[PATCH -V2 15/16] ext4: Implement rich acl for ext4

Aneesh Kumar K.V
2010-07-02T18:45:37Z

Support the richacl permission model in ext4. The richacls are stored
in "system.richacl" xattrs.This need to be enabled by tune2fs or during
mkfs.ext4

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
---
fs/ext4/Kconfig | 15 +++
fs/ext4/Makefile | 1 +
fs/ext4/ext4.h | 4 +
fs/ext4/file.c | 4 +
fs/ext4/ialloc.c | 7 +-
fs/ext4/inode.c | 19 +++-
fs/ext4/namei.c | 7 ++
fs/ext4/richacl.c | 293 +++++++++++++++++++++++++++++++++++++++++++++++++++++
fs/ext4/richacl.h | 56 ++++++++++
fs/ext4/super.c | 12 ++-
fs/ext4/xattr.c | 6 +
fs/ext4/xattr.h | 2 +
12 files changed, 420 insertions(+), 6 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 9ed1bb1..a22b8f1 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -83,3 +83,18 @@ 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/kernel/debug/ext4/mballoc-debug"
+
+config EXT4_FS_RICHACL
+ bool "Ext4 Rich Access Control Lists (EXPERIMENTAL)"
+ depends on EXT4_FS_XATTR && EXPERIMENTAL
+ 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 8867b2a..4acbffe 100644
--- a/fs/ext4/Makefile
+++ b/fs/ext4/Makefile
@@ -11,3 +11,4 @@ ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o \
ext4-$(CONFIG_EXT4_FS_XATTR) += xattr.o xattr_user.o xattr_trusted.o
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o
+ext4-$(CONFIG_EXT4_FS_RICHACL) += richacl.o
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 651379b..966d0cb 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -836,6 +836,10 @@ struct ext4_inode_info {
*/
tid_t i_sync_tid;
tid_t i_datasync_tid;
+#ifdef CONFIG_EXT4_FS_RICHACL
+ struct richacl *i_richacl;
+#endif
+
};

/*
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 5313ae4..0e5a463 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -28,6 +28,7 @@
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
+#include "richacl.h"

/*
* Called when an inode is released. Note that this is different
@@ -160,5 +161,8 @@ const struct inode_operations ext4_file_inode_operations = {
.check_acl = ext4_check_acl,
.fallocate = ext4_fallocate,
.fiemap = ext4_fiemap,
+ .permission = ext4_permission,
+ .may_create = ext4_may_create,
+ .may_delete = ext4_may_delete,
};

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 25c4b31..57e885d 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -28,6 +28,7 @@
#include "ext4_jbd2.h"
#include "xattr.h"
#include "acl.h"
+#include "richacl.h"

#include <trace/events/ext4.h>

@@ -1023,7 +1024,11 @@ 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_acl(handle, inode, dir);
+
if (err)
goto fail_free_drop;

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 42272d6..93550e3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -45,6 +45,7 @@
#include "xattr.h"
#include "acl.h"
#include "ext4_extents.h"
+#include "richacl.h"

#include <trace/events/ext4.h>

@@ -5020,6 +5021,9 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);

ei->i_state_flags = 0;
+#ifdef CONFIG_EXT4_FS_RICHACL
+ ei->i_richacl = EXT4_RICHACL_NOT_CACHED;
+#endif
ei->i_dir_start_lookup = 0;
ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
/* We now have enough fields to check if the inode was active or not.
@@ -5446,7 +5450,11 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
int error, rc = 0;
const unsigned int ia_valid = attr->ia_valid;

- error = inode_change_ok(inode, attr);
+ if (EXT4_IS_RICHACL(inode))
+ error = richacl_inode_change_ok(inode, attr,
+ ext4_richacl_permission);
+ else
+ error = inode_change_ok(inode, attr);
if (error)
return error;

@@ -5537,9 +5545,12 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
if (inode->i_nlink)
ext4_orphan_del(NULL, inode);

- if (!rc && (ia_valid & ATTR_MODE))
- rc = ext4_acl_chmod(inode);
-
+ if (!rc && (ia_valid & ATTR_MODE)) {
+ if (EXT4_IS_RICHACL(inode))
+ rc = ext4_richacl_chmod(inode);
+ else
+ rc = ext4_acl_chmod(inode);
+ }
err_out:
ext4_std_error(inode->i_sb, error);
if (!error)
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index a43e661..d792b63 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -39,6 +39,7 @@

#include "xattr.h"
#include "acl.h"
+#include "richacl.h"

