// 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 */
// 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 */