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