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 } 290