| // 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 }, |
| }; |
| |
| /** |
| * lookup_constant - Look up a constant by name in an ordered table |
| * @tbl: The table of constants to search. |
| * @tbl_size: The size of the table. |
| * @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, size_t tbl_size, |
| const char *name, int not_found) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < tbl_size; i++) |
| if (strcmp(name, tbl[i].name) == 0) |
| return tbl[i].value; |
| |
| return not_found; |
| } |
| EXPORT_SYMBOL(__lookup_constant); |
| |
| static const struct fs_parameter_spec *fs_lookup_key( |
| const struct fs_parameter_description *desc, |
| const char *name) |
| { |
| const struct fs_parameter_spec *p; |
| |
| if (!desc->specs) |
| return NULL; |
| |
| for (p = desc->specs; p->name; p++) |
| if (strcmp(p->name, name) == 0) |
| return p; |
| |
| return NULL; |
| } |
| |
| /* |
| * 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 fs_context *fc, |
| const struct fs_parameter_description *desc, |
| struct fs_parameter *param, |
| struct fs_parse_result *result) |
| { |
| const struct fs_parameter_spec *p; |
| const struct fs_parameter_enum *e; |
| int ret = -ENOPARAM, b; |
| |
| result->has_value = !!param->string; |
| result->negated = false; |
| result->uint_64 = 0; |
| |
| p = fs_lookup_key(desc, param->key); |
| if (!p) { |
| /* If we didn't find something that looks like "noxxx", see if |
| * "xxx" takes the "no"-form negative - but only if there |
| * wasn't an value. |
| */ |
| if (result->has_value) |
| goto unknown_parameter; |
| if (param->key[0] != 'n' || param->key[1] != 'o' || !param->key[2]) |
| goto unknown_parameter; |
| |
| p = fs_lookup_key(desc, param->key + 2); |
| if (!p) |
| goto unknown_parameter; |
| if (!(p->flags & fs_param_neg_with_no)) |
| goto unknown_parameter; |
| result->boolean = false; |
| result->negated = true; |
| } |
| |
| if (p->flags & fs_param_deprecated) |
| warnf(fc, "%s: Deprecated parameter '%s'", |
| desc->name, param->key); |
| |
| if (result->negated) |
| goto okay; |
| |
| /* Certain parameter types only take a string and convert it. */ |
| switch (p->type) { |
| case __fs_param_wasnt_defined: |
| return -EINVAL; |
| case fs_param_is_u32: |
| case fs_param_is_u32_octal: |
| case fs_param_is_u32_hex: |
| case fs_param_is_s32: |
| case fs_param_is_u64: |
| case fs_param_is_enum: |
| case fs_param_is_string: |
| if (param->type != fs_value_is_string) |
| goto bad_value; |
| if (!result->has_value) { |
| if (p->flags & fs_param_v_optional) |
| goto okay; |
| goto bad_value; |
| } |
| /* Fall through */ |
| default: |
| break; |
| } |
| |
| /* Try to turn the type we were given into the type desired by the |
| * parameter and give an error if we can't. |
| */ |
| switch (p->type) { |
| case fs_param_is_flag: |
| if (param->type != fs_value_is_flag && |
| (param->type != fs_value_is_string || result->has_value)) |
| return invalf(fc, "%s: Unexpected value for '%s'", |
| desc->name, param->key); |
| result->boolean = true; |
| goto okay; |
| |
| case fs_param_is_bool: |
| switch (param->type) { |
| case fs_value_is_flag: |
| result->boolean = true; |
| goto okay; |
| case fs_value_is_string: |
| if (param->size == 0) { |
| result->boolean = true; |
| goto okay; |
| } |
| b = lookup_constant(bool_names, param->string, -1); |
| if (b == -1) |
| goto bad_value; |
| result->boolean = b; |
| goto okay; |
| default: |
| goto bad_value; |
| } |
| |
| case fs_param_is_u32: |
| ret = kstrtouint(param->string, 0, &result->uint_32); |
| goto maybe_okay; |
| case fs_param_is_u32_octal: |
| ret = kstrtouint(param->string, 8, &result->uint_32); |
| goto maybe_okay; |
| case fs_param_is_u32_hex: |
| ret = kstrtouint(param->string, 16, &result->uint_32); |
| goto maybe_okay; |
| case fs_param_is_s32: |
| ret = kstrtoint(param->string, 0, &result->int_32); |
| goto maybe_okay; |
| case fs_param_is_u64: |
| ret = kstrtoull(param->string, 0, &result->uint_64); |
| goto maybe_okay; |
| |
| case fs_param_is_enum: |
| for (e = desc->enums; e->name[0]; e++) { |
| if (e->opt == p->opt && |
| strcmp(e->name, param->string) == 0) { |
