freebsd-nq/module/zfs/zpl_xattr.c
Brian Behlendorf 0037b49e83 Rename zfs_sb_t -> zfsvfs_t
The use of zfs_sb_t instead of zfsvfs_t results in unnecessary
conflicts with the upstream source.  Change all instances of
zfs_sb_t to zfsvfs_t including updating the variables names.

Whenever possible the code was updated to be consistent with
hope it appears in the upstream OpenZFS source.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
2017-03-10 09:51:33 -08:00

1544 lines
38 KiB
C

/*
* 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. It also comes with a
* steep performance penalty when accessing small xattrs because they
* are not stored with the parent file.
*
* 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 namespace 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.
*
* The value under Linux to limited to 65536 bytes of binary data.
* In practice, individual xattrs tend to be much smaller than this
* and are typically less than 100 bytes. A good example of this
* are the security.selinux xattrs which are less than 100 bytes and
* exist for every file when xattr labeling is enabled.
*
* The Linux xattr implementation has been written to take advantage of
* this typical usage. When the dataset property 'xattr=sa' is set,
* then xattrs will be preferentially stored as System Attributes (SA).
* This allows tiny xattrs (~100 bytes) to be stored with the dnode and
* up to 64k of xattrs to be stored in the spill block. If additional
* xattr space is required, which is unlikely under Linux, they will
* be stored using the traditional directory approach.
*
* This optimization results in roughly a 3x performance improvement
* when accessing xattrs because it avoids the need to perform a seek
* for every xattr value. When multiple xattrs are stored per-file
* the performance improvements are even greater because all of the
* xattrs stored in the spill block will be cached.
*
* However, by default SA based xattrs are disabled in the Linux port
* to maximize compatibility with other implementations. If you do
* enable SA based xattrs then they will not be visible on platforms
* which do not support this feature.
*
* NOTE: One additional consequence of the xattr directory 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. Enabling SA based xattrs
* largely avoids the issue except in the overflow case.
*/
#include <sys/zfs_vfsops.h>
#include <sys/zfs_vnops.h>
#include <sys/zfs_znode.h>
#include <sys/zap.h>
#include <sys/vfs.h>
#include <sys/zpl.h>
typedef struct xattr_filldir {
size_t size;
size_t offset;
char *buf;
struct dentry *dentry;
} xattr_filldir_t;
static const struct xattr_handler *zpl_xattr_handler(const char *);
static int
zpl_xattr_permission(xattr_filldir_t *xf, const char *name, int name_len)
{
static const struct xattr_handler *handler;
struct dentry *d = xf->dentry;
handler = zpl_xattr_handler(name);
if (!handler)
return (0);
if (handler->list) {
#if defined(HAVE_XATTR_LIST_SIMPLE)
if (!handler->list(d))
return (0);
#elif defined(HAVE_XATTR_LIST_DENTRY)
if (!handler->list(d, NULL, 0, name, name_len, 0))
return (0);
#elif defined(HAVE_XATTR_LIST_HANDLER)
if (!handler->list(handler, d, NULL, 0, name, name_len))
return (0);
#elif defined(HAVE_XATTR_LIST_INODE)
if (!handler->list(d->d_inode, NULL, 0, name, name_len))
return (0);
#endif
}
return (1);
}
/*
* Determine is a given xattr name should be visible and if so copy it
* in to the provided buffer (xf->buf).
*/
static int
zpl_xattr_filldir(xattr_filldir_t *xf, const char *name, int name_len)
{
/* Check permissions using the per-namespace list xattr handler. */
if (!zpl_xattr_permission(xf, name, name_len))
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);
}
/*
* Read as many directory entry names as will fit in to the provided buffer,
* or when no buffer is provided calculate the required buffer size.
