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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 ([email protected]) | |
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 | 48 | |
48ce73b1 AV |
49 | static inline bool is_flag(const struct fs_parameter_spec *p) |
50 | { | |
328de528 | 51 | return p->type == NULL; |
48ce73b1 AV |
52 | } |
53 | ||
31d921c7 | 54 | static const struct fs_parameter_spec *fs_lookup_key( |
d7167b14 | 55 | const struct fs_parameter_spec *desc, |
48ce73b1 | 56 | struct fs_parameter *param, bool *negated) |
31d921c7 | 57 | { |
48ce73b1 AV |
58 | const struct fs_parameter_spec *p, *other = NULL; |
59 | const char *name = param->key; | |
60 | bool want_flag = param->type == fs_value_is_flag; | |
61 | ||
62 | *negated = false; | |
63 | for (p = desc; p->name; p++) { | |
64 | if (strcmp(p->name, name) != 0) | |
65 | continue; | |
66 | if (likely(is_flag(p) == want_flag)) | |
31d921c7 | 67 | return p; |
48ce73b1 AV |
68 | other = p; |
69 | } | |
70 | if (want_flag) { | |
71 | if (name[0] == 'n' && name[1] == 'o' && name[2]) { | |
72 | for (p = desc; p->name; p++) { | |
73 | if (strcmp(p->name, name + 2) != 0) | |
74 | continue; | |
75 | if (!(p->flags & fs_param_neg_with_no)) | |
76 | continue; | |
77 | *negated = true; | |
78 | return p; | |
79 | } | |
80 | } | |
81 | } | |
82 | return other; | |
31d921c7 DH |
83 | } |
84 | ||
85 | /* | |
86 | * fs_parse - Parse a filesystem configuration parameter | |
87 | * @fc: The filesystem context to log errors through. | |
88 | * @desc: The parameter description to use. | |
89 | * @param: The parameter. | |
90 | * @result: Where to place the result of the parse | |
91 | * | |
92 | * Parse a filesystem configuration parameter and attempt a conversion for a | |
93 | * simple parameter for which this is requested. If successful, the determined | |
94 | * parameter ID is placed into @result->key, the desired type is indicated in | |
95 | * @result->t and any converted value is placed into an appropriate member of | |
96 | * the union in @result. | |
97 | * | |
98 | * The function returns the parameter number if the parameter was matched, | |
99 | * -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that | |
100 | * unknown parameters are okay and -EINVAL if there was a conversion issue or | |
101 | * the parameter wasn't recognised and unknowns aren't okay. | |
102 | */ | |
7f5d3814 | 103 | int __fs_parse(struct p_log *log, |
d7167b14 | 104 | const struct fs_parameter_spec *desc, |
31d921c7 DH |
105 | struct fs_parameter *param, |
106 | struct fs_parse_result *result) | |
107 | { | |
108 | const struct fs_parameter_spec *p; | |
31d921c7 | 109 | |
31d921c7 DH |
110 | result->uint_64 = 0; |
111 | ||
48ce73b1 AV |
112 | p = fs_lookup_key(desc, param, &result->negated); |
113 | if (!p) | |
114 | return -ENOPARAM; | |
31d921c7 DH |
115 | |
116 | if (p->flags & fs_param_deprecated) | |
7f5d3814 | 117 | warn_plog(log, "Deprecated parameter '%s'", param->key); |
31d921c7 | 118 | |
31d921c7 DH |
119 | /* Try to turn the type we were given into the type desired by the |
120 | * parameter and give an error if we can't. | |
121 | */ | |
328de528 | 122 | if (is_flag(p)) { |
0f89589a | 123 | if (param->type != fs_value_is_flag) |
7f5d3814 AV |
124 | return inval_plog(log, "Unexpected value for '%s'", |
125 | param->key); | |
48ce73b1 | 126 | result->boolean = !result->negated; |
328de528 AV |
127 | } else { |
128 | int ret = p->type(log, p, param, result); | |
129 | if (ret) | |
130 | return ret; | |
31d921c7 | 131 | } |
31d921c7 | 132 | return p->opt; |
31d921c7 | 133 | } |
7f5d3814 AV |
134 | EXPORT_SYMBOL(__fs_parse); |
135 | ||
31d921c7 DH |
136 | /** |
137 | * fs_lookup_param - Look up a path referred to by a parameter | |
138 | * @fc: The filesystem context to log errors through. | |
139 | * @param: The parameter. | |
140 | * @want_bdev: T if want a blockdev | |
141 | * @_path: The result of the lookup | |
142 | */ | |
143 | int fs_lookup_param(struct fs_context *fc, | |
144 | struct fs_parameter *param, | |
145 | bool want_bdev, | |
146 | struct path *_path) | |
147 | { | |
148 | struct filename *f; | |
149 | unsigned int flags = 0; | |