| result->uint_32 = e->value; |
| goto okay; |
| } |
| } |
| goto bad_value; |
| |
| case fs_param_is_string: |
| goto okay; |
| case fs_param_is_blob: |
| if (param->type != fs_value_is_blob) |
| goto bad_value; |
| goto okay; |
| |
| case fs_param_is_fd: { |
| if (param->type != fs_value_is_file) |
| goto bad_value; |
| goto okay; |
| } |
| |
| case fs_param_is_blockdev: |
| case fs_param_is_path: |
| goto okay; |
| default: |
| BUG(); |
| } |
| |
| maybe_okay: |
| if (ret < 0) |
| goto bad_value; |
| okay: |
| return p->opt; |
| |
| bad_value: |
| return invalf(fc, "%s: Bad value for '%s'", desc->name, param->key); |
| unknown_parameter: |
| return -ENOPARAM; |
| } |
| 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 |
| * @_path: The result of the lookup |
| */ |
| int fs_lookup_param(struct fs_context *fc, |
| struct fs_parameter *param, |
| bool want_bdev, |
| struct path *_path) |
| { |
| struct filename *f; |
| unsigned int flags = 0; |
| 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_empty: |
| flags = LOOKUP_EMPTY; |
| /* Fall through */ |
| case fs_value_is_filename: |
| f = param->name; |
| put_f = false; |
| break; |
| default: |
| return invalf(fc, "%s: not usable as path", param->key); |
| } |
| |
| f->refcnt++; /* filename_lookup() drops our ref. */ |
| 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); |
| |
| #ifdef CONFIG_VALIDATE_FS_PARSER |
| /** |
| * validate_constant_table - Validate a constant table |
| * @name: Name to use in reporting |
| * @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 |
| * @desc: The parameter description to validate. |
| */ |
| bool fs_validate_description(const struct fs_parameter_description *desc) |
| { |
| const struct fs_parameter_spec *param, *p2; |
| const struct fs_parameter_enum *e; |
| const char *name = desc->name; |
| unsigned int nr_params = 0; |
| bool good = true, enums = false; |
| |
| pr_notice("*** VALIDATE %s ***\n", name); |
| |
| if (!name[0]) { |
| pr_err("VALIDATE Parser: No name\n"); |
| name = "Unknown"; |
| good = false; |
| } |
| |
| if (desc->specs) { |
| for (param = desc->specs; param->name; param++) { |
| enum fs_parameter_type t = param->type; |
| |
| /* Check that the type is in range */ |
| if (t == __fs_param_wasnt_defined || |
| t >= nr__fs_parameter_type) { |
| pr_err("VALIDATE %s: PARAM[%s] Bad type %u\n", |
| name, param->name, t); |
| good = false; |
| } else if (t == fs_param_is_enum) { |
| enums = true; |
| } |
| |
| /* Check for duplicate parameter names */ |
| for (p2 = desc->specs; p2 < param; p2++) { |
| if (strcmp(param->name, p2->name) == 0) { |
| pr_err("VALIDATE %s: PARAM[%s]: Duplicate\n", |
| name, param->name); |
| good = false; |
| } |
| } |
| } |
| |
| nr_params = param - desc->specs; |
| } |
| |
| if (desc->enums) { |
| if (!nr_params) { |
| pr_err("VALIDATE %s: Enum table but no parameters\n", |
| name); |
| good = false; |
| goto no_enums; |
| } |
| if (!enums) { |
| pr_err("VALIDATE %s: Enum table but no enum-type values\n", |
| name); |
| good = false; |
| goto no_enums; |
| } |
| |
| for (e = desc->enums; e->name[0]; e++) { |
| /* Check that all entries in the enum table have at |
| * least one parameter that uses them. |
| */ |
| for (param = desc->specs; param->name; param++) { |
| if (param->opt == e->opt && |
| param->type != fs_param_is_enum) { |
| pr_err("VALIDATE %s: e[%tu] enum val for %s\n", |
| name, e - desc->enums, param->name); |
| good = false; |
| } |
| } |
| } |
| |
| /* Check that all enum-type parameters have at least one enum |
| * value in the enum table. |
| */ |
| for (param = desc->specs; param->name; param++) { |
| if (param->type != fs_param_is_enum) |
| continue; |
| for (e = desc->enums; e->name[0]; e++) |
| if (e->opt == param->opt) |
| break; |
| if (!e->name[0]) { |
| pr_err("VALIDATE %s: PARAM[%s] enum with no values\n", |
| name, param->name); |
| good = false; |
| } |
| } |
| } else { |
| if (enums) { |
| pr_err("VALIDATE %s: enum-type values, but no enum table\n", |
| name); |
| good = false; |
| goto no_enums; |
| } |
| } |
| |
| no_enums: |
| return good; |
| } |
| #endif /* CONFIG_VALIDATE_FS_PARSER */ |