*/
int
zpl_xattr_readdir(struct inode *dxip, xattr_filldir_t *xf)
{
zap_cursor_t zc;
zap_attribute_t zap;
int error;
zap_cursor_init(&zc, ITOZSB(dxip)->z_os, ITOZ(dxip)->z_id);
while ((error = -zap_cursor_retrieve(&zc, &zap)) == 0) {
if (zap.za_integer_length != 8 || zap.za_num_integers != 1) {
error = -ENXIO;
break;
}
error = zpl_xattr_filldir(xf, zap.za_name, strlen(zap.za_name));
if (error)
break;
zap_cursor_advance(&zc);
}
zap_cursor_fini(&zc);
if (error == -ENOENT)
error = 0;
return (error);
}
static ssize_t
zpl_xattr_list_dir(xattr_filldir_t *xf, cred_t *cr)
{
struct inode *ip = xf->dentry->d_inode;
struct inode *dxip = NULL;
int error;
/* Lookup the xattr directory */
error = -zfs_lookup(ip, NULL, &dxip, LOOKUP_XATTR, cr, NULL, NULL);
if (error) {
if (error == -ENOENT)
error = 0;
return (error);
}
error = zpl_xattr_readdir(dxip, xf);
iput(dxip);
return (error);
}
static ssize_t
zpl_xattr_list_sa(xattr_filldir_t *xf)
{
znode_t *zp = ITOZ(xf->dentry->d_inode);
nvpair_t *nvp = NULL;
int error = 0;
mutex_enter(&zp->z_lock);
if (zp->z_xattr_cached == NULL)
error = -zfs_sa_get_xattr(zp);
mutex_exit(&zp->z_lock);
if (error)
return (error);
ASSERT(zp->z_xattr_cached);
while ((nvp = nvlist_next_nvpair(zp->z_xattr_cached, nvp)) != NULL) {
ASSERT3U(nvpair_type(nvp), ==, DATA_TYPE_BYTE_ARRAY);
error = zpl_xattr_filldir(xf, nvpair_name(nvp),
strlen(nvpair_name(nvp)));
if (error)
return (error);
}
return (0);
}
ssize_t
zpl_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size)
{
znode_t *zp = ITOZ(dentry->d_inode);
zfsvfs_t *zfsvfs = ZTOZSB(zp);
xattr_filldir_t xf = { buffer_size, 0, buffer, dentry };
cred_t *cr = CRED();
fstrans_cookie_t cookie;
int error = 0;
crhold(cr);
cookie = spl_fstrans_mark();
rrm_enter_read(&(zfsvfs)->z_teardown_lock, FTAG);
rw_enter(&zp->z_xattr_lock, RW_READER);
if (zfsvfs->z_use_sa && zp->z_is_sa) {
error = zpl_xattr_list_sa(&xf);
if (error)
goto out;
}
error = zpl_xattr_list_dir(&xf, cr);
if (error)
goto out;
error = xf.offset;
out:
rw_exit(&zp->z_xattr_lock);
rrm_exit(&(zfsvfs)->z_teardown_lock, FTAG);
spl_fstrans_unmark(cookie);
crfree(cr);
return (error);
}
static int
zpl_xattr_get_dir(struct inode *ip, const char *name, void *value,
size_t size, cred_t *cr)
{
struct inode *dxip = NULL;
struct inode *xip = NULL;
loff_t pos = 0;
int error;
/* 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;
}
if (size < i_size_read(xip)) {
error = -ERANGE;
goto out;
}
error = zpl_read_common(xip, value, size, &pos, UIO_SYSSPACE, 0, cr);
out:
if (xip)
iput(xip);
if (dxip)
iput(dxip);
return (error);
}
static int
zpl_xattr_get_sa(struct inode *ip, const char *name, void *value, size_t size)
{
znode_t *zp = ITOZ(ip);
uchar_t *nv_value;
uint_t nv_size;
int error = 0;
ASSERT(RW_LOCK_HELD(&zp->z_xattr_lock));
mutex_enter(&zp->z_lock);
if (zp->z_xattr_cached == NULL)
error = -zfs_sa_get_xattr(zp);
mutex_exit(&zp->z_lock);
if (error)
return (error);
ASSERT(zp->z_xattr_cached);
error = -nvlist_lookup_byte_array(zp->z_xattr_cached, name,
&nv_value, &nv_size);
if (error)
return (error);
if (!size)
return (nv_size);
if (size < nv_size)
return (-ERANGE);
memcpy(value, nv_value, nv_size);
return (nv_size);
}
static int
__zpl_xattr_get(struct inode *ip, const char *name, void *value, size_t size,
cred_t *cr)
{
znode_t *zp = ITOZ(ip);
zfsvfs_t *zfsvfs = ZTOZSB(zp);
int error;
ASSERT(RW_LOCK_HELD(&zp->z_xattr_lock));
if (zfsvfs->z_use_sa && zp->z_is_sa) {
error = zpl_xattr_get_sa(ip, name, value, size);
if (error != -ENOENT)
goto out;
}
error = zpl_xattr_get_dir(ip, name, value, size, cr);
out:
if (error == -ENOENT)
error = -ENODATA;
return (error);
}
#define XATTR_NOENT 0x0
#define XATTR_IN_SA 0x1
#define XATTR_IN_DIR 0x2
/* check where the xattr resides */
static int
__zpl_xattr_where(struct inode *ip, const char *name, int *where, cred_t *cr)
{
znode_t *zp = ITOZ(ip);
zfsvfs_t *zfsvfs = ZTOZSB(zp);
int error;
ASSERT(where);
ASSERT(RW_LOCK_HELD(&zp->z_xattr_lock));
*where = XATTR_NOENT;
if (zfsvfs->z_use_sa && zp->z_is_sa) {
error = zpl_xattr_get_sa(ip, name, NULL, 0);
if (error >= 0)
*where |= XATTR_IN_SA;
else if (error != -ENOENT)
return (error);
}
error = zpl_xattr_get_dir(ip, name, NULL, 0, cr);
if (error >= 0)
*where |= XATTR_IN_DIR;
else if (error != -ENOENT)
return (error);
if (*where == (XATTR_IN_SA|XATTR_IN_DIR))
cmn_err(CE_WARN, "ZFS: inode %p has xattr \"%s\""
" in both SA and dir", ip, name);
if (*where == XATTR_NOENT)
error = -ENODATA;
else
error = 0;
return (error);
}
static int
zpl_xattr_get(struct inode *ip, const char *name, void *value, size_t size)
{
znode_t *zp = ITOZ(ip);
zfsvfs_t *zfsvfs = ZTOZSB(zp);
cred_t *cr = CRED();
fstrans_cookie_t cookie;
int error;
crhold(cr);
cookie = spl_fstrans_mark();
rrm_enter_read(&(zfsvfs)->z_teardown_lock, FTAG);
rw_enter(&zp->z_xattr_lock, RW_READER);
error = __zpl_xattr_get(ip, name, value, size, cr);
rw_exit(&zp->z_xattr_lock);
rrm_exit(&(zfsvfs)->z_teardown_lock, FTAG);
spl_fstrans_unmark(cookie);
crfree(cr);
return (error);
}
static int
zpl_xattr_set_dir(struct inode *ip, const char *name, const void *value,
size_t size, int flags, cred_t *cr)
{
struct inode *dxip = NULL;
struct inode *xip = NULL;
vattr_t *vap = NULL;
ssize_t wrote;
int lookup_flags, error;
const int xattr_mode = S_IFREG | 0644;
loff_t pos = 0;
/*
* Lookup the xattr directory. When we're adding an entry pass
* CREATE_XATTR_DIR to ensure the xattr directory is created.
