1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * linux/fs/adfs/dir_fplus.c |
4 | * |
5 | * Copyright (C) 1997-1999 Russell King |
6 | */ |
7 | #include "adfs.h" |
8 | #include "dir_fplus.h" |
9 | |
10 | /* Return the byte offset to directory entry pos */ |
11 | static unsigned int adfs_fplus_offset(const struct adfs_bigdirheader *h, |
12 | unsigned int pos) |
13 | { |
14 | return offsetof(struct adfs_bigdirheader, bigdirname) + |
15 | ALIGN(le32_to_cpu(h->bigdirnamelen), 4) + |
16 | pos * sizeof(struct adfs_bigdirentry); |
17 | } |
18 | |
19 | static int (const struct adfs_bigdirheader *h) |
20 | { |
21 | unsigned int size = le32_to_cpu(h->bigdirsize); |
22 | unsigned int len; |
23 | |
24 | if (h->bigdirversion[0] != 0 || h->bigdirversion[1] != 0 || |
25 | h->bigdirversion[2] != 0 || |
26 | h->bigdirstartname != cpu_to_le32(BIGDIRSTARTNAME) || |
27 | !size || size & 2047 || size > SZ_4M) |
28 | return -EIO; |
29 | |
30 | size -= sizeof(struct adfs_bigdirtail) + |
31 | offsetof(struct adfs_bigdirheader, bigdirname); |
32 | |
33 | /* Check that bigdirnamelen fits within the directory */ |
34 | len = ALIGN(le32_to_cpu(h->bigdirnamelen), 4); |
35 | if (len > size) |
36 | return -EIO; |
37 | |
38 | size -= len; |
39 | |
40 | /* Check that bigdirnamesize fits within the directory */ |
41 | len = le32_to_cpu(h->bigdirnamesize); |
42 | if (len > size) |
43 | return -EIO; |
44 | |
45 | size -= len; |
46 | |
47 | /* |
48 | * Avoid division, we know that absolute maximum number of entries |
49 | * can not be so large to cause overflow of the multiplication below. |
50 | */ |
51 | len = le32_to_cpu(h->bigdirentries); |
52 | if (len > SZ_4M / sizeof(struct adfs_bigdirentry) || |
53 | len * sizeof(struct adfs_bigdirentry) > size) |
54 | return -EIO; |
55 | |
56 | return 0; |
57 | } |
58 | |
59 | static int adfs_fplus_validate_tail(const struct adfs_bigdirheader *h, |
60 | const struct adfs_bigdirtail *t) |
61 | { |
62 | if (t->bigdirendname != cpu_to_le32(BIGDIRENDNAME) || |
63 | t->bigdirendmasseq != h->startmasseq || |
64 | t->reserved[0] != 0 || t->reserved[1] != 0) |
65 | return -EIO; |
66 | |
67 | return 0; |
68 | } |
69 | |
70 | static u8 adfs_fplus_checkbyte(struct adfs_dir *dir) |
71 | { |
72 | struct adfs_bigdirheader *h = dir->bighead; |
73 | struct adfs_bigdirtail *t = dir->bigtail; |
74 | unsigned int end, bs, bi, i; |
75 | __le32 *bp; |
76 | u32 dircheck; |
77 | |
78 | end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)) + |
79 | le32_to_cpu(h->bigdirnamesize); |
80 | |
81 | /* Accumulate the contents of the header, entries and names */ |
82 | for (dircheck = 0, bi = 0; end; bi++) { |
83 | bp = (void *)dir->bhs[bi]->b_data; |
84 | bs = dir->bhs[bi]->b_size; |
85 | if (bs > end) |
86 | bs = end; |
87 | |
88 | for (i = 0; i < bs; i += sizeof(u32)) |
89 | dircheck = ror32(word: dircheck, shift: 13) ^ le32_to_cpup(p: bp++); |
90 | |
91 | end -= bs; |
92 | } |
93 | |
94 | /* Accumulate the contents of the tail except for the check byte */ |
95 | dircheck = ror32(word: dircheck, shift: 13) ^ le32_to_cpu(t->bigdirendname); |
