Re: [PATCH -V1 10/22] richacl: In-memory representation and helper functions

Kinglong Mee
2014-05-06T09:35:39Z

于 4/28/2014 00:14, Aneesh Kumar K.V 写道:
> From: Andreas Gruenbacher <agruen@kernel.org>
>
> A richacl consists of an NFSv4 acl and an owner, group, and other mask.
> These three masks correspond to the owner, group, and other file
> permission bits, but they contain NFSv4 permissions instead of POSIX
> permissions.
>
> Each entry in the NFSv4 acl applies to the file owner (OWNER@), the
> owning group (GROUP@), literally everyone (EVERYONE@), or to a specific
> uid or gid.
>
> As in the standard POSIX file permission model, each process is the
> owner, group, or other file class. A richacl grants a requested access
> only if the NFSv4 acl in the richacl grants the access (according to the
> NFSv4 permission check algorithm), and the file mask that applies to the
> process includes the requested permissions.
>
> Signed-off-by: Andreas Gruenbacher <agruen@kernel.org>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
> fs/Makefile | 2 +
> fs/richacl_base.c | 69 ++++++++++++++
> include/linux/richacl.h | 237 ++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 308 insertions(+)
> create mode 100644 fs/richacl_base.c
> create mode 100644 include/linux/richacl.h
>
> diff --git a/fs/Makefile b/fs/Makefile
> index f9cb9876e466..5b7ed5d022ec 100644
> --- a/fs/Makefile
> +++ b/fs/Makefile
> @@ -48,6 +48,8 @@ obj-$(CONFIG_COREDUMP) += coredump.o
> obj-$(CONFIG_SYSCTL) += drop_caches.o
>
> obj-$(CONFIG_FHANDLE) += fhandle.o
> +obj-$(CONFIG_FS_RICHACL) += richacl.o
> +richacl-y := richacl_base.o
>
> obj-y += quota/
>
> diff --git a/fs/richacl_base.c b/fs/richacl_base.c
> new file mode 100644
> index 000000000000..689e1a6dace7
> --- /dev/null
> +++ b/fs/richacl_base.c
> @@ -0,0 +1,69 @@
> +/*
> + * Copyright (C) 2006, 2010 Novell, Inc.
> + * Written by Andreas Gruenbacher <agruen@kernel.org>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2, or (at your option) any
> + * later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + */
> +
> +#include <linux/sched.h>
> +#include <linux/module.h>
> +#include <linux/fs.h>
> +#include <linux/richacl.h>
> +
> +MODULE_LICENSE("GPL");
> +
> +/**
> + * richacl_alloc - allocate a richacl
> + * @count: number of entries
> + */
> +struct richacl *
> +richacl_alloc(int count)
> +{
> + size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
> + struct richacl *acl = kzalloc(size, GFP_KERNEL);
> +
> + if (acl) {
> + atomic_set(&acl->a_refcount, 1);
> + acl->a_count = count;
> + }
> + return acl;
> +}
> +EXPORT_SYMBOL_GPL(richacl_alloc);
> +
> +/**
> + * richacl_clone - create a copy of a richacl
> + */
> +static struct richacl *
> +richacl_clone(const struct richacl *acl)
> +{
> + int count = acl->a_count;
> + size_t size = sizeof(struct richacl) + count * sizeof(struct richace);
> + struct richacl *dup = kmalloc(size, GFP_KERNEL);
> +
> + if (dup) {
> + memcpy(dup, acl, size);
> + atomic_set(&dup->a_refcount, 1);
> + }

I'd like kmemdup as posix_acl_clone.

> + return dup;
> +}
> +
> +/**
> + * richace_is_same_identifier - are both identifiers the same?
> + */
> +int
> +richace_is_same_identifier(const struct richace *a, const struct richace *b)
> +{
> +#define WHO_FLAGS (ACE4_SPECIAL_WHO | ACE4_IDENTIFIER_GROUP)
> + if ((a->e_flags & WHO_FLAGS) != (b->e_flags & WHO_FLAGS))
> + return 0;
> + return a->e_id == b->e_id;
> +#undef WHO_FLAGS
> +}
> diff --git a/include/linux/richacl.h b/include/linux/richacl.h
> new file mode 100644
> index 000000000000..51d6937651f1
> --- /dev/null
> +++ b/include/linux/richacl.h
> @@ -0,0 +1,237 @@
> +/*
> + * Copyright (C) 2006, 2010 Novell, Inc.
> + * Written by Andreas Gruenbacher <agruen@kernel.org>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2, or (at your option) any
> + * later version.
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License for more details.
> + */
> +
> +#ifndef __RICHACL_H
> +#define __RICHACL_H
> +#include <linux/slab.h>
> +
> +#define ACE_OWNER_ID 130

why start from 130 ?

