xref: /freebsd/sys/compat/linux/linux_xattr.c (revision 59c8e88e72633afbc47a4ace0d2170d00d51f7dc)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2023 Dmitry Chagin <dchagin@FreeBSD.org>
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/param.h>
29 #include <sys/extattr.h>
30 #include <sys/fcntl.h>
31 #include <sys/namei.h>
32 #include <sys/proc.h>
33 #include <sys/syscallsubr.h>
34 
35 #ifdef COMPAT_LINUX32
36 #include <machine/../linux32/linux.h>
37 #include <machine/../linux32/linux32_proto.h>
38 #else
39 #include <machine/../linux/linux.h>
40 #include <machine/../linux/linux_proto.h>
41 #endif
42 
43 #include <compat/linux/linux_util.h>
44 
45 #define	LINUX_XATTR_SIZE_MAX	65536
46 #define	LINUX_XATTR_LIST_MAX	65536
47 #define	LINUX_XATTR_NAME_MAX	255
48 
49 #define	LINUX_XATTR_CREATE	0x1
50 #define	LINUX_XATTR_REPLACE	0x2
51 #define	LINUX_XATTR_FLAGS	LINUX_XATTR_CREATE|LINUX_XATTR_REPLACE
52 
53 struct listxattr_args {
54 	int		fd;
55 	const char	*path;
56 	char		*list;
57 	l_size_t	size;
58 	int		follow;
59 };
60 
61 struct setxattr_args {
62 	int		fd;
63 	const char	*path;
64 	const char	*name;
65 	void 		*value;
66 	l_size_t	size;
67 	l_int		flags;
68 	int		follow;
69 };
70 
71 struct getxattr_args {
72 	int		fd;
73 	const char	*path;
74 	const char	*name;
75 	void 		*value;
76 	l_size_t	size;
77 	int		follow;
78 };
79 
80 struct removexattr_args {
81 	int		fd;
82 	const char	*path;
83 	const char	*name;
84 	int		follow;
85 };
86 
87 static char *extattr_namespace_names[] = EXTATTR_NAMESPACE_NAMES;
88 
89 
90 static int
91 error_to_xattrerror(int attrnamespace, int error)
92 {
93 
94 	if (attrnamespace == EXTATTR_NAMESPACE_SYSTEM && error == EPERM)
95 		return (ENOTSUP);
96 	else
97 		return (error);
98 }
99 
100 static int
101 xatrr_to_extattr(const char *uattrname, int *attrnamespace, char *attrname)
102 {
103 	char uname[LINUX_XATTR_NAME_MAX + 1], *dot;
104 	size_t len, cplen;
105 	int error;
106 
107 	error = copyinstr(uattrname, uname, sizeof(uname), &cplen);
108 	if (error != 0)
109 		return (error);
110 	if (cplen == sizeof(uname))
111 		return (ERANGE);
112 	dot = strchr(uname, '.');
113 	if (dot == NULL)
114 		return (ENOTSUP);
115 	*dot = '\0';
116 	for (*attrnamespace = EXTATTR_NAMESPACE_USER;
117 	    *attrnamespace < nitems(extattr_namespace_names);
118 	    (*attrnamespace)++) {
119 		if (bcmp(uname, extattr_namespace_names[*attrnamespace],
120 		    dot - uname + 1) == 0) {
121 			dot++;
122 			len = strlen(dot) + 1;
123 			bcopy(dot, attrname, len);
124 			return (0);
125 		}
126 	}
127 	return (ENOTSUP);
128 }
129 
130 static int
131 listxattr(struct thread *td, struct listxattr_args *args)
132 {
133 	char attrname[LINUX_XATTR_NAME_MAX + 1];
134 	char *data, *prefix, *key;
135 	struct uio auio;
136 	struct iovec aiov;
137 	unsigned char keylen;
138 	size_t sz, cnt, rs, prefixlen, pairlen;
139 	int attrnamespace, error;
140 
141 	if (args->size != 0)
142 		sz = min(LINUX_XATTR_LIST_MAX, args->size);
143 	else
144 		sz = LINUX_XATTR_LIST_MAX;
145 
146 	data = malloc(sz, M_LINUX, M_WAITOK);
147 	auio.uio_iov = &aiov;
148 	auio.uio_iovcnt = 1;
149 	auio.uio_rw = UIO_READ;
150 	auio.uio_segflg = UIO_SYSSPACE;
151 	auio.uio_td = td;
152 	cnt = 0;
153 	for (attrnamespace = EXTATTR_NAMESPACE_USER;
154 	    attrnamespace < nitems(extattr_namespace_names);
155 	    attrnamespace++) {
156 		aiov.iov_base = data;
157 		aiov.iov_len = sz;
158 		auio.uio_resid = sz;
159 		auio.uio_offset = 0;
160 
161 		if (args->path != NULL)
162 			error = kern_extattr_list_path(td, args->path,
163 			    attrnamespace, &auio, args->follow, UIO_USERSPACE);
164 		else
165 			error = kern_extattr_list_fd(td, args->fd,
166 			    attrnamespace, &auio);
167 		rs = sz - auio.uio_resid;
168 		if (error == EPERM)
169 			break;
170 		if (error != 0 || rs == 0)
171 			continue;
172 		prefix = extattr_namespace_names[attrnamespace];
173 		prefixlen = strlen(prefix);
174 		key = data;
175 		while (rs > 0) {
176 			keylen = (unsigned char)key[0];
177 			pairlen = prefixlen + 1 + keylen + 1;
178 			cnt += pairlen;
179 			if (cnt > LINUX_XATTR_LIST_MAX) {
180 				error = E2BIG;
181 				break;
182 			}
183 			/*
184 			 * If size is specified as zero, return the current size
185 			 * of the list of extended attribute names.