96 | dircheck = ror32(word: dircheck, shift: 13) ^ t->bigdirendmasseq; |
97 | dircheck = ror32(word: dircheck, shift: 13) ^ t->reserved[0]; |
98 | dircheck = ror32(word: dircheck, shift: 13) ^ t->reserved[1]; |
99 | |
100 | return dircheck ^ dircheck >> 8 ^ dircheck >> 16 ^ dircheck >> 24; |
101 | } |
102 | |
103 | static int adfs_fplus_read(struct super_block *sb, u32 indaddr, |
104 | unsigned int size, struct adfs_dir *dir) |
105 | { |
106 | struct adfs_bigdirheader *h; |
107 | struct adfs_bigdirtail *t; |
108 | unsigned int dirsize; |
109 | int ret; |
110 | |
111 | /* Read first buffer */ |
112 | ret = adfs_dir_read_buffers(sb, indaddr, size: sb->s_blocksize, dir); |
113 | if (ret) |
114 | return ret; |
115 | |
116 | dir->bighead = h = (void *)dir->bhs[0]->b_data; |
117 | ret = adfs_fplus_validate_header(h); |
118 | if (ret) { |
119 | adfs_error(sb, "dir %06x has malformed header" , indaddr); |
120 | goto out; |
121 | } |
122 | |
123 | dirsize = le32_to_cpu(h->bigdirsize); |
124 | if (size && dirsize != size) { |
125 | adfs_msg(sb, KERN_WARNING, |
126 | fmt: "dir %06x header size %X does not match directory size %X" , |
127 | indaddr, dirsize, size); |
128 | } |
129 | |
130 | /* Read remaining buffers */ |
131 | ret = adfs_dir_read_buffers(sb, indaddr, size: dirsize, dir); |
132 | if (ret) |
133 | return ret; |
134 | |
135 | dir->bigtail = t = (struct adfs_bigdirtail *) |
136 | (dir->bhs[dir->nr_buffers - 1]->b_data + (sb->s_blocksize - 8)); |
137 | |
138 | ret = adfs_fplus_validate_tail(h, t); |
139 | if (ret) { |
140 | adfs_error(sb, "dir %06x has malformed tail" , indaddr); |
141 | goto out; |
142 | } |
143 | |
144 | if (adfs_fplus_checkbyte(dir) != t->bigdircheckbyte) { |
145 | adfs_error(sb, "dir %06x checkbyte mismatch\n" , indaddr); |
146 | goto out; |
147 | } |
148 | |
149 | dir->parent_id = le32_to_cpu(h->bigdirparent); |
150 | return 0; |
151 | |
152 | out: |
153 | adfs_dir_relse(dir); |
154 | |
155 | return ret; |
156 | } |
157 | |
158 | static int |
159 | adfs_fplus_setpos(struct adfs_dir *dir, unsigned int fpos) |
160 | { |
161 | int ret = -ENOENT; |
162 | |
163 | if (fpos <= le32_to_cpu(dir->bighead->bigdirentries)) { |
164 | dir->pos = fpos; |
165 | ret = 0; |
166 | } |
167 | |
168 | return ret; |
169 | } |
170 | |
171 | static int |
172 | adfs_fplus_getnext(struct adfs_dir *dir, struct object_info *obj) |
173 | { |
174 | struct adfs_bigdirheader *h = dir->bighead; |
175 | struct adfs_bigdirentry bde; |
176 | unsigned int offset; |
177 | int ret; |
178 | |
179 | if (dir->pos >= le32_to_cpu(h->bigdirentries)) |
180 | return -ENOENT; |
181 | |
182 | offset = adfs_fplus_offset(h, pos: dir->pos); |
183 | |
184 | ret = adfs_dir_copyfrom(dst: &bde, dir, offset, |
185 | len: sizeof(struct adfs_bigdirentry)); |
186 | if (ret) |
187 | return ret; |
188 | |
189 | obj->loadaddr = le32_to_cpu(bde.bigdirload); |
190 | obj->execaddr = le32_to_cpu(bde.bigdirexec); |
191 | obj->size = le32_to_cpu(bde.bigdirlen); |
192 | obj->indaddr = le32_to_cpu(bde.bigdirindaddr); |
