Date:	Wed, 23 Sep 2015 08:00:42 +0530
From:	"Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To:	Andreas Gruenbacher <agruenba@...hat.com>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	linux-nfs@...r.kernel.org, linux-api@...r.kernel.org,
	linux-cifs@...r.kernel.org, linux-security-module@...r.kernel.org
Subject: Re: [RFC v7 18/41] ext4: Add richacl support

Andreas Gruenbacher <agruenba@...hat.com> writes:

> From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
>
> Support the richacl permission model in ext4.  The richacls are stored
> in "system.richacl" xattrs.  Richacls need to be enabled by tune2fs or
> at file system create time.
>

 Signed-off-by:  Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>

> Signed-off-by: Andreas Gruenbacher <agruenba@...hat.com>
> ---
>  fs/ext4/Kconfig   |  15 ++++
>  fs/ext4/Makefile  |   1 +
>  fs/ext4/acl.c     |   6 +-
>  fs/ext4/acl.h     |  12 +--
>  fs/ext4/file.c    |   6 +-
>  fs/ext4/ialloc.c  |   7 +-
>  fs/ext4/inode.c   |  10 ++-
>  fs/ext4/namei.c   |  11 ++-
>  fs/ext4/richacl.c | 213 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  fs/ext4/richacl.h |  47 ++++++++++++
>  fs/ext4/xattr.c   |   6 ++
>  fs/ext4/xattr.h   |   1 +
>  12 files changed, 316 insertions(+), 19 deletions(-)
>  create mode 100644 fs/ext4/richacl.c
>  create mode 100644 fs/ext4/richacl.h
>
> diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
> index bf8bc8a..77a386d 100644
> --- a/fs/ext4/Kconfig
> +++ b/fs/ext4/Kconfig
> @@ -96,3 +96,18 @@ config EXT4_DEBUG
>  	  If you select Y here, then you will be able to turn on debugging
>  	  with a command such as:
>  		echo 1 > /sys/module/ext4/parameters/mballoc_debug
> +
> +config EXT4_FS_RICHACL
> +	bool "Ext4 Rich Access Control Lists (EXPERIMENTAL)"
> +	depends on EXT4_FS
> +	select FS_RICHACL
> +	help
> +	  Rich ACLs are an implementation of NFSv4 ACLs, extended by file masks
> +	  to fit into the standard POSIX file permission model.  They are
> +	  designed to work seamlessly locally as well as across the NFSv4 and
> +	  CIFS/SMB2 network file system protocols.
> +
> +	  To learn more about Rich ACL, visit
> +	  http://acl.bestbits.at/richacl/
> +
> +	  If you don't know what Rich ACLs are, say N
> diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile
> index 75285ea..ea0d539 100644
> --- a/fs/ext4/Makefile
> +++ b/fs/ext4/Makefile
> @@ -14,3 +14,4 @@ ext4-$(CONFIG_EXT4_FS_POSIX_ACL)	+= acl.o
>  ext4-$(CONFIG_EXT4_FS_SECURITY)		+= xattr_security.o
>  ext4-$(CONFIG_EXT4_FS_ENCRYPTION)	+= crypto_policy.o crypto.o \
>  		crypto_key.o crypto_fname.o
> +ext4-$(CONFIG_EXT4_FS_RICHACL) 		+= richacl.o
> diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
> index 69b1e73..d965fa6 100644
> --- a/fs/ext4/acl.c
> +++ b/fs/ext4/acl.c
> @@ -140,7 +140,7 @@ fail:
>   * inode->i_mutex: don't care
>   */
>  struct posix_acl *
> -ext4_get_acl(struct inode *inode, int type)
> +ext4_get_posix_acl(struct inode *inode, int type)
>  {
>  	int name_index;
>  	char *value = NULL;
> @@ -234,7 +234,7 @@ __ext4_set_acl(handle_t *handle, struct inode *inode, int type,
>  }
>
>  int
> -ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type)
> +ext4_set_posix_acl(struct inode *inode, struct posix_acl *acl, int type)
>  {
>  	handle_t *handle;
>  	int error, retries = 0;
> @@ -259,7 +259,7 @@ retry:
>   * inode->i_mutex: up (access to inode is still exclusive)
