mirror of https://github.com/openzfs/zfs.git
Add Hooks for Linux Xattr Operations
The Linux specific xattr operations have all been located in the file zpl_xattr.c. These functions primarily rely on the reworked zfs_* functions to do their job. They are also responsible for converting the possible Solaris style error codes to negative Linux errors.
This commit is contained in:
Brian Behlendorf
parent
51f0bbe425
commit
cc5f931cfd
|
|
@ -0,0 +1,432 @@
|
|||
/*
|
||||
* CDDL HEADER START
|
||||
*
|
||||
* The contents of this file are subject to the terms of the
|
||||
* Common Development and Distribution License (the "License").
|
||||
* You may not use this file except in compliance with the License.
|
||||
*
|
||||
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
|
||||
* or http://www.opensolaris.org/os/licensing.
|
||||
* See the License for the specific language governing permissions
|
||||
* and limitations under the License.
|
||||
*
|
||||
* When distributing Covered Code, include this CDDL HEADER in each
|
||||
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
|
||||
* If applicable, add the following below this CDDL HEADER, with the
|
||||
* fields enclosed by brackets "[]" replaced with your own identifying
|
||||
* information: Portions Copyright [yyyy] [name of copyright owner]
|
||||
*
|
||||
* CDDL HEADER END
|
||||
*/
|
||||
/*
|
||||
* Copyright (c) 2011, Lawrence Livermore National Security, LLC.
|
||||
*
|
||||
* Extended attributes (xattr) on Solaris are implemented as files
|
||||
* which exist in a hidden xattr directory. These extended attributes
|
||||
* can be accessed using the attropen() system call which opens
|
||||
* the extended attribute. It can then be manipulated just like
|
||||
* a standard file descriptor. This has a couple advantages such
|
||||
* as practically no size limit on the file, and the extended
|
||||
* attributes permissions may differ from those of the parent file.
|
||||
* This interface is really quite clever, but it's also completely
|
||||
* different than what is supported on Linux.
|
||||
*
|
||||
* Under Linux extended attributes are manipulated by the system
|
||||
* calls getxattr(2), setxattr(2), and listxattr(2). They consider
|
||||
* extended attributes to be name/value pairs where the name is a
|
||||
* NULL terminated string. The name must also include one of the
|
||||
* following name space prefixes:
|
||||
*
|
||||
* user - No restrictions and is available to user applications.
|
||||
* trusted - Restricted to kernel and root (CAP_SYS_ADMIN) use.
|
||||
* system - Used for access control lists (system.nfs4_acl, etc).
|
||||
* security - Used by SELinux to store a files security context.
|
||||
*
|
||||
* This Linux interface is implemented internally using the more
|
||||
* flexible Solaris style extended attributes. Every extended
|
||||
* attribute is store as a file in a hidden directory associated
|
||||
* with the parent file. This ensures on disk compatibility with
|
||||
* zfs implementations on other platforms (Solaris, FreeBSD, MacOS).
|
||||
*
|
||||
* One consequence of this implementation is that when an extended
|
||||
* attribute is manipulated an inode is created. This inode will
|
||||
* exist in the Linux inode cache but there will be no associated
|
||||
* entry in the dentry cache which references it. This is safe
|
||||
* but it may result in some confusion.
|
||||
*
|
||||
* Longer term I would like to see the 'security.selinux' extended
|
||||
* attribute moved to a SA. This should significantly improve
|
||||
* performance on a SELinux enabled system by minimizing the
|
||||
* number of seeks required to access a file. However, for now
|
||||
* this xattr is still stored in a file because I'm pretty sure
|
||||
* adding a new SA will break on-disk compatibility.
