ext2: add block bitmap validation
[linux-2.6] / fs / udf / misc.c
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/udf_fs.h>
27 #include <linux/buffer_head.h>
28
29 #include "udf_i.h"
30 #include "udf_sb.h"
31
32 struct buffer_head *udf_tgetblk(struct super_block *sb, int block)
33 {
34         if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
35                 return sb_getblk(sb, udf_fixed_to_variable(block));
36         else
37                 return sb_getblk(sb, block);
38 }
39
40 struct buffer_head *udf_tread(struct super_block *sb, int block)
41 {
42         if (UDF_QUERY_FLAG(sb, UDF_FLAG_VARCONV))
43                 return sb_bread(sb, udf_fixed_to_variable(block));
44         else
45                 return sb_bread(sb, block);
46 }
47
48 struct genericFormat *udf_add_extendedattr(struct inode *inode, uint32_t size,
49                                            uint32_t type, uint8_t loc)
50 {
51         uint8_t *ea = NULL, *ad = NULL;
52         int offset;
53         uint16_t crclen;
54         int i;
55
56         ea = UDF_I_DATA(inode);
57         if (UDF_I_LENEATTR(inode)) {
58                 ad = UDF_I_DATA(inode) + UDF_I_LENEATTR(inode);
59         } else {
60                 ad = ea;
61                 size += sizeof(struct extendedAttrHeaderDesc);
62         }
63
64         offset = inode->i_sb->s_blocksize - udf_file_entry_alloc_offset(inode) -
65                 UDF_I_LENALLOC(inode);
66
67         /* TODO - Check for FreeEASpace */
68
69         if (loc & 0x01 && offset >= size) {
70                 struct extendedAttrHeaderDesc *eahd;
71                 eahd = (struct extendedAttrHeaderDesc *)ea;
72
73                 if (UDF_I_LENALLOC(inode)) {
74                         memmove(&ad[size], ad, UDF_I_LENALLOC(inode));
75                 }
76
77                 if (UDF_I_LENEATTR(inode)) {
78                         /* check checksum/crc */
79                         if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
80                             le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum) {
81                                 return NULL;
82                         }
83                 } else {
84                         size -= sizeof(struct extendedAttrHeaderDesc);
85                         UDF_I_LENEATTR(inode) += sizeof(struct extendedAttrHeaderDesc);
86                         eahd->descTag.tagIdent = cpu_to_le16(TAG_IDENT_EAHD);
87                         if (UDF_SB_UDFREV(inode->i_sb) >= 0x0200)
88                                 eahd->descTag.descVersion = cpu_to_le16(3);
89                         else
90                                 eahd->descTag.descVersion = cpu_to_le16(2);
91                         eahd->descTag.tagSerialNum = cpu_to_le16(UDF_SB_SERIALNUM(inode->i_sb));
92                         eahd->descTag.tagLocation = cpu_to_le32(UDF_I_LOCATION(inode).logicalBlockNum);
93                         eahd->impAttrLocation = cpu_to_le32(0xFFFFFFFF);
94                         eahd->appAttrLocation = cpu_to_le32(0xFFFFFFFF);
95                 }
96
97                 offset = UDF_I_LENEATTR(inode);
98                 if (type < 2048) {
99                         if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode)) {
100                                 uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
101                                 memmove(&ea[offset - aal + size],
102                                         &ea[aal], offset - aal);
103                                 offset -= aal;
104                                 eahd->appAttrLocation = cpu_to_le32(aal + size);
105                         }
106                         if (le32_to_cpu(eahd->impAttrLocation) < UDF_I_LENEATTR(inode)) {
107                                 uint32_t ial = le32_to_cpu(eahd->impAttrLocation);
108                                 memmove(&ea[offset - ial + size],
109                                         &ea[ial], offset - ial);
110                                 offset -= ial;
111                                 eahd->impAttrLocation = cpu_to_le32(ial + size);
112                         }
113                 } else if (type < 65536) {
114                         if (le32_to_cpu(eahd->appAttrLocation) < UDF_I_LENEATTR(inode)) {
115                                 uint32_t aal = le32_to_cpu(eahd->appAttrLocation);
116                                 memmove(&ea[offset - aal + size],
117                                         &ea[aal], offset - aal);
118                                 offset -= aal;
119                                 eahd->appAttrLocation = cpu_to_le32(aal + size);
120                         }
121                 }
122                 /* rewrite CRC + checksum of eahd */
123                 crclen = sizeof(struct extendedAttrHeaderDesc) - sizeof(tag);
124                 eahd->descTag.descCRCLength = cpu_to_le16(crclen);
125                 eahd->descTag.descCRC = cpu_to_le16(udf_crc((char *)eahd +
126                                                             sizeof(tag), crclen, 0));
127                 eahd->descTag.tagChecksum = 0;
128                 for (i = 0; i < 16; i++)
129                         if (i != 4)
