]>
Commit | Line | Data |
---|---|---|
b4d0d230 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
31d921c7 DH |
2 | /* Filesystem parameter parser. |
3 | * | |
4 | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | |
5 | * Written by David Howells (dhowells@redhat.com) | |
31d921c7 DH |
6 | */ |
7 | ||
8 | #include <linux/export.h> | |
9 | #include <linux/fs_context.h> | |
10 | #include <linux/fs_parser.h> | |
11 | #include <linux/slab.h> | |
12 | #include <linux/security.h> | |
13 | #include <linux/namei.h> | |
14 | #include "internal.h" | |
15 | ||
16 | static const struct constant_table bool_names[] = { | |
17 | { "0", false }, | |
18 | { "1", true }, | |
19 | { "false", false }, | |
20 | { "no", false }, | |
21 | { "true", true }, | |
22 | { "yes", true }, | |
34264ae3 | 23 | { }, |
31d921c7 DH |
24 | }; |
25 | ||
34264ae3 AV |
26 | static const struct constant_table * |
27 | __lookup_constant(const struct constant_table *tbl, const char *name) | |
28 | { | |
29 | for ( ; tbl->name; tbl++) | |
30 | if (strcmp(name, tbl->name) == 0) | |
31 | return tbl; | |
32 | return NULL; | |
33 | } | |
34 | ||
31d921c7 DH |
35 | /** |
36 | * lookup_constant - Look up a constant by name in an ordered table | |
37 | * @tbl: The table of constants to search. | |
31d921c7 DH |
38 | * @name: The name to look up. |
39 | * @not_found: The value to return if the name is not found. | |
40 | */ | |
34264ae3 | 41 | int lookup_constant(const struct constant_table *tbl, const char *name, int not_found) |
31d921c7 | 42 | { |
34264ae3 | 43 | const struct constant_table *p = __lookup_constant(tbl, name); |
31d921c7 | 44 | |
34264ae3 | 45 | return p ? p->value : not_found; |
31d921c7 | 46 | } |
34264ae3 | 47 | EXPORT_SYMBOL(lookup_constant); |
31d921c7 DH |
48 | |
49 | static const struct fs_parameter_spec *fs_lookup_key( | |
50 | const struct fs_parameter_description *desc, | |
51 | const char *name) | |
52 | { | |
53 | const struct fs_parameter_spec *p; | |
54 | ||
55 | if (!desc->specs) | |
56 | return NULL; | |
57 | ||
58 | for (p = desc->specs; p->name; p++) | |
59 | if (strcmp(p->name, name) == 0) | |
60 | return p; | |
61 | ||
62 | return NULL; | |
63 | } | |
64 | ||
65 | /* | |
66 | * fs_parse - Parse a filesystem configuration parameter | |
67 | * @fc: The filesystem context to log errors through. | |
68 | * @desc: The parameter description to use. | |
69 | * @param: The parameter. | |
70 | * @result: Where to place the result of the parse | |
71 | * | |
72 | * Parse a filesystem configuration parameter and attempt a conversion for a | |
73 | * simple parameter for which this is requested. If successful, the determined | |
74 | * parameter ID is placed into @result->key, the desired type is indicated in | |
75 | * @result->t and any converted value is placed into an appropriate member of | |
76 | * the union in @result. | |
77 | * | |
78 | * The function returns the parameter number if the parameter was matched, | |
79 | * -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that | |
80 | * unknown parameters are okay and -EINVAL if there was a conversion issue or | |
81 | * the parameter wasn't recognised and unknowns aren't okay. | |
82 | */ | |
7f5d3814 | 83 | int __fs_parse(struct p_log *log, |
31d921c7 DH |
84 | const struct fs_parameter_description *desc, |
85 | struct fs_parameter *param, | |
86 | struct fs_parse_result *result) | |
87 | { | |