|
||||
*/
|
||||
|
||||
|
||||
#include <sys/zfs_vfsops.h>
|
||||
#include <sys/zfs_vnops.h>
|
||||
#include <sys/zfs_znode.h>
|
||||
#include <sys/vfs.h>
|
||||
#include <sys/zpl.h>
|
||||
|
||||
typedef struct xattr_filldir {
|
||||
size_t size;
|
||||
size_t offset;
|
||||
char *buf;
|
||||
struct inode *inode;
|
||||
} xattr_filldir_t;
|
||||
|
||||
static int
|
||||
zpl_xattr_filldir(void *arg, const char *name, int name_len,
|
||||
loff_t offset, uint64_t objnum, unsigned int d_type)
|
||||
{
|
||||
xattr_filldir_t *xf = arg;
|
||||
|
||||
if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN))
|
||||
if (!(ITOZSB(xf->inode)->z_flags & ZSB_XATTR_USER))
|
||||
return (0);
|
||||
|
||||
if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
|
||||
if (!capable(CAP_SYS_ADMIN))
|
||||
return (0);
|
||||
|
||||
/* When xf->buf is NULL only calculate the required size. */
|
||||
if (xf->buf) {
|
||||
if (xf->offset + name_len + 1 > xf->size)
|
||||
return (-ERANGE);
|
||||
|
||||
memcpy(xf->buf + xf->offset, name, name_len);
|
||||
xf->buf[xf->offset + name_len] = '\0';
|
||||
}
|
||||
|
||||
xf->offset += (name_len + 1);
|
||||
|
||||
return (0);
|
||||
}
|
||||
|
||||
ssize_t
|
||||
zpl_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
|
||||
{
|
||||
struct inode *ip = dentry->d_inode;
|
||||
struct inode *dxip = NULL;
|
||||
loff_t pos = 3; /* skip '.', '..', and '.zfs' entries. */
|
||||
cred_t *cr;
|
||||
int error;
|
||||
xattr_filldir_t xf = { buffer_size, 0, buffer, ip };
|
||||
|
||||
cr = (cred_t *)get_current_cred();
|
||||
|
||||
/* Lookup the xattr directory */
|
||||
error = -zfs_lookup(ip, NULL, &dxip, LOOKUP_XATTR, cr, NULL, NULL);
|
||||
if (error) {
|
||||
if (error == -ENOENT)
|
||||
error = 0;
|
||||
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* Fill provided buffer via zpl_zattr_filldir helper */
|
||||
error = -zfs_readdir(dxip, (void *)&xf, zpl_xattr_filldir, &pos, cr);
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
error = xf.offset;
|
||||
out:
|
||||
if (dxip)
|
||||
iput(dxip);
|
||||
|
||||
put_cred(cr);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
zpl_xattr_get(struct inode *ip, const char *name, void *buf, size_t size)
|
||||
{
|
||||
struct inode *dxip = NULL;
|
||||
struct inode *xip = NULL;
|
||||
cred_t *cr;
|
||||
int error;
|
||||
|
||||
cr = (cred_t *)get_current_cred();
|
||||
|
||||
/* Lookup the xattr directory */
|
||||
error = -zfs_lookup(ip, NULL, &dxip, LOOKUP_XATTR, cr, NULL, NULL);
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
/* Lookup a specific xattr name in the directory */
|
||||
error = -zfs_lookup(dxip, (char *)name, &xip, 0, cr, NULL, NULL);
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
if (!size) {
|
||||
error = i_size_read(xip);
|
||||
goto out;
|
||||
}
|
||||
|
||||
error = zpl_read_common(xip, buf, size, 0, UIO_SYSSPACE, 0, cr);
|
||||
out:
|
||||
if (xip)
|
||||
iput(xip);
|
||||
|
||||
if (dxip)
|
||||
iput(dxip);
|
||||
|
||||
put_cred(cr);
|
||||
|
||||
if (error == -ENOENT)
|
||||
error = -ENODATA;
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
zpl_xattr_set(struct inode *ip, const char *name, const void *value,
|
||||
size_t size, int flags)
|
||||
{