/*
* define how far ahead to read directories while searching them.
@@ -2550,6 +2551,9 @@ const struct inode_operations ext4_dir_inode_operations = {
#endif
.check_acl = ext4_check_acl,
.fiemap = ext4_fiemap,
+ .permission = ext4_permission,
+ .may_create = ext4_may_create,
+ .may_delete = ext4_may_delete,
};

const struct inode_operations ext4_special_inode_operations = {
@@ -2561,4 +2565,7 @@ const struct inode_operations ext4_special_inode_operations = {
.removexattr = generic_removexattr,
#endif
.check_acl = ext4_check_acl,
+ .permission = ext4_permission,
+ .may_create = ext4_may_create,
+ .may_delete = ext4_may_delete,
};
diff --git a/fs/ext4/richacl.c b/fs/ext4/richacl.c
new file mode 100644
index 0000000..5dfba2b
--- /dev/null
+++ b/fs/ext4/richacl.c
@@ -0,0 +1,293 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.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"
+
+static inline struct richacl *
+ext4_iget_richacl(struct inode *inode)
+{
+ struct richacl *acl = EXT4_RICHACL_NOT_CACHED;
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ spin_lock(&inode->i_lock);
+ if (ei->i_richacl != EXT4_RICHACL_NOT_CACHED)
+ acl = richacl_get(ei->i_richacl);
+ spin_unlock(&inode->i_lock);
+
+ return acl;
+}
+
+static inline void
+ext4_iset_richacl(struct inode *inode, struct richacl *acl)
+{
+ struct ext4_inode_info *ei = EXT4_I(inode);
+
+ spin_lock(&inode->i_lock);
+ if (ei->i_richacl != EXT4_RICHACL_NOT_CACHED)
+ richacl_put(ei->i_richacl);
+ ei->i_richacl = richacl_get(acl);
+ spin_unlock(&inode->i_lock);
+}
+
+static 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 = ext4_iget_richacl(inode);
+ if (acl != EXT4_RICHACL_NOT_CACHED)
+ return acl;
+ retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
+ if (retval > 0) {
+ value = kmalloc(retval, GFP_KERNEL);
+ if (!value)
+ return ERR_PTR(-ENOMEM);
+ retval = ext4_xattr_get(inode, name_index, "", value, retval);
+ }
+ if (retval > 0) {
+ acl = richacl_from_xattr(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_OR_NULL(acl))
+ ext4_iset_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_KERNEL);
+ if (!value)
+ return -ENOMEM;
+ richacl_to_xattr(acl, value);
+ }
+ 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)
+ ext4_iset_richacl(inode, acl);
+
+ return retval;
+}
+
+int
+ext4_richacl_permission(struct inode *inode, unsigned int mask)
+{
+ struct richacl *acl;
+ int retval;
+
+ if (!IS_RICHACL(inode))
+ BUG();
+
+ acl = ext4_get_richacl(inode);
+ if (acl && IS_ERR(acl))
+ retval = PTR_ERR(acl);
+ else {
+ retval = richacl_inode_permission(inode, acl, mask);
+ richacl_put(acl);
+ }
+
+ return retval;
+}
+
+int ext4_permission(struct inode *inode, int mask)
+{
+ if (IS_RICHACL(inode))
+ return ext4_richacl_permission(inode,
+ richacl_want_to_mask(mask));
+ else
+ return generic_permission(inode, mask, ext4_check_acl);
+}
+
+int ext4_may_create(struct inode *dir, int isdir)
+{
+ return richacl_may_create(dir, isdir, ext4_richacl_permission);
+}
+
+int ext4_may_delete(struct inode *dir, struct inode *inode, int replace)
+{
+ return richacl_may_delete(dir, inode, replace, ext4_richacl_permission);
+}
+
+int
+ext4_init_richacl(handle_t *handle, struct inode *inode, struct inode *dir)
+{
+ struct richacl *dir_acl = NULL;
+
+ if (!S_ISLNK(inode->i_mode)) {
+ dir_acl = ext4_get_richacl(dir);
+ if (IS_ERR(dir_acl))
+ return PTR_ERR(dir_acl);
+ }
+ if (dir_acl) {
+ struct richacl *acl;
+ int retval;
+
+ acl = richacl_inherit_inode(dir_acl, inode);
+ richacl_put(dir_acl);
+
+ retval = PTR_ERR(acl);
+ if (acl && !IS_ERR(acl)) {
+ retval = ext4_set_richacl(handle, inode, acl);
+ richacl_put(acl);
+ }
+ return retval;
+ } else {
+ inode->i_mode &= ~current_umask();
+ return 0;
+ }
+}
+
+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(dentry->d_inode))
+ 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;
+ size_t size;
+
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ acl = ext4_get_richacl(dentry->d_inode);
+ if (IS_ERR(acl))
+ return PTR_ERR(acl);
+ if (acl == NULL)
+ return -ENODATA;
+ size = richacl_xattr_size(acl);
+ if (buffer) {
+ if (size > buffer_size)
+ return -ERANGE;
+ richacl_to_xattr(acl, buffer);
+ }
+ richacl_put(acl);
+
+ return size;
+}
+
+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 = dentry->d_inode;
+
+ if (!IS_RICHACL(dentry->d_inode))
+ return -EOPNOTSUPP;
+ if (S_ISLNK(inode->i_mode))
+ return -EOPNOTSUPP;
+ if (strcmp(name, "") != 0)
+ return -EINVAL;
+ if (current_fsuid() != inode->i_uid &&
+ ext4_richacl_permission(inode, ACE4_WRITE_ACL) &&
+ !capable(CAP_FOWNER))
+ return -EPERM;
+ if (value) {
+ acl = richacl_from_xattr(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_DATA_TRANS_BLOCKS(inode->i_sb));
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+ ext4_mark_inode_dirty(handle, inode);
+ 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..00d89f2
--- /dev/null
+++ b/fs/ext4/richacl.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright IBM Corporation, 2010
+ * Author Aneesh Kumar K.V <aneesh.kumar@linux.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)
+
+/* Value for i_richacl if RICHACL has not been cached */
+# define EXT4_RICHACL_NOT_CACHED ((void *)-1)
+
+extern int ext4_permission(struct inode *, int);
+extern int ext4_richacl_permission(struct inode *, unsigned int);
+extern int ext4_may_create(struct inode *, int);
+extern int ext4_may_delete(struct inode *, struct inode *, int);
+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_permission NULL
+# define ext4_may_create NULL
+# define ext4_may_delete NULL
+# define ext4_richacl_permission 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/super.c b/fs/ext4/super.c
index 3836908..520ab44 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -46,6 +46,7 @@
#include "xattr.h"
#include "acl.h"
#include "mballoc.h"
+#include "richacl.h"