186 			 */
187 			if ((args->size > 0 && cnt > args->size) ||
188 			    pairlen >= sizeof(attrname)) {
189 				error = ERANGE;
190 				break;
191 			}
192 			++key;
193 			if (args->list != NULL && args->size > 0) {
194 				sprintf(attrname, "%s.%.*s", prefix, keylen, key);
195 				error = copyout(attrname, args->list, pairlen);
196 				if (error != 0)
197 					break;
198 				args->list += pairlen;
199 			}
200 			key += keylen;
201 			rs -= (keylen + 1);
202 		}
203 	}
204 	if (error == 0)
205 		td->td_retval[0] = cnt;
206 	free(data, M_LINUX);
207 	return (error_to_xattrerror(attrnamespace, error));
208 }
209 
210 int
211 linux_listxattr(struct thread *td, struct linux_listxattr_args *args)
212 {
213 	struct listxattr_args eargs = {
214 		.fd = -1,
215 		.path = args->path,
216 		.list = args->list,
217 		.size = args->size,
218 		.follow = FOLLOW,
219 	};
220 
221 	return (listxattr(td, &eargs));
222 }
223 
224 int
225 linux_llistxattr(struct thread *td, struct linux_llistxattr_args *args)
226 {
227 	struct listxattr_args eargs = {
228 		.fd = -1,
229 		.path = args->path,
230 		.list = args->list,
231 		.size = args->size,
232 		.follow = NOFOLLOW,
233 	};
234 
235 	return (listxattr(td, &eargs));
236 }
237 
238 int
239 linux_flistxattr(struct thread *td, struct linux_flistxattr_args *args)
240 {
241 	struct listxattr_args eargs = {
242 		.fd = args->fd,
243 		.path = NULL,
244 		.list = args->list,
245 		.size = args->size,
246 		.follow = 0,
247 	};
248 
249 	return (listxattr(td, &eargs));
250 }
251 
252 static int
253 removexattr(struct thread *td, struct removexattr_args *args)
254 {
255 	char attrname[LINUX_XATTR_NAME_MAX + 1];
256 	int attrnamespace, error;
257 
258 	error = xatrr_to_extattr(args->name, &attrnamespace, attrname);
259 	if (error != 0)
260 		return (error);
261 	if (args->path != NULL)
262 		error = kern_extattr_delete_path(td, args->path, attrnamespace,
263 		    attrname, args->follow, UIO_USERSPACE);
264 	else
265 		error = kern_extattr_delete_fd(td, args->fd, attrnamespace,
266 		    attrname);
267 	return (error_to_xattrerror(attrnamespace, error));
268 }
269 
270 int
271 linux_removexattr(struct thread *td, struct linux_removexattr_args *args)
272 {
273 	struct removexattr_args eargs = {
274 		.fd = -1,
275 		.path = args->path,
276 		.name = args->name,
277 		.follow = FOLLOW,
278 	};
279 
280 	return (removexattr(td, &eargs));
281 }
282 
283 int
284 linux_lremovexattr(struct thread *td, struct linux_lremovexattr_args *args)
285 {
286 	struct removexattr_args eargs = {
287 		.fd = -1,
288 		.path = args->path,
289 		.name = args->name,
290 		.follow = NOFOLLOW,
291 	};
292 
293 	return (removexattr(td, &eargs));
294 }
295 
296 int
297 linux_fremovexattr(struct thread *td, struct linux_fremovexattr_args *args)
298 {
299 	struct removexattr_args eargs = {
300 		.fd = args->fd,
301 		.path = NULL,
302 		.name = args->name,
303 		.follow = 0,
304 	};
305 
306 	return (removexattr(td, &eargs));
307 }
308 
309 static int
310 getxattr(struct thread *td, struct getxattr_args *args)
311 {
312 	char attrname[LINUX_XATTR_NAME_MAX + 1];
313 	int attrnamespace, error;
314 
315 	error = xatrr_to_extattr(args->name, &attrnamespace, attrname);
316 	if (error != 0)
317 		return (error);
318 	if (args->path != NULL)
319 		error = kern_extattr_get_path(td, args->path, attrnamespace,
320 		    attrname, args->value, args->size, args->follow, UIO_USERSPACE);
321 	else
322 		error = kern_extattr_get_fd(td, args->fd, attrnamespace,