130                                 eahd->descTag.tagChecksum += ((uint8_t *)&(eahd->descTag))[i];
131                 UDF_I_LENEATTR(inode) += size;
132                 return (struct genericFormat *)&ea[offset];
133         }
134         if (loc & 0x02) {
135         }
136
137         return NULL;
138 }
139
140 struct genericFormat *udf_get_extendedattr(struct inode *inode, uint32_t type,
141                                            uint8_t subtype)
142 {
143         struct genericFormat *gaf;
144         uint8_t *ea = NULL;
145         uint32_t offset;
146
147         ea = UDF_I_DATA(inode);
148
149         if (UDF_I_LENEATTR(inode)) {
150                 struct extendedAttrHeaderDesc *eahd;
151                 eahd = (struct extendedAttrHeaderDesc *)ea;
152
153                 /* check checksum/crc */
154                 if (le16_to_cpu(eahd->descTag.tagIdent) != TAG_IDENT_EAHD ||
155                     le32_to_cpu(eahd->descTag.tagLocation) != UDF_I_LOCATION(inode).logicalBlockNum) {
156                         return NULL;
157                 }
158
159                 if (type < 2048)
160                         offset = sizeof(struct extendedAttrHeaderDesc);
161                 else if (type < 65536)
162                         offset = le32_to_cpu(eahd->impAttrLocation);
163                 else
164                         offset = le32_to_cpu(eahd->appAttrLocation);
165
166                 while (offset < UDF_I_LENEATTR(inode)) {
167                         gaf = (struct genericFormat *)&ea[offset];
168                         if (le32_to_cpu(gaf->attrType) == type && gaf->attrSubtype == subtype)
169                                 return gaf;
170                         else
171                                 offset += le32_to_cpu(gaf->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         tag *tag_p;
192         struct buffer_head *bh = NULL;
193         register uint8_t checksum;
194         register int i;
195
196         /* Read the block */
197         if (block == 0xFFFFFFFF)
198                 return NULL;
199
200         bh = udf_tread(sb, block + UDF_SB_SESSION(sb));
201         if (!bh) {
202                 udf_debug("block=%d, location=%d: read failed\n",
203                           block + UDF_SB_SESSION(sb), location);
204                 return NULL;
205         }
206
207         tag_p = (tag *)(bh->b_data);
208
209         *ident = le16_to_cpu(tag_p->tagIdent);
210
211         if (location != le32_to_cpu(tag_p->tagLocation)) {
212                 udf_debug("location mismatch block %u, tag %u != %u\n",
213                           block + UDF_SB_SESSION(sb), le32_to_cpu(tag_p->tagLocation), location);
214                 goto error_out;
215         }
216
217         /* Verify the tag checksum */
218         checksum = 0U;
219         for (i = 0; i < 4; i++)
220                 checksum += (uint8_t)(bh->b_data[i]);
221         for (i = 5; i < 16; i++)
222                 checksum += (uint8_t)(bh->b_data[i]);
223         if (checksum != tag_p->tagChecksum) {
224                 printk(KERN_ERR "udf: tag checksum failed block %d\n", block);
225                 goto error_out;
226         }
227
228         /* Verify the tag version */
229         if (le16_to_cpu(tag_p->descVersion) != 0x0002U &&
230             le16_to_cpu(tag_p->descVersion) != 0x0003U) {
231                 udf_debug("tag version 0x%04x != 0x0002 || 0x0003 block %d\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(tag) > sb->s_blocksize ||
238             le16_to_cpu(tag_p->descCRC) == udf_crc(bh->b_data + sizeof(tag),
239                                                    le16_to_cpu(tag_p->descCRCLength), 0)) {
240                 return bh;
241         }
242         udf_debug("Crc failure block %d: crc = %d, crclen = %d\n",
243                   block + UDF_SB_SESSION(sb), le16_to_cpu(tag_p->descCRC),
244                   le16_to_cpu(tag_p->descCRCLength));
245
246 error_out:
247         brelse(bh);
248         return NULL;
249 }
250
251 struct buffer_head *udf_read_ptagged(struct super_block *sb, kernel_lb_addr loc,
252                                      uint32_t offset, uint16_t * ident)
253 {
254         return udf_read_tagged(sb, udf_get_lb_pblock(sb, loc, offset),
255                                loc.logicalBlockNum + offset, ident);
256 }
257
258 void udf_update_tag(char *data, int length)
259 {
260         tag *tptr = (tag *)data;
261         int i;
262
263         length -= sizeof(tag);
264
265         tptr->tagChecksum = 0;
266         tptr->descCRCLength = cpu_to_le16(length);
267         tptr->descCRC = cpu_to_le16(udf_crc(data + sizeof(tag), length, 0));
268
269         for (i = 0; i < 16; i++)
270                 if (i != 4)
271                         tptr->tagChecksum += (uint8_t)(data[i]);
272 }
273
274 void udf_new_tag(char *data, uint16_t ident, uint16_t version, uint16_t snum,
275                  uint32_t loc, int length)
276 {
277         tag *tptr = (tag *)data;
278         tptr->tagIdent = cpu_to_le16(ident);
279         tptr->descVersion = cpu_to_le16(version);
280         tptr->tagSerialNum = cpu_to_le16(snum);
281         tptr->tagLocation = cpu_to_le32(loc);
282         udf_update_tag(data, length);
283 }