88 | const struct fs_parameter_spec *p; | |
5eede625 | 89 | const struct constant_table *e; |
31d921c7 DH |
90 | int ret = -ENOPARAM, b; |
91 | ||
31d921c7 DH |
92 | result->negated = false; |
93 | result->uint_64 = 0; | |
94 | ||
95 | p = fs_lookup_key(desc, param->key); | |
96 | if (!p) { | |
97 | /* If we didn't find something that looks like "noxxx", see if | |
98 | * "xxx" takes the "no"-form negative - but only if there | |
99 | * wasn't an value. | |
100 | */ | |
0f89589a | 101 | if (param->type != fs_value_is_flag) |
31d921c7 DH |
102 | goto unknown_parameter; |
103 | if (param->key[0] != 'n' || param->key[1] != 'o' || !param->key[2]) | |
104 | goto unknown_parameter; | |
105 | ||
106 | p = fs_lookup_key(desc, param->key + 2); | |
107 | if (!p) | |
108 | goto unknown_parameter; | |
109 | if (!(p->flags & fs_param_neg_with_no)) | |
110 | goto unknown_parameter; | |
111 | result->boolean = false; | |
112 | result->negated = true; | |
113 | } | |
114 | ||
115 | if (p->flags & fs_param_deprecated) | |
7f5d3814 | 116 | warn_plog(log, "Deprecated parameter '%s'", param->key); |
31d921c7 DH |
117 | |
118 | if (result->negated) | |
119 | goto okay; | |
120 | ||
121 | /* Certain parameter types only take a string and convert it. */ | |
122 | switch (p->type) { | |
123 | case __fs_param_wasnt_defined: | |
124 | return -EINVAL; | |
125 | case fs_param_is_u32: | |
126 | case fs_param_is_u32_octal: | |
127 | case fs_param_is_u32_hex: | |
128 | case fs_param_is_s32: | |
129 | case fs_param_is_u64: | |
130 | case fs_param_is_enum: | |
131 | case fs_param_is_string: | |
0f89589a AV |
132 | if (param->type == fs_value_is_string) { |
133 | if (p->flags & fs_param_v_optional) | |
134 | break; | |
135 | if (!*param->string) | |
136 | goto bad_value; | |
137 | break; | |
138 | } | |
139 | if (param->type == fs_value_is_flag) { | |
31d921c7 DH |
140 | if (p->flags & fs_param_v_optional) |
141 | goto okay; | |
31d921c7 | 142 | } |
0f89589a | 143 | goto bad_value; |
31d921c7 DH |
144 | default: |
145 | break; | |
146 | } | |
147 | ||
148 | /* Try to turn the type we were given into the type desired by the | |
149 | * parameter and give an error if we can't. | |
150 | */ | |
151 | switch (p->type) { | |
152 | case fs_param_is_flag: | |
0f89589a | 153 | if (param->type != fs_value_is_flag) |
7f5d3814 AV |
154 | return inval_plog(log, "Unexpected value for '%s'", |
155 | param->key); | |
31d921c7 DH |
156 | result->boolean = true; |
157 | goto okay; | |
158 | ||
159 | case fs_param_is_bool: | |
160 | switch (param->type) { | |
161 | case fs_value_is_flag: | |
162 | result->boolean = true; | |
163 | goto okay; | |
164 | case fs_value_is_string: | |
165 | if (param->size == 0) { | |
166 | result->boolean = true; | |
167 | goto okay; | |
168 | } | |
169 | b = lookup_constant(bool_names, param->string, -1); | |
170 | if (b == -1) | |
171 | goto bad_value; | |
172 | result->boolean = b; | |
173 | goto okay; | |
174 | default: | |
175 | goto bad_value; | |
176 | } | |
177 | ||
178 | case fs_param_is_u32: | |
179 | ret = kstrtouint(param->string, 0, &result->uint_32); | |
180 | goto maybe_okay; | |
181 | case fs_param_is_u32_octal: | |
182 | ret = kstrtouint(param->string, 8, &result->uint_32); | |
183 | goto maybe_okay; | |
184 | case fs_param_is_u32_hex: | |
185 | ret = kstrtouint(param->string, 16, &result->uint_32); | |
186 | goto maybe_okay; | |
187 | case fs_param_is_s32: | |
