fs/udf/misc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * misc.c
   4  *
   5  * PURPOSE
   6  *      Miscellaneous routines for the OSTA-UDF(tm) filesystem.
   7  *
   8  * COPYRIGHT
   9  *  (C) 1998 Dave Boynton
  10  *  (C) 1998-2004 Ben Fennema
  11  *  (C) 1999-2000 Stelias Computing Inc
  12  *
  13  * HISTORY
  14  *
  15  *  04/19/99 blf  partial support for reading/writing specific EA's
  16  */
  17
  18 #include "udfdecl.h"
  19
  20 #include <linux/fs.h>
  21 #include <linux/string.h>
  22 #include <linux/crc-itu-t.h>
  23
  24 #include "udf_i.h"
  25 #include "udf_sb.h"
  26
  27 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
  28                                            uint32_t type, uint8_t loc)
  29 {
  30         uint8_t *ea = NULL, *ad = NULL;
  31         int offset;
  32         uint16_t crclen;
  33         struct udf_inode_info *iinfo = UDF_I(inode);
  34
  35         ea = iinfo->i_data;
  36         if (iinfo->i_lenEAttr) {
  37                 ad = iinfo->i_data + iinfo->i_lenEAttr;
  38         } else {
  39                 ad = ea;
  40                 size += sizeof(struct extendedAttrHeaderDesc);
  41         }
  42
  43         offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
  44                 iinfo->i_lenAlloc;
  45
  46         /* TODO - Check for FreeEASpace */
  47
  48         if (loc & 0x01 && offset >= size) {
  49                 struct extendedAttrHeaderDesc *eahd;
  50                 eahd = (struct extendedAttrHeaderDesc *)ea;
  51
  52                 if (iinfo->i_lenAlloc)
  53                         memmove(&ad[size], ad, iinfo->i_lenAlloc);
  54
  55                 if (iinfo->i_lenEAttr) {
  56                         /* check checksum/crc */
  57                         if (eahd->descTag.tagIdent !=
  58                                         cpu_to_le16(TAG_IDENT_EAHD) ||
  59                             le32_to_cpu(eahd->descTag.tagLocation) !=
  60                                         iinfo->i_location.logicalBlockNum)
  61                                 return NULL;
  62                 } else {
  63                         struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
  64
  65                         size -= sizeof(struct extendedAttrHeaderDesc);
  66                         iinfo->i_lenEAttr +=
  67                                 sizeof(struct extendedAttrHeaderDesc);
  68                         eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
  69                         if (sbi->s_udfrev >= 0x0200)
  70                                 eahd->descTag.descVersion = cpu_to_le16(3);
  71                         else
  72                                 eahd->descTag.descVersion = cpu_to_le16(2);
  73                         eahd->descTag.tagSerialNum =
  74                                         cpu_to_le16(sbi->s_serial_number);
  75                         eahd->descTag.tagLocation = cpu_to_le32(
  76                                         iinfo->i_location.logicalBlockNum);
  77                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
  78                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
  79                 }
  80
  81                 offset = iinfo->i_lenEAttr;
  82                 if (type < 2048) {
  83                         if (le32_to_cpu(eahd->appAttrLocation) <
  84                                         iinfo->i_lenEAttr) {
  85                                 uint32_t aal =
  86                                         le32_to_cpu(eahd->appAttrLocation);
  87                                 memmove(&ea[offset - aal + size],
  88                                         &ea[aal], offset - aal);
  89                                 offset -= aal;
  90                                 eahd->appAttrLocation =
  91                                                 cpu_to_le32(aal + size);
  92                         }
  93                         if (le32_to_cpu(eahd->impAttrLocation) <
  94                                         iinfo->i_lenEAttr) {
  95                                 uint32_t ial =
  96                                         le32_to_cpu(eahd->impAttrLocation);
  97                                 memmove(&ea[offset - ial + size],
  98                                         &ea[ial], offset - ial);
  99                                 offset -= ial;
 100                                 eahd->impAttrLocation =
 101                                                 cpu_to_le32(ial + size);
 102                         }
 103                 } else if (type < 65536) {
 104                         if (le32_to_cpu(eahd->appAttrLocation) <
 105                                         iinfo->i_lenEAttr) {
 106                                 uint32_t aal =
 107                                         le32_to_cpu(eahd->appAttrLocation);
 108                                 memmove(&ea[offset - aal + size],
 109                                         &ea[aal], offset - aal);
 110                                 offset -= aal;
 111                                 eahd->appAttrLocation =
 112                                                 cpu_to_le32(aal + size);
 113                         }
 114                 }
 115                 /* rewrite CRC + checksum of eahd */
 116                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);
 117                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
 118                 eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
 119                                                 sizeof(struct tag), crclen));
 120                 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
 121                 iinfo->i_lenEAttr += size;
 122                 return (struct genericFormat *)&ea[offset];
 123         }
 124
 125         return NULL;
 126 }
 127
 128 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
 129                                            uint8_t subtype)
 130 {
 131         struct genericFormat *gaf;
