linux/fs/orangefs/xattr.c
Christian Brauner 39f60c1cce
fs: port xattr to mnt_idmap
Convert to struct mnt_idmap.

Last cycle we merged the necessary infrastructure in
256c8aed2b ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
2023-01-19 09:24:28 +01:00

563 lines
15 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* (C) 2001 Clemson University and The University of Chicago
* Copyright 2018 Omnibond Systems, L.L.C.
*
* See COPYING in top-level directory.
*/
/*
* Linux VFS extended attribute operations.
*/
#include "protocol.h"
#include "orangefs-kernel.h"
#include "orangefs-bufmap.h"
#include <linux/posix_acl_xattr.h>
#include <linux/xattr.h>
#include <linux/hashtable.h>
#define SYSTEM_ORANGEFS_KEY "system.pvfs2."
#define SYSTEM_ORANGEFS_KEY_LEN 13
/*
* this function returns
* 0 if the key corresponding to name is not meant to be printed as part
* of a listxattr.
* 1 if the key corresponding to name is meant to be returned as part of
* a listxattr.
* The ones that start SYSTEM_ORANGEFS_KEY are the ones to avoid printing.
*/
static int is_reserved_key(const char *key, size_t size)
{
if (size < SYSTEM_ORANGEFS_KEY_LEN)
return 1;
return strncmp(key, SYSTEM_ORANGEFS_KEY, SYSTEM_ORANGEFS_KEY_LEN) ? 1 : 0;
}
static inline int convert_to_internal_xattr_flags(int setxattr_flags)
{
int internal_flag = 0;
if (setxattr_flags & XATTR_REPLACE) {
/* Attribute must exist! */
internal_flag = ORANGEFS_XATTR_REPLACE;
} else if (setxattr_flags & XATTR_CREATE) {
/* Attribute must not exist */
internal_flag = ORANGEFS_XATTR_CREATE;
}
return internal_flag;
}
static unsigned int xattr_key(const char *key)
{
unsigned int i = 0;
while (key)
i += *key++;
return i % 16;
}
static struct orangefs_cached_xattr *find_cached_xattr(struct inode *inode,
const char *key)
{
struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
struct orangefs_cached_xattr *cx;
struct hlist_head *h;
struct hlist_node *tmp;
h = &orangefs_inode->xattr_cache[xattr_key(key)];
if (hlist_empty(h))
return NULL;
hlist_for_each_entry_safe(cx, tmp, h, node) {
/* if (!time_before(jiffies, cx->timeout)) {
hlist_del(&cx->node);
kfree(cx);
continue;
}*/
if (!strcmp(cx->key, key))
return cx;
}
return NULL;
}
/*
* Tries to get a specified key's attributes of a given
* file into a user-specified buffer. Note that the getxattr
* interface allows for the users to probe the size of an
* extended attribute by passing in a value of 0 to size.
* Thus our return value is always the size of the attribute
* unless the key does not exist for the file and/or if
* there were errors in fetching the attribute value.
*/
ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
void *buffer, size_t size)
{
struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
struct orangefs_kernel_op_s *new_op = NULL;
struct orangefs_cached_xattr *cx;
ssize_t ret = -ENOMEM;
ssize_t length = 0;
int fsuid;
int fsgid;
gossip_debug(GOSSIP_XATTR_DEBUG,
"%s: name %s, buffer_size %zd\n",
__func__, name, size);
if (S_ISLNK(inode->i_mode))
return -EOPNOTSUPP;
if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
return -EINVAL;
fsuid = from_kuid(&init_user_ns, current_fsuid());
fsgid = from_kgid(&init_user_ns, current_fsgid());
gossip_debug(GOSSIP_XATTR_DEBUG,
"getxattr on inode %pU, name %s "
"(uid %o, gid %o)\n",
get_khandle_from_ino(inode),
name,
fsuid,
fsgid);
down_read(&orangefs_inode->xattr_sem);
cx = find_cached_xattr(inode, name);
if (cx && time_before(jiffies, cx->timeout)) {
if (cx->length == -1) {
ret = -ENODATA;
goto out_unlock;
} else {
if (size == 0) {
ret = cx->length;
goto out_unlock;
}
if (cx->length > size) {
ret = -ERANGE;
goto out_unlock;
}
memcpy(buffer, cx->val, cx->length);
memset(buffer + cx->length, 0, size - cx->length);
ret = cx->length;
goto out_unlock;
}
}
new_op = op_alloc(ORANGEFS_VFS_OP_GETXATTR);
if (!new_op)
goto out_unlock;
new_op->upcall.req.getxattr.refn = orangefs_inode->refn;
strcpy(new_op->upcall.req.getxattr.key, name);
/*
* NOTE: Although keys are meant to be NULL terminated textual
* strings, I am going to explicitly pass the length just in case
* we change this later on...