#define CREATE_TRACE_POINTS
#include <trace/events/ext4.h>
@@ -740,7 +741,9 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
ei = kmem_cache_alloc(ext4_inode_cachep, GFP_NOFS);
if (!ei)
return NULL;
-
+#ifdef CONFIG_EXT4_FS_RICHACL
+ ei->i_richacl = EXT4_RICHACL_NOT_CACHED;
+#endif
ei->vfs_inode.i_version = 1;
ei->vfs_inode.i_data.writeback_index = 0;
memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
@@ -816,6 +819,13 @@ static void destroy_inodecache(void)
static void ext4_clear_inode(struct inode *inode)
{
dquot_drop(inode);
+#ifdef CONFIG_EXT4_FS_RICHACL
+ if (EXT4_I(inode)->i_richacl &&
+ EXT4_I(inode)->i_richacl != EXT4_RICHACL_NOT_CACHED) {
+ richacl_put(EXT4_I(inode)->i_richacl);
+ EXT4_I(inode)->i_richacl = EXT4_RICHACL_NOT_CACHED;
+ }
+#endif
ext4_discard_preallocations(inode);
if (EXT4_JOURNAL(inode))
jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 0433800..a4c8382 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -107,6 +107,9 @@ 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[] = {
@@ -119,6 +122,9 @@ 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 518e96e..d65a62f 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -21,6 +21,7 @@
#define EXT4_XATTR_INDEX_TRUSTED 4
#define EXT4_XATTR_INDEX_LUSTRE 5
#define EXT4_XATTR_INDEX_SECURITY 6
+#define EXT4_XATTR_INDEX_RICHACL 7

struct ext4_xattr_header {
__le32 h_magic; /* magic number for identification */
@@ -70,6 +71,7 @@ extern const struct xattr_handler ext4_xattr_trusted_handler;
extern const struct xattr_handler ext4_xattr_acl_access_handler;
extern const struct xattr_handler ext4_xattr_acl_default_handler;
extern const struct xattr_handler ext4_xattr_security_handler;
+extern const struct xattr_handler ext4_richacl_xattr_handler;

extern ssize_t ext4_listxattr(struct dentry *, char *, size_t);

--
1.7.2.rc1