|  | // SPDX-License-Identifier: GPL-2.0-or-later | 
|  | /* Filesystem parameter parser. | 
|  | * | 
|  | * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | 
|  | * Written by David Howells (dhowells@redhat.com) | 
|  | */ | 
|  |  | 
|  | #include <linux/export.h> | 
|  | #include <linux/fs_context.h> | 
|  | #include <linux/fs_parser.h> | 
|  | #include <linux/slab.h> | 
|  | #include <linux/security.h> | 
|  | #include <linux/namei.h> | 
|  | #include "internal.h" | 
|  |  | 
|  | static const struct constant_table bool_names[] = { | 
|  | { "0",		false }, | 
|  | { "1",		true }, | 
|  | { "false",	false }, | 
|  | { "no",		false }, | 
|  | { "true",	true }, | 
|  | { "yes",	true }, | 
|  | { }, | 
|  | }; | 
|  |  | 
|  | static const struct constant_table * | 
|  | __lookup_constant(const struct constant_table *tbl, const char *name) | 
|  | { | 
|  | for ( ; tbl->name; tbl++) | 
|  | if (strcmp(name, tbl->name) == 0) | 
|  | return tbl; | 
|  | return NULL; | 
|  | } | 
|  |  | 
|  | /** | 
|  | * lookup_constant - Look up a constant by name in an ordered table | 
|  | * @tbl: The table of constants to search. | 
|  | * @name: The name to look up. | 
|  | * @not_found: The value to return if the name is not found. | 
|  | */ | 
|  | int lookup_constant(const struct constant_table *tbl, const char *name, int not_found) | 
|  | { | 
|  | const struct constant_table *p = __lookup_constant(tbl, name); | 
|  |  | 
|  | return p ? p->value : not_found; | 
|  | } | 
|  | EXPORT_SYMBOL(lookup_constant); | 
|  |  | 
|  | static inline bool is_flag(const struct fs_parameter_spec *p) | 
|  | { | 
|  | return p->type == NULL; | 
|  | } | 
|  |  | 
|  | static const struct fs_parameter_spec *fs_lookup_key( | 
|  | const struct fs_parameter_spec *desc, | 
|  | struct fs_parameter *param, bool *negated) | 
|  | { | 
|  | const struct fs_parameter_spec *p, *other = NULL; | 
|  | const char *name = param->key; | 
|  | bool want_flag = param->type == fs_value_is_flag; | 
|  |  | 
|  | *negated = false; | 
|  | for (p = desc; p->name; p++) { | 
|  | if (strcmp(p->name, name) != 0) | 
|  | continue; | 
|  | if (likely(is_flag(p) == want_flag)) | 
|  | return p; | 
|  | other = p; | 
|  | } | 
|  | if (want_flag) { | 
|  | if (name[0] == 'n' && name[1] == 'o' && name[2]) { | 
|  | for (p = desc; p->name; p++) { | 
|  | if (strcmp(p->name, name + 2) != 0) | 
|  | continue; | 
|  | if (!(p->flags & fs_param_neg_with_no)) | 
|  | continue; | 
|  | *negated = true; | 
|  | return p; | 
|  | } | 
|  | } | 
|  | } | 
|  | return other; | 
|  | } | 
|  |  | 
|  | /* | 
|  | * fs_parse - Parse a filesystem configuration parameter | 
|  | * @fc: The filesystem context to log errors through. | 
|  | * @desc: The parameter description to use. | 
|  | * @param: The parameter. | 
|  | * @result: Where to place the result of the parse | 
|  | * | 
|  | * Parse a filesystem configuration parameter and attempt a conversion for a | 
|  | * simple parameter for which this is requested.  If successful, the determined | 
|  | * parameter ID is placed into @result->key, the desired type is indicated in | 
|  | * @result->t and any converted value is placed into an appropriate member of | 
|  | * the union in @result. | 
|  | * | 
|  | * The function returns the parameter number if the parameter was matched, | 
|  | * -ENOPARAM if it wasn't matched and @desc->ignore_unknown indicated that | 
|  | * unknown parameters are okay and -EINVAL if there was a conversion issue or | 
|  | * the parameter wasn't recognised and unknowns aren't okay. | 
|  | */ | 
|  | int __fs_parse(struct p_log *log, | 
|  | const struct fs_parameter_spec *desc, | 
|  | struct fs_parameter *param, | 
|  | struct fs_parse_result *result) | 
|  | { | 
|  | const struct fs_parameter_spec *p; | 
|  |  | 
|  | result->uint_64 = 0; | 
|  |  | 
|  | p = fs_lookup_key(desc, param, &result->negated); | 
|  | if (!p) | 
|  | return -ENOPARAM; | 
|  |  | 
|  | if (p->flags & fs_param_deprecated) | 
|  | warn_plog(log, "Deprecated parameter '%s'", param->key); | 
|  |  | 
|  | /* Try to turn the type we were given into the type desired by the | 
|  | * parameter and give an error if we can't. | 
|  | */ | 
|  | if (is_flag(p)) { | 