>   */
>  int
> -ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
> +ext4_init_posix_acl(handle_t *handle, struct inode *inode, struct inode *dir)
>  {
>  	struct posix_acl *default_acl, *acl;
>  	int error;
> diff --git a/fs/ext4/acl.h b/fs/ext4/acl.h
> index da2c795..450b4d1 100644
> --- a/fs/ext4/acl.h
> +++ b/fs/ext4/acl.h
> @@ -54,17 +54,17 @@ static inline int ext4_acl_count(size_t size)
>  #ifdef CONFIG_EXT4_FS_POSIX_ACL
>
>  /* acl.c */
> -struct posix_acl *ext4_get_acl(struct inode *inode, int type);
> -int ext4_set_acl(struct inode *inode, struct posix_acl *acl, int type);
> -extern int ext4_init_acl(handle_t *, struct inode *, struct inode *);
> +struct posix_acl *ext4_get_posix_acl(struct inode *inode, int type);
> +int ext4_set_posix_acl(struct inode *inode, struct posix_acl *acl, int type);
> +extern int ext4_init_posix_acl(handle_t *, struct inode *, struct inode *);
>
>  #else  /* CONFIG_EXT4_FS_POSIX_ACL */
>  #include <linux/sched.h>
> -#define ext4_get_acl NULL
> -#define ext4_set_acl NULL
> +#define ext4_get_posix_acl NULL
> +#define ext4_set_posix_acl NULL
>
>  static inline int
> -ext4_init_acl(handle_t *handle, struct inode *inode, struct inode *dir)
> +ext4_init_posix_acl(handle_t *handle, struct inode *inode, struct inode *dir)
>  {
>  	return 0;
>  }
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index bc313ac..3d3fcc8 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -29,6 +29,7 @@
>  #include "ext4_jbd2.h"
>  #include "xattr.h"
>  #include "acl.h"
> +#include "richacl.h"
>
>  /*
>   * Called when an inode is released. Note that this is different
> @@ -659,8 +660,9 @@ const struct inode_operations ext4_file_inode_operations = {
>  	.getxattr	= generic_getxattr,
>  	.listxattr	= ext4_listxattr,
>  	.removexattr	= generic_removexattr,
> -	.get_acl	= ext4_get_acl,
> -	.set_acl	= ext4_set_acl,
> +	.get_acl	= ext4_get_posix_acl,
> +	.set_acl	= ext4_set_posix_acl,
> +	.get_richacl	= ext4_get_richacl,
>  	.fiemap		= ext4_fiemap,
>  };
>
> diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> index 173c1ae..aa5d1e1 100644
> --- a/fs/ext4/ialloc.c
> +++ b/fs/ext4/ialloc.c
> @@ -27,6 +27,7 @@
>  #include "ext4_jbd2.h"
>  #include "xattr.h"
>  #include "acl.h"
> +#include "richacl.h"
>
>  #include <trace/events/ext4.h>
>
> @@ -1050,7 +1051,11 @@ got:
>  	if (err)
>  		goto fail_drop;
>
> -	err = ext4_init_acl(handle, inode, dir);
> +	if (EXT4_IS_RICHACL(dir))
> +		err = ext4_init_richacl(handle, inode, dir);
> +	else
> +		err = ext4_init_posix_acl(handle, inode, dir);
> +
>  	if (err)
>  		goto fail_free_drop;
>
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index cecf9aa..7f6bbe8 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -41,6 +41,7 @@
>  #include "xattr.h"
>  #include "acl.h"
>  #include "truncate.h"
> +#include "richacl.h"
>
>  #include <trace/events/ext4.h>
>
> @@ -4782,9 +4783,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
>  	if (orphan && inode->i_nlink)
>  		ext4_orphan_del(NULL, inode);
>
> -	if (!rc && (ia_valid & ATTR_MODE))
> -		rc = posix_acl_chmod(inode, inode->i_mode);
> -
> +	if (!rc && (ia_valid & ATTR_MODE)) {
> +		if (EXT4_IS_RICHACL(inode))
> +			rc = ext4_richacl_chmod(inode);
> +		else
> +			rc = posix_acl_chmod(inode, inode->i_mode);
> +	}
>  err_out:
>  	ext4_std_error(inode->i_sb, error);
>  	if (!error)
> diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
> index 011dcfb..9be6a8a 100644
> --- a/fs/ext4/namei.c
> +++ b/fs/ext4/namei.c
> @@ -38,6 +38,7 @@
>
>  #include "xattr.h"
>  #include "acl.h"
> +#include "richacl.h"
>
>  #include <trace/events/ext4.h>
>  /*
> @@ -3821,8 +3822,9 @@ const struct inode_operations ext4_dir_inode_operations = {
>  	.getxattr	= generic_getxattr,
>  	.listxattr	= ext4_listxattr,
>  	.removexattr	= generic_removexattr,
> -	.get_acl	= ext4_get_acl,
> -	.set_acl	= ext4_set_acl,
> +	.get_acl	= ext4_get_posix_acl,
> +	.set_acl	= ext4_set_posix_acl,
> +	.get_richacl	= ext4_get_richacl,
>  	.fiemap         = ext4_fiemap,
>  };
>
> @@ -3832,6 +3834,7 @@ const struct inode_operations ext4_special_inode_operations = {
>  	.getxattr	= generic_getxattr,
>  	.listxattr	= ext4_listxattr,
>  	.removexattr	= generic_removexattr,
> -	.get_acl	= ext4_get_acl,
> -	.set_acl	= ext4_set_acl,
> +	.get_acl	= ext4_get_posix_acl,
> +	.set_acl	= ext4_set_posix_acl,
> +	.get_richacl	= ext4_get_richacl,
>  };
> diff --git a/fs/ext4/richacl.c b/fs/ext4/richacl.c
> new file mode 100644
> index 0000000..6758def
> --- /dev/null
> +++ b/fs/ext4/richacl.c
> @@ -0,0 +1,213 @@
> +/*
> + * Copyright IBM Corporation, 2010
> + * Copyright (C) 2015  Red Hat, Inc.
> + * Author Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of version 2.1 of the GNU Lesser General Public License
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + *
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/fs.h>
> +#include <linux/richacl_xattr.h>
> +
> +#include "ext4.h"
> +#include "ext4_jbd2.h"
> +#include "xattr.h"
> +#include "acl.h"
> +#include "richacl.h"
> +
> +struct richacl *
> +ext4_get_richacl(struct inode *inode)
> +{
> +	const int name_index = EXT4_XATTR_INDEX_RICHACL;
> +	void *value = NULL;
> +	struct richacl *acl;
> +	int retval;
> +
> +	if (!IS_RICHACL(inode))
> +		return ERR_PTR(-EOPNOTSUPP);
> +	acl = get_cached_richacl(inode);
> +	if (acl != ACL_NOT_CACHED)
> +		return acl;
> +	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
> +	if (retval > 0) {
> +		value = kmalloc(retval, GFP_NOFS);
> +		if (!value)
> +			return ERR_PTR(-ENOMEM);
> +		retval = ext4_xattr_get(inode, name_index, "", value, retval);
> +	}
> +	if (retval > 0) {
> +		acl = richacl_from_xattr(&init_user_ns, value, retval);
> +		if (acl == ERR_PTR(-EINVAL))
> +			acl = ERR_PTR(-EIO);
> +	} else if (retval == -ENODATA || retval == -ENOSYS)
> +		acl = NULL;
> +	else
> +		acl = ERR_PTR(retval);
> +	kfree(value);
> +
> +	if (!IS_ERR(acl))
> +		set_cached_richacl(inode, acl);
> +
> +	return acl;
> +}
> +
> +static int
> +ext4_set_richacl(handle_t *handle, struct inode *inode, struct richacl *acl)
> +{
> +	const int name_index = EXT4_XATTR_INDEX_RICHACL;
> +	size_t size = 0;
> +	void *value = NULL;
> +	int retval;
> +
> +	if (acl) {
> +		mode_t mode = inode->i_mode;
> +
> +		if (richacl_equiv_mode(acl, &mode) == 0) {
> +			inode->i_mode = mode;
> +			ext4_mark_inode_dirty(handle, inode);
> +			acl = NULL;
> +		}
> +	}
> +	if (acl) {
> +		size = richacl_xattr_size(acl);
> +		value = kmalloc(size, GFP_NOFS);
> +		if (!value)
> +			return -ENOMEM;
> +		richacl_to_xattr(&init_user_ns, acl, value, size);
> +	}
> +	if (handle)
> +		retval = ext4_xattr_set_handle(handle, inode, name_index, "",
> +					       value, size, 0);
> +	else
> +		retval = ext4_xattr_set(inode, name_index, "", value, size, 0);
