xattr.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * (C) 2001 Clemson University and The University of Chicago
  4 * Copyright 2018 Omnibond Systems, L.L.C.
  5 *
  6 * See COPYING in top-level directory.
  7 */
  8
  9/*
 10 *  Linux VFS extended attribute operations.
 11 */
 12
 13#include "protocol.h"
 14#include "orangefs-kernel.h"
 15#include "orangefs-bufmap.h"
 16#include <linux/posix_acl_xattr.h>
 17#include <linux/xattr.h>
 18#include <linux/hashtable.h>
 19
 20#define SYSTEM_ORANGEFS_KEY "system.pvfs2."
 21#define SYSTEM_ORANGEFS_KEY_LEN 13
 22
 23/*
 24 * this function returns
 25 *   0 if the key corresponding to name is not meant to be printed as part
 26 *     of a listxattr.
 27 *   1 if the key corresponding to name is meant to be returned as part of
 28 *     a listxattr.
 29 * The ones that start SYSTEM_ORANGEFS_KEY are the ones to avoid printing.
 30 */
 31static int is_reserved_key(const char *key, size_t size)
 32{
 33
 34	if (size < SYSTEM_ORANGEFS_KEY_LEN)
 35		return 1;
 36
 37	return strncmp(key, SYSTEM_ORANGEFS_KEY, SYSTEM_ORANGEFS_KEY_LEN) ?  1 : 0;
 38}
 39
 40static inline int convert_to_internal_xattr_flags(int setxattr_flags)
 41{
 42	int internal_flag = 0;
 43
 44	if (setxattr_flags & XATTR_REPLACE) {
 45		/* Attribute must exist! */
 46		internal_flag = ORANGEFS_XATTR_REPLACE;
 47	} else if (setxattr_flags & XATTR_CREATE) {
 48		/* Attribute must not exist */
 49		internal_flag = ORANGEFS_XATTR_CREATE;
 50	}
 51	return internal_flag;
 52}
 53
 54static unsigned int xattr_key(const char *key)
 55{
 56	unsigned int i = 0;
 57	if (!key)
 58		return 0;
 59	while (*key)
 60		i += *key++;
 61	return i % 16;
 62}
 63
 64static struct orangefs_cached_xattr *find_cached_xattr(struct inode *inode,
 65    const char *key)
 66{
 67	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 68	struct orangefs_cached_xattr *cx;
 69	struct hlist_head *h;
 70	struct hlist_node *tmp;
 71	h = &orangefs_inode->xattr_cache[xattr_key(key)];
 72	if (hlist_empty(h))
 73		return NULL;
 74	hlist_for_each_entry_safe(cx, tmp, h, node) {
 75/*		if (!time_before(jiffies, cx->timeout)) {
 76			hlist_del(&cx->node);
 77			kfree(cx);
 78			continue;
 79		}*/
 80		if (!strcmp(cx->key, key))
 81			return cx;
 82	}
 83	return NULL;
 84}
 85
 86/*
 87 * Tries to get a specified key's attributes of a given
 88 * file into a user-specified buffer. Note that the getxattr
 89 * interface allows for the users to probe the size of an
 90 * extended attribute by passing in a value of 0 to size.
 91 * Thus our return value is always the size of the attribute
 92 * unless the key does not exist for the file and/or if
 93 * there were errors in fetching the attribute value.
