fs/hpfs/map.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  linux/fs/hpfs/map.c
   4  *
   5  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
   6  *
   7  *  mapping structures to memory with some minimal checks
   8  */
   9
  10 #include "hpfs_fn.h"
  11
  12 __le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
  13 {
  14         return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
  15 }
  16
  17 __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
  18                          struct quad_buffer_head *qbh, char *id)
  19 {
  20         secno sec;
  21         __le32 *ret;
  22         unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  23         if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
  24                 hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
  25                 return NULL;
  26         }
  27         sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  28         if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
  29                 hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
  30                 return NULL;
  31         }
  32         ret = hpfs_map_4sectors(s, sec, qbh, 4);
  33         if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
  34         return ret;
  35 }
  36
  37 void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
  38 {
  39         unsigned to_prefetch, next_prefetch;
  40         unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
  41         if (unlikely(bmp_block >= n_bands))
  42                 return;
  43         to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
  44         if (unlikely(bmp_block + 1 >= n_bands))
  45                 next_prefetch = 0;
  46         else
  47                 next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
  48         hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
  49 }
  50
  51 /*
  52  * Load first code page into kernel memory, return pointer to 256-byte array,
  53  * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
  54  * lowercasing table
  55  */
  56
  57 unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
  58 {
  59         struct buffer_head *bh;
  60         secno cpds;
  61         unsigned cpi;
  62         unsigned char *ptr;
  63         unsigned char *cp_table;
  64         int i;
  65         struct code_page_data *cpd;
  66         struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
  67         if (!cp) return NULL;
  68         if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
  69                 pr_err("Code page directory magic doesn't match (magic = %08x)\n",
  70                         le32_to_cpu(cp->magic));
  71                 brelse(bh);
  72                 return NULL;
  73         }
  74         if (!le32_to_cpu(cp->n_code_pages)) {
  75                 pr_err("n_code_pages == 0\n");
  76                 brelse(bh);
  77                 return NULL;
  78         }
  79         cpds = le32_to_cpu(cp->array[0].code_page_data);
  80         cpi = le16_to_cpu(cp->array[0].index);
  81         brelse(bh);
  82
  83         if (cpi >= 3) {
  84                 pr_err("Code page index out of array\n");
  85                 return NULL;
  86         }
  87
  88         if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
  89         if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
  90                 pr_err("Code page index out of sector\n");
  91                 brelse(bh);
  92                 return NULL;
  93         }
  94         ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
  95         if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
  96                 pr_err("out of memory for code page table\n");
  97                 brelse(bh);
  98                 return NULL;
  99         }
 100         memcpy(cp_table, ptr, 128);
 101         brelse(bh);
 102
 103         /* Try to build lowercasing table from uppercasing one */
 104
 105         for (i=128; i<256; i++) cp_table[i]=i;
 106         for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
 107                 cp_table[cp_table[i-128]] = i;
 108
 109         return cp_table;
 110 }
 111
 112 __le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
 113 {
 114         struct buffer_head *bh;
 115         int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
 116         int i;
 117         __le32 *b;
 118         if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
 119                 pr_err("can't allocate memory for bitmap directory\n");
 120                 return NULL;
 121         }
 122         for (i=0;i<n;i++) {
 123                 __le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
 124                 if (!d) {
 125                         kfree(b);
 126                         return NULL;
 127                 }
 128                 memcpy((char *)b + 512 * i, d, 512);
 129                 brelse(bh);
 130         }
 131         return b;
 132 }
 133
 134 void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
 135 {
 136         struct quad_buffer_head qbh;
 137         __le32 *directory;
 138         u32 n_hotfixes, n_used_hotfixes;
 139         unsigned i;
 140
 141         n_hotfixes = le32_to_cpu(spareblock->n_spares);
 142         n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
 143
 144         if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
 145                 hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
 146                 return;
 147         }
 148         if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
 149                 hpfs_error(s, "can't load hotfix map");
 150                 return;
 151         }
 152         for (i = 0; i < n_used_hotfixes; i++) {
 153                 hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
 154                 hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
 155         }
 156         hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
 157         hpfs_brelse4(&qbh);
 158 }
 159
 160 /*
 161  * Load fnode to memory
 162  */
 163
 164 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
 165 {
 166         struct fnode *fnode;
 167         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
 168                 return NULL;
 169         }
 170         if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
 171                 if (hpfs_sb(s)->sb_chk) {
 172                         struct extended_attribute *ea;
 173                         struct extended_attribute *ea_end;
 174                         if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
 175                                 hpfs_error(s, "bad magic on fnode %08lx",
 176                                         (unsigned long)ino);
 177                                 goto bail;
 178                         }
 179                         if (!fnode_is_dir(fnode)) {
 180                                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
 181                                     (bp_internal(&fnode->btree) ? 12 : 8)) {
 182                                         hpfs_error(s,
 183                                            "bad number of nodes in fnode %08lx",
 184                                             (unsigned long)ino);
 185                                         goto bail;
 186                                 }
 187                                 if (le16_to_cpu(fnode->btree.first_free) !=
