| /* Filesystem parameter parser. | 
 |  * | 
 |  * Copyright (C) 2018 Red Hat, Inc. All Rights Reserved. | 
 |  * Written by David Howells (dhowells@redhat.com) | 
 |  * | 
 |  * This program is free software; you can redistribute it and/or | 
 |  * modify it under the terms of the GNU General Public Licence | 
 |  * as published by the Free Software Foundation; either version | 
 |  * 2 of the Licence, or (at your option) any later version. | 
 |  */ | 
 |  | 
 | #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); | 
 | 	} | 
 |  | 
 | 	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[%lu] 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 */ |