188 | ret = kstrtoint(param->string, 0, &result->int_32); | |
189 | goto maybe_okay; | |
190 | case fs_param_is_u64: | |
191 | ret = kstrtoull(param->string, 0, &result->uint_64); | |
192 | goto maybe_okay; | |
193 | ||
194 | case fs_param_is_enum: | |
34264ae3 AV |
195 | e = __lookup_constant(p->data, param->string); |
196 | if (e) { | |
197 | result->uint_32 = e->value; | |
198 | goto okay; | |
31d921c7 DH |
199 | } |
200 | goto bad_value; | |
201 | ||
202 | case fs_param_is_string: | |
203 | goto okay; | |
204 | case fs_param_is_blob: | |
205 | if (param->type != fs_value_is_blob) | |
206 | goto bad_value; | |
207 | goto okay; | |
208 | ||
209 | case fs_param_is_fd: { | |
74983ac2 DH |
210 | switch (param->type) { |
211 | case fs_value_is_string: | |
74983ac2 DH |
212 | ret = kstrtouint(param->string, 0, &result->uint_32); |
213 | break; | |
214 | case fs_value_is_file: | |
215 | result->uint_32 = param->dirfd; | |
216 | ret = 0; | |
217 | default: | |
31d921c7 | 218 | goto bad_value; |
74983ac2 DH |
219 | } |
220 | ||
221 | if (result->uint_32 > INT_MAX) | |
222 | goto bad_value; | |
223 | goto maybe_okay; | |
31d921c7 DH |
224 | } |
225 | ||
226 | case fs_param_is_blockdev: | |
227 | case fs_param_is_path: | |
228 | goto okay; | |
229 | default: | |
230 | BUG(); | |
231 | } | |
232 | ||
233 | maybe_okay: | |
234 | if (ret < 0) | |
235 | goto bad_value; | |
236 | okay: | |
237 | return p->opt; | |
238 | ||
239 | bad_value: | |
7f5d3814 | 240 | return inval_plog(log, "Bad value for '%s'", param->key); |
31d921c7 DH |
241 | unknown_parameter: |
242 | return -ENOPARAM; | |
243 | } | |
7f5d3814 AV |
244 | EXPORT_SYMBOL(__fs_parse); |
245 | ||
31d921c7 DH |
246 | /** |
247 | * fs_lookup_param - Look up a path referred to by a parameter | |
248 | * @fc: The filesystem context to log errors through. | |
249 | * @param: The parameter. | |
250 | * @want_bdev: T if want a blockdev | |
251 | * @_path: The result of the lookup | |
252 | */ | |
253 | int fs_lookup_param(struct fs_context *fc, | |
254 | struct fs_parameter *param, | |
255 | bool want_bdev, | |
256 | struct path *_path) | |
257 | { | |
258 | struct filename *f; | |
259 | unsigned int flags = 0; | |
260 | bool put_f; | |
261 | int ret; | |
262 | ||
263 | switch (param->type) { | |
264 | case fs_value_is_string: | |
265 | f = getname_kernel(param->string); | |
266 | if (IS_ERR(f)) | |
267 | return PTR_ERR(f); | |
268 | put_f = true; | |
269 | break; | |
31d921c7 DH |
270 | case fs_value_is_filename: |
271 | f = param->name; | |
272 | put_f = false; | |
273 | break; | |
274 | default: | |
275 | return invalf(fc, "%s: not usable as path", param->key); | |
276 | } | |
277 | ||
7cdfa442 | 278 | f->refcnt++; /* filename_lookup() drops our ref. */ |
31d921c7 DH |
279 | ret = filename_lookup(param->dirfd, f, flags, _path, NULL); |
280 | if (ret < 0) { | |
281 | errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name); | |
282 | goto out; | |
283 | } | |
284 | ||
285 | if (want_bdev && | |
286 | !S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) { | |
287 | path_put(_path); | |
288 | _path->dentry = NULL; | |
289 | _path->mnt = NULL; | |
290 | errorf(fc, "%s: Non-blockdev passed as '%s'", | |
291 | param->key, f->name); | |
292 | ret = -ENOTBLK; | |
293 | } | |
294 | ||
295 | out: | |
296 | if (put_f) | |
297 | putname(f); | |
298 | return ret; | |
299 | } | |
300 | EXPORT_SYMBOL(fs_lookup_param); | |
301 | ||