> +	kfree(value);
> +	if (!retval)
> +		set_cached_richacl(inode, acl);
> +
> +	return retval;
> +}
> +
> +int
> +ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
> +{
> +	struct richacl *acl = richacl_create(inode, dir);
> +	int error;
> +
> +	error = PTR_ERR(acl);
> +	if (IS_ERR(acl))
> +		return error;
> +	if (acl) {
> +		error = ext4_set_richacl(handle, inode, acl);
> +		richacl_put(acl);
> +	}
> +	return error;
> +}
> +
> +int
> +ext4_richacl_chmod(struct inode *inode)
> +{
> +	struct richacl *acl;
> +	int retval;
> +
> +	if (S_ISLNK(inode->i_mode))
> +		return -EOPNOTSUPP;
> +	acl = ext4_get_richacl(inode);
> +	if (IS_ERR_OR_NULL(acl))
> +		return PTR_ERR(acl);
> +	acl = richacl_chmod(acl, inode->i_mode);
> +	if (IS_ERR(acl))
> +		return PTR_ERR(acl);
> +	retval = ext4_set_richacl(NULL, inode, acl);
> +	richacl_put(acl);
> +
> +	return retval;
> +}
> +
> +static size_t
> +ext4_xattr_list_richacl(struct dentry *dentry, char *list, size_t list_len,
> +			const char *name, size_t name_len, int type)
> +{
> +	const size_t size = sizeof(XATTR_NAME_RICHACL);
> +
> +	if (!IS_RICHACL(d_inode(dentry)))
> +		return 0;
> +	if (list && size <= list_len)
> +		memcpy(list, XATTR_NAME_RICHACL, size);
> +	return size;
> +}
> +
> +static int
> +ext4_xattr_get_richacl(struct dentry *dentry, const char *name, void *buffer,
> +		size_t buffer_size, int type)
> +{
> +	struct richacl *acl;
> +	int error;
> +
> +	if (strcmp(name, "") != 0)
> +		return -EINVAL;
> +	acl = ext4_get_richacl(d_inode(dentry));
> +	if (IS_ERR(acl))
> +		return PTR_ERR(acl);
> +	if (acl == NULL)
> +		return -ENODATA;
> +
> +	error = richacl_to_xattr(&init_user_ns, acl, buffer, buffer_size);
> +	richacl_put(acl);
> +	return error;
> +}
> +
> +static int
> +ext4_xattr_set_richacl(struct dentry *dentry, const char *name,
> +		const void *value, size_t size, int flags, int type)
> +{
> +	handle_t *handle;
> +	struct richacl *acl = NULL;
> +	int retval, retries = 0;
> +	struct inode *inode = d_inode(dentry);
> +
> +	if (!IS_RICHACL(d_inode(dentry)))
> +		return -EOPNOTSUPP;
> +	if (S_ISLNK(inode->i_mode))
> +		return -EOPNOTSUPP;
> +	if (strcmp(name, "") != 0)
> +		return -EINVAL;
> +	if (!uid_eq(current_fsuid(), inode->i_uid) &&
> +	    inode_permission(inode, MAY_CHMOD) &&
> +	    !capable(CAP_FOWNER))
> +		return -EPERM;
> +	if (value) {
> +		acl = richacl_from_xattr(&init_user_ns, value, size);
> +		if (IS_ERR(acl))
> +			return PTR_ERR(acl);
> +
> +		inode->i_mode &= ~S_IRWXUGO;
> +		inode->i_mode |= richacl_masks_to_mode(acl);
> +	}
> +
> +retry:
> +	handle = ext4_journal_start(inode, EXT4_HT_XATTR,
> +				    EXT4_DATA_TRANS_BLOCKS(inode->i_sb));
> +	if (IS_ERR(handle))
> +		return PTR_ERR(handle);
> +	retval = ext4_set_richacl(handle, inode, acl);
> +	ext4_journal_stop(handle);
> +	if (retval == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
> +		goto retry;
> +	richacl_put(acl);
> +	return retval;
> +}
> +
> +const struct xattr_handler ext4_richacl_xattr_handler = {
> +	.prefix	= XATTR_NAME_RICHACL,
> +	.list	= ext4_xattr_list_richacl,
> +	.get	= ext4_xattr_get_richacl,
> +	.set	= ext4_xattr_set_richacl,
> +};
> diff --git a/fs/ext4/richacl.h b/fs/ext4/richacl.h
> new file mode 100644
> index 0000000..09a5cad
> --- /dev/null
> +++ b/fs/ext4/richacl.h
> @@ -0,0 +1,47 @@
> +/*
> + * Copyright IBM Corporation, 2010
> + * Copyright (C)  2015 Red Hat, Inc.