* When removing an entry this flag is not passed to avoid
* unnecessarily creating a new xattr directory.
*/
lookup_flags = LOOKUP_XATTR;
if (value != NULL)
lookup_flags |= CREATE_XATTR_DIR;
error = -zfs_lookup(ip, NULL, &dxip, lookup_flags, 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 && (error != -ENOENT))
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, 0);
goto out;
}
/* Lookup failed create a new xattr. */
if (xip == NULL) {
vap = kmem_zalloc(sizeof (vattr_t), KM_SLEEP);
vap->va_mode = xattr_mode;
vap->va_mask = ATTR_MODE;
vap->va_uid = crgetfsuid(cr);
vap->va_gid = crgetfsgid(cr);
error = -zfs_create(dxip, (char *)name, vap, 0, 0644, &xip,
cr, 0, NULL);
if (error)
goto out;
}
ASSERT(xip != NULL);
error = -zfs_freesp(ITOZ(xip), 0, 0, xattr_mode, TRUE);
if (error)
goto out;
wrote = zpl_write_common(xip, value, size, &pos, 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);
if (error == -ENOENT)
error = -ENODATA;
ASSERT3S(error, <=, 0);
return (error);
}
static int
zpl_xattr_set_sa(struct inode *ip, const char *name, const void *value,
size_t size, int flags, cred_t *cr)
{
znode_t *zp = ITOZ(ip);
nvlist_t *nvl;
size_t sa_size;
int error = 0;
mutex_enter(&zp->z_lock);
if (zp->z_xattr_cached == NULL)
error = -zfs_sa_get_xattr(zp);
mutex_exit(&zp->z_lock);
if (error)
return (error);
ASSERT(zp->z_xattr_cached);
nvl = zp->z_xattr_cached;
if (value == NULL) {
error = -nvlist_remove(nvl, name, DATA_TYPE_BYTE_ARRAY);
if (error == -ENOENT)
error = zpl_xattr_set_dir(ip, name, NULL, 0, flags, cr);
} else {
/* Limited to 32k to keep nvpair memory allocations small */
if (size > DXATTR_MAX_ENTRY_SIZE)
return (-EFBIG);
/* Prevent the DXATTR SA from consuming the entire SA region */
error = -nvlist_size(nvl, &sa_size, NV_ENCODE_XDR);
if (error)
return (error);
if (sa_size > DXATTR_MAX_SA_SIZE)
return (-EFBIG);
error = -nvlist_add_byte_array(nvl, name,
(uchar_t *)value, size);
}
/*
* Update the SA for additions, modifications, and removals. On
* error drop the inconsistent cached version of the nvlist, it
* will be reconstructed from the ARC when next accessed.
*/
if (error == 0)
error = -zfs_sa_set_xattr(zp);
if (error) {
nvlist_free(nvl);
zp->z_xattr_cached = NULL;
}
ASSERT3S(error, <=, 0);
return (error);
}
static int
zpl_xattr_set(struct inode *ip, const char *name, const void *value,
size_t size, int flags)
{
znode_t *zp = ITOZ(ip);
zfsvfs_t *zfsvfs = ZTOZSB(zp);
cred_t *cr = CRED();
fstrans_cookie_t cookie;
int where;
int error;
crhold(cr);
cookie = spl_fstrans_mark();
rrm_enter_read(&(zfsvfs)->z_teardown_lock, FTAG);
rw_enter(&ITOZ(ip)->z_xattr_lock, RW_WRITER);
/*
* Before setting the xattr check to see if it already exists.
* This is done to ensure the following optional flags are honored.
*
* XATTR_CREATE: fail if xattr already exists
* XATTR_REPLACE: fail if xattr does not exist
*
* We also want to know if it resides in sa or dir, so we can make
* sure we don't end up with duplicate in both places.
