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
udf_tgetblk(struct super_block * sb,udf_pblk_t block)31 struct buffer_head *udf_tgetblk(struct super_block *sb, udf_pblk_t block)
32 {
33 if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
34 return sb_getblk(sb, udf_fixed_to_variable(block));
35 else
36 return sb_getblk(sb, block);
37 }
38
udf_tread(struct super_block * sb,udf_pblk_t block)39 struct buffer_head *udf_tread(struct super_block *sb, udf_pblk_t block)
40 {
41 if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
42 return sb_bread(sb, udf_fixed_to_variable(block));
43 else
44 return sb_bread(sb, block);
45 }
46
udf_add_extendedattr(struct inode * inode,uint32_t size,uint32_t type,uint8_t loc)47 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
48 uint32_t type, uint8_t loc)
49 {
50 uint8_t *ea = NULL, *ad = NULL;
51 int offset;
52 uint16_t crclen;
53 struct udf_inode_info *iinfo = UDF_I(inode);
54
55 ea = iinfo->i_data;
56 if (iinfo->i_lenEAttr) {
57 ad = iinfo->i_data + iinfo->i_lenEAttr;
58 } else {
59 ad = ea;
60 size += sizeof(struct extendedAttrHeaderDesc);
61 }
62
63 offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
64 iinfo->i_lenAlloc;
65
66 /* TODO - Check for FreeEASpace */
67
68 if (loc & 0x01 && offset >= size) {
69 struct extendedAttrHeaderDesc *eahd;
70 eahd = (struct extendedAttrHeaderDesc *)ea;
71
72 if (iinfo->i_lenAlloc)
73 memmove(&ad[size], ad, iinfo->i_lenAlloc);
74
75 if (iinfo->i_lenEAttr) {
76 /* check checksum/crc */
77 if (eahd->descTag.tagIdent !=
78 cpu_to_le16(TAG_IDENT_EAHD) ||
79 le32_to_cpu(eahd->descTag.tagLocation) !=
80 iinfo->i_location.logicalBlockNum)
81 return NULL;
82 } else {
83 struct udf_sb_info *sbi = UDF_SB(inode->i_sb);
84
85 size -= sizeof(struct extendedAttrHeaderDesc);
86 iinfo->i_lenEAttr +=
87 sizeof(struct extendedAttrHeaderDesc);
88 eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
89 if (sbi->s_udfrev >= 0x0200)
90 eahd->descTag.descVersion = cpu_to_le16(3);
91 else
92 eahd->descTag.descVersion = cpu_to_le16(2);
93 eahd->descTag.tagSerialNum =
94 cpu_to_le16(sbi->s_serial_number);
95 eahd->descTag.tagLocation = cpu_to_le32(
96 iinfo->i_location.logicalBlockNum);
97 eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
98 eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
99 }
100
101 offset = iinfo->i_lenEAttr;
102 if (type < 2048) {
103 if (le32_to_cpu(eahd->appAttrLocation) <
104 iinfo->i_lenEAttr) {
105 uint32_t aal =
106 le32_to_cpu(eahd->appAttrLocation);
107 memmove(&ea[offset - aal + size],
108 &ea[aal], offset - aal);
109 offset -= aal;
110 eahd->appAttrLocation =
111 cpu_to_le32(aal + size);
112 }
113 if (le32_to_cpu(eahd->impAttrLocation) <
114 iinfo->i_lenEAttr) {
115 uint32_t ial =
116 le32_to_cpu(eahd->impAttrLocation);
117 memmove(&ea[offset - ial + size],
118 &ea[ial], offset - ial);
119 offset -= ial;
120 eahd->impAttrLocation =
121 cpu_to_le32(ial + size);
122 }
123 } else if (type < 65536) {
124 if (le32_to_cpu(eahd->appAttrLocation) <
125 iinfo->i_lenEAttr) {
126 uint32_t aal =
127 le32_to_cpu(eahd->appAttrLocation);
128 memmove(&ea[offset - aal + size],
129 &ea[aal], offset - aal);
130 offset -= aal;
131 eahd->appAttrLocation =
132 cpu_to_le32(aal + size);
133 }
134 }
135 /* rewrite CRC + checksum of eahd */
136 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(struct tag);
137 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
138 eahd->descTag.descCRC = cpu_to_le16(crc_itu_t(0, (char *)eahd +
139 sizeof(struct tag), crclen));
140 eahd->descTag.tagChecksum = udf_tag_checksum(&eahd->descTag);
141 iinfo->i_lenEAttr += size;
142 return (struct genericFormat *)&ea[offset];
143 }
144
145 return NULL;
146 }
147
udf_get_extendedattr(struct inode * inode,uint32_t type,uint8_t subtype)148 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
149 uint8_t subtype)
150 {
151 struct genericFormat *gaf;
152 uint8_t *ea = NULL;
153 uint32_t offset;
154 struct udf_inode_info *iinfo = UDF_I(inode);
155
156 ea = iinfo->i_data;
157
158 if (iinfo->i_lenEAttr) {
159 struct extendedAttrHeaderDesc *eahd;
160 eahd = (struct extendedAttrHeaderDesc *)ea;
161
162 /* check checksum/crc */
163 if (eahd->descTag.tagIdent !=
164 cpu_to_le16(TAG_IDENT_EAHD) ||
165 le32_to_cpu(eahd->descTag.tagLocation) !=
166 iinfo->i_location.logicalBlockNum)
167 return NULL;
168
169 if (type < 2048)
170 offset = sizeof(struct extendedAttrHeaderDesc);
171 else if (type < 65536)
172 offset = le32_to_cpu(eahd->impAttrLocation);
173 else
174 offset = le32_to_cpu(eahd->appAttrLocation);
175
176 while (offset + sizeof(*gaf) < iinfo->i_lenEAttr) {
177 uint32_t attrLength;
178
179 gaf = (struct genericFormat *)&ea[offset];
180 attrLength = le32_to_cpu(gaf->attrLength);
181
182 /* Detect undersized elements and buffer overflows */
183 if ((attrLength < sizeof(*gaf)) ||
184 (attrLength > (iinfo->i_lenEAttr - offset)))
185 break;
186
187 if (le32_to_cpu(gaf->attrType) == type &&
188 gaf->attrSubtype == subtype)
189 return gaf;
190 else
191 offset += attrLength;
192 }
193 }
194
195 return NULL;
196 }
197
198 /*
199 * udf_read_tagged
200 *
201 * PURPOSE
202 * Read the first block of a tagged descriptor.
