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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * misc.c4 *5 * PURPOSE6 * Miscellaneous routines for the OSTA-UDF(tm) filesystem.7 *8 * COPYRIGHT9 * (C) 1998 Dave Boynton10 * (C) 1998-2004 Ben Fennema11 * (C) 1999-2000 Stelias Computing Inc12 *13 * HISTORY14 *15 * 04/19/99 blf partial support for reading/writing specific EA's16 */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 27struct 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 else72 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 128struct 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 else154 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 else171 offset += attrLength;172 }173 }174 175 return NULL;176}177 178/*179 * udf_read_tagged180 *181 * PURPOSE182 * Read the first block of a tagged descriptor.183 *184 * HISTORY185 * July 1, 1997 - Andrew E. Mileski186 * Written, tested, and released.187 */188struct 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));242error_out:243 brelse(bh);244 return NULL;245}246 247struct 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 255void 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 265void 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 276u8 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