*/
new_op->upcall.req.getxattr.key_sz = strlen(name) + 1;
ret = service_operation(new_op, "orangefs_inode_getxattr",
get_interruptible_flag(inode));
if (ret != 0) {
if (ret == -ENOENT) {
ret = -ENODATA;
gossip_debug(GOSSIP_XATTR_DEBUG,
"orangefs_inode_getxattr: inode %pU key %s"
" does not exist!\n",
get_khandle_from_ino(inode),
(char *)new_op->upcall.req.getxattr.key);
cx = kmalloc(sizeof *cx, GFP_KERNEL);
if (cx) {
strcpy(cx->key, name);
cx->length = -1;
cx->timeout = jiffies +
orangefs_getattr_timeout_msecs*HZ/1000;
hash_add(orangefs_inode->xattr_cache, &cx->node,
xattr_key(cx->key));
}
}
goto out_release_op;
}
/*
* Length returned includes null terminator.
*/
length = new_op->downcall.resp.getxattr.val_sz;
/*
* Just return the length of the queried attribute.
*/
if (size == 0) {
ret = length;
goto out_release_op;
}
/*
* Check to see if key length is > provided buffer size.
*/
if (length > size) {
ret = -ERANGE;
goto out_release_op;
}
memcpy(buffer, new_op->downcall.resp.getxattr.val, length);
memset(buffer + length, 0, size - length);
gossip_debug(GOSSIP_XATTR_DEBUG,
"orangefs_inode_getxattr: inode %pU "
"key %s key_sz %d, val_len %d\n",
get_khandle_from_ino(inode),
(char *)new_op->
upcall.req.getxattr.key,
(int)new_op->
upcall.req.getxattr.key_sz,
(int)ret);
ret = length;
if (cx) {
strcpy(cx->key, name);
memcpy(cx->val, buffer, length);
cx->length = length;
cx->timeout = jiffies + HZ;
} else {
cx = kmalloc(sizeof *cx, GFP_KERNEL);
if (cx) {
strcpy(cx->key, name);
memcpy(cx->val, buffer, length);
cx->length = length;
cx->timeout = jiffies + HZ;
hash_add(orangefs_inode->xattr_cache, &cx->node,
xattr_key(cx->key));
}
}
out_release_op:
op_release(new_op);
out_unlock:
up_read(&orangefs_inode->xattr_sem);
return ret;
}
static int orangefs_inode_removexattr(struct inode *inode, const char *name,
int flags)
{
struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
struct orangefs_kernel_op_s *new_op = NULL;
struct orangefs_cached_xattr *cx;
struct hlist_head *h;
struct hlist_node *tmp;
int ret = -ENOMEM;
if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
return -EINVAL;
down_write(&orangefs_inode->xattr_sem);
new_op = op_alloc(ORANGEFS_VFS_OP_REMOVEXATTR);
if (!new_op)
goto out_unlock;
new_op->upcall.req.removexattr.refn = orangefs_inode->refn;
/*
* NOTE: Although keys are meant to be NULL terminated
* textual strings, I am going to explicitly pass the
* length just in case we change this later on...
*/
strcpy(new_op->upcall.req.removexattr.key, name);
new_op->upcall.req.removexattr.key_sz = strlen(name) + 1;
gossip_debug(GOSSIP_XATTR_DEBUG,
"orangefs_inode_removexattr: key %s, key_sz %d\n",
(char *)new_op->upcall.req.removexattr.key,
(int)new_op->upcall.req.removexattr.key_sz);
ret = service_operation(new_op,
"orangefs_inode_removexattr",
get_interruptible_flag(inode));
if (ret == -ENOENT) {
/*
* Request to replace a non-existent attribute is an error.