 94 */
 95ssize_t orangefs_inode_getxattr(struct inode *inode, const char *name,
 96				void *buffer, size_t size)
 97{
 98	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
 99	struct orangefs_kernel_op_s *new_op = NULL;
100	struct orangefs_cached_xattr *cx;
101	ssize_t ret = -ENOMEM;
102	ssize_t length = 0;
103	int fsuid;
104	int fsgid;
105
106	gossip_debug(GOSSIP_XATTR_DEBUG,
107		     "%s: name %s, buffer_size %zd\n",
108		     __func__, name, size);
109
110	if (S_ISLNK(inode->i_mode))
111		return -EOPNOTSUPP;
112
113	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
114		return -EINVAL;
115
116	fsuid = from_kuid(&init_user_ns, current_fsuid());
117	fsgid = from_kgid(&init_user_ns, current_fsgid());
118
119	gossip_debug(GOSSIP_XATTR_DEBUG,
120		     "getxattr on inode %pU, name %s "
121		     "(uid %o, gid %o)\n",
122		     get_khandle_from_ino(inode),
123		     name,
124		     fsuid,
125		     fsgid);
126
127	down_read(&orangefs_inode->xattr_sem);
128
129	cx = find_cached_xattr(inode, name);
130	if (cx && time_before(jiffies, cx->timeout)) {
131		if (cx->length == -1) {
132			ret = -ENODATA;
133			goto out_unlock;
134		} else {
135			if (size == 0) {
136				ret = cx->length;
137				goto out_unlock;
138			}
139			if (cx->length > size) {
140				ret = -ERANGE;
141				goto out_unlock;
142			}
143			memcpy(buffer, cx->val, cx->length);
144			memset(buffer + cx->length, 0, size - cx->length);
145			ret = cx->length;
146			goto out_unlock;
147		}
148	}
149
150	new_op = op_alloc(ORANGEFS_VFS_OP_GETXATTR);
151	if (!new_op)
152		goto out_unlock;
153
154	new_op->upcall.req.getxattr.refn = orangefs_inode->refn;
155	strcpy(new_op->upcall.req.getxattr.key, name);
156
157	/*
158	 * NOTE: Although keys are meant to be NULL terminated textual
159	 * strings, I am going to explicitly pass the length just in case
160	 * we change this later on...
161	 */
162	new_op->upcall.req.getxattr.key_sz = strlen(name) + 1;
163
164	ret = service_operation(new_op, "orangefs_inode_getxattr",
165				get_interruptible_flag(inode));
166	if (ret != 0) {
167		if (ret == -ENOENT) {
168			ret = -ENODATA;
169			gossip_debug(GOSSIP_XATTR_DEBUG,
170				     "orangefs_inode_getxattr: inode %pU key %s"
171				     " does not exist!\n",
172				     get_khandle_from_ino(inode),
173				     (char *)new_op->upcall.req.getxattr.key);
174			cx = kmalloc(sizeof *cx, GFP_KERNEL);
175			if (cx) {
176				strcpy(cx->key, name);
177				cx->length = -1;
178				cx->timeout = jiffies +
179				    orangefs_getattr_timeout_msecs*HZ/1000;
180				hlist_add_head( &cx->node,
181                                   &orangefs_inode->xattr_cache[xattr_key(cx->key)]);
182			}
183		}
184		goto out_release_op;
185	}
186
187	/*
188	 * Length returned includes null terminator.
189	 */
190	length = new_op->downcall.resp.getxattr.val_sz;
191
192	/*
193	 * Just return the length of the queried attribute.
194	 */
195	if (size == 0) {
196		ret = length;
197		goto out_release_op;
198	}
199
200	/*
201	 * Check to see if key length is > provided buffer size.
