[RFC v6 18/40] ext4: Add richacl support

From: Andreas Gruenbacher
Date: Tue Aug 04 2015 - 08:06:19 EST

From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>

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: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
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..4385f6d
--- /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@xxxxxxxxxxxxxxxxxx>
+ *
+ * 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(RICHACL_XATTR);
+
+ if (!IS_RICHACL(d_inode(dentry)))
+ return 0;
+ if (list && size <= list_len)
+ memcpy(list, RICHACL_XATTR, 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 = RICHACL_XATTR,
+ .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@xxxxxxxxxxxxxxxxxx>
+ *
+ * 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"

--
2.5.0

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