1 /*
2 * FUSE: Filesystem in Userspace
3 * Copyright (C) 2001-2016 Miklos Szeredi <miklos@szeredi.hu>
4 *
5 * This program can be distributed under the terms of the GNU GPL.
6 * See the file COPYING.
7 */
8
9 #include "fuse_i.h"
10
11 #include <linux/xattr.h>
12 #include <linux/posix_acl_xattr.h>
13
fuse_setxattr(struct inode * inode,const char * name,const void * value,size_t size,int flags,unsigned int extra_flags)14 int fuse_setxattr(struct inode *inode, const char *name, const void *value,
15 size_t size, int flags, unsigned int extra_flags)
16 {
17 struct fuse_mount *fm = get_fuse_mount(inode);
18 FUSE_ARGS(args);
19 struct fuse_setxattr_in inarg;
20 int err;
21
22 if (fm->fc->no_setxattr)
23 return -EOPNOTSUPP;
24
25 memset(&inarg, 0, sizeof(inarg));
26 inarg.size = size;
27 inarg.flags = flags;
28 inarg.setxattr_flags = extra_flags;
29
30 args.opcode = FUSE_SETXATTR;
31 args.nodeid = get_node_id(inode);
32 args.in_numargs = 3;
33 args.in_args[0].size = fm->fc->setxattr_ext ?
34 sizeof(inarg) : FUSE_COMPAT_SETXATTR_IN_SIZE;
35 args.in_args[0].value = &inarg;
36 args.in_args[1].size = strlen(name) + 1;
37 args.in_args[1].value = name;
38 args.in_args[2].size = size;
39 args.in_args[2].value = value;
40 err = fuse_simple_request(fm, &args);
41 if (err == -ENOSYS) {
42 fm->fc->no_setxattr = 1;
43 err = -EOPNOTSUPP;
44 }
45 if (!err)
46 fuse_update_ctime(inode);
47
48 return err;
49 }
50
fuse_getxattr(struct inode * inode,const char * name,void * value,size_t size)51 ssize_t fuse_getxattr(struct inode *inode, const char *name, void *value,
52 size_t size)
53 {
54 struct fuse_mount *fm = get_fuse_mount(inode);
55 FUSE_ARGS(args);
56 struct fuse_getxattr_in inarg;
57 struct fuse_getxattr_out outarg;
58 ssize_t ret;
59
60 if (fm->fc->no_getxattr)
61 return -EOPNOTSUPP;
62
63 memset(&inarg, 0, sizeof(inarg));
64 inarg.size = size;
65 args.opcode = FUSE_GETXATTR;
66 args.nodeid = get_node_id(inode);
67 args.in_numargs = 2;
68 args.in_args[0].size = sizeof(inarg);
69 args.in_args[0].value = &inarg;
70 args.in_args[1].size = strlen(name) + 1;
71 args.in_args[1].value = name;
72 /* This is really two different operations rolled into one */
73 args.out_numargs = 1;
74 if (size) {
75 args.out_argvar = true;
76 args.out_args[0].size = size;
77 args.out_args[0].value = value;
78 } else {
79 args.out_args[0].size = sizeof(outarg);
80 args.out_args[0].value = &outarg;
81 }
82 ret = fuse_simple_request(fm, &args);
83 if (!ret && !size)
84 ret = min_t(ssize_t, outarg.size, XATTR_SIZE_MAX);
85 if (ret == -ENOSYS) {
86 fm->fc->no_getxattr = 1;
87 ret = -EOPNOTSUPP;
88 }
89 return ret;
90 }
91
fuse_verify_xattr_list(char * list,size_t size)92 static int fuse_verify_xattr_list(char *list, size_t size)
93 {
94 size_t origsize = size;
95
96 while (size) {
97 size_t thislen = strnlen(list, size);
98
99 if (!thislen || thislen == size)
100 return -EIO;
101
102 size -= thislen + 1;
103 list += thislen + 1;
104 }
105
106 return origsize;
107 }
108