> + * Author Aneesh Kumar K.V <aneesh.kumar@...ux.vnet.ibm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of version 2.1 of the GNU Lesser General Public License
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it would be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> + *
> + */
> +
> +#ifndef __FS_EXT4_RICHACL_H
> +#define __FS_EXT4_RICHACL_H
> +
> +#include <linux/richacl.h>
> +
> +#ifdef CONFIG_EXT4_FS_RICHACL
> +
> +#define EXT4_IS_RICHACL(inode) IS_RICHACL(inode)
> +
> +extern struct richacl *ext4_get_richacl(struct inode *);
> +extern int ext4_init_richacl(handle_t *, struct inode *, struct inode *);
> +extern int ext4_richacl_chmod(struct inode *);
> +
> +#else  /* CONFIG_FS_EXT4_RICHACL */
> +
> +#define EXT4_IS_RICHACL(inode) (0)
> +#define ext4_get_richacl   NULL
> +
> +static inline int
> +ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
> +{
> +	return 0;
> +}
> +
> +static inline int
> +ext4_richacl_chmod(struct inode *inode)
> +{
> +	return 0;
> +}
> +
> +#endif  /* CONFIG_FS_EXT4_RICHACL */
> +#endif  /* __FS_EXT4_RICHACL_H */
> diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
> index 16e28c0..c1dee9b 100644
> --- a/fs/ext4/xattr.c
> +++ b/fs/ext4/xattr.c
> @@ -99,6 +99,9 @@ static const struct xattr_handler *ext4_xattr_handler_map[] = {
>  #ifdef CONFIG_EXT4_FS_SECURITY
>  	[EXT4_XATTR_INDEX_SECURITY]	     = &ext4_xattr_security_handler,
>  #endif
> +#ifdef CONFIG_EXT4_FS_RICHACL
> +	[EXT4_XATTR_INDEX_RICHACL]           = &ext4_richacl_xattr_handler,
> +#endif
>  };
>
>  const struct xattr_handler *ext4_xattr_handlers[] = {
> @@ -111,6 +114,9 @@ const struct xattr_handler *ext4_xattr_handlers[] = {
>  #ifdef CONFIG_EXT4_FS_SECURITY
>  	&ext4_xattr_security_handler,
>  #endif
> +#ifdef CONFIG_EXT4_FS_RICHACL
> +	&ext4_richacl_xattr_handler,
> +#endif
>  	NULL
>  };
>
> diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
> index ddc0957..f315493 100644
> --- a/fs/ext4/xattr.h
> +++ b/fs/ext4/xattr.h
> @@ -98,6 +98,7 @@ struct ext4_xattr_ibody_find {
>  extern const struct xattr_handler ext4_xattr_user_handler;
>  extern const struct xattr_handler ext4_xattr_trusted_handler;
>  extern const struct xattr_handler ext4_xattr_security_handler;
> +extern const struct xattr_handler ext4_richacl_xattr_handler;
>
>  #define EXT4_XATTR_NAME_ENCRYPTION_CONTEXT "c"
>
> -- 
> 2.4.3

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