*/
error = __zpl_xattr_where(ip, name, &where, cr);
if (error < 0) {
if (error != -ENODATA)
goto out;
if (flags & XATTR_REPLACE)
goto out;
/* The xattr to be removed already doesn't exist */
error = 0;
if (value == NULL)
goto out;
} else {
error = -EEXIST;
if (flags & XATTR_CREATE)
goto out;
}
/* Preferentially store the xattr as a SA for better performance */
if (zfsvfs->z_use_sa && zp->z_is_sa &&
(zfsvfs->z_xattr_sa || (value == NULL && where & XATTR_IN_SA))) {
error = zpl_xattr_set_sa(ip, name, value, size, flags, cr);
if (error == 0) {
/*
* Successfully put into SA, we need to clear the one
* in dir.
*/
if (where & XATTR_IN_DIR)
zpl_xattr_set_dir(ip, name, NULL, 0, 0, cr);
goto out;
}
}
error = zpl_xattr_set_dir(ip, name, value, size, flags, cr);
/*
* Successfully put into dir, we need to clear the one in SA.
*/
if (error == 0 && (where & XATTR_IN_SA))
zpl_xattr_set_sa(ip, name, NULL, 0, 0, cr);
out:
rw_exit(&ITOZ(ip)->z_xattr_lock);
rrm_exit(&(zfsvfs)->z_teardown_lock, FTAG);
spl_fstrans_unmark(cookie);
crfree(cr);
ASSERT3S(error, <=, 0);
return (error);
}
/*
* Extended user attributes
*
* "Extended user attributes may be assigned to files and directories for
* storing arbitrary additional information such as the mime type,
* character set or encoding of a file. The access permissions for user
* attributes are defined by the file permission bits: read permission
* is required to retrieve the attribute value, and writer permission is
* required to change it.
*
* The file permission bits of regular files and directories are
* interpreted differently from the file permission bits of special
* files and symbolic links. For regular files and directories the file
* permission bits define access to the file's contents, while for
* device special files they define access to the device described by
* the special file. The file permissions of symbolic links are not
* used in access checks. These differences would allow users to
* consume filesystem resources in a way not controllable by disk quotas
* for group or world writable special files and directories.
*
* For this reason, extended user attributes are allowed only for
* regular files and directories, and access to extended user attributes
* is restricted to the owner and to users with appropriate capabilities
* for directories with the sticky bit set (see the chmod(1) manual page
* for an explanation of the sticky bit)." - xattr(7)
*
* ZFS allows extended user attributes to be disabled administratively
* by setting the 'xattr=off' property on the dataset.
*/
static int
__zpl_xattr_user_list(struct inode *ip, char *list, size_t list_size,
const char *name, size_t name_len)
{
return (ITOZSB(ip)->z_flags & ZSB_XATTR);
}
ZPL_XATTR_LIST_WRAPPER(zpl_xattr_user_list);
static int
__zpl_xattr_user_get(struct inode *ip, const char *name,
void *value, size_t size)
{
char *xattr_name;
int error;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") == 0)
return (-EINVAL);
#endif
if (!(ITOZSB(ip)->z_flags & ZSB_XATTR))
return (-EOPNOTSUPP);
xattr_name = kmem_asprintf("%s%s", XATTR_USER_PREFIX, name);
error = zpl_xattr_get(ip, xattr_name, value, size);
strfree(xattr_name);
return (error);
}
ZPL_XATTR_GET_WRAPPER(zpl_xattr_user_get);
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;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") == 0)
return (-EINVAL);
#endif
if (!(ITOZSB(ip)->z_flags & ZSB_XATTR))
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);
}
ZPL_XATTR_SET_WRAPPER(zpl_xattr_user_set);
xattr_handler_t zpl_xattr_user_handler =
{
.prefix = XATTR_USER_PREFIX,
.list = zpl_xattr_user_list,
.get = zpl_xattr_user_get,
.set = zpl_xattr_user_set,
};
/*
* Trusted extended attributes
*
* "Trusted extended attributes are visible and accessible only to
* processes that have the CAP_SYS_ADMIN capability. Attributes in this
* class are used to implement mechanisms in user space (i.e., outside
* the kernel) which keep information in extended attributes to which
* ordinary processes should not have access." - xattr(7)
*/
static int
__zpl_xattr_trusted_list(struct inode *ip, char *list, size_t list_size,
const char *name, size_t name_len)
{
return (capable(CAP_SYS_ADMIN));
}
ZPL_XATTR_LIST_WRAPPER(zpl_xattr_trusted_list);
static int
__zpl_xattr_trusted_get(struct inode *ip, const char *name,
void *value, size_t size)
{
char *xattr_name;
int error;
if (!capable(CAP_SYS_ADMIN))
return (-EACCES);
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") == 0)
return (-EINVAL);
#endif
xattr_name = kmem_asprintf("%s%s", XATTR_TRUSTED_PREFIX, name);
error = zpl_xattr_get(ip, xattr_name, value, size);
strfree(xattr_name);
return (error);
}
ZPL_XATTR_GET_WRAPPER(zpl_xattr_trusted_get);
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);