202	 */
203	if (length > size) {
204		ret = -ERANGE;
205		goto out_release_op;
206	}
207
208	memcpy(buffer, new_op->downcall.resp.getxattr.val, length);
209	memset(buffer + length, 0, size - length);
210	gossip_debug(GOSSIP_XATTR_DEBUG,
211	     "orangefs_inode_getxattr: inode %pU "
212	     "key %s key_sz %d, val_len %d\n",
213	     get_khandle_from_ino(inode),
214	     (char *)new_op->
215		upcall.req.getxattr.key,
216		     (int)new_op->
217		upcall.req.getxattr.key_sz,
218	     (int)ret);
219
220	ret = length;
221
222	if (cx) {
223		strcpy(cx->key, name);
224		memcpy(cx->val, buffer, length);
225		cx->length = length;
226		cx->timeout = jiffies + HZ;
227	} else {
228		cx = kmalloc(sizeof *cx, GFP_KERNEL);
229		if (cx) {
230			strcpy(cx->key, name);
231			memcpy(cx->val, buffer, length);
232			cx->length = length;
233			cx->timeout = jiffies + HZ;
234			hlist_add_head(&cx->node,
235				&orangefs_inode->xattr_cache[xattr_key(cx->key)]);
236		}
237	}
238
239out_release_op:
240	op_release(new_op);
241out_unlock:
242	up_read(&orangefs_inode->xattr_sem);
243	return ret;
244}
245
246static int orangefs_inode_removexattr(struct inode *inode, const char *name,
247				      int flags)
248{
249	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
250	struct orangefs_kernel_op_s *new_op = NULL;
251	struct orangefs_cached_xattr *cx;
252	struct hlist_head *h;
253	struct hlist_node *tmp;
254	int ret = -ENOMEM;
255
256	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
257		return -EINVAL;
258
259	down_write(&orangefs_inode->xattr_sem);
260	new_op = op_alloc(ORANGEFS_VFS_OP_REMOVEXATTR);
261	if (!new_op)
262		goto out_unlock;
263
264	new_op->upcall.req.removexattr.refn = orangefs_inode->refn;
265	/*
266	 * NOTE: Although keys are meant to be NULL terminated
267	 * textual strings, I am going to explicitly pass the
268	 * length just in case we change this later on...
269	 */
270	strcpy(new_op->upcall.req.removexattr.key, name);
271	new_op->upcall.req.removexattr.key_sz = strlen(name) + 1;
272
273	gossip_debug(GOSSIP_XATTR_DEBUG,
274		     "orangefs_inode_removexattr: key %s, key_sz %d\n",
275		     (char *)new_op->upcall.req.removexattr.key,
276		     (int)new_op->upcall.req.removexattr.key_sz);
277
278	ret = service_operation(new_op,
279				"orangefs_inode_removexattr",
280				get_interruptible_flag(inode));
281	if (ret == -ENOENT) {
282		/*
283		 * Request to replace a non-existent attribute is an error.
284		 */
285		if (flags & XATTR_REPLACE)
286			ret = -ENODATA;
287		else
288			ret = 0;
289	}
290
291	gossip_debug(GOSSIP_XATTR_DEBUG,
292		     "orangefs_inode_removexattr: returning %d\n", ret);
293
294	op_release(new_op);
295
296	h = &orangefs_inode->xattr_cache[xattr_key(name)];
297	hlist_for_each_entry_safe(cx, tmp, h, node) {
298		if (!strcmp(cx->key, name)) {
299			hlist_del(&cx->node);
300			kfree(cx);
301			break;
302		}
303	}
304
305out_unlock:
306	up_write(&orangefs_inode->xattr_sem);
307	return ret;
308}
309
310/*
311 * Tries to set an attribute for a given key on a file.
312 *
313 * Returns a -ve number on error and 0 on success.  Key is text, but value
314 * can be binary!
315 */
316int orangefs_inode_setxattr(struct inode *inode, const char *name,
317			    const void *value, size_t size, int flags)
318{
319	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
320	struct orangefs_kernel_op_s *new_op;
321	int internal_flag = 0;
322	struct orangefs_cached_xattr *cx;
323	struct hlist_head *h;
324	struct hlist_node *tmp;
325	int ret = -ENOMEM;
326
327	gossip_debug(GOSSIP_XATTR_DEBUG,
328		     "%s: name %s, buffer_size %zd\n",
329		     __func__, name, size);
330
331	if (size > ORANGEFS_MAX_XATTR_VALUELEN)
332		return -EINVAL;
333	if (strlen(name) >= ORANGEFS_MAX_XATTR_NAMELEN)
334		return -EINVAL;
335
336	internal_flag = convert_to_internal_xattr_flags(flags);
337
338	/* This is equivalent to a removexattr */
339	if (size == 0 && !value) {
340		gossip_debug(GOSSIP_XATTR_DEBUG,
341			     "removing xattr (%s)\n",
342			     name);
343		return orangefs_inode_removexattr(inode, name, flags);
344	}
345
346	gossip_debug(GOSSIP_XATTR_DEBUG,
347		     "setxattr on inode %pU, name %s\n",
348		     get_khandle_from_ino(inode),
349		     name);
350
351	down_write(&orangefs_inode->xattr_sem);
352	new_op = op_alloc(ORANGEFS_VFS_OP_SETXATTR);
353	if (!new_op)
354		goto out_unlock;
355
356
357	new_op->upcall.req.setxattr.refn = orangefs_inode->refn;
358	new_op->upcall.req.setxattr.flags = internal_flag;
359	/*
360	 * NOTE: Although keys are meant to be NULL terminated textual
361	 * strings, I am going to explicitly pass the length just in
362	 * case we change this later on...
