// 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 * @_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:		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); 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);	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 ||	    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 ||	    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 ||	    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);	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)		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 (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 * @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 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 */