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 } 286