363	 */
364	strcpy(new_op->upcall.req.setxattr.keyval.key, name);
365	new_op->upcall.req.setxattr.keyval.key_sz = strlen(name) + 1;
366	memcpy(new_op->upcall.req.setxattr.keyval.val, value, size);
367	new_op->upcall.req.setxattr.keyval.val_sz = size;
368
369	gossip_debug(GOSSIP_XATTR_DEBUG,
370		     "orangefs_inode_setxattr: key %s, key_sz %d "
371		     " value size %zd\n",
372		     (char *)new_op->upcall.req.setxattr.keyval.key,
373		     (int)new_op->upcall.req.setxattr.keyval.key_sz,
374		     size);
375
376	ret = service_operation(new_op,
377				"orangefs_inode_setxattr",
378				get_interruptible_flag(inode));
379
380	gossip_debug(GOSSIP_XATTR_DEBUG,
381		     "orangefs_inode_setxattr: returning %d\n",
382		     ret);
383
384	/* when request is serviced properly, free req op struct */
385	op_release(new_op);
386
387	h = &orangefs_inode->xattr_cache[xattr_key(name)];
388	hlist_for_each_entry_safe(cx, tmp, h, node) {
389		if (!strcmp(cx->key, name)) {
390			hlist_del(&cx->node);
391			kfree(cx);
392			break;
393		}
394	}
395
396out_unlock:
397	up_write(&orangefs_inode->xattr_sem);
398	return ret;
399}
400
401/*
402 * Tries to get a specified object's keys into a user-specified buffer of a
403 * given size.  Note that like the previous instances of xattr routines, this
404 * also allows you to pass in a NULL pointer and 0 size to probe the size for
405 * subsequent memory allocations. Thus our return value is always the size of
406 * all the keys unless there were errors in fetching the keys!
407 */
408ssize_t orangefs_listxattr(struct dentry *dentry, char *buffer, size_t size)
409{
410	struct inode *inode = dentry->d_inode;
411	struct orangefs_inode_s *orangefs_inode = ORANGEFS_I(inode);
412	struct orangefs_kernel_op_s *new_op;
413	__u64 token = ORANGEFS_ITERATE_START;
414	ssize_t ret = -ENOMEM;
415	ssize_t total = 0;
416	int count_keys = 0;
417	int key_size;
418	int i = 0;
419	int returned_count = 0;
420
421	if (size > 0 && !buffer) {
422		gossip_err("%s: bogus NULL pointers\n", __func__);
423		return -EINVAL;
424	}
425
426	down_read(&orangefs_inode->xattr_sem);
427	new_op = op_alloc(ORANGEFS_VFS_OP_LISTXATTR);
428	if (!new_op)
429		goto out_unlock;
430
431	if (buffer && size > 0)
432		memset(buffer, 0, size);
433
434try_again:
435	key_size = 0;
436	new_op->upcall.req.listxattr.refn = orangefs_inode->refn;
437	new_op->upcall.req.listxattr.token = token;
438	new_op->upcall.req.listxattr.requested_count =
439	    (size == 0) ? 0 : ORANGEFS_MAX_XATTR_LISTLEN;
440	ret = service_operation(new_op, __func__,
441				get_interruptible_flag(inode));
442	if (ret != 0)
443		goto done;
444
445	if (size == 0) {
446		/*
447		 * This is a bit of a big upper limit, but I did not want to
448		 * spend too much time getting this correct, since users end
449		 * up allocating memory rather than us...