203 *
204 * HISTORY
205 * July 1, 1997 - Andrew E. Mileski
206 * Written, tested, and released.
207 */
udf_read_tagged(struct super_block * sb,uint32_t block,uint32_t location,uint16_t * ident)208 struct buffer_head *udf_read_tagged(struct super_block *sb, uint32_t block,
209 uint32_t location, uint16_t *ident)
210 {
211 struct tag *tag_p;
212 struct buffer_head *bh = NULL;
213 u8 checksum;
214
215 /* Read the block */
216 if (block == 0xFFFFFFFF)
217 return NULL;
218
219 bh = udf_tread(sb, block);
220 if (!bh) {
221 udf_err(sb, "read failed, block=%u, location=%u\n",
222 block, location);
223 return NULL;
224 }
225
226 tag_p = (struct tag *)(bh->b_data);
227
228 *ident = le16_to_cpu(tag_p->tagIdent);
229
230 if (location != le32_to_cpu(tag_p->tagLocation)) {
231 udf_debug("location mismatch block %u, tag %u != %u\n",
232 block, le32_to_cpu(tag_p->tagLocation), location);
233 goto error_out;
234 }
235
236 /* Verify the tag checksum */
237 checksum = udf_tag_checksum(tag_p);
238 if (checksum != tag_p->tagChecksum) {
239 udf_err(sb, "tag checksum failed, block %u: 0x%02x != 0x%02x\n",
240 block, checksum, tag_p->tagChecksum);
241 goto error_out;
242 }
243
244 /* Verify the tag version */
245 if (tag_p->descVersion != cpu_to_le16(0x0002U) &&
246 tag_p->descVersion != cpu_to_le16(0x0003U)) {
247 udf_err(sb, "tag version 0x%04x != 0x0002 || 0x0003, block %u\n",
248 le16_to_cpu(tag_p->descVersion), block);
249 goto error_out;
250 }
251
252 /* Verify the descriptor CRC */
253 if (le16_to_cpu(tag_p->descCRCLength) + sizeof(struct tag) > sb->s_blocksize ||
254 le16_to_cpu(tag_p->descCRC) == crc_itu_t(0,
255 bh->b_data + sizeof(struct tag),
256 le16_to_cpu(tag_p->descCRCLength)))
257 return bh;
258
259 udf_debug("Crc failure block %u: crc = %u, crclen = %u\n", block,
260 le16_to_cpu(tag_p->descCRC),
261 le16_to_cpu(tag_p->descCRCLength));
262 error_out:
263 brelse(bh);
264 return NULL;
265 }
266
udf_read_ptagged(struct super_block * sb,struct kernel_lb_addr * loc,uint32_t offset,uint16_t * ident)267 struct buffer_head *udf_read_ptagged(struct super_block *sb,
268 struct kernel_lb_addr *loc,
269 uint32_t offset, uint16_t *ident)
270 {
271 return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
272 loc->logicalBlockNum + offset, ident);
273 }
274
udf_update_tag(char * data,int length)275 void udf_update_tag(char *data, int length)
276 {
277 struct tag *tptr = (struct tag *)data;
278 length -= sizeof(struct tag);
279
280 tptr->descCRCLength = cpu_to_le16(length);
281 tptr->descCRC = cpu_to_le16(crc_itu_t(0, data + sizeof(struct tag), length));
282 tptr->tagChecksum = udf_tag_checksum(tptr);
283 }
284
udf_new_tag(char * data,uint16_t ident,uint16_t version,uint16_t snum,uint32_t loc,int length)285 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
286 uint32_t loc, int length)
287 {
288 struct tag *tptr = (struct tag *)data;
289 tptr->tagIdent = cpu_to_le16(ident);
290 tptr->descVersion = cpu_to_le16(version);
291 tptr->tagSerialNum = cpu_to_le16(snum);
292 tptr->tagLocation = cpu_to_le32(loc);
293 udf_update_tag(data, length);
294 }
295
udf_tag_checksum(const struct tag * t)296 u8 udf_tag_checksum(const struct tag *t)
297 {
298 u8 *data = (u8 *)t;
299 u8 checksum = 0;
300 int i;
301 for (i = 0; i < sizeof(struct tag); ++i)
302 if (i != 4) /* position of checksum */
303 checksum += data[i];
304 return checksum;
305 }
306