150 | bool put_f; | |
151 | int ret; | |
152 | ||
153 | switch (param->type) { | |
154 | case fs_value_is_string: | |
155 | f = getname_kernel(param->string); | |
156 | if (IS_ERR(f)) | |
157 | return PTR_ERR(f); | |
158 | put_f = true; | |
159 | break; | |
31d921c7 DH |
160 | case fs_value_is_filename: |
161 | f = param->name; | |
162 | put_f = false; | |
163 | break; | |
164 | default: | |
165 | return invalf(fc, "%s: not usable as path", param->key); | |
166 | } | |
167 | ||
168 | ret = filename_lookup(param->dirfd, f, flags, _path, NULL); | |
169 | if (ret < 0) { | |
170 | errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name); | |
171 | goto out; | |
172 | } | |
173 | ||
174 | if (want_bdev && | |
175 | !S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) { | |
176 | path_put(_path); | |
177 | _path->dentry = NULL; | |
178 | _path->mnt = NULL; | |
179 | errorf(fc, "%s: Non-blockdev passed as '%s'", | |
180 | param->key, f->name); | |
181 | ret = -ENOTBLK; | |
182 | } | |
183 | ||
184 | out: | |
185 | if (put_f) | |
186 | putname(f); | |
187 | return ret; | |
188 | } | |
189 | EXPORT_SYMBOL(fs_lookup_param); | |
190 | ||
97383c74 | 191 | static int fs_param_bad_value(struct p_log *log, struct fs_parameter *param) |
328de528 AV |
192 | { |
193 | return inval_plog(log, "Bad value for '%s'", param->key); | |
194 | } | |
195 | ||
196 | int fs_param_is_bool(struct p_log *log, const struct fs_parameter_spec *p, | |
197 | struct fs_parameter *param, struct fs_parse_result *result) | |
198 | { | |
199 | int b; | |
200 | if (param->type != fs_value_is_string) | |
201 | return fs_param_bad_value(log, param); | |
202 | b = lookup_constant(bool_names, param->string, -1); | |
203 | if (b == -1) | |
204 | return fs_param_bad_value(log, param); | |
205 | result->boolean = b; | |
206 | return 0; | |
207 | } | |
208 | EXPORT_SYMBOL(fs_param_is_bool); | |
209 | ||
210 | int fs_param_is_u32(struct p_log *log, const struct fs_parameter_spec *p, | |
211 | struct fs_parameter *param, struct fs_parse_result *result) | |
212 | { | |
213 | int base = (unsigned long)p->data; | |
214 | if (param->type != fs_value_is_string || | |
215 | kstrtouint(param->string, base, &result->uint_32) < 0) | |
216 | return fs_param_bad_value(log, param); | |
217 | return 0; | |
218 | } | |
219 | EXPORT_SYMBOL(fs_param_is_u32); | |
220 | ||
221 | int fs_param_is_s32(struct p_log *log, const struct fs_parameter_spec *p, | |
222 | struct fs_parameter *param, struct fs_parse_result *result) | |
223 | { | |
224 | if (param->type != fs_value_is_string || | |
225 | kstrtoint(param->string, 0, &result->int_32) < 0) | |
226 | return fs_param_bad_value(log, param); | |
227 | return 0; | |
228 | } | |
229 | EXPORT_SYMBOL(fs_param_is_s32); | |
230 | ||
231 | int fs_param_is_u64(struct p_log *log, const struct fs_parameter_spec *p, | |
232 | struct fs_parameter *param, struct fs_parse_result *result) | |
233 | { | |
234 | if (param->type != fs_value_is_string || | |
235 | kstrtoull(param->string, 0, &result->uint_64) < 0) | |
236 | return fs_param_bad_value(log, param); | |
237 | return 0; | |
238 | } | |
239 | EXPORT_SYMBOL(fs_param_is_u64); | |
240 | ||
241 | int fs_param_is_enum(struct p_log *log, const struct fs_parameter_spec *p, | |
242 | struct fs_parameter *param, struct fs_parse_result *result) | |
243 | { | |
244 | const struct constant_table *c; | |
245 | if (param->type != fs_value_is_string) | |
246 | return fs_param_bad_value(log, param); | |
247 | c = __lookup_constant(p->data, param->string); | |
248 | if (!c) | |
249 | return fs_param_bad_value(log, param); | |
250 | result->uint_32 = c->value; | |
251 | return 0; | |
252 | } | |
253 | EXPORT_SYMBOL(fs_param_is_enum); | |
254 | ||
255 | int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p, | |
256 | struct fs_parameter *param, struct fs_parse_result *result) | |
257 | { | |
258 | if (param->type != fs_value_is_string || !*param->string) | |
259 | return fs_param_bad_value(log, param); | |
260 | return 0; | |
261 | } | |
262 | EXPORT_SYMBOL(fs_param_is_string); | |
263 | ||
264 | int fs_param_is_blob(struct p_log *log, const struct fs_parameter_spec *p, | |