|  | if (param->type != fs_value_is_flag) | 
|  | return inval_plog(log, "Unexpected value for '%s'", | 
|  | param->key); | 
|  | result->boolean = !result->negated; | 
|  | } else  { | 
|  | int ret = p->type(log, p, param, result); | 
|  | if (ret) | 
|  | return ret; | 
|  | } | 
|  | return p->opt; | 
|  | } | 
|  | EXPORT_SYMBOL(__fs_parse); | 
|  |  | 
|  | /** | 
|  | * fs_lookup_param - Look up a path referred to by a parameter | 
|  | * @fc: The filesystem context to log errors through. | 
|  | * @param: The parameter. | 
|  | * @want_bdev: T if want a blockdev | 
|  | * @flags: Pathwalk flags passed to filename_lookup() | 
|  | * @_path: The result of the lookup | 
|  | */ | 
|  | int fs_lookup_param(struct fs_context *fc, | 
|  | struct fs_parameter *param, | 
|  | bool want_bdev, | 
|  | unsigned int flags, | 
|  | struct path *_path) | 
|  | { | 
|  | struct filename *f; | 
|  | bool put_f; | 
|  | int ret; | 
|  |  | 
|  | switch (param->type) { | 
|  | case fs_value_is_string: | 
|  | f = getname_kernel(param->string); | 
|  | if (IS_ERR(f)) | 
|  | return PTR_ERR(f); | 
|  | put_f = true; | 
|  | break; | 
|  | case fs_value_is_filename: | 
|  | f = param->name; | 
|  | put_f = false; | 
|  | break; | 
|  | default: | 
|  | return invalf(fc, "%s: not usable as path", param->key); | 
|  | } | 
|  |  | 
|  | ret = filename_lookup(param->dirfd, f, flags, _path, NULL); | 
|  | if (ret < 0) { | 
|  | errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name); | 
|  | goto out; | 
|  | } | 
|  |  | 
|  | if (want_bdev && | 
|  | !S_ISBLK(d_backing_inode(_path->dentry)->i_mode)) { | 
|  | path_put(_path); | 
|  | _path->dentry = NULL; | 
|  | _path->mnt = NULL; | 
|  | errorf(fc, "%s: Non-blockdev passed as '%s'", | 
|  | param->key, f->name); | 
|  | ret = -ENOTBLK; | 
|  | } | 
|  |  | 
|  | out: | 
|  | if (put_f) | 
|  | putname(f); | 
|  | return ret; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_lookup_param); | 
|  |  | 
|  | static int fs_param_bad_value(struct p_log *log, struct fs_parameter *param) | 
|  | { | 
|  | return inval_plog(log, "Bad value for '%s'", param->key); | 
|  | } | 
|  |  | 
|  | int fs_param_is_bool(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | int b; | 
|  | if (param->type != fs_value_is_string) | 
|  | return fs_param_bad_value(log, param); | 
|  | if (!*param->string && (p->flags & fs_param_can_be_empty)) | 
|  | return 0; | 
|  | b = lookup_constant(bool_names, param->string, -1); | 
|  | if (b == -1) | 
|  | return fs_param_bad_value(log, param); | 
|  | result->boolean = b; | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_bool); | 
|  |  | 
|  | int fs_param_is_u32(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | int base = (unsigned long)p->data; | 
|  | if (param->type != fs_value_is_string) | 
|  | return fs_param_bad_value(log, param); | 
|  | if (!*param->string && (p->flags & fs_param_can_be_empty)) | 
|  | return 0; | 
|  | if (kstrtouint(param->string, base, &result->uint_32) < 0) | 
|  | return fs_param_bad_value(log, param); | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_u32); | 
|  |  | 
|  | int fs_param_is_s32(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | if (param->type != fs_value_is_string) | 
|  | return fs_param_bad_value(log, param); | 
|  | if (!*param->string && (p->flags & fs_param_can_be_empty)) | 
|  | return 0; | 
|  | if (kstrtoint(param->string, 0, &result->int_32) < 0) | 
|  | return fs_param_bad_value(log, param); | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_s32); | 
|  |  | 
|  | int fs_param_is_u64(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | if (param->type != fs_value_is_string) | 
|  | return fs_param_bad_value(log, param); | 
|  | if (!*param->string && (p->flags & fs_param_can_be_empty)) | 
|  | return 0; | 
|  | if (kstrtoull(param->string, 0, &result->uint_64) < 0) | 
|  | return fs_param_bad_value(log, param); | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_u64); | 
|  |  | 
|  | int fs_param_is_enum(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | const struct constant_table *c; | 
|  | if (param->type != fs_value_is_string) | 
|  | return fs_param_bad_value(log, param); | 
|  | if (!*param->string && (p->flags & fs_param_can_be_empty)) | 