> +#define ACE_GROUP_ID 131
> +#define ACE_EVERYONE_ID 110

why not 132 for ACE_EVERYONE_ID?

> +
> +struct richace {
> + unsigned short e_type;
> + unsigned short e_flags;
> + unsigned int e_mask;
> + unsigned int e_id;
> +};
> +
> +struct richacl {
> + atomic_t a_refcount;
> + unsigned int a_owner_mask;
> + unsigned int a_group_mask;
> + unsigned int a_other_mask;
> + unsigned short a_count;
> + unsigned short a_flags;
> + struct richace a_entries[0];
> +};
> +
> +#define richacl_for_each_entry(_ace, _acl) \
> + for (_ace = _acl->a_entries; \
> + _ace != _acl->a_entries + _acl->a_count; \
> + _ace++)
> +
> +#define richacl_for_each_entry_reverse(_ace, _acl) \
> + for (_ace = _acl->a_entries + _acl->a_count - 1; \
> + _ace != _acl->a_entries - 1; \
> + _ace--)
> +
> +/* Flag values defined by rich-acl */
> +#define ACL4_MASKED 0x80

For rich-acl, should not using ACL4_*** or ACE4_***.

thanks,
Kinglong Mee

> +
> +#define ACL4_VALID_FLAGS ( \
> + ACL4_MASKED)
> +
> +/* e_type values */
> +#define ACE4_ACCESS_ALLOWED_ACE_TYPE 0x0000
> +#define ACE4_ACCESS_DENIED_ACE_TYPE 0x0001
> +/*#define ACE4_SYSTEM_AUDIT_ACE_TYPE 0x0002*/
> +/*#define ACE4_SYSTEM_ALARM_ACE_TYPE 0x0003*/
> +
> +/* e_flags bitflags */
> +#define ACE4_FILE_INHERIT_ACE 0x0001
> +#define ACE4_DIRECTORY_INHERIT_ACE 0x0002
> +#define ACE4_NO_PROPAGATE_INHERIT_ACE 0x0004
> +#define ACE4_INHERIT_ONLY_ACE 0x0008
> +/*#define ACE4_SUCCESSFUL_ACCESS_ACE_FLAG 0x0010*/
> +/*#define ACE4_FAILED_ACCESS_ACE_FLAG 0x0020*/
> +#define ACE4_IDENTIFIER_GROUP 0x0040
> +/* richacl specific flag values */
> +#define ACE4_SPECIAL_WHO 0x4000
> +
> +#define ACE4_VALID_FLAGS ( \
> + ACE4_FILE_INHERIT_ACE | \
> + ACE4_DIRECTORY_INHERIT_ACE | \
> + ACE4_NO_PROPAGATE_INHERIT_ACE | \
> + ACE4_INHERIT_ONLY_ACE | \
> + ACE4_IDENTIFIER_GROUP | \
> + ACE4_SPECIAL_WHO)
> +
> +/* e_mask bitflags */
> +#define ACE4_READ_DATA 0x00000001
> +#define ACE4_LIST_DIRECTORY 0x00000001
> +#define ACE4_WRITE_DATA 0x00000002
> +#define ACE4_ADD_FILE 0x00000002
> +#define ACE4_APPEND_DATA 0x00000004
> +#define ACE4_ADD_SUBDIRECTORY 0x00000004
> +#define ACE4_READ_NAMED_ATTRS 0x00000008
> +#define ACE4_WRITE_NAMED_ATTRS 0x00000010
> +#define ACE4_EXECUTE 0x00000020
> +#define ACE4_DELETE_CHILD 0x00000040
> +#define ACE4_READ_ATTRIBUTES 0x00000080
> +#define ACE4_WRITE_ATTRIBUTES 0x00000100
> +#define ACE4_WRITE_RETENTION 0x00000200
> +#define ACE4_WRITE_RETENTION_HOLD 0x00000400
> +#define ACE4_DELETE 0x00010000
> +#define ACE4_READ_ACL 0x00020000
> +#define ACE4_WRITE_ACL 0x00040000
> +#define ACE4_WRITE_OWNER 0x00080000
> +#define ACE4_SYNCHRONIZE 0x00100000
> +
> +/* Valid ACE4_* flags for directories and non-directories */
> +#define ACE4_VALID_MASK ( \
> + ACE4_READ_DATA | ACE4_LIST_DIRECTORY | \
> + ACE4_WRITE_DATA | ACE4_ADD_FILE | \
> + ACE4_APPEND_DATA | ACE4_ADD_SUBDIRECTORY | \
> + ACE4_READ_NAMED_ATTRS | \
> + ACE4_WRITE_NAMED_ATTRS | \
> + ACE4_EXECUTE | \
> + ACE4_DELETE_CHILD | \
> + ACE4_READ_ATTRIBUTES | \
> + ACE4_WRITE_ATTRIBUTES | \
