Merge tag 'drm-misc-next-fixes-2021-11-10' of git://anongit.freedesktop.org/drm/drm...
[linux-block.git] / fs / fs_parser.c
CommitLineData
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
16static 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
26static 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 41int 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 47EXPORT_SYMBOL(lookup_constant);
31d921c7 48
48ce73b1
AV
49static inline bool is_flag(const struct fs_parameter_spec *p)
50{
328de528 51 return p->type == NULL;
48ce73b1
AV
52}
53
31d921c7 54static 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 103int __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
134EXPORT_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 */
143int 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
184out:
185 if (put_f)
186 putname(f);
187 return ret;
188}
189EXPORT_SYMBOL(fs_lookup_param);
190
97383c74 191static 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
196int 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}
208EXPORT_SYMBOL(fs_param_is_bool);
209
210int 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}
219EXPORT_SYMBOL(fs_param_is_u32);
220
221int 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}
229EXPORT_SYMBOL(fs_param_is_s32);
230
231int 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}
239EXPORT_SYMBOL(fs_param_is_u64);
240
241int 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}
253EXPORT_SYMBOL(fs_param_is_enum);
254
255int 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}
262EXPORT_SYMBOL(fs_param_is_string);
263
264int 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}
271EXPORT_SYMBOL(fs_param_is_blob);
272
273int 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}
293EXPORT_SYMBOL(fs_param_is_fd);
294
295int 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}
300EXPORT_SYMBOL(fs_param_is_blockdev);
301
302int 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}
307EXPORT_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 */
318bool 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 364bool 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 */