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
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