Commit 85ff872d authored by Aneesh Kumar K.V's avatar Aneesh Kumar K.V Committed by Eric Van Hensbergen
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fs/9p: Implement POSIX ACL permission checking function



The ACL value is fetched as a part of inode initialization
from the server and the permission checking function use the
cached value of the ACL
Signed-off-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarVenkateswararao Jujjuri <jvrao@linux.vnet.ibm.com>
Signed-off-by: default avatarEric Van Hensbergen <ericvh@gmail.com>
parent 8e44a080
......@@ -17,3 +17,16 @@ config 9P_FSCACHE
Choose Y here to enable persistent, read-only local
caching support for 9p clients using FS-Cache
config 9P_FS_POSIX_ACL
bool "9P POSIX Access Control Lists"
depends on 9P_FS
select FS_POSIX_ACL
help
POSIX Access Control Lists (ACLs) support permissions for users and
groups beyond the owner/group/world scheme.
To learn more about Access Control Lists, visit the POSIX ACLs for
Linux website <http://acl.bestbits.at/>.
If you don't know what Access Control Lists are, say N
......@@ -13,3 +13,4 @@ obj-$(CONFIG_9P_FS) := 9p.o
xattr_user.o
9p-$(CONFIG_9P_FSCACHE) += cache.o
9p-$(CONFIG_9P_FS_POSIX_ACL) += acl.o
/*
* 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/module.h>
#include <linux/fs.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
#include <linux/slab.h>
#include <linux/posix_acl_xattr.h>
#include "xattr.h"
#include "acl.h"
static struct posix_acl *__v9fs_get_acl(struct p9_fid *fid, char *name)
{
ssize_t size;
void *value = NULL;
struct posix_acl *acl = NULL;;
size = v9fs_fid_xattr_get(fid, name, NULL, 0);
if (size > 0) {
value = kzalloc(size, GFP_NOFS);
if (!value)
return ERR_PTR(-ENOMEM);
size = v9fs_fid_xattr_get(fid, name, value, size);
if (size > 0) {
acl = posix_acl_from_xattr(value, size);
if (IS_ERR(acl))
goto err_out;
}
} else if (size == -ENODATA || size == 0 ||
size == -ENOSYS || size == -EOPNOTSUPP) {
acl = NULL;
} else
acl = ERR_PTR(-EIO);
err_out:
kfree(value);
return acl;
}
int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
{
int retval = 0;
struct posix_acl *pacl, *dacl;
/* get the default/access acl values and cache them */
dacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_DEFAULT);
pacl = __v9fs_get_acl(fid, POSIX_ACL_XATTR_ACCESS);
if (!IS_ERR(dacl) && !IS_ERR(pacl)) {
set_cached_acl(inode, ACL_TYPE_DEFAULT, dacl);
set_cached_acl(inode, ACL_TYPE_ACCESS, pacl);
posix_acl_release(dacl);
posix_acl_release(pacl);
} else
retval = -EIO;
return retval;
}
static struct posix_acl *v9fs_get_cached_acl(struct inode *inode, int type)
{
struct posix_acl *acl;
/*
* 9p Always cache the acl value when
* instantiating the inode (v9fs_inode_from_fid)
*/
acl = get_cached_acl(inode, type);
BUG_ON(acl == ACL_NOT_CACHED);
return acl;
}
int v9fs_check_acl(struct inode *inode, int mask)
{
struct posix_acl *acl = v9fs_get_cached_acl(inode, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return PTR_ERR(acl);
if (acl) {
int error = posix_acl_permission(inode, acl, mask);
posix_acl_release(acl);
return error;
}
return -EAGAIN;
}
/*
* 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_9P_ACL_H
#define FS_9P_ACL_H
#ifdef CONFIG_9P_FS_POSIX_ACL
extern int v9fs_get_acl(struct inode *, struct p9_fid *);
extern int v9fs_check_acl(struct inode *inode, int mask);
#else
#define v9fs_check_acl NULL
static inline int v9fs_get_acl(struct inode *inode, struct p9_fid *fid)
{
return 0;
}
#endif
#endif /* FS_9P_XATTR_H */
......@@ -36,6 +36,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/xattr.h>
#include <linux/posix_acl.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
......@@ -44,6 +45,7 @@
#include "fid.h"
#include "cache.h"
#include "xattr.h"
#include "acl.h"
static const struct inode_operations v9fs_dir_inode_operations;
static const struct inode_operations v9fs_dir_inode_operations_dotu;
......@@ -500,6 +502,11 @@ v9fs_inode_dotl(struct v9fs_session_info *v9ses, struct p9_fid *fid,
v9fs_vcookie_set_qid(ret, &st->qid);
v9fs_cache_inode_get_cookie(ret);
#endif
err = v9fs_get_acl(ret, fid);
if (err) {
iput(ret);
goto error;
}
kfree(st);
return ret;
error:
......@@ -1959,7 +1966,7 @@ static const struct inode_operations v9fs_dir_inode_operations_dotl = {
.getxattr = generic_getxattr,
.removexattr = generic_removexattr,
.listxattr = v9fs_listxattr,
.check_acl = v9fs_check_acl,
};
static const struct inode_operations v9fs_dir_inode_operations = {
......@@ -1986,6 +1993,7 @@ static const struct inode_operations v9fs_file_inode_operations_dotl = {
.getxattr = generic_getxattr,
.removexattr = generic_removexattr,
.listxattr = v9fs_listxattr,
.check_acl = v9fs_check_acl,
};
static const struct inode_operations v9fs_symlink_inode_operations = {
......
