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