323 		    attrname, args->value, args->size);
324 	return (error == EPERM ? ENOATTR : error);
325 }
326 
327 int
328 linux_getxattr(struct thread *td, struct linux_getxattr_args *args)
329 {
330 	struct getxattr_args eargs = {
331 		.fd = -1,
332 		.path = args->path,
333 		.name = args->name,
334 		.value = args->value,
335 		.size = args->size,
336 		.follow = FOLLOW,
337 	};
338 
339 	return (getxattr(td, &eargs));
340 }
341 
342 int
343 linux_lgetxattr(struct thread *td, struct linux_lgetxattr_args *args)
344 {
345 	struct getxattr_args eargs = {
346 		.fd = -1,
347 		.path = args->path,
348 		.name = args->name,
349 		.value = args->value,
350 		.size = args->size,
351 		.follow = NOFOLLOW,
352 	};
353 
354 	return (getxattr(td, &eargs));
355 }
356 
357 int
358 linux_fgetxattr(struct thread *td, struct linux_fgetxattr_args *args)
359 {
360 	struct getxattr_args eargs = {
361 		.fd = args->fd,
362 		.path = NULL,
363 		.name = args->name,
364 		.value = args->value,
365 		.size = args->size,
366 		.follow = 0,
367 	};
368 
369 	return (getxattr(td, &eargs));
370 }
371 
372 static int
373 setxattr(struct thread *td, struct setxattr_args *args)
374 {
375 	char attrname[LINUX_XATTR_NAME_MAX + 1];
376 	int attrnamespace, error;
377 
378 	if ((args->flags & ~(LINUX_XATTR_FLAGS)) != 0 ||
379 	    args->flags == (LINUX_XATTR_FLAGS))
380 		return (EINVAL);
381 	error = xatrr_to_extattr(args->name, &attrnamespace, attrname);
382 	if (error != 0)
383 		return (error);
384 
385 	if ((args->flags & (LINUX_XATTR_FLAGS)) != 0 ) {
386 		if (args->path != NULL)
387 			error = kern_extattr_get_path(td, args->path,
388 			    attrnamespace, attrname, NULL, args->size,
389 			    args->follow, UIO_USERSPACE);
390 		else
391 			error = kern_extattr_get_fd(td, args->fd,
392 			    attrnamespace, attrname, NULL, args->size);
393 		if ((args->flags & LINUX_XATTR_CREATE) != 0) {
394 			if (error == 0)
395 				error = EEXIST;
396 			else if (error == ENOATTR)
397 				error = 0;
398 		}
399 		if (error != 0)
400 			goto out;
401 	}
402 	if (args->path != NULL)
403 		error = kern_extattr_set_path(td, args->path, attrnamespace,
404 		    attrname, args->value, args->size, args->follow,
405 		    UIO_USERSPACE);
406 	else
407 		error = kern_extattr_set_fd(td, args->fd, attrnamespace,
408 		    attrname, args->value, args->size);
409 out:
410 	td->td_retval[0] = 0;
411 	return (error_to_xattrerror(attrnamespace, error));
412 }
413 
414 int
415 linux_setxattr(struct thread *td, struct linux_setxattr_args *args)
416 {
417 	struct setxattr_args eargs = {
418 		.fd = -1,
419 		.path = args->path,
420 		.name = args->name,
421 		.value = args->value,
422 		.size = args->size,
423 		.flags = args->flags,
424 		.follow = FOLLOW,
425 	};
426 
427 	return (setxattr(td, &eargs));
428 }
429 
430 int
431 linux_lsetxattr(struct thread *td, struct linux_lsetxattr_args *args)
432 {
433 	struct setxattr_args eargs = {
434 		.fd = -1,
435 		.path = args->path,
436 		.name = args->name,
437 		.value = args->value,
438 		.size = args->size,
439 		.flags = args->flags,
440 		.follow = NOFOLLOW,
441 	};
442 
443 	return (setxattr(td, &eargs));
444 }
445 
446 int
447 linux_fsetxattr(struct thread *td, struct linux_fsetxattr_args *args)
448 {
449 	struct setxattr_args eargs = {
450 		.fd = args->fd,
451 		.path = NULL,
452 		.name = args->name,
453 		.value = args->value,
454 		.size = args->size,
455 		.flags = args->flags,
456 		.follow = 0,
457 	};
458 
459 	return (setxattr(td, &eargs));
460 }
461