 132         uint8_t *ea = NULL;
 133         uint32_t offset;
 134         struct udf_inode_info *iinfo = UDF_I(inode);
 135
 136         ea = iinfo->i_data;
 137
 138         if (iinfo->i_lenEAttr) {
 139                 struct extendedAttrHeaderDesc *eahd;
 140                 eahd = (struct extendedAttrHeaderDesc *)ea;
 141
 142                 /* check checksum/crc */
 143                 if (eahd->descTag.tagIdent !=
 144                                 cpu_to_le16(TAG_IDENT_EAHD) ||
 145                     le32_to_cpu(eahd->descTag.tagLocation) !=
 146                                 iinfo->i_location.logicalBlockNum)
 147                         return NULL;
 148
 149                 if (type < 2048)
 150                         offset = sizeof(struct extendedAttrHeaderDesc);
 151                 else if (type < 65536)
 152                         offset = le32_to_cpu(eahd->impAttrLocation);
 153                 else
 154                         offset = le32_to_cpu(eahd->appAttrLocation);
 155
 156                 while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) {
 157                         uint32_t attrLength;
 158
 159                         gaf = (struct genericFormat *)&ea[offset];
 160                         attrLength = le32_to_cpu(gaf->attrLength);
 161
 162                         /* Detect undersized elements and buffer overflows */
 163                         if ((attrLength < sizeof(*gaf)) ||
 164                             (attrLength > (iinfo->i_lenEAttr - offset)))
 165                                 break;
 166
 167                         if (le32_to_cpu(gaf->attrType) == type &&
 168                                         gaf->attrSubtype == subtype)
 169                                 return gaf;
 170                         else
 171                                 offset += attrLength;
 172                 }
 173         }
 174
 175         return NULL;
 176 }
 177
 178 /*
 179  * udf_read_tagged
 180  *
 181  * PURPOSE
 182  *      Read the first block of a tagged descriptor.
 183  *
 184  * HISTORY
 185  *      July 1, 1997 - Andrew E. Mileski
 186  *      Written, tested, and released.
 187  */
 188 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
 189                                     uint32_t location, uint16_t *ident)
 190 {
 191         struct tag *tag_p;
 192         struct buffer_head *bh = NULL;
 193         u8 checksum;
 194
 195         /* Read the block */
 196         if (block == 0xFFFFFFFF)
 197                 return NULL;
 198
 199         bh = sb_bread(sb, block);
 200         if (!bh) {
 201                 udf_err(sb, "read failed, block=%u, location=%u\n",
 202                         block, location);
 203                 return NULL;
 204         }
 205
 206         tag_p = (struct tag *)(bh->b_data);
 207
 208         *ident = le16_to_cpu(tag_p->tagIdent);
 209
 210         if (location != le32_to_cpu(tag_p->tagLocation)) {
 211                 udf_debug("location mismatch block %u, tag %u != %u\n",
 212                           block, le32_to_cpu(tag_p->tagLocation), location);
 213                 goto error_out;
 214         }
 215
 216         /* Verify the tag checksum */
 217         checksum = udf_tag_checksum(tag_p);
 218         if (checksum != tag_p->tagChecksum) {
 219                 udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
 220                         block, checksum, tag_p->tagChecksum);
 221                 goto error_out;
 222         }
 223
 224         /* Verify the tag version */
 225         if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
 226             tag_p->descVersion != cpu_to_le16(0x0003U)) {
 227                 udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
 228                         le16_to_cpu(tag_p->descVersion), block);
 229                 goto error_out;
 230         }
 231
 232         /* Verify the descriptor CRC */
 233         if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
 234             le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
 235                                         bh->b_data + sizeof(struct tag),
 236                                         le16_to_cpu(tag_p->descCRCLength)))
 237                 return bh;
 238
 239         udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block,
 240                   le16_to_cpu(tag_p->descCRC),
 241                   le16_to_cpu(tag_p->descCRCLength));
 242 error_out:
 243         brelse(bh);
 244         return NULL;
 245 }
 246
 247 struct buffer_head *udf_read_ptagged(struct super_block *sb,
 248                                      struct kernel_lb_addr *loc,
 249                                      uint32_t offset, uint16_t *ident)
 250 {
 251         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
 252                                loc->logicalBlockNum + offset, ident);
 253 }
 254
 255 void udf_update_tag(char *data, int length)
 256 {
 257         struct tag *tptr = (struct tag *)data;
 258         length -= sizeof(struct tag);
 259
 260         tptr->descCRCLength = cpu_to_le16(length);
 261         tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
 262         tptr->tagChecksum = udf_tag_checksum(tptr);
 263 }
 264
 265 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
 266                  uint32_t loc, int length)
 267 {
 268         struct tag *tptr = (struct tag *)data;
 269         tptr->tagIdent = cpu_to_le16(ident);
 270         tptr->descVersion = cpu_to_le16(version);
 271         tptr->tagSerialNum = cpu_to_le16(snum);
 272         tptr->tagLocation = cpu_to_le32(loc);
 273         udf_update_tag(data, length);
 274 }
 275
 276 u8 udf_tag_checksum(const struct tag *t)
 277 {
 278         u8 *data = (u8 *)t;
 279         u8 checksum = 0;
 280         int i;
 281         for (i = 0; i < sizeof(struct tag); ++i)
 282                 if (i != 4) /* position of checksum */
 283                         checksum += data[i];
 284         return checksum;
 285 }