|  | return 0; | 
|  | c = __lookup_constant(p->data, param->string); | 
|  | if (!c) | 
|  | return fs_param_bad_value(log, param); | 
|  | result->uint_32 = c->value; | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_enum); | 
|  |  | 
|  | int fs_param_is_string(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | if (param->type != fs_value_is_string || | 
|  | (!*param->string && !(p->flags & fs_param_can_be_empty))) | 
|  | return fs_param_bad_value(log, param); | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_string); | 
|  |  | 
|  | int fs_param_is_blob(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | if (param->type != fs_value_is_blob) | 
|  | return fs_param_bad_value(log, param); | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_blob); | 
|  |  | 
|  | int fs_param_is_fd(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | switch (param->type) { | 
|  | case fs_value_is_string: | 
|  | if ((!*param->string && !(p->flags & fs_param_can_be_empty)) || | 
|  | kstrtouint(param->string, 0, &result->uint_32) < 0) | 
|  | break; | 
|  | if (result->uint_32 <= INT_MAX) | 
|  | return 0; | 
|  | break; | 
|  | case fs_value_is_file: | 
|  | result->uint_32 = param->dirfd; | 
|  | if (result->uint_32 <= INT_MAX) | 
|  | return 0; | 
|  | break; | 
|  | default: | 
|  | break; | 
|  | } | 
|  | return fs_param_bad_value(log, param); | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_fd); | 
|  |  | 
|  | int fs_param_is_blockdev(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_blockdev); | 
|  |  | 
|  | int fs_param_is_path(struct p_log *log, const struct fs_parameter_spec *p, | 
|  | struct fs_parameter *param, struct fs_parse_result *result) | 
|  | { | 
|  | return 0; | 
|  | } | 
|  | EXPORT_SYMBOL(fs_param_is_path); | 
|  |  | 
|  | #ifdef CONFIG_VALIDATE_FS_PARSER | 
|  | /** | 
|  | * validate_constant_table - Validate a constant table | 
|  | * @tbl: The constant table to validate. | 
|  | * @tbl_size: The size of the table. | 
|  | * @low: The lowest permissible value. | 
|  | * @high: The highest permissible value. | 
|  | * @special: One special permissible value outside of the range. | 
|  | */ | 
|  | bool validate_constant_table(const struct constant_table *tbl, size_t tbl_size, | 
|  | int low, int high, int special) | 
|  | { | 
|  | size_t i; | 
|  | bool good = true; | 
|  |  | 
|  | if (tbl_size == 0) { | 
|  | pr_warn("VALIDATE C-TBL: Empty\n"); | 
|  | return true; | 
|  | } | 
|  |  | 
|  | for (i = 0; i < tbl_size; i++) { | 
|  | if (!tbl[i].name) { | 
|  | pr_err("VALIDATE C-TBL[%zu]: Null\n", i); | 
|  | good = false; | 
|  | } else if (i > 0 && tbl[i - 1].name) { | 
|  | int c = strcmp(tbl[i-1].name, tbl[i].name); | 
|  |  | 
|  | if (c == 0) { | 
|  | pr_err("VALIDATE C-TBL[%zu]: Duplicate %s\n", | 
|  | i, tbl[i].name); | 
|  | good = false; | 
|  | } | 
|  | if (c > 0) { | 
|  | pr_err("VALIDATE C-TBL[%zu]: Missorted %s>=%s\n", | 
|  | i, tbl[i-1].name, tbl[i].name); | 
|  | good = false; | 
|  | } | 
|  | } | 
|  |  | 
|  | if (tbl[i].value != special && | 
|  | (tbl[i].value < low || tbl[i].value > high)) { | 
|  | pr_err("VALIDATE C-TBL[%zu]: %s->%d const out of range (%d-%d)\n", | 
|  | i, tbl[i].name, tbl[i].value, low, high); | 
|  | good = false; | 
|  | } | 
|  | } | 
|  |  | 
|  | return good; | 
|  | } | 
|  |  | 
|  | /** | 
|  | * fs_validate_description - Validate a parameter description | 
|  | * @name: The parameter name to search for. | 
|  | * @desc: The parameter description to validate. | 
|  | */ | 
|  | bool fs_validate_description(const char *name, | 
|  | const struct fs_parameter_spec *desc) | 
|  | { | 
|  | const struct fs_parameter_spec *param, *p2; | 
|  | bool good = true; | 
|  |  | 
|  | for (param = desc; param->name; param++) { | 
|  | /* Check for duplicate parameter names */ | 
|  | for (p2 = desc; p2 < param; p2++) { | 
|  | if (strcmp(param->name, p2->name) == 0) { | 
|  | if (is_flag(param) != is_flag(p2)) | 
|  | continue; | 
|  | pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n", | 
|  | name, param->name); | 
|  | good = false; | 
|  | } | 
|  | } | 
|  | } | 
|  | return good; | 
|  | } | 
|  | #endif /* CONFIG_VALIDATE_FS_PARSER */ |