302 | #ifdef CONFIG_VALIDATE_FS_PARSER | |
303 | /** | |
304 | * validate_constant_table - Validate a constant table | |
305 | * @name: Name to use in reporting | |
306 | * @tbl: The constant table to validate. | |
307 | * @tbl_size: The size of the table. | |
308 | * @low: The lowest permissible value. | |
309 | * @high: The highest permissible value. | |
310 | * @special: One special permissible value outside of the range. | |
311 | */ | |
312 | bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, | |
313 | int low, int high, int special) | |
314 | { | |
315 | size_t i; | |
316 | bool good = true; | |
317 | ||
318 | if (tbl_size == 0) { | |
319 | pr_warn("VALIDATE C-TBL: Empty\n"); | |
320 | return true; | |
321 | } | |
322 | ||
323 | for (i = 0; i < tbl_size; i++) { | |
324 | if (!tbl[i].name) { | |
325 | pr_err("VALIDATE C-TBL[%zu]: Null\n", i); | |
326 | good = false; | |
327 | } else if (i > 0 && tbl[i - 1].name) { | |
328 | int c = strcmp(tbl[i-1].name, tbl[i].name); | |
329 | ||
330 | if (c == 0) { | |
331 | pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n", | |
332 | i, tbl[i].name); | |
333 | good = false; | |
334 | } | |
335 | if (c > 0) { | |
336 | pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n", | |
337 | i, tbl[i-1].name, tbl[i].name); | |
338 | good = false; | |
339 | } | |
340 | } | |
341 | ||
342 | if (tbl[i].value != special && | |
343 | (tbl[i].value < low || tbl[i].value > high)) { | |
344 | pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n", | |
345 | i, tbl[i].name, tbl[i].value, low, high); | |
346 | good = false; | |
347 | } | |
348 | } | |
349 | ||
350 | return good; | |
351 | } | |
352 | ||
353 | /** | |
354 | * fs_validate_description - Validate a parameter description | |
355 | * @desc: The parameter description to validate. | |
356 | */ | |
357 | bool fs_validate_description(const struct fs_parameter_description *desc) | |
358 | { | |
359 | const struct fs_parameter_spec *param, *p2; | |
31d921c7 | 360 | const char *name = desc->name; |
2710c957 | 361 | bool good = true; |
31d921c7 DH |
362 | |
363 | pr_notice("*** VALIDATE %s ***\n", name); | |
364 | ||
365 | if (!name[0]) { | |
366 | pr_err("VALIDATE Parser: No name\n"); | |
367 | name = "Unknown"; | |
368 | good = false; | |
369 | } | |
370 | ||
371 | if (desc->specs) { | |
372 | for (param = desc->specs; param->name; param++) { | |
373 | enum fs_parameter_type t = param->type; | |
374 | ||
375 | /* Check that the type is in range */ | |
376 | if (t == __fs_param_wasnt_defined || | |
377 | t >= nr__fs_parameter_type) { | |
378 | pr_err("VALIDATE %s: PARAM[%s] Bad type %u\n", | |
379 | name, param->name, t); | |
380 | good = false; | |
381 | } else if (t == fs_param_is_enum) { | |
5eede625 | 382 | const struct constant_table *e = param->data; |
2710c957 AV |
383 | if (!e || !e->name) { |
384 | pr_err("VALIDATE %s: PARAM[%s] enum with no values\n", | |
385 | name, param->name); | |
386 | good = false; | |
387 | } | |
31d921c7 DH |
388 | } |
389 | ||
390 | /* Check for duplicate parameter names */ | |
391 | for (p2 = desc->specs; p2 < param; p2++) { | |
392 | if (strcmp(param->name, p2->name) == 0) { | |
393 | pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n", | |
394 | name, param->name); | |
395 | good = false; | |
396 | } | |
397 | } | |
398 | } | |
31d921c7 | 399 | } |
31d921c7 DH |
400 | return good; |
401 | } | |
402 | #endif /* CONFIG_VALIDATE_FS_PARSER */ |