fs/udf/misc.c

   1 /*
   2  * misc.c
   3  *
   4  * PURPOSE
   5  *      Miscellaneous routines for the OSTA-UDF(tm) filesystem.
   6  *
   7  * COPYRIGHT
   8  *      This file is distributed under the terms of the GNU General Public
   9  *      License (GPL). Copies of the GPL can be obtained from:
  10  *              ftp://prep.ai.mit.edu/pub/gnu/GPL
  11  *      Each contributing author retains all rights to their own work.
  12  *
  13  *  (C) 1998 Dave Boynton
  14  *  (C) 1998-2004 Ben Fennema
  15  *  (C) 1999-2000 Stelias Computing Inc
  16  *
  17  * HISTORY
  18  *
  19  *  04/19/99 blf  partial support for reading/writing specific EA's
  20  */
  21
  22 #include "udfdecl.h"
  23
  24 #include <linux/fs.h>
  25 #include <linux/string.h>
  26 #include <linux/crc-itu-t.h>
  27
  28 #include "udf_i.h"
  29 #include "udf_sb.h"
  30
  31 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
  32                                            uint32_t type, uint8_t loc)
  33 {
  34         uint8_t *ea = NULL, *ad = NULL;
  35         int offset;
  36         uint16_t crclen;
  37         struct udf_inode_info *iinfo = UDF_I(inode);
  38
  39         ea = iinfo->i_data;
  40         if (iinfo->i_lenEAttr) {
  41                 ad = iinfo->i_data + iinfo->i_lenEAttr;
  42         } else {
  43                 ad = ea;
  44                 size += sizeof(struct extendedAttrHeaderDesc);
  45         }
  46
  47         offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
  48                 iinfo->i_lenAlloc;
  49
  50         /* TODO - Check for FreeEASpace */
  51
  52         if (loc & 0x01 && offset >= size) {
  53                 struct extendedAttrHeaderDesc *eahd;
  54                 eahd = (struct extendedAttrHeaderDesc *)ea;
  55
  56                 if (iinfo->i_lenAlloc)
  57                         memmove(&ad[size], ad, iinfo->i_lenAlloc);
  58
  59                 if (iinfo->i_lenEAttr) {
  60                         /* check checksum/crc */
  61                         if (eahd->descTag.tagIdent !=
  62                                         cpu_to_le16(TAG_IDENT_EAHD) ||
  63                             le32_to_cpu(eahd->descTag.tagLocation) !=
  64                                         iinfo->i_location.logicalBlockNum)
  65                                 return NULL;
  66                 } else {
  67                         struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
  68
  69                         size -= sizeof(struct extendedAttrHeaderDesc);
  70                         iinfo->i_lenEAttr +=
  71                                 sizeof(struct extendedAttrHeaderDesc);
  72                         eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
  73                         if (sbi->s_udfrev >= 0x0200)
  74                                 eahd->descTag.descVersion = cpu_to_le16(3);
  75                         else
  76                                 eahd->descTag.descVersion = cpu_to_le16(2);
  77                         eahd->descTag.tagSerialNum =
  78                                         cpu_to_le16(sbi->s_serial_number);
  79                         eahd->descTag.tagLocation = cpu_to_le32(
  80                                         iinfo->i_location.logicalBlockNum);
  81                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
  82                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
  83                 }
  84
  85                 offset = iinfo->i_lenEAttr;
  86                 if (type < 2048) {
  87                         if (le32_to_cpu(eahd->appAttrLocation) <
  88                                         iinfo->i_lenEAttr) {
  89                                 uint32_t aal =
  90                                         le32_to_cpu(eahd->appAttrLocation);
  91                                 memmove(&ea[offset - aal + size],
  92                                         &ea[aal], offset - aal);
  93                                 offset -= aal;
  94                                 eahd->appAttrLocation =
  95                                                 cpu_to_le32(aal + size);
  96                         }
  97                         if (le32_to_cpu(eahd->impAttrLocation) <
  98                                         iinfo->i_lenEAttr) {
  99                                 uint32_t ial =
 100                                         le32_to_cpu(eahd->impAttrLocation);
 101                                 memmove(&ea[offset - ial + size],
 102                                         &ea[ial], offset - ial);
 103                                 offset -= ial;
 104                                 eahd->impAttrLocation =
 105                                                 cpu_to_le32(ial + size);
 106                         }
 107                 } else if (type < 65536) {
 108                         if (le32_to_cpu(eahd->appAttrLocation) <
 109                                         iinfo->i_lenEAttr) {
 110                                 uint32_t aal =
 111                                         le32_to_cpu(eahd->appAttrLocation);
 112                                 memmove(&ea[offset - aal + size],
 113                                         &ea[aal], offset - aal);
 114                                 offset -= aal;
 115                                 eahd->appAttrLocation =
 116                                                 cpu_to_le32(aal + size);
 117                         }
 118                 }
 119                 /* rewrite CRC + checksum of eahd */
 120                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);
 121                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
 122                 eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
 123                                                 sizeof(struct tag), crclen));
 124                 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
 125                 iinfo->i_lenEAttr += size;
 126                 return (struct genericFormat *)&ea[offset];
 127         }
 128
 129         return NULL;
 130 }
 131
 132 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