> + ACE4_WRITE_RETENTION | \
> + ACE4_WRITE_RETENTION_HOLD | \
> + ACE4_DELETE | \
> + ACE4_READ_ACL | \
> + ACE4_WRITE_ACL | \
> + ACE4_WRITE_OWNER | \
> + ACE4_SYNCHRONIZE)
> +
> +/**
> + * richacl_get - grab another reference to a richacl handle
> + */
> +static inline struct richacl *
> +richacl_get(struct richacl *acl)
> +{
> + if (acl)
> + atomic_inc(&acl->a_refcount);
> + return acl;
> +}
> +
> +/**
> + * richacl_put - free a richacl handle
> + */
> +static inline void
> +richacl_put(struct richacl *acl)
> +{
> + if (acl && atomic_dec_and_test(&acl->a_refcount))
> + kfree(acl);
> +}
> +
> +/**
> + * richace_is_owner - check if @ace is an OWNER@ entry
> + */
> +static inline int
> +richace_is_owner(const struct richace *ace)
> +{
> + return (ace->e_flags & ACE4_SPECIAL_WHO) &&
> + ace->e_id == ACE_OWNER_ID;
> +}
> +
> +/**
> + * richace_is_group - check if @ace is a GROUP@ entry
> + */
> +static inline int
> +richace_is_group(const struct richace *ace)
> +{
> + return (ace->e_flags & ACE4_SPECIAL_WHO) &&
> + ace->e_id == ACE_GROUP_ID;
> +}
> +
> +/**
> + * richace_is_everyone - check if @ace is an EVERYONE@ entry
> + */
> +static inline int
> +richace_is_everyone(const struct richace *ace)
> +{
> + return (ace->e_flags & ACE4_SPECIAL_WHO) &&
> + ace->e_id == ACE_EVERYONE_ID;
> +}
> +
> +/**
> + * richace_is_unix_id - check if @ace applies to a specific uid or gid
> + */
> +static inline int
> +richace_is_unix_id(const struct richace *ace)
> +{
> + return !(ace->e_flags & ACE4_SPECIAL_WHO);
> +}
> +
> +/**
> + * richace_is_inherit_only - check if @ace is for inheritance only
> + *
> + * ACEs with the %ACE4_INHERIT_ONLY_ACE flag set have no effect during
> + * permission checking.
> + */
> +static inline int
> +richace_is_inherit_only(const struct richace *ace)
> +{
> + return ace->e_flags & ACE4_INHERIT_ONLY_ACE;
> +}
> +
> +/**
> + * richace_is_inheritable - check if @ace is inheritable
> + */
> +static inline int
> +richace_is_inheritable(const struct richace *ace)
> +{
> + return ace->e_flags & (ACE4_FILE_INHERIT_ACE |
> + ACE4_DIRECTORY_INHERIT_ACE);
> +}
> +
> +/**
> + * richace_clear_inheritance_flags - clear all inheritance flags in @ace
> + */
> +static inline void
> +richace_clear_inheritance_flags(struct richace *ace)
> +{
> + ace->e_flags &= ~(ACE4_FILE_INHERIT_ACE |
> + ACE4_DIRECTORY_INHERIT_ACE |
> + ACE4_NO_PROPAGATE_INHERIT_ACE |
> + ACE4_INHERIT_ONLY_ACE);
> +}
> +
> +/**
> + * richace_is_allow - check if @ace is an %ALLOW type entry
> + */
> +static inline int
> +richace_is_allow(const struct richace *ace)
> +{
> + return ace->e_type == ACE4_ACCESS_ALLOWED_ACE_TYPE;
> +}
> +
> +/**
> + * richace_is_deny - check if @ace is a %DENY type entry
> + */
> +static inline int
> +richace_is_deny(const struct richace *ace)
> +{
> + return ace->e_type == ACE4_ACCESS_DENIED_ACE_TYPE;
> +}
> +
> +extern struct richacl *richacl_alloc(int);
> +extern int richace_is_same_identifier(const struct richace *,
> + const struct richace *);
> +#endif /* __RICHACL_H */
>