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") == 0)
return (-EINVAL);
#endif
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);
}
ZPL_XATTR_SET_WRAPPER(zpl_xattr_trusted_set);
xattr_handler_t zpl_xattr_trusted_handler =
{
.prefix = XATTR_TRUSTED_PREFIX,
.list = zpl_xattr_trusted_list,
.get = zpl_xattr_trusted_get,
.set = zpl_xattr_trusted_set,
};
/*
* Extended security attributes
*
* "The security attribute namespace is used by kernel security modules,
* such as Security Enhanced Linux, and also to implement file
* capabilities (see capabilities(7)). Read and write access
* permissions to security attributes depend on the policy implemented
* for each security attribute by the security module. When no security
* module is loaded, all processes have read access to extended security
* attributes, and write access is limited to processes that have the
* CAP_SYS_ADMIN capability." - xattr(7)
*/
static int
__zpl_xattr_security_list(struct inode *ip, char *list, size_t list_size,
const char *name, size_t name_len)
{
return (1);
}
ZPL_XATTR_LIST_WRAPPER(zpl_xattr_security_list);
static int
__zpl_xattr_security_get(struct inode *ip, const char *name,
void *value, size_t size)
{
char *xattr_name;
int error;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") == 0)
return (-EINVAL);
#endif
xattr_name = kmem_asprintf("%s%s", XATTR_SECURITY_PREFIX, name);
error = zpl_xattr_get(ip, xattr_name, value, size);
strfree(xattr_name);
return (error);
}
ZPL_XATTR_GET_WRAPPER(zpl_xattr_security_get);
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;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") == 0)
return (-EINVAL);
#endif
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);
}
ZPL_XATTR_SET_WRAPPER(zpl_xattr_security_set);
#ifdef HAVE_CALLBACK_SECURITY_INODE_INIT_SECURITY
static int
__zpl_xattr_security_init(struct inode *ip, const struct xattr *xattrs,
void *fs_info)
{
const struct xattr *xattr;
int error = 0;
for (xattr = xattrs; xattr->name != NULL; xattr++) {
error = __zpl_xattr_security_set(ip,
xattr->name, xattr->value, xattr->value_len, 0);
if (error < 0)
break;
}
return (error);
}
int
zpl_xattr_security_init(struct inode *ip, struct inode *dip,
const struct qstr *qstr)
{
return security_inode_init_security(ip, dip, qstr,
&__zpl_xattr_security_init, NULL);
}
#else
int
zpl_xattr_security_init(struct inode *ip, struct inode *dip,
const struct qstr *qstr)
{
int error;
size_t len;
void *value;
char *name;
error = zpl_security_inode_init_security(ip, dip, qstr,
&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);
}
#endif /* HAVE_CALLBACK_SECURITY_INODE_INIT_SECURITY */
/*
* Security xattr namespace handlers.
*/
xattr_handler_t zpl_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.list = zpl_xattr_security_list,
.get = zpl_xattr_security_get,
.set = zpl_xattr_security_set,
};
/*
* Extended system attributes
*
* "Extended system attributes are used by the kernel to store system
* objects such as Access Control Lists. Read and write access permissions
* to system attributes depend on the policy implemented for each system
* attribute implemented by filesystems in the kernel." - xattr(7)
*/
#ifdef CONFIG_FS_POSIX_ACL
int
zpl_set_acl(struct inode *ip, struct posix_acl *acl, int type)
{
struct super_block *sb = ITOZSB(ip)->z_sb;
char *name, *value = NULL;
int error = 0;
size_t size = 0;
if (S_ISLNK(ip->i_mode))
return (-EOPNOTSUPP);
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
if (acl) {
zpl_equivmode_t mode = ip->i_mode;
error = posix_acl_equiv_mode(acl, &mode);
if (error < 0) {
return (error);
} else {
/*
* The mode bits will have been set by
* ->zfs_setattr()->zfs_acl_chmod_setattr()
* using the ZFS ACL conversion. If they
* differ from the Posix ACL conversion dirty
* the inode to write the Posix mode bits.
*/
if (ip->i_mode != mode) {
ip->i_mode = mode;
ip->i_ctime = current_fs_time(sb);
zfs_mark_inode_dirty(ip);
}
if (error == 0)
acl = NULL;
}
}
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
if (!S_ISDIR(ip->i_mode))
return (acl ? -EACCES : 0);
break;
default:
return (-EINVAL);
}
if (acl) {
size = posix_acl_xattr_size(acl->a_count);
value = kmem_alloc(size, KM_SLEEP);
error = zpl_acl_to_xattr(acl, value, size);
if (error < 0) {
kmem_free(value, size);
return (error);
}
}
error = zpl_xattr_set(ip, name, value, size, 0);
if (value)
kmem_free(value, size);
if (!error) {
if (acl)
zpl_set_cached_acl(ip, type, acl);
else
zpl_forget_cached_acl(ip, type);
}
return (error);
}
struct posix_acl *
zpl_get_acl(struct inode *ip, int type)
{
struct posix_acl *acl;
void *value = NULL;
char *name;
int size;
/*
* As of Linux 3.14, the kernel get_acl will check this for us.
* Also as of Linux 4.7, comparing against ACL_NOT_CACHED is wrong
* as the kernel get_acl will set it to temporary sentinel value.