|
||||
struct inode *dxip = NULL;
|
||||
struct inode *xip = NULL;
|
||||
vattr_t *vap = NULL;
|
||||
cred_t *cr;
|
||||
ssize_t wrote;
|
||||
int error;
|
||||
|
||||
cr = (cred_t *)get_current_cred();
|
||||
|
||||
/* Lookup the xattr directory and create it if required. */
|
||||
error = -zfs_lookup(ip, NULL, &dxip, LOOKUP_XATTR | CREATE_XATTR_DIR,
|
||||
cr, NULL, NULL);
|
||||
if (error)
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* Lookup a specific xattr name in the directory, two failure modes:
|
||||
* XATTR_CREATE: fail if xattr already exists
|
||||
* XATTR_REMOVE: fail if xattr does not exist
|
||||
*/
|
||||
error = -zfs_lookup(dxip, (char *)name, &xip, 0, cr, NULL, NULL);
|
||||
if (error) {
|
||||
if (error != -ENOENT)
|
||||
goto out;
|
||||
|
||||
if ((error == -ENOENT) && (flags & XATTR_REPLACE))
|
||||
goto out;
|
||||
} else {
|
||||
error = -EEXIST;
|
||||
if (flags & XATTR_CREATE)
|
||||
goto out;
|
||||
}
|
||||
error = 0;
|
||||
|
||||
/* Remove a specific name xattr when value is set to NULL. */
|
||||
if (value == NULL) {
|
||||
if (xip)
|
||||
error = -zfs_remove(dxip, (char *)name, cr);
|
||||
|
||||
goto out;
|
||||
}
|
||||
|
||||
/* Lookup failed create a new xattr. */
|
||||
if (xip == NULL) {
|
||||
vap = kmem_zalloc(sizeof(vattr_t), KM_SLEEP);
|
||||
vap->va_mode = S_IFREG | 0644;
|
||||
vap->va_mask = ATTR_MODE;
|
||||
vap->va_uid = current_fsuid();
|
||||
vap->va_gid = current_fsgid();
|
||||
|
||||
error = -zfs_create(dxip, (char *)name, vap, 0, 0644, &xip,
|
||||
cr, 0, NULL);
|
||||
if (error)
|
||||
goto out;
|
||||
}
|
||||
|
||||
ASSERT(xip != NULL);
|
||||
wrote = zpl_write_common(xip, value, size, 0, UIO_SYSSPACE, 0, cr);
|
||||
if (wrote < 0)
|
||||
error = wrote;
|
||||
|
||||
out:
|
||||
if (vap)
|
||||
kmem_free(vap, sizeof(vattr_t));
|
||||
|
||||
if (xip)
|
||||
iput(xip);
|
||||
|
||||
if (dxip)
|
||||
iput(dxip);
|
||||
|
||||
put_cred(cr);
|
||||
if (error == -ENOENT)
|
||||
error = -ENODATA;
|
||||
|
||||
ASSERT3S(error, <=, 0);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
zpl_xattr_user_get(struct inode *ip, const char *name,
|
||||
void *buffer, size_t size)
|
||||
{
|
||||
char *xattr_name;
|
||||
int error;
|
||||
|
||||
if (strcmp(name, "") == 0)
|
||||
return -EINVAL;
|
||||
|
||||
if (!(ITOZSB(ip)->z_flags & ZSB_XATTR_USER))
|
||||
return -EOPNOTSUPP;
|
||||
|
||||
xattr_name = kmem_asprintf("%s%s", XATTR_USER_PREFIX, name);
|
||||
error = zpl_xattr_get(ip, xattr_name, buffer, size);
|
||||
strfree(xattr_name);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
zpl_xattr_user_set(struct inode *ip, const char *name,
|
||||
const void *value, size_t size, int flags)
|
||||
{
|
||||
char *xattr_name;
|
||||
int error;
|
||||
|
||||
if (strcmp(name, "") == 0)
|
||||
return -EINVAL;
|
||||
|
||||
if (!(ITOZSB(ip)->z_flags & ZSB_XATTR_USER))
|
||||
return -EOPNOTSUPP;
|
||||
|
||||
xattr_name = kmem_asprintf("%s%s", XATTR_USER_PREFIX, name);
|
||||
error = zpl_xattr_set(ip, xattr_name, value, size, flags);
|
||||
strfree(xattr_name);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
struct xattr_handler zpl_xattr_user_handler = {
|
||||
.prefix = XATTR_USER_PREFIX,
|
||||
.get = zpl_xattr_user_get,