 188                                     8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
 189                                         hpfs_error(s,
 190                                             "bad first_free pointer in fnode %08lx",
 191                                             (unsigned long)ino);
 192                                         goto bail;
 193                                 }
 194                         }
 195                         if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
 196                            le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
 197                                 hpfs_error(s,
 198                                         "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
 199                                         (unsigned long)ino,
 200                                         le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
 201                                 goto bail;
 202                         }
 203                         ea = fnode_ea(fnode);
 204                         ea_end = fnode_end_ea(fnode);
 205                         while (ea != ea_end) {
 206                                 if (ea > ea_end) {
 207                                         hpfs_error(s, "bad EA in fnode %08lx",
 208                                                 (unsigned long)ino);
 209                                         goto bail;
 210                                 }
 211                                 ea = next_ea(ea);
 212                         }
 213                 }
 214         }
 215         return fnode;
 216         bail:
 217         brelse(*bhp);
 218         return NULL;
 219 }
 220
 221 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
 222 {
 223         struct anode *anode;
 224         if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
 225         if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
 226                 if (hpfs_sb(s)->sb_chk) {
 227                         if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
 228                                 hpfs_error(s, "bad magic on anode %08x", ano);
 229                                 goto bail;
 230                         }
 231                         if (le32_to_cpu(anode->self) != ano) {
 232                                 hpfs_error(s, "self pointer invalid on anode %08x", ano);
 233                                 goto bail;
 234                         }
 235                         if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
 236                             (bp_internal(&anode->btree) ? 60 : 40)) {
 237                                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
 238                                 goto bail;
 239                         }
 240                         if (le16_to_cpu(anode->btree.first_free) !=
 241                             8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
 242                                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
 243                                 goto bail;
 244                         }
 245                 }
 246         return anode;
 247         bail:
 248         brelse(*bhp);
 249         return NULL;
 250 }
 251
 252 /*
 253  * Load dnode to memory and do some checks
 254  */
 255
 256 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
 257                              struct quad_buffer_head *qbh)
 258 {
 259         struct dnode *dnode;
 260         if (hpfs_sb(s)->sb_chk) {
 261                 if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
 262                 if (secno & 3) {
 263                         hpfs_error(s, "dnode %08x not byte-aligned", secno);
 264                         return NULL;
 265                 }
 266         }
 267         if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
 268                 if (hpfs_sb(s)->sb_chk) {
 269                         unsigned p, pp = 0;
 270                         unsigned char *d = (unsigned char *)dnode;
 271                         int b = 0;
 272                         if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
 273                                 hpfs_error(s, "bad magic on dnode %08x", secno);
 274                                 goto bail;
 275                         }
 276                         if (le32_to_cpu(dnode->self) != secno)
 277                                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
 278                         /* Check dirents - bad dirents would cause infinite
 279                            loops or shooting to memory */
 280                         if (le32_to_cpu(dnode->first_free) > 2048) {
 281                                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
 282                                 goto bail;
 283                         }
 284                         for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
 285                                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
 286                                 if (le16_to_cpu(de->length) > 292 || (le16_to_cpu(de->length) < 32) || (le16_to_cpu(de->length) & 3) || p + le16_to_cpu(de->length) > 2048) {
 287                                         hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 288                                         goto bail;
 289                                 }
 290                                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
 291                                         if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
 292                                         hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 293                                         goto bail;
 294                                 }
 295                                 ok:
 296                                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
 297                                 if (de->down) if (de_down_pointer(de) < 0x10) {
 298                                         hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
 299                                         goto bail;
 300                                 }
 301                                 pp = p;
 302
 303                         }
 304                         if (p != le32_to_cpu(dnode->first_free)) {
 305                                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
 306                                 goto bail;
 307                         }
 308                         if (d[pp + 30] != 1 || d[pp + 31] != 255) {
 309                                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
 310                                 goto bail;
 311                         }
 312                         if (b == 3)
 313                                 pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n",
 314                                         secno);
 315                 }
 316         return dnode;
 317         bail:
 318         hpfs_brelse4(qbh);
 319         return NULL;
 320 }
 321
 322 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
 323 {
 324         struct buffer_head *bh;
 325         struct fnode *fnode;
 326         dnode_secno dno;
 327
 328         fnode = hpfs_map_fnode(s, ino, &bh);
 329         if (!fnode)
 330                 return 0;
 331
 332         dno = le32_to_cpu(fnode->u.external[0].disk_secno);
 333         brelse(bh);
 334         return dno;
 335 }