*/
#ifndef HAVE_KERNEL_GET_ACL_HANDLE_CACHE
acl = get_cached_acl(ip, type);
if (acl != ACL_NOT_CACHED)
return (acl);
#endif
switch (type) {
case ACL_TYPE_ACCESS:
name = XATTR_NAME_POSIX_ACL_ACCESS;
break;
case ACL_TYPE_DEFAULT:
name = XATTR_NAME_POSIX_ACL_DEFAULT;
break;
default:
return (ERR_PTR(-EINVAL));
}
size = zpl_xattr_get(ip, name, NULL, 0);
if (size > 0) {
value = kmem_alloc(size, KM_SLEEP);
size = zpl_xattr_get(ip, name, value, size);
}
if (size > 0) {
acl = zpl_acl_from_xattr(value, size);
} else if (size == -ENODATA || size == -ENOSYS) {
acl = NULL;
} else {
acl = ERR_PTR(-EIO);
}
if (size > 0)
kmem_free(value, size);
/* As of Linux 4.7, the kernel get_acl will set this for us */
#ifndef HAVE_KERNEL_GET_ACL_HANDLE_CACHE
if (!IS_ERR(acl))
zpl_set_cached_acl(ip, type, acl);
#endif
return (acl);
}
#if !defined(HAVE_GET_ACL)
static int
__zpl_check_acl(struct inode *ip, int mask)
{
struct posix_acl *acl;
int error;
acl = zpl_get_acl(ip, ACL_TYPE_ACCESS);
if (IS_ERR(acl))
return (PTR_ERR(acl));
if (acl) {
error = posix_acl_permission(ip, acl, mask);
zpl_posix_acl_release(acl);
return (error);
}
return (-EAGAIN);
}
#if defined(HAVE_CHECK_ACL_WITH_FLAGS)
int
zpl_check_acl(struct inode *ip, int mask, unsigned int flags)
{
return (__zpl_check_acl(ip, mask));
}
#elif defined(HAVE_CHECK_ACL)
int
zpl_check_acl(struct inode *ip, int mask)
{
return (__zpl_check_acl(ip, mask));
}
#elif defined(HAVE_PERMISSION_WITH_NAMEIDATA)
int
zpl_permission(struct inode *ip, int mask, struct nameidata *nd)
{
return (generic_permission(ip, mask, __zpl_check_acl));
}
#elif defined(HAVE_PERMISSION)
int
zpl_permission(struct inode *ip, int mask)
{
return (generic_permission(ip, mask, __zpl_check_acl));
}
#endif /* HAVE_CHECK_ACL | HAVE_PERMISSION */
#endif /* !HAVE_GET_ACL */
int
zpl_init_acl(struct inode *ip, struct inode *dir)
{
struct posix_acl *acl = NULL;
int error = 0;
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (0);
if (!S_ISLNK(ip->i_mode)) {
if (ITOZSB(ip)->z_acl_type == ZFS_ACLTYPE_POSIXACL) {
acl = zpl_get_acl(dir, ACL_TYPE_DEFAULT);
if (IS_ERR(acl))
return (PTR_ERR(acl));
}
if (!acl) {
ip->i_mode &= ~current_umask();
ip->i_ctime = current_fs_time(ITOZSB(ip)->z_sb);
zfs_mark_inode_dirty(ip);
return (0);
}
}
if ((ITOZSB(ip)->z_acl_type == ZFS_ACLTYPE_POSIXACL) && acl) {
umode_t mode;
if (S_ISDIR(ip->i_mode)) {
error = zpl_set_acl(ip, acl, ACL_TYPE_DEFAULT);
if (error)
goto out;
}
mode = ip->i_mode;
error = __posix_acl_create(&acl, GFP_KERNEL, &mode);
if (error >= 0) {
ip->i_mode = mode;
zfs_mark_inode_dirty(ip);
if (error > 0)
error = zpl_set_acl(ip, acl, ACL_TYPE_ACCESS);
}
}
out:
zpl_posix_acl_release(acl);
return (error);
}
int
zpl_chmod_acl(struct inode *ip)
{
struct posix_acl *acl;
int error;
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (0);
if (S_ISLNK(ip->i_mode))
return (-EOPNOTSUPP);
acl = zpl_get_acl(ip, ACL_TYPE_ACCESS);
if (IS_ERR(acl) || !acl)
return (PTR_ERR(acl));
error = __posix_acl_chmod(&acl, GFP_KERNEL, ip->i_mode);
if (!error)
error = zpl_set_acl(ip, acl, ACL_TYPE_ACCESS);
zpl_posix_acl_release(acl);
return (error);
}
static int
__zpl_xattr_acl_list_access(struct inode *ip, char *list, size_t list_size,
const char *name, size_t name_len)
{
char *xattr_name = XATTR_NAME_POSIX_ACL_ACCESS;
size_t xattr_size = sizeof (XATTR_NAME_POSIX_ACL_ACCESS);
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (0);
if (list && xattr_size <= list_size)
memcpy(list, xattr_name, xattr_size);
return (xattr_size);
}
ZPL_XATTR_LIST_WRAPPER(zpl_xattr_acl_list_access);
static int
__zpl_xattr_acl_list_default(struct inode *ip, char *list, size_t list_size,
const char *name, size_t name_len)
{
char *xattr_name = XATTR_NAME_POSIX_ACL_DEFAULT;
