1 /*
2  *  linux/fs/hpfs/map.c
3  *
4  *  Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
5  *
6  *  mapping structures to memory with some minimal checks
7  */
8 
9 #include "hpfs_fn.h"
10 
hpfs_map_dnode_bitmap(struct super_block * s,struct quad_buffer_head * qbh)11 unsigned *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
12 {
13 	return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
14 }
15 
hpfs_map_bitmap(struct super_block * s,unsigned bmp_block,struct quad_buffer_head * qbh,char * id)16 unsigned int *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
17 			 struct quad_buffer_head *qbh, char *id)
18 {
19 	secno sec;
20 	if (hpfs_sb(s)->sb_chk) if (bmp_block * 16384 > hpfs_sb(s)->sb_fs_size) {
21 		hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
22 		return NULL;
23 	}
24 	sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
25 	if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
26 		hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
27 		return NULL;
28 	}
29 	return hpfs_map_4sectors(s, sec, qbh, 4);
30 }
31 
32 /*
33  * Load first code page into kernel memory, return pointer to 256-byte array,
34  * first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
35  * lowercasing table
36  */
37 
hpfs_load_code_page(struct super_block * s,secno cps)38 unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
39 {
40 	struct buffer_head *bh;
41 	secno cpds;
42 	unsigned cpi;
43 	unsigned char *ptr;
44 	unsigned char *cp_table;
45 	int i;
46 	struct code_page_data *cpd;
47 	struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
48 	if (!cp) return NULL;
49 	if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
50 		printk("HPFS: Code page directory magic doesn't match (magic = %08x)\n", le32_to_cpu(cp->magic));
51 		brelse(bh);
52 		return NULL;
53 	}
54 	if (!le32_to_cpu(cp->n_code_pages)) {
55 		printk("HPFS: n_code_pages == 0\n");
56 		brelse(bh);
57 		return NULL;
58 	}
59 	cpds = le32_to_cpu(cp->array[0].code_page_data);
60 	cpi = le16_to_cpu(cp->array[0].index);
61 	brelse(bh);
62 
63 	if (cpi >= 3) {
64 		printk("HPFS: Code page index out of array\n");
65 		return NULL;
66 	}
67 
68 	if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
69 	if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
70 		printk("HPFS: Code page index out of sector\n");
71 		brelse(bh);
72 		return NULL;
73 	}
74 	ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
75 	if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
76 		printk("HPFS: out of memory for code page table\n");
77 		brelse(bh);
78 		return NULL;
79 	}
80 	memcpy(cp_table, ptr, 128);
81 	brelse(bh);
82 
83 	/* Try to build lowercasing table from uppercasing one */
84 
85 	for (i=128; i<256; i++) cp_table[i]=i;
86 	for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
87 		cp_table[cp_table[i-128]] = i;
88 
89 	return cp_table;
90 }
91 
hpfs_load_bitmap_directory(struct super_block * s,secno bmp)92 secno *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
93 {
94 	struct buffer_head *bh;
95 	int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
96 	int i;
97 	secno *b;
98 	if (!(b = kmalloc(n * 512, GFP_KERNEL))) {
99 		printk("HPFS: can't allocate memory for bitmap directory\n");
100 		return NULL;
101 	}
102 	for (i=0;i<n;i++) {
103 		secno *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
104 		if (!d) {
105 			kfree(b);
106 			return NULL;
107 		}
108 		memcpy((char *)b + 512 * i, d, 512);
109 		brelse(bh);
110 	}
111 	return b;
112 }
113 
114 /*
115  * Load fnode to memory
116  */
117 
hpfs_map_fnode(struct super_block * s,ino_t ino,struct buffer_head ** bhp)118 struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
119 {
120 	struct fnode *fnode;
121 	if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
122 		return NULL;
123 	}
124 	if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
125 		if (hpfs_sb(s)->sb_chk) {
126 			struct extended_attribute *ea;
127 			struct extended_attribute *ea_end;
128 			if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
129 				hpfs_error(s, "bad magic on fnode %08lx",
130 					(unsigned long)ino);
131 				goto bail;
132 			}
133 			if (!fnode->dirflag) {
134 				if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
135 				    (fnode->btree.internal ? 12 : 8)) {
136 					hpfs_error(s,
137 					   "bad number of nodes in fnode %08lx",
138 					    (unsigned long)ino);
139 					goto bail;
140 				}
141 				if (le16_to_cpu(fnode->btree.first_free) !=
142 				    8 + fnode->btree.n_used_nodes * (fnode->btree.internal ? 8 : 12)) {
143 					hpfs_error(s,
144 					    "bad first_free pointer in fnode %08lx",
145 					    (unsigned long)ino);