450		 */
451		total = new_op->downcall.resp.listxattr.returned_count *
452			ORANGEFS_MAX_XATTR_NAMELEN;
453		goto done;
454	}
455
456	returned_count = new_op->downcall.resp.listxattr.returned_count;
457	if (returned_count < 0 ||
458	    returned_count > ORANGEFS_MAX_XATTR_LISTLEN) {
459		gossip_err("%s: impossible value for returned_count:%d:\n",
460		__func__,
461		returned_count);
462		ret = -EIO;
463		goto done;
464	}
465
466	/*
467	 * Check to see how much can be fit in the buffer. Fit only whole keys.
468	 */
469	for (i = 0; i < returned_count; i++) {
470		if (new_op->downcall.resp.listxattr.lengths[i] < 0 ||
471		    new_op->downcall.resp.listxattr.lengths[i] >
472		    ORANGEFS_MAX_XATTR_NAMELEN) {
473			gossip_err("%s: impossible value for lengths[%d]\n",
474			    __func__,
475			    new_op->downcall.resp.listxattr.lengths[i]);
476			ret = -EIO;
477			goto done;
478		}
479		if (total + new_op->downcall.resp.listxattr.lengths[i] > size)
480			goto done;
481
482		/*
483		 * Since many dumb programs try to setxattr() on our reserved
484		 * xattrs this is a feeble attempt at defeating those by not
485		 * listing them in the output of listxattr.. sigh
486		 */
487		if (is_reserved_key(new_op->downcall.resp.listxattr.key +
488				    key_size,
489				    new_op->downcall.resp.
490					listxattr.lengths[i])) {
491			gossip_debug(GOSSIP_XATTR_DEBUG, "Copying key %d -> %s\n",
492					i, new_op->downcall.resp.listxattr.key +
493						key_size);
494			memcpy(buffer + total,
495				new_op->downcall.resp.listxattr.key + key_size,
496				new_op->downcall.resp.listxattr.lengths[i]);
497			total += new_op->downcall.resp.listxattr.lengths[i];
498			count_keys++;
499		} else {
500			gossip_debug(GOSSIP_XATTR_DEBUG, "[RESERVED] key %d -> %s\n",
501					i, new_op->downcall.resp.listxattr.key +
502						key_size);
503		}
504		key_size += new_op->downcall.resp.listxattr.lengths[i];
505	}
506
507	/*
508	 * Since the buffer was large enough, we might have to continue
509	 * fetching more keys!
510	 */
511	token = new_op->downcall.resp.listxattr.token;
512	if (token != ORANGEFS_ITERATE_END)
513		goto try_again;
514
515done:
516	gossip_debug(GOSSIP_XATTR_DEBUG, "%s: returning %d"
517		     " [size of buffer %ld] (filled in %d keys)\n",
518		     __func__,
519		     ret ? (int)ret : (int)total,
520		     (long)size,
521		     count_keys);
522	op_release(new_op);
523	if (ret == 0)
524		ret = total;
525out_unlock:
526	up_read(&orangefs_inode->xattr_sem);
527	return ret;
528}
529
530static int orangefs_xattr_set_default(const struct xattr_handler *handler,
531				      struct mnt_idmap *idmap,
532				      struct dentry *unused,
533				      struct inode *inode,
534				      const char *name,
535				      const void *buffer,
536				      size_t size,
537				      int flags)
538{
539	return orangefs_inode_setxattr(inode, name, buffer, size, flags);
540}
541
542static int orangefs_xattr_get_default(const struct xattr_handler *handler,
543				      struct dentry *unused,
544				      struct inode *inode,
545				      const char *name,
546				      void *buffer,
547				      size_t size)
548{
549	return orangefs_inode_getxattr(inode, name, buffer, size);
550
551}
552
553static const struct xattr_handler orangefs_xattr_default_handler = {
554	.prefix = "",  /* match any name => handlers called with full name */
555	.get = orangefs_xattr_get_default,
556	.set = orangefs_xattr_set_default,
557};
558
559const struct xattr_handler * const orangefs_xattr_handlers[] = {
560	&orangefs_xattr_default_handler,
561	NULL
562};