size_t xattr_size = sizeof (XATTR_NAME_POSIX_ACL_DEFAULT);
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (0);
if (list && xattr_size <= list_size)
memcpy(list, xattr_name, xattr_size);
return (xattr_size);
}
ZPL_XATTR_LIST_WRAPPER(zpl_xattr_acl_list_default);
static int
__zpl_xattr_acl_get_access(struct inode *ip, const char *name,
void *buffer, size_t size)
{
struct posix_acl *acl;
int type = ACL_TYPE_ACCESS;
int error;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") != 0)
return (-EINVAL);
#endif
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (-EOPNOTSUPP);
acl = zpl_get_acl(ip, type);
if (IS_ERR(acl))
return (PTR_ERR(acl));
if (acl == NULL)
return (-ENODATA);
error = zpl_acl_to_xattr(acl, buffer, size);
zpl_posix_acl_release(acl);
return (error);
}
ZPL_XATTR_GET_WRAPPER(zpl_xattr_acl_get_access);
static int
__zpl_xattr_acl_get_default(struct inode *ip, const char *name,
void *buffer, size_t size)
{
struct posix_acl *acl;
int type = ACL_TYPE_DEFAULT;
int error;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") != 0)
return (-EINVAL);
#endif
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (-EOPNOTSUPP);
acl = zpl_get_acl(ip, type);
if (IS_ERR(acl))
return (PTR_ERR(acl));
if (acl == NULL)
return (-ENODATA);
error = zpl_acl_to_xattr(acl, buffer, size);
zpl_posix_acl_release(acl);
return (error);
}
ZPL_XATTR_GET_WRAPPER(zpl_xattr_acl_get_default);
static int
__zpl_xattr_acl_set_access(struct inode *ip, const char *name,
const void *value, size_t size, int flags)
{
struct posix_acl *acl;
int type = ACL_TYPE_ACCESS;
int error = 0;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") != 0)
return (-EINVAL);
#endif
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (-EOPNOTSUPP);
if (!zpl_inode_owner_or_capable(ip))
return (-EPERM);
if (value) {
acl = zpl_acl_from_xattr(value, size);
if (IS_ERR(acl))
return (PTR_ERR(acl));
else if (acl) {
error = zpl_posix_acl_valid(ip, acl);
if (error) {
zpl_posix_acl_release(acl);
return (error);
}
}
} else {
acl = NULL;
}
error = zpl_set_acl(ip, acl, type);
zpl_posix_acl_release(acl);
return (error);
}
ZPL_XATTR_SET_WRAPPER(zpl_xattr_acl_set_access);
static int
__zpl_xattr_acl_set_default(struct inode *ip, const char *name,
const void *value, size_t size, int flags)
{
struct posix_acl *acl;
int type = ACL_TYPE_DEFAULT;
int error = 0;
/* xattr_resolve_name will do this for us if this is defined */
#ifndef HAVE_XATTR_HANDLER_NAME
if (strcmp(name, "") != 0)
return (-EINVAL);
#endif
if (ITOZSB(ip)->z_acl_type != ZFS_ACLTYPE_POSIXACL)
return (-EOPNOTSUPP);
if (!zpl_inode_owner_or_capable(ip))
return (-EPERM);
if (value) {
acl = zpl_acl_from_xattr(value, size);
if (IS_ERR(acl))
return (PTR_ERR(acl));
else if (acl) {
error = zpl_posix_acl_valid(ip, acl);
if (error) {
zpl_posix_acl_release(acl);
return (error);
}
}
} else {
acl = NULL;
}
error = zpl_set_acl(ip, acl, type);
zpl_posix_acl_release(acl);
return (error);
}
ZPL_XATTR_SET_WRAPPER(zpl_xattr_acl_set_default);
/*
* ACL access xattr namespace handlers.
*
* Use .name instead of .prefix when available. xattr_resolve_name will match
* whole name and reject anything that has .name only as prefix.
*/
xattr_handler_t zpl_xattr_acl_access_handler =
{
#ifdef HAVE_XATTR_HANDLER_NAME
.name = XATTR_NAME_POSIX_ACL_ACCESS,
#else
.prefix = XATTR_NAME_POSIX_ACL_ACCESS,
#endif
.list = zpl_xattr_acl_list_access,
.get = zpl_xattr_acl_get_access,
.set = zpl_xattr_acl_set_access,
#if defined(HAVE_XATTR_LIST_SIMPLE) || \
defined(HAVE_XATTR_LIST_DENTRY) || \
defined(HAVE_XATTR_LIST_HANDLER)
.flags = ACL_TYPE_ACCESS,
#endif
};
/*
* ACL default xattr namespace handlers.
*
* Use .name instead of .prefix when available. xattr_resolve_name will match
* whole name and reject anything that has .name only as prefix.
