fs/hpfs/map.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  *  linux/fs/hpfs/map.c
0004  *
0005  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
0006  *
0007  *  mapping structures to memory with some minimal checks
0008  */
0009
0010 #include "hpfs_fn.h"
0011
0012 __le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
0013 {
0014     return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
0015 }
0016
0017 __le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
0018              struct quad_buffer_head *qbh, char *id)
0019 {
0020     secno sec;
0021     __le32 *ret;
0022     unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
0023     if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
0024         hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
0025         return NULL;
0026     }
0027     sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
0028     if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
0029         hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
0030         return NULL;
0031     }
0032     ret = hpfs_map_4sectors(s, sec, qbh, 4);
0033     if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
0034     return ret;
0035 }
0036
0037 void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
0038 {
0039     unsigned to_prefetch, next_prefetch;
0040     unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
0041     if (unlikely(bmp_block >= n_bands))
0042         return;
0043     to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
0044     if (unlikely(bmp_block + 1 >= n_bands))
0045         next_prefetch = 0;
0046     else
0047         next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
0048     hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
0049 }
0050
0051 /*
0052  * Load first code page into kernel memory, return pointer to 256-byte array,
0053  * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
0054  * lowercasing table
0055  */
0056
0057 unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
0058 {
0059     struct buffer_head *bh;
0060     secno cpds;
0061     unsigned cpi;
0062     unsigned char *ptr;
0063     unsigned char *cp_table;
0064     int i;
0065     struct code_page_data *cpd;
0066     struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
0067     if (!cp) return NULL;
0068     if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
0069         pr_err("Code page directory magic doesn't match (magic = %08x)\n",
0070             le32_to_cpu(cp->magic));
0071         brelse(bh);
0072         return NULL;
0073     }
0074     if (!le32_to_cpu(cp->n_code_pages)) {
0075         pr_err("n_code_pages == 0\n");
0076         brelse(bh);
0077         return NULL;
0078     }
0079     cpds = le32_to_cpu(cp->array[0].code_page_data);
0080     cpi = le16_to_cpu(cp->array[0].index);
0081     brelse(bh);
0082
0083     if (cpi >= 3) {
0084         pr_err("Code page index out of array\n");
0085         return NULL;
0086     }
0087
0088     if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
0089     if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
0090         pr_err("Code page index out of sector\n");
0091         brelse(bh);
0092         return NULL;
0093     }
0094     ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
0095     if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
0096         pr_err("out of memory for code page table\n");
0097         brelse(bh);
0098         return NULL;
0099     }
0100     memcpy(cp_table, ptr, 128);
0101     brelse(bh);
0102
0103     /* Try to build lowercasing table from uppercasing one */
0104
0105     for (i=128; i<256; i++) cp_table[i]=i;
0106     for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
0107         cp_table[cp_table[i-128]] = i;
0108
0109     return cp_table;
0110 }
0111
0112 __le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
0113 {
0114     struct buffer_head *bh;
0115     int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
0116     int i;
0117     __le32 *b;
0118     if (!(b = kmalloc_array(n, 512, GFP_KERNEL))) {
0119         pr_err("can't allocate memory for bitmap directory\n");
0120         return NULL;
0121     }
0122     for (i=0;i<n;i++) {
0123         __le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
0124         if (!d) {
0125             kfree(b);
0126             return NULL;
0127         }
0128         memcpy((char *)b + 512 * i, d, 512);
0129         brelse(bh);
0130     }
0131     return b;
0132 }
0133
0134 void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
0135 {
0136     struct quad_buffer_head qbh;
0137     __le32 *directory;
0138     u32 n_hotfixes, n_used_hotfixes;
0139     unsigned i;
0140
0141     n_hotfixes = le32_to_cpu(spareblock->n_spares);
0142     n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
0143
0144     if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
0145         hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
0146         return;
0147     }
0148     if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
0149         hpfs_error(s, "can't load hotfix map");
0150         return;
0151     }
0152     for (i = 0; i < n_used_hotfixes; i++) {
0153         hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
0154         hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
0155     }
0156     hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
0157     hpfs_brelse4(&qbh);
0158 }
0159
0160 /*
0161  * Load fnode to memory
0162  */
0163
0164 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
0165 {
0166     struct fnode *fnode;
0167     if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
0168         return NULL;
0169     }
0170     if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
0171         if (hpfs_sb(s)->sb_chk) {
0172             struct extended_attribute *ea;
0173             struct extended_attribute *ea_end;
0174             if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
0175                 hpfs_error(s, "bad magic on fnode %08lx",
0176                     (unsigned long)ino);
0177                 goto bail;
0178             }
0179             if (!fnode_is_dir(fnode)) {
0180                 if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