|
||||
.set = zpl_xattr_user_set,
|
||||
};
|
||||
|
||||
static int
|
||||
zpl_xattr_trusted_get(struct inode *ip, const char *name,
|
||||
void *buffer, size_t size)
|
||||
{
|
||||
char *xattr_name;
|
||||
int error;
|
||||
|
||||
if (!capable(CAP_SYS_ADMIN))
|
||||
return -EACCES;
|
||||
|
||||
if (strcmp(name, "") == 0)
|
||||
return -EINVAL;
|
||||
|
||||
xattr_name = kmem_asprintf("%s%s", XATTR_TRUSTED_PREFIX, name);
|
||||
error = zpl_xattr_get(ip, xattr_name, buffer, size);
|
||||
strfree(xattr_name);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
zpl_xattr_trusted_set(struct inode *ip, const char *name,
|
||||
const void *value, size_t size, int flags)
|
||||
{
|
||||
char *xattr_name;
|
||||
int error;
|
||||
|
||||
if (!capable(CAP_SYS_ADMIN))
|
||||
return -EACCES;
|
||||
|
||||
if (strcmp(name, "") == 0)
|
||||
return -EINVAL;
|
||||
|
||||
xattr_name = kmem_asprintf("%s%s", XATTR_TRUSTED_PREFIX, name);
|
||||
error = zpl_xattr_set(ip, xattr_name, value, size, flags);
|
||||
strfree(xattr_name);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
struct xattr_handler zpl_xattr_trusted_handler = {
|
||||
.prefix = XATTR_TRUSTED_PREFIX,
|
||||
.get = zpl_xattr_trusted_get,
|
||||
.set = zpl_xattr_trusted_set,
|
||||
};
|
||||
|
||||
static int
|
||||
zpl_xattr_security_get(struct inode *ip, const char *name,
|
||||
void *buffer, size_t size)
|
||||
{
|
||||
char *xattr_name;
|
||||
int error;
|
||||
|
||||
if (strcmp(name, "") == 0)
|
||||
return -EINVAL;
|
||||
|
||||
xattr_name = kmem_asprintf("%s%s", XATTR_SECURITY_PREFIX, name);
|
||||
error = zpl_xattr_get(ip, xattr_name, buffer, size);
|
||||
strfree(xattr_name);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
zpl_xattr_security_set(struct inode *ip, const char *name,
|
||||
const void *value, size_t size, int flags)
|
||||
{
|
||||
char *xattr_name;
|
||||
int error;
|
||||
|
||||
if (strcmp(name, "") == 0)
|
||||
return -EINVAL;
|
||||
|
||||
xattr_name = kmem_asprintf("%s%s", XATTR_SECURITY_PREFIX, name);
|
||||
error = zpl_xattr_set(ip, xattr_name, value, size, flags);
|
||||
strfree(xattr_name);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
int
|
||||
zpl_xattr_security_init(struct inode *ip, struct inode *dip)
|
||||
{
|
||||
int error;
|
||||
size_t len;
|
||||
void *value;
|
||||
char *name;
|
||||
|
||||
error = security_inode_init_security(ip, dip, &name, &value, &len);
|
||||
if (error) {
|
||||
if (error == -EOPNOTSUPP)
|
||||
return 0;
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
error = zpl_xattr_security_set(ip, name, value, len, 0);
|
||||
|
||||
kfree(name);
|
||||
kfree(value);
|
||||
|
||||
return (error);
|
||||
}
|
||||
|
||||
struct xattr_handler zpl_xattr_security_handler = {
|
||||
.prefix = XATTR_SECURITY_PREFIX,
|
||||
.get = zpl_xattr_security_get,
|
||||
.set = zpl_xattr_security_set,
|
||||
};
|
||||
|
||||
struct xattr_handler *zpl_xattr_handlers[] = {
|
||||
&zpl_xattr_security_handler,
|
||||
&zpl_xattr_trusted_handler,
|
||||
&zpl_xattr_user_handler,
|
||||
#ifdef HAVE_POSIX_ACLS
|
||||
&zpl_xattr_acl_access_handler,
|
||||
&zpl_xattr_acl_default_handler,
|
||||
#endif /* HAVE_POSIX_ACLS */
|
||||
};
|
||||
Loading…
Reference in New Issue