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linux/fs/udf/misc.c
Jan Kara 101ee137d3 udf: Drop VARCONV support 
UDF was supporting a strange mode where the media was containing 7
blocks of unknown data for every 32 blocks of the filesystem. I have yet
to see the media that would need such conversion (maybe it comes from
packet writing times) and the conversions have been inconsistent in the
code. In particular any write will write to a wrong block and corrupt
the media. This is an indication and no user actually needs this so
let's just drop the support instead of trying to fix it.

Signed-off-by: Jan Kara <jack@suse.cz>
2023-01-26 16:46:32 +01:00

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/*
* misc.c
*
* PURPOSE
* Miscellaneous 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) 1998 Dave Boynton
* (C) 1998-2004 Ben Fennema
* (C) 1999-2000 Stelias Computing Inc
*
* HISTORY
*
* 04/19/99 blf partial support for reading/writing specific EA's
*/
#include "udfdecl.h"
#include <linux/fs.h>
#include <linux/string.h>
#include <linux/crc-itu-t.h>
#include "udf_i.h"
#include "udf_sb.h"
struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
uint32_t type, uint8_t loc)
{
uint8_t *ea = NULL, *ad = NULL;
int offset;
uint16_t crclen;
struct udf_inode_info *iinfo = UDF_I(inode);
ea = iinfo->i_data;
if (iinfo->i_lenEAttr) {
ad = iinfo->i_data + iinfo->i_lenEAttr;
} else {
ad = ea;
size += sizeof(struct extendedAttrHeaderDesc);
}
offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
iinfo->i_lenAlloc;
/* TODO - Check for FreeEASpace */
if (loc & 0x01 && offset >= size) {
struct extendedAttrHeaderDesc *eahd;
eahd = (struct extendedAttrHeaderDesc *)ea;
if (iinfo->i_lenAlloc)
memmove(&ad[size], ad, iinfo->i_lenAlloc);
if (iinfo->i_lenEAttr) {
/* check checksum/crc */
if (eahd->descTag.tagIdent !=
cpu_to_le16(TAG_IDENT_EAHD) ||
le32_to_cpu(eahd->descTag.tagLocation) !=
iinfo->i_location.logicalBlockNum)
return NULL;
} else {
struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
size -= sizeof(struct extendedAttrHeaderDesc);
iinfo->i_lenEAttr +=
sizeof(struct extendedAttrHeaderDesc);
eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
if (sbi->s_udfrev >= 0x0200)
eahd->descTag.descVersion = cpu_to_le16(3);
else
eahd->descTag.descVersion = cpu_to_le16(2);
eahd->descTag.tagSerialNum =
cpu_to_le16(sbi->s_serial_number);
eahd->descTag.tagLocation = cpu_to_le32(
iinfo->i_location.logicalBlockNum);
eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
}
offset = iinfo->i_lenEAttr;
if (type < 2048) {
if (le32_to_cpu(eahd->appAttrLocation) <
iinfo->i_lenEAttr) {
uint32_t aal =
le32_to_cpu(eahd->appAttrLocation);
memmove(&ea[offset - aal + size],
&ea[aal], offset - aal);
offset -= aal;
eahd->appAttrLocation =
cpu_to_le32(aal + size);
}
if (le32_to_cpu(eahd->impAttrLocation) <
iinfo->i_lenEAttr) {
uint32_t ial =
le32_to_cpu(eahd->impAttrLocation);
memmove(&ea[offset - ial + size],
&ea[ial], offset - ial);
offset -= ial;
eahd->impAttrLocation =
cpu_to_le32(ial + size);
}
} else if (type < 65536) {
if (le32_to_cpu(eahd->appAttrLocation) <
iinfo->i_lenEAttr) {
uint32_t aal =
le32_to_cpu(eahd->appAttrLocation);
memmove(&ea[offset - aal + size],
&ea[aal], offset - aal);
offset -= aal;
eahd->appAttrLocation =
cpu_to_le32(aal + size);
}
}
/* rewrite CRC + checksum of eahd */
crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);
eahd->descTag.descCRCLength = cpu_to_le16(crclen);
eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
sizeof(struct tag), crclen));
eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
iinfo->i_lenEAttr += size;
return (struct genericFormat *)&ea[offset];
}
return NULL;
}
struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
uint8_t subtype)
{
struct genericFormat *gaf;
uint8_t *ea = NULL;
uint32_t offset;
struct udf_inode_info *iinfo = UDF_I(inode);
ea = iinfo->i_data;
if (iinfo->i_lenEAttr) {
struct extendedAttrHeaderDesc *eahd;
eahd = (struct extendedAttrHeaderDesc *)ea;
/* check checksum/crc */
if (eahd->descTag.tagIdent !=
cpu_to_le16(TAG_IDENT_EAHD) ||
le32_to_cpu(eahd->descTag.tagLocation) !=
iinfo->i_location.logicalBlockNum)
return NULL;
if (type < 2048)
offset = sizeof(struct extendedAttrHeaderDesc);
else if (type < 65536)
offset = le32_to_cpu(eahd->impAttrLocation);
else
offset = le32_to_cpu(eahd->appAttrLocation);
while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) {
uint32_t attrLength;
gaf = (struct genericFormat *)&ea[offset];
attrLength = le32_to_cpu(gaf->attrLength);
/* Detect undersized elements and buffer overflows */
if ((attrLength < sizeof(*gaf)) ||
(attrLength > (iinfo->i_lenEAttr - offset)))
break;
if (le32_to_cpu(gaf->attrType) == type &&
gaf->attrSubtype == subtype)
return gaf;
else
offset += attrLength;
}
}
return NULL;
}
/*
* udf_read_tagged
*
* PURPOSE
* Read the first block of a tagged descriptor.
*
* HISTORY
* July 1, 1997 - Andrew E. Mileski
* Written, tested, and released.
*/
struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
uint32_t location, uint16_t *ident)
{
struct tag *tag_p;
struct buffer_head *bh = NULL;
u8 checksum;
/* Read the block */
if (block == 0xFFFFFFFF)
return NULL;
bh = sb_bread(sb, block);
if (!bh) {
udf_err(sb, "read failed, block=%u, location=%u\n",
block, location);
return NULL;
}
tag_p = (struct tag *)(bh->b_data);
*ident = le16_to_cpu(tag_p->tagIdent);
if (location != le32_to_cpu(tag_p->tagLocation)) {
udf_debug("location mismatch block %u, tag %u != %u\n",
block, le32_to_cpu(tag_p->tagLocation), location);
goto error_out;
}
/* Verify the tag checksum */
checksum = udf_tag_checksum(tag_p);
if (checksum != tag_p->tagChecksum) {
udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
block, checksum, tag_p->tagChecksum);
goto error_out;
}
/* Verify the tag version */
if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
tag_p->descVersion != cpu_to_le16(0x0003U)) {
udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
le16_to_cpu(tag_p->descVersion), block);
goto error_out;
}
/* Verify the descriptor CRC */
if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
bh->b_data + sizeof(struct tag),
le16_to_cpu(tag_p->descCRCLength)))
return bh;
udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block,
le16_to_cpu(tag_p->descCRC),
le16_to_cpu(tag_p->descCRCLength));
error_out:
brelse(bh);
return NULL;
}
struct buffer_head *udf_read_ptagged(struct super_block *sb,
struct kernel_lb_addr *loc,
uint32_t offset, uint16_t *ident)
{
return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
loc->logicalBlockNum + offset, ident);
}
void udf_update_tag(char *data, int length)
{
struct tag *tptr = (struct tag *)data;
length -= sizeof(struct tag);
tptr->descCRCLength = cpu_to_le16(length);
tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
tptr->tagChecksum = udf_tag_checksum(tptr);
}
void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
uint32_t loc, int length)
{
struct tag *tptr = (struct tag *)data;
tptr->tagIdent = cpu_to_le16(ident);
tptr->descVersion = cpu_to_le16(version);
tptr->tagSerialNum = cpu_to_le16(snum);
tptr->tagLocation = cpu_to_le32(loc);
udf_update_tag(data, length);
}
u8 udf_tag_checksum(const struct tag *t)
{
u8 *data = (u8 *)t;
u8 checksum = 0;
int i;
for (i = 0; i < sizeof(struct tag); ++i)
if (i != 4) /* position of checksum */
checksum += data[i];
return checksum;
}
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