fuse_listxattr(struct dentry * entry,char * list,size_t size)109 ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size)
110 {
111 struct inode *inode = d_inode(entry);
112 struct fuse_mount *fm = get_fuse_mount(inode);
113 FUSE_ARGS(args);
114 struct fuse_getxattr_in inarg;
115 struct fuse_getxattr_out outarg;
116 ssize_t ret;
117
118 #ifdef CONFIG_FUSE_BPF
119 struct fuse_err_ret fer;
120
121 fer = fuse_bpf_backing(inode, struct fuse_getxattr_io,
122 fuse_listxattr_initialize,
123 fuse_listxattr_backing, fuse_listxattr_finalize,
124 entry, list, size);
125 if (fer.ret)
126 return PTR_ERR(fer.result);
127 #endif
128
129 if (fuse_is_bad(inode))
130 return -EIO;
131
132 if (!fuse_allow_current_process(fm->fc))
133 return -EACCES;
134
135 if (fm->fc->no_listxattr)
136 return -EOPNOTSUPP;
137
138 memset(&inarg, 0, sizeof(inarg));
139 inarg.size = size;
140 args.opcode = FUSE_LISTXATTR;
141 args.nodeid = get_node_id(inode);
142 args.in_numargs = 1;
143 args.in_args[0].size = sizeof(inarg);
144 args.in_args[0].value = &inarg;
145 /* This is really two different operations rolled into one */
146 args.out_numargs = 1;
147 if (size) {
148 args.out_argvar = true;
149 args.out_args[0].size = size;
150 args.out_args[0].value = list;
151 } else {
152 args.out_args[0].size = sizeof(outarg);
153 args.out_args[0].value = &outarg;
154 }
155 ret = fuse_simple_request(fm, &args);
156 if (!ret && !size)
157 ret = min_t(ssize_t, outarg.size, XATTR_LIST_MAX);
158 if (ret > 0 && size)
159 ret = fuse_verify_xattr_list(list, ret);
160 if (ret == -ENOSYS) {
161 fm->fc->no_listxattr = 1;
162 ret = -EOPNOTSUPP;
163 }
164 return ret;
165 }
166
fuse_removexattr(struct inode * inode,const char * name)167 int fuse_removexattr(struct inode *inode, const char *name)
168 {
169 struct fuse_mount *fm = get_fuse_mount(inode);
170 FUSE_ARGS(args);
171 int err;
172
173 if (fm->fc->no_removexattr)
174 return -EOPNOTSUPP;
175
176 args.opcode = FUSE_REMOVEXATTR;
177 args.nodeid = get_node_id(inode);
178 args.in_numargs = 1;
179 args.in_args[0].size = strlen(name) + 1;
180 args.in_args[0].value = name;
181 err = fuse_simple_request(fm, &args);
182 if (err == -ENOSYS) {
183 fm->fc->no_removexattr = 1;
184 err = -EOPNOTSUPP;
185 }
186 if (!err)
187 fuse_update_ctime(inode);
188
189 return err;
190 }
191
fuse_xattr_get(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * value,size_t size)192 static int fuse_xattr_get(const struct xattr_handler *handler,
193 struct dentry *dentry, struct inode *inode,
194 const char *name, void *value, size_t size)
195 {
196 #ifdef CONFIG_FUSE_BPF
197 struct fuse_err_ret fer;
198
199 fer = fuse_bpf_backing(inode, struct fuse_getxattr_io,
200 fuse_getxattr_initialize, fuse_getxattr_backing,
201 fuse_getxattr_finalize,
202 dentry, name, value, size);
203 if (fer.ret)
204 return PTR_ERR(fer.result);
205 #endif
206
207 if (fuse_is_bad(inode))
208 return -EIO;
209
210 return fuse_getxattr(inode, name, value, size);
211 }
212
fuse_xattr_set(const struct xattr_handler * handler,struct user_namespace * mnt_userns,