*/
if (flags & XATTR_REPLACE)
ret = -ENODATA;
else
ret = 0;
}
gossip_debug(GOSSIP_XATTR_DEBUG,
"orangefs_inode_removexattr: returning %d\n", ret);
op_release(new_op);
h = &orangefs_inode->xattr_cache[xattr_key(name)];
hlist_for_each_entry_safe(cx, tmp, h, node) {
if (!strcmp(cx->key, name)) {
hlist_del(&cx->node);
kfree(cx);
break;
}
}
out_unlock:
up_write(&orangefs_inode->xattr_sem);
return ret;
}
/*
* Tries to set an attribute for a given key on a file.
*
* Returns a -ve number on error and 0 on success. Key is text, but value
* can be binary!
*/
int orangefs_inode_setxattr(struct inode *inode, const char *name,
const void *value, size_t size, int flags)
{
struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
struct orangefs_kernel_op_s *new_op;
int internal_flag = 0;
struct orangefs_cached_xattr *cx;
struct hlist_head *h;
struct hlist_node *tmp;
int ret = -ENOMEM;
gossip_debug(GOSSIP_XATTR_DEBUG,
"%s: name %s, buffer_size %zd\n",
__func__, name, size);
if (size > ORANGEFS_MAX_XATTR_VALUELEN)
return -EINVAL;
if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
return -EINVAL;
internal_flag = convert_to_internal_xattr_flags(flags);
/* This is equivalent to a removexattr */
if (size == 0 && !value) {
gossip_debug(GOSSIP_XATTR_DEBUG,
"removing xattr (%s)\n",
name);
return orangefs_inode_removexattr(inode, name, flags);
}
gossip_debug(GOSSIP_XATTR_DEBUG,
"setxattr on inode %pU, name %s\n",
get_khandle_from_ino(inode),
name);
down_write(&orangefs_inode->xattr_sem);
new_op = op_alloc(ORANGEFS_VFS_OP_SETXATTR);
if (!new_op)
goto out_unlock;
new_op->upcall.req.setxattr.refn = orangefs_inode->refn;
new_op->upcall.req.setxattr.flags = internal_flag;
/*
* NOTE: Although keys are meant to be NULL terminated textual
* strings, I am going to explicitly pass the length just in
* case we change this later on...
*/
strcpy(new_op->upcall.req.setxattr.keyval.key, name);
new_op->upcall.req.setxattr.keyval.key_sz = strlen(name) + 1;
memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
new_op->upcall.req.setxattr.keyval.val_sz = size;
gossip_debug(GOSSIP_XATTR_DEBUG,
"orangefs_inode_setxattr: key %s, key_sz %d "
" value size %zd\n",
(char *)new_op->upcall.req.setxattr.keyval.key,
(int)new_op->upcall.req.setxattr.keyval.key_sz,
size);
ret = service_operation(new_op,
"orangefs_inode_setxattr",
get_interruptible_flag(inode));
gossip_debug(GOSSIP_XATTR_DEBUG,
"orangefs_inode_setxattr: returning %d\n",
ret);
/* when request is serviced properly, free req op struct */
op_release(new_op);
h = &orangefs_inode->xattr_cache[xattr_key(name)];
hlist_for_each_entry_safe(cx, tmp, h, node) {
if (!strcmp(cx->key, name)) {
hlist_del(&cx->node);
kfree(cx);
break;
}
}
out_unlock:
up_write(&orangefs_inode->xattr_sem);
return ret;
}
/*
* Tries to get a specified object's keys into a user-specified buffer of a
* given size. Note that like the previous instances of xattr routines, this
* also allows you to pass in a NULL pointer and 0 size to probe the size for
* subsequent memory allocations. Thus our return value is always the size of
* all the keys unless there were errors in fetching the keys!