......@@ -46,6 +46,7 @@
#include "v9fs_vfs.h"
#include "fid.h"
#include "xattr.h"
#include "acl.h"
static const struct super_operations v9fs_super_ops, v9fs_super_ops_dotl;
......@@ -88,6 +89,10 @@ v9fs_fill_super(struct super_block *sb, struct v9fs_session_info *v9ses,
sb->s_flags = flags | MS_ACTIVE | MS_SYNCHRONOUS | MS_DIRSYNC |
MS_NOATIME;
#ifdef CONFIG_9P_FS_POSIX_ACL
sb->s_flags |= MS_POSIXACL;
#endif
save_mount_options(sb, data);
}
......@@ -149,7 +154,6 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
goto release_sb;
}
sb->s_root = root;
if (v9fs_proto_dotl(v9ses)) {
struct p9_stat_dotl *st = NULL;
st = p9_client_getattr_dotl(fid, P9_STATS_BASIC);
......@@ -174,6 +178,9 @@ static int v9fs_get_sb(struct file_system_type *fs_type, int flags,
p9stat_free(st);
kfree(st);
}
retval = v9fs_get_acl(inode, fid);
if (retval)
goto release_sb;
v9fs_fid_add(root, fid);
......
......@@ -21,30 +21,13 @@
#include "fid.h"
#include "xattr.h"
/*
* v9fs_xattr_get()
*
* Copy an extended attribute into the buffer
* provided, or compute the buffer size required.
* Buffer is NULL to compute the size of the buffer required.
*
* Returns a negative error number on failure, or the number of bytes
* used / required on success.
*/
ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
void *buffer, size_t buffer_size)
ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char *name,
void *buffer, size_t buffer_size)
{
ssize_t retval;
int msize, read_count;
u64 offset = 0, attr_size;
struct p9_fid *fid, *attr_fid;
P9_DPRINTK(P9_DEBUG_VFS, "%s: name = %s value_len = %zu\n",
__func__, name, buffer_size);
fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid))
return PTR_ERR(fid);
struct p9_fid *attr_fid;
attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
if (IS_ERR(attr_fid)) {
......@@ -88,6 +71,31 @@ error:
}
/*
* v9fs_xattr_get()
*
* Copy an extended attribute into the buffer
* provided, or compute the buffer size required.
* Buffer is NULL to compute the size of the buffer required.
*
* Returns a negative error number on failure, or the number of bytes
* used / required on success.
*/
ssize_t v9fs_xattr_get(struct dentry *dentry, const char *name,
void *buffer, size_t buffer_size)
{
struct p9_fid *fid;
P9_DPRINTK(P9_DEBUG_VFS, "%s: name = %s value_len = %zu\n",
__func__, name, buffer_size);
fid = v9fs_fid_lookup(dentry);
if (IS_ERR(fid))
return PTR_ERR(fid);
return v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
}
/*
* v9fs_xattr_set()
*
......
......@@ -15,10 +15,14 @@
#define FS_9P_XATTR_H
#include <linux/xattr.h>
#include <net/9p/9p.h>
#include <net/9p/client.h>
extern const struct xattr_handler *v9fs_xattr_handlers[];
extern struct xattr_handler v9fs_xattr_user_handler;
extern ssize_t v9fs_fid_xattr_get(struct p9_fid *, const char *,
void *, size_t);
extern ssize_t v9fs_xattr_get(struct dentry *, const char *,
void *, size_t);
extern int v9fs_xattr_set(struct dentry *, const char *,
......
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