linux/fs/fs_parser.c
Thomas Gleixner b4d0d230cc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:11 +02:00

444 lines
11 KiB
C

// 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);
}
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 */