146 					goto bail;
147 				}
148 			}
149 			if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
150 			   le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
151 				hpfs_error(s,
152 					"bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
153 					(unsigned long)ino,
154 					le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
155 				goto bail;
156 			}
157 			ea = fnode_ea(fnode);
158 			ea_end = fnode_end_ea(fnode);
159 			while (ea != ea_end) {
160 				if (ea > ea_end) {
161 					hpfs_error(s, "bad EA in fnode %08lx",
162 						(unsigned long)ino);
163 					goto bail;
164 				}
165 				ea = next_ea(ea);
166 			}
167 		}
168 	}
169 	return fnode;
170 	bail:
171 	brelse(*bhp);
172 	return NULL;
173 }
174 
hpfs_map_anode(struct super_block * s,anode_secno ano,struct buffer_head ** bhp)175 struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
176 {
177 	struct anode *anode;
178 	if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
179 	if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
180 		if (hpfs_sb(s)->sb_chk) {
181 			if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
182 				hpfs_error(s, "bad magic on anode %08x", ano);
183 				goto bail;
184 			}
185 			if (le32_to_cpu(anode->self) != ano) {
186 				hpfs_error(s, "self pointer invalid on anode %08x", ano);
187 				goto bail;
188 			}
189 			if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
190 			    (anode->btree.internal ? 60 : 40)) {
191 				hpfs_error(s, "bad number of nodes in anode %08x", ano);
192 				goto bail;
193 			}
194 			if (le16_to_cpu(anode->btree.first_free) !=
195 			    8 + anode->btree.n_used_nodes * (anode->btree.internal ? 8 : 12)) {
196 				hpfs_error(s, "bad first_free pointer in anode %08x", ano);
197 				goto bail;
198 			}
199 		}
200 	return anode;
201 	bail:
202 	brelse(*bhp);
203 	return NULL;
204 }
205 
206 /*
207  * Load dnode to memory and do some checks
208  */
209 
hpfs_map_dnode(struct super_block * s,unsigned secno,struct quad_buffer_head * qbh)210 struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
211 			     struct quad_buffer_head *qbh)
212 {
213 	struct dnode *dnode;
214 	if (hpfs_sb(s)->sb_chk) {
215 		if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
216 		if (secno & 3) {
217 			hpfs_error(s, "dnode %08x not byte-aligned", secno);
218 			return NULL;
219 		}
220 	}
221 	if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
222 		if (hpfs_sb(s)->sb_chk) {
223 			unsigned p, pp = 0;
224 			unsigned char *d = (unsigned char *)dnode;
225 			int b = 0;
226 			if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
227 				hpfs_error(s, "bad magic on dnode %08x", secno);
228 				goto bail;
229 			}
230 			if (le32_to_cpu(dnode->self) != secno)
231 				hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
232 			/* Check dirents - bad dirents would cause infinite
233 			   loops or shooting to memory */
234 			if (le32_to_cpu(dnode->first_free) > 2048) {
235 				hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
236 				goto bail;
237 			}
238 			for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
239 				struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
240 				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) {
241 					hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
242 					goto bail;
243 				}
244 				if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
245 					if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & MS_RDONLY) goto ok;
246 					hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
247 					goto bail;
248 				}
249 				ok:
250 				if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
251 				if (de->down) if (de_down_pointer(de) < 0x10) {
252 					hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
253 					goto bail;
254 				}
255 				pp = p;
256 
257 			}
258 			if (p != le32_to_cpu(dnode->first_free)) {
259 				hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
260 				goto bail;
261 			}
262 			if (d[pp + 30] != 1 || d[pp + 31] != 255) {
263 				hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
264 				goto bail;
265 			}
266 			if (b == 3) printk("HPFS: warning: unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n", secno);
267 		}
268 	return dnode;
269 	bail:
270 	hpfs_brelse4(qbh);
271 	return NULL;
272 }
273 
hpfs_fnode_dno(struct super_block * s,ino_t ino)274 dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
275 {
276 	struct buffer_head *bh;
277 	struct fnode *fnode;
278 	dnode_secno dno;
279 
280 	fnode = hpfs_map_fnode(s, ino, &bh);
281 	if (!fnode)
282 		return 0;
283 
284 	dno = le32_to_cpu(fnode->u.external[0].disk_secno);
285 	brelse(bh);
286 	return dno;
287 }
288