*/
xattr_handler_t zpl_xattr_acl_default_handler =
{
#ifdef HAVE_XATTR_HANDLER_NAME
.name = XATTR_NAME_POSIX_ACL_DEFAULT,
#else
.prefix = XATTR_NAME_POSIX_ACL_DEFAULT,
#endif
.list = zpl_xattr_acl_list_default,
.get = zpl_xattr_acl_get_default,
.set = zpl_xattr_acl_set_default,
#if defined(HAVE_XATTR_LIST_SIMPLE) || \
defined(HAVE_XATTR_LIST_DENTRY) || \
defined(HAVE_XATTR_LIST_HANDLER)
.flags = ACL_TYPE_DEFAULT,
#endif
};
#endif /* CONFIG_FS_POSIX_ACL */
xattr_handler_t *zpl_xattr_handlers[] = {
&zpl_xattr_security_handler,
&zpl_xattr_trusted_handler,
&zpl_xattr_user_handler,
#ifdef CONFIG_FS_POSIX_ACL
&zpl_xattr_acl_access_handler,
&zpl_xattr_acl_default_handler,
#endif /* CONFIG_FS_POSIX_ACL */
NULL
};
static const struct xattr_handler *
zpl_xattr_handler(const char *name)
{
if (strncmp(name, XATTR_USER_PREFIX,
XATTR_USER_PREFIX_LEN) == 0)
return (&zpl_xattr_user_handler);
if (strncmp(name, XATTR_TRUSTED_PREFIX,
XATTR_TRUSTED_PREFIX_LEN) == 0)
return (&zpl_xattr_trusted_handler);
if (strncmp(name, XATTR_SECURITY_PREFIX,
XATTR_SECURITY_PREFIX_LEN) == 0)
return (&zpl_xattr_security_handler);
#ifdef CONFIG_FS_POSIX_ACL
if (strncmp(name, XATTR_NAME_POSIX_ACL_ACCESS,
sizeof (XATTR_NAME_POSIX_ACL_ACCESS)) == 0)
return (&zpl_xattr_acl_access_handler);
if (strncmp(name, XATTR_NAME_POSIX_ACL_DEFAULT,
sizeof (XATTR_NAME_POSIX_ACL_DEFAULT)) == 0)
return (&zpl_xattr_acl_default_handler);
#endif /* CONFIG_FS_POSIX_ACL */
return (NULL);
}
#if !defined(HAVE_POSIX_ACL_RELEASE) || defined(HAVE_POSIX_ACL_RELEASE_GPL_ONLY)
struct acl_rel_struct {
struct acl_rel_struct *next;
struct posix_acl *acl;
clock_t time;
};
#define ACL_REL_GRACE (60*HZ)
#define ACL_REL_WINDOW (1*HZ)
#define ACL_REL_SCHED (ACL_REL_GRACE+ACL_REL_WINDOW)
/*
* Lockless multi-producer single-consumer fifo list.
* Nodes are added to tail and removed from head. Tail pointer is our
* synchronization point. It always points to the next pointer of the last
* node, or head if list is empty.
*/
static struct acl_rel_struct *acl_rel_head = NULL;
static struct acl_rel_struct **acl_rel_tail = &acl_rel_head;
static void
zpl_posix_acl_free(void *arg)
{
struct acl_rel_struct *freelist = NULL;
struct acl_rel_struct *a;
clock_t new_time;
boolean_t refire = B_FALSE;
ASSERT3P(acl_rel_head, !=, NULL);
while (acl_rel_head) {
a = acl_rel_head;
if (ddi_get_lbolt() - a->time >= ACL_REL_GRACE) {
/*
* If a is the last node we need to reset tail, but we
* need to use cmpxchg to make sure it is still the
* last node.
*/
if (acl_rel_tail == &a->next) {
acl_rel_head = NULL;
if (cmpxchg(&acl_rel_tail, &a->next,
&acl_rel_head) == &a->next) {
ASSERT3P(a->next, ==, NULL);
a->next = freelist;
freelist = a;
break;
}
}
/*
* a is not last node, make sure next pointer is set
* by the adder and advance the head.
*/
while (ACCESS_ONCE(a->next) == NULL)
cpu_relax();
acl_rel_head = a->next;
a->next = freelist;
freelist = a;
} else {
/*
* a is still in grace period. We are responsible to
* reschedule the free task, since adder will only do
* so if list is empty.
*/
new_time = a->time + ACL_REL_SCHED;
refire = B_TRUE;
break;
}
}
if (refire)
taskq_dispatch_delay(system_delay_taskq, zpl_posix_acl_free,
NULL, TQ_SLEEP, new_time);
while (freelist) {
a = freelist;
freelist = a->next;
kfree(a->acl);
kmem_free(a, sizeof (struct acl_rel_struct));
}
}
void
zpl_posix_acl_release_impl(struct posix_acl *acl)
{
struct acl_rel_struct *a, **prev;
a = kmem_alloc(sizeof (struct acl_rel_struct), KM_SLEEP);
a->next = NULL;
a->acl = acl;
a->time = ddi_get_lbolt();
/* atomically points tail to us and get the previous tail */
prev = xchg(&acl_rel_tail, &a->next);
ASSERT3P(*prev, ==, NULL);
*prev = a;
/* if it was empty before, schedule the free task */
if (prev == &acl_rel_head)
taskq_dispatch_delay(system_delay_taskq, zpl_posix_acl_free,
NULL, TQ_SLEEP, ddi_get_lbolt() + ACL_REL_SCHED);
}
#endif