193 | obj->attr = le32_to_cpu(bde.bigdirattr); |
194 | obj->name_len = le32_to_cpu(bde.bigdirobnamelen); |
195 | |
196 | offset = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)); |
197 | offset += le32_to_cpu(bde.bigdirobnameptr); |
198 | |
199 | ret = adfs_dir_copyfrom(dst: obj->name, dir, offset, len: obj->name_len); |
200 | if (ret) |
201 | return ret; |
202 | |
203 | adfs_object_fixup(dir, obj); |
204 | |
205 | dir->pos += 1; |
206 | |
207 | return 0; |
208 | } |
209 | |
210 | static int adfs_fplus_iterate(struct adfs_dir *dir, struct dir_context *ctx) |
211 | { |
212 | struct object_info obj; |
213 | |
214 | if ((ctx->pos - 2) >> 32) |
215 | return 0; |
216 | |
217 | if (adfs_fplus_setpos(dir, fpos: ctx->pos - 2)) |
218 | return 0; |
219 | |
220 | while (!adfs_fplus_getnext(dir, obj: &obj)) { |
221 | if (!dir_emit(ctx, name: obj.name, namelen: obj.name_len, |
222 | ino: obj.indaddr, DT_UNKNOWN)) |
223 | break; |
224 | ctx->pos++; |
225 | } |
226 | |
227 | return 0; |
228 | } |
229 | |
230 | static int adfs_fplus_update(struct adfs_dir *dir, struct object_info *obj) |
231 | { |
232 | struct adfs_bigdirheader *h = dir->bighead; |
233 | struct adfs_bigdirentry bde; |
234 | int offset, end, ret; |
235 | |
236 | offset = adfs_fplus_offset(h, pos: 0) - sizeof(bde); |
237 | end = adfs_fplus_offset(h, le32_to_cpu(h->bigdirentries)); |
238 | |
239 | do { |
240 | offset += sizeof(bde); |
241 | if (offset >= end) { |
242 | adfs_error(dir->sb, "unable to locate entry to update" ); |
243 | return -ENOENT; |
244 | } |
245 | ret = adfs_dir_copyfrom(dst: &bde, dir, offset, len: sizeof(bde)); |
246 | if (ret) { |
247 | adfs_error(dir->sb, "error reading directory entry" ); |
248 | return -ENOENT; |
249 | } |
250 | } while (le32_to_cpu(bde.bigdirindaddr) != obj->indaddr); |
251 | |
252 | bde.bigdirload = cpu_to_le32(obj->loadaddr); |
253 | bde.bigdirexec = cpu_to_le32(obj->execaddr); |
254 | bde.bigdirlen = cpu_to_le32(obj->size); |
255 | bde.bigdirindaddr = cpu_to_le32(obj->indaddr); |
256 | bde.bigdirattr = cpu_to_le32(obj->attr); |
257 | |
258 | return adfs_dir_copyto(dir, offset, src: &bde, len: sizeof(bde)); |
259 | } |
260 | |
261 | static int adfs_fplus_commit(struct adfs_dir *dir) |
262 | { |
263 | int ret; |
264 | |
265 | /* Increment directory sequence number */ |
266 | dir->bighead->startmasseq += 1; |
267 | dir->bigtail->bigdirendmasseq += 1; |
268 | |
269 | /* Update directory check byte */ |
270 | dir->bigtail->bigdircheckbyte = adfs_fplus_checkbyte(dir); |
271 | |
272 | /* Make sure the directory still validates correctly */ |
273 | ret = adfs_fplus_validate_header(h: dir->bighead); |
274 | if (ret == 0) |
275 | ret = adfs_fplus_validate_tail(h: dir->bighead, t: dir->bigtail); |
276 | |
277 | return ret; |
278 | } |
279 | |
280 | const struct adfs_dir_ops adfs_fplus_dir_ops = { |
281 | .read = adfs_fplus_read, |
282 | .iterate = adfs_fplus_iterate, |
283 | .setpos = adfs_fplus_setpos, |
284 | .getnext = adfs_fplus_getnext, |
285 | .update = adfs_fplus_update, |
286 | .commit = adfs_fplus_commit, |
287 | }; |
288 | |