265 | struct fs_parameter *param, struct fs_parse_result *result) | |
266 | { | |
267 | if (param->type != fs_value_is_blob) | |
268 | return fs_param_bad_value(log, param); | |
269 | return 0; | |
270 | } | |
271 | EXPORT_SYMBOL(fs_param_is_blob); | |
272 | ||
273 | int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p, | |
274 | struct fs_parameter *param, struct fs_parse_result *result) | |
275 | { | |
276 | switch (param->type) { | |
277 | case fs_value_is_string: | |
278 | if (kstrtouint(param->string, 0, &result->uint_32) < 0) | |
279 | break; | |
280 | if (result->uint_32 <= INT_MAX) | |
281 | return 0; | |
282 | break; | |
283 | case fs_value_is_file: | |
284 | result->uint_32 = param->dirfd; | |
285 | if (result->uint_32 <= INT_MAX) | |
286 | return 0; | |
287 | break; | |
288 | default: | |
289 | break; | |
290 | } | |
291 | return fs_param_bad_value(log, param); | |
292 | } | |
293 | EXPORT_SYMBOL(fs_param_is_fd); | |
294 | ||
295 | int fs_param_is_blockdev(struct p_log *log, const struct fs_parameter_spec *p, | |
296 | struct fs_parameter *param, struct fs_parse_result *result) | |
297 | { | |
298 | return 0; | |
299 | } | |
300 | EXPORT_SYMBOL(fs_param_is_blockdev); | |
301 | ||
302 | int fs_param_is_path(struct p_log *log, const struct fs_parameter_spec *p, | |
303 | struct fs_parameter *param, struct fs_parse_result *result) | |
304 | { | |
305 | return 0; | |
306 | } | |
307 | EXPORT_SYMBOL(fs_param_is_path); | |
308 | ||
31d921c7 DH |
309 | #ifdef CONFIG_VALIDATE_FS_PARSER |
310 | /** | |
311 | * validate_constant_table - Validate a constant table | |
31d921c7 DH |
312 | * @tbl: The constant table to validate. |
313 | * @tbl_size: The size of the table. | |
314 | * @low: The lowest permissible value. | |
315 | * @high: The highest permissible value. | |
316 | * @special: One special permissible value outside of the range. | |
317 | */ | |
318 | bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, | |
319 | int low, int high, int special) | |
320 | { | |
321 | size_t i; | |
322 | bool good = true; | |
323 | ||
324 | if (tbl_size == 0) { | |
325 | pr_warn("VALIDATE C-TBL: Empty\n"); | |
326 | return true; | |
327 | } | |
328 | ||
329 | for (i = 0; i < tbl_size; i++) { | |
330 | if (!tbl[i].name) { | |
331 | pr_err("VALIDATE C-TBL[%zu]: Null\n", i); | |
332 | good = false; | |
333 | } else if (i > 0 && tbl[i - 1].name) { | |
334 | int c = strcmp(tbl[i-1].name, tbl[i].name); | |
335 | ||
336 | if (c == 0) { | |
337 | pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n", | |
338 | i, tbl[i].name); | |
339 | good = false; | |
340 | } | |
341 | if (c > 0) { | |
342 | pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n", | |
343 | i, tbl[i-1].name, tbl[i].name); | |
344 | good = false; | |
345 | } | |
346 | } | |
347 | ||
348 | if (tbl[i].value != special && | |
349 | (tbl[i].value < low || tbl[i].value > high)) { | |
350 | pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n", | |
351 | i, tbl[i].name, tbl[i].value, low, high); | |
352 | good = false; | |
353 | } | |
354 | } | |
355 | ||
356 | return good; | |
357 | } | |
358 | ||
359 | /** | |
360 | * fs_validate_description - Validate a parameter description | |
21ae3ad1 | 361 | * @name: The parameter name to search for. |
31d921c7 DH |
362 | * @desc: The parameter description to validate. |
363 | */ | |
96cafb9c | 364 | bool fs_validate_description(const char *name, |
d7167b14 | 365 | const struct fs_parameter_spec *desc) |
31d921c7 DH |
366 | { |
367 | const struct fs_parameter_spec *param, *p2; | |
2710c957 | 368 | bool good = true; |
31d921c7 | 369 | |
d7167b14 | 370 | for (param = desc; param->name; param++) { |
d7167b14 AV |
371 | /* Check for duplicate parameter names */ |
372 | for (p2 = desc; p2 < param; p2++) { | |
373 | if (strcmp(param->name, p2->name) == 0) { | |
48ce73b1 AV |
374 | if (is_flag(param) != is_flag(p2)) |
375 | continue; | |
d7167b14 AV |
376 | pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n", |
377 | name, param->name); | |
378 | good = false; | |
31d921c7 DH |
379 | } |
380 | } | |
31d921c7 | 381 | } |
31d921c7 DH |
382 | return good; |
383 | } | |
384 | #endif /* CONFIG_VALIDATE_FS_PARSER */ |