*/
ssize_t orangefs_listxattr(struct dentry *dentry, char *buffer, size_t size)
{
struct inode *inode = dentry->d_inode;
struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
struct orangefs_kernel_op_s *new_op;
__u64 token = ORANGEFS_ITERATE_START;
ssize_t ret = -ENOMEM;
ssize_t total = 0;
int count_keys = 0;
int key_size;
int i = 0;
int returned_count = 0;
if (size > 0 && !buffer) {
gossip_err("%s: bogus NULL pointers\n", __func__);
return -EINVAL;
}
down_read(&orangefs_inode->xattr_sem);
new_op = op_alloc(ORANGEFS_VFS_OP_LISTXATTR);
if (!new_op)
goto out_unlock;
if (buffer && size > 0)
memset(buffer, 0, size);
try_again:
key_size = 0;
new_op->upcall.req.listxattr.refn = orangefs_inode->refn;
new_op->upcall.req.listxattr.token = token;
new_op->upcall.req.listxattr.requested_count =
(size == 0) ? 0 : ORANGEFS_MAX_XATTR_LISTLEN;
ret = service_operation(new_op, __func__,
get_interruptible_flag(inode));
if (ret != 0)
goto done;
if (size == 0) {
/*
* This is a bit of a big upper limit, but I did not want to
* spend too much time getting this correct, since users end
* up allocating memory rather than us...
*/
total = new_op->downcall.resp.listxattr.returned_count *
ORANGEFS_MAX_XATTR_NAMELEN;
goto done;
}
returned_count = new_op->downcall.resp.listxattr.returned_count;
if (returned_count < 0 ||
returned_count > ORANGEFS_MAX_XATTR_LISTLEN) {
gossip_err("%s: impossible value for returned_count:%d:\n",
__func__,
returned_count);
ret = -EIO;
goto done;
}
/*
* Check to see how much can be fit in the buffer. Fit only whole keys.
*/
for (i = 0; i < returned_count; i++) {
if (new_op->downcall.resp.listxattr.lengths[i] < 0 ||
new_op->downcall.resp.listxattr.lengths[i] >
ORANGEFS_MAX_XATTR_NAMELEN) {
gossip_err("%s: impossible value for lengths[%d]\n",
__func__,
new_op->downcall.resp.listxattr.lengths[i]);
ret = -EIO;
goto done;
}
if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
goto done;
/*
* Since many dumb programs try to setxattr() on our reserved
* xattrs this is a feeble attempt at defeating those by not
* listing them in the output of listxattr.. sigh
*/
if (is_reserved_key(new_op->downcall.resp.listxattr.key +
key_size,
new_op->downcall.resp.
listxattr.lengths[i])) {
gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s\n",
i, new_op->downcall.resp.listxattr.key +
key_size);
memcpy(buffer + total,
new_op->downcall.resp.listxattr.key + key_size,
new_op->downcall.resp.listxattr.lengths[i]);
total += new_op->downcall.resp.listxattr.lengths[i];
count_keys++;
} else {
gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s\n",
i, new_op->downcall.resp.listxattr.key +
key_size);
}
key_size += new_op->downcall.resp.listxattr.lengths[i];
}
/*
* Since the buffer was large enough, we might have to continue
* fetching more keys!
*/
token = new_op->downcall.resp.listxattr.token;
if (token != ORANGEFS_ITERATE_END)
goto try_again;
done:
gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
" [size of buffer %ld] (filled in %d keys)\n",
__func__,
ret ? (int)ret : (int)total,
(long)size,
count_keys);
op_release(new_op);
if (ret == 0)
ret = total;
out_unlock:
up_read(&orangefs_inode->xattr_sem);
return ret;
}
static int orangefs_xattr_set_default(const struct xattr_handler *handler,
struct mnt_idmap *idmap,
struct dentry *unused,
struct inode *inode,
const char *name,
const void *buffer,
size_t size,
int flags)
{
return orangefs_inode_setxattr(inode, name, buffer, size, flags);
}
static int orangefs_xattr_get_default(const struct xattr_handler *handler,
struct dentry *unused,
struct inode *inode,
const char *name,
void *buffer,
size_t size)
{
return orangefs_inode_getxattr(inode, name, buffer, size);
}
static const struct xattr_handler orangefs_xattr_default_handler = {
.prefix = "", /* match any name => handlers called with full name */
.get = orangefs_xattr_get_default,
.set = orangefs_xattr_set_default,
};
const struct xattr_handler *orangefs_xattr_handlers[] = {
&posix_acl_access_xattr_handler,
&posix_acl_default_xattr_handler,
&orangefs_xattr_default_handler,
NULL
};