0181                     (bp_internal(&fnode->btree) ? 12 : 8)) {
0182                     hpfs_error(s,
0183                        "bad number of nodes in fnode %08lx",
0184                         (unsigned long)ino);
0185                     goto bail;
0186                 }
0187                 if (le16_to_cpu(fnode->btree.first_free) !=
0188                     8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
0189                     hpfs_error(s,
0190                         "bad first_free pointer in fnode %08lx",
0191                         (unsigned long)ino);
0192                     goto bail;
0193                 }
0194             }
0195             if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
0196                le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
0197                 hpfs_error(s,
0198                     "bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
0199                     (unsigned long)ino,
0200                     le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
0201                 goto bail;
0202             }
0203             ea = fnode_ea(fnode);
0204             ea_end = fnode_end_ea(fnode);
0205             while (ea != ea_end) {
0206                 if (ea > ea_end) {
0207                     hpfs_error(s, "bad EA in fnode %08lx",
0208                         (unsigned long)ino);
0209                     goto bail;
0210                 }
0211                 ea = next_ea(ea);
0212             }
0213         }
0214     }
0215     return fnode;
0216     bail:
0217     brelse(*bhp);
0218     return NULL;
0219 }
0220
0221 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
0222 {
0223     struct anode *anode;
0224     if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
0225     if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
0226         if (hpfs_sb(s)->sb_chk) {
0227             if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
0228                 hpfs_error(s, "bad magic on anode %08x", ano);
0229                 goto bail;
0230             }
0231             if (le32_to_cpu(anode->self) != ano) {
0232                 hpfs_error(s, "self pointer invalid on anode %08x", ano);
0233                 goto bail;
0234             }
0235             if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
0236                 (bp_internal(&anode->btree) ? 60 : 40)) {
0237                 hpfs_error(s, "bad number of nodes in anode %08x", ano);
0238                 goto bail;
0239             }
0240             if (le16_to_cpu(anode->btree.first_free) !=
0241                 8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
0242                 hpfs_error(s, "bad first_free pointer in anode %08x", ano);
0243                 goto bail;
0244             }
0245         }
0246     return anode;
0247     bail:
0248     brelse(*bhp);
0249     return NULL;
0250 }
0251
0252 /*
0253  * Load dnode to memory and do some checks
0254  */
0255
0256 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
0257                  struct quad_buffer_head *qbh)
0258 {
0259     struct dnode *dnode;
0260     if (hpfs_sb(s)->sb_chk) {
0261         if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
0262         if (secno & 3) {
0263             hpfs_error(s, "dnode %08x not byte-aligned", secno);
0264             return NULL;
0265         }
0266     }
0267     if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
0268         if (hpfs_sb(s)->sb_chk) {
0269             unsigned p, pp = 0;
0270             unsigned char *d = (unsigned char *)dnode;
0271             int b = 0;
0272             if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
0273                 hpfs_error(s, "bad magic on dnode %08x", secno);
0274                 goto bail;
0275             }
0276             if (le32_to_cpu(dnode->self) != secno)
0277                 hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
0278             /* Check dirents - bad dirents would cause infinite
0279                loops or shooting to memory */
0280             if (le32_to_cpu(dnode->first_free) > 2048) {
0281                 hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
0282                 goto bail;
0283             }
0284             for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
0285                 struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
0286                 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) {
0287                     hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
0288                     goto bail;
0289                 }
0290                 if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
0291                     if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & SB_RDONLY) goto ok;
0292                     hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
0293                     goto bail;
0294                 }
0295                 ok:
0296                 if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
0297                 if (de->down) if (de_down_pointer(de) < 0x10) {
0298                     hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
0299                     goto bail;
0300                 }
0301                 pp = p;
0302
0303             }
0304             if (p != le32_to_cpu(dnode->first_free)) {
0305                 hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
0306                 goto bail;
0307             }
0308             if (d[pp + 30] != 1 || d[pp + 31] != 255) {
0309                 hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
0310                 goto bail;
0311             }
0312             if (b == 3)
0313                 pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n",
0314                     secno);
0315         }
0316     return dnode;
0317     bail:
0318     hpfs_brelse4(qbh);
0319     return NULL;
0320 }
0321
0322 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
0323 {
0324     struct buffer_head *bh;
0325     struct fnode *fnode;
0326     dnode_secno dno;
0327
0328     fnode = hpfs_map_fnode(s, ino, &bh);
0329     if (!fnode)
0330         return 0;
0331
0332     dno = le32_to_cpu(fnode->u.external[0].disk_secno);
0333     brelse(bh);
0334     return dno;
0335 }