_buffer_dirty_inode(epos.bh, inode);
}
}
/* This inode entry is in-memory only and thus we don't have to mark
* the inode dirty */
iinfo->i_lenExtents = lbcount;
brelse(epos.bh);
}
static void udf_update_alloc_ext_desc(struct inode *inode,
struct extent_position *epos,
u32 lenalloc)
{
struct super_block *sb = inode->i_sb;
struct udf_sb_info *sbi = UDF_SB(sb);
struct allocExtDesc *aed = (struct allocExtDesc *) (epos->bh->b_data);
int len = sizeof(struct allocExtDesc);
aed->lengthAllocDescs = cpu_to_le32(lenalloc);
if (!UDF_QUERY_FLAG(sb, UDF_FLAG_STRICT) || sbi->s_udfrev >= 0x0201)
len += lenalloc;
udf_update_tag(epos->bh->b_data, len);
mark_buffer_dirty_inode(epos->bh, inode);
}
/*
* Truncate extents of inode to inode->i_size. This function can be used only
* for making file shorter. For making file longer, udf_extend_file() has to
* be used.
*/
void udf_truncate_extents(struct inode *inode)
{
struct extent_position epos;
struct kernel_lb_addr eloc, neloc = {};
uint32_t elen, nelen = 0, indirect_ext_len = 0, lenalloc;
int8_t etype;
struct super_block *sb = inode->i_sb;
sector_t first_block = inode->i_size >> sb->s_blocksize_bits, offset;
loff_t byte_offset;
int adsize;
struct udf_inode_info *iinfo = UDF_I(inode);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
adsize = sizeof(struct short_ad);
else if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_LONG)
adsize = sizeof(struct long_ad);
else
BUG();
etype = inode_bmap(inode, first_block, &epos, &eloc, &elen, &offset);
byte_offset = (offset << sb->s_blocksize_bits) +
(inode->i_size & (sb->s_blocksize - 1));
if (etype == -1) {
/* We should extend the file? */
WARN_ON(byte_offset);
return;
}
epos.offset -= adsize;
extent_trunc(inode, &epos, &eloc, etype, elen, byte_offset);
epos.offset += adsize;
if (byte_offset)
lenalloc = epos.offset;
else
lenalloc = epos.offset - adsize;
if (!epos.bh)
lenalloc -= udf_file_entry_alloc_offset(inode);
else
lenalloc -= sizeof(struct allocExtDesc);
while ((etype = udf_current_aext(inode, &epos, &eloc,
&elen, 0)) != -1) {
if (etype == (EXT_NEXT_EXTENT_ALLOCDECS >> 30)) {
udf_write_aext(inode, &epos, &neloc, nelen, 0);
if (indirect_ext_len) {
/* We managed to free all extents in the
* indirect extent - free it too */
BUG_ON(!epos.bh);
udf_free_blocks(sb, NULL, &epos.block,
0, indirect_ext_len);
} else if (!epos.bh) {
iinfo->i_lenAlloc = lenalloc;
mark_inode_dirty(inode);
} else
udf_update_alloc_ext_desc(inode,
&epos, lenalloc);
brelse(epos.bh);
epos.offset = sizeof(struct allocExtDesc);
epos.block = eloc;
epos.bh = udf_tread(sb,
udf_get_lb_pblock(sb, &eloc, 0));
if (elen)
indirect_ext_len =
(elen + sb->s_blocksize - 1) >>
sb->s_blocksize_bits;
else
indirect_ext_len = 1;
} else {
extent_trunc(inode, &epos, &eloc, etype, elen, 0);
epos.offset += adsize;
}
}
if (indirect_ext_len) {
BUG_ON(!epos.bh);
udf_free_blocks(sb, NULL, &epos.block, 0, indirect_ext_len);
} else if (!epos.bh) {
iinfo->i_lenAlloc = lenalloc;
mark_inode_dirty(inode);
} else
udf_update_alloc_ext_desc(inode, &epos, lenalloc);
iinfo->i_lenExtents = inode->i_size;
brelse(epos.bh);
}
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