 133                                            uint8_t subtype)
 134 {
 135         struct genericFormat *gaf;
 136         uint8_t *ea = NULL;
 137         uint32_t offset;
 138         struct udf_inode_info *iinfo = UDF_I(inode);
 139
 140         ea = iinfo->i_data;
 141
 142         if (iinfo->i_lenEAttr) {
 143                 struct extendedAttrHeaderDesc *eahd;
 144                 eahd = (struct extendedAttrHeaderDesc *)ea;
 145
 146                 /* check checksum/crc */
 147                 if (eahd->descTag.tagIdent !=
 148                                 cpu_to_le16(TAG_IDENT_EAHD) ||
 149                     le32_to_cpu(eahd->descTag.tagLocation) !=
 150                                 iinfo->i_location.logicalBlockNum)
 151                         return NULL;
 152
 153                 if (type < 2048)
 154                         offset = sizeof(struct extendedAttrHeaderDesc);
 155                 else if (type < 65536)
 156                         offset = le32_to_cpu(eahd->impAttrLocation);
 157                 else
 158                         offset = le32_to_cpu(eahd->appAttrLocation);
 159
 160                 while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) {
 161                         uint32_t attrLength;
 162
 163                         gaf = (struct genericFormat *)&ea[offset];
 164                         attrLength = le32_to_cpu(gaf->attrLength);
 165
 166                         /* Detect undersized elements and buffer overflows */
 167                         if ((attrLength < sizeof(*gaf)) ||
 168                             (attrLength > (iinfo->i_lenEAttr - offset)))
 169                                 break;
 170
 171                         if (le32_to_cpu(gaf->attrType) == type &&
 172                                         gaf->attrSubtype == subtype)
 173                                 return gaf;
 174                         else
 175                                 offset += attrLength;
 176                 }
 177         }
 178
 179         return NULL;
 180 }
 181
 182 /*
 183  * udf_read_tagged
 184  *
 185  * PURPOSE
 186  *      Read the first block of a tagged descriptor.
 187  *
 188  * HISTORY
 189  *      July 1, 1997 - Andrew E. Mileski
 190  *      Written, tested, and released.
 191  */
 192 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
 193                                     uint32_t location, uint16_t *ident)
 194 {
 195         struct tag *tag_p;
 196         struct buffer_head *bh = NULL;
 197         u8 checksum;
 198
 199         /* Read the block */
 200         if (block == 0xFFFFFFFF)
 201                 return NULL;
 202
 203         bh = sb_bread(sb, block);
 204         if (!bh) {
 205                 udf_err(sb, "read failed, block=%u, location=%u\n",
 206                         block, location);
 207                 return NULL;
 208         }
 209
 210         tag_p = (struct tag *)(bh->b_data);
 211
 212         *ident = le16_to_cpu(tag_p->tagIdent);
 213
 214         if (location != le32_to_cpu(tag_p->tagLocation)) {
 215                 udf_debug("location mismatch block %u, tag %u != %u\n",
 216                           block, le32_to_cpu(tag_p->tagLocation), location);
 217                 goto error_out;
 218         }
 219
 220         /* Verify the tag checksum */
 221         checksum = udf_tag_checksum(tag_p);
 222         if (checksum != tag_p->tagChecksum) {
 223                 udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
 224                         block, checksum, tag_p->tagChecksum);
 225                 goto error_out;
 226         }
 227
 228         /* Verify the tag version */
 229         if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
 230             tag_p->descVersion != cpu_to_le16(0x0003U)) {
 231                 udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
 232                         le16_to_cpu(tag_p->descVersion), block);
 233                 goto error_out;
 234         }
 235
 236         /* Verify the descriptor CRC */
 237         if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
 238             le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
 239                                         bh->b_data + sizeof(struct tag),
 240                                         le16_to_cpu(tag_p->descCRCLength)))
 241                 return bh;
 242
 243         udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block,
 244                   le16_to_cpu(tag_p->descCRC),
 245                   le16_to_cpu(tag_p->descCRCLength));
 246 error_out:
 247         brelse(bh);
 248         return NULL;
 249 }
 250
 251 struct buffer_head *udf_read_ptagged(struct super_block *sb,
 252                                      struct kernel_lb_addr *loc,
 253                                      uint32_t offset, uint16_t *ident)
 254 {
 255         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
 256                                loc->logicalBlockNum + offset, ident);
 257 }
 258
 259 void udf_update_tag(char *data, int length)
 260 {
 261         struct tag *tptr = (struct tag *)data;
 262         length -= sizeof(struct tag);
 263
 264         tptr->descCRCLength = cpu_to_le16(length);
 265         tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
 266         tptr->tagChecksum = udf_tag_checksum(tptr);
 267 }
 268
 269 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
 270                  uint32_t loc, int length)
 271 {
 272         struct tag *tptr = (struct tag *)data;
 273         tptr->tagIdent = cpu_to_le16(ident);
 274         tptr->descVersion = cpu_to_le16(version);
 275         tptr->tagSerialNum = cpu_to_le16(snum);
 276         tptr->tagLocation = cpu_to_le32(loc);
 277         udf_update_tag(data, length);
 278 }
 279
 280 u8 udf_tag_checksum(const struct tag *t)
 281 {
 282         u8 *data = (u8 *)t;
 283         u8 checksum = 0;
 284         int i;
 285         for (i = 0; i < sizeof(struct tag); ++i)
 286                 if (i != 4) /* position of checksum */
 287                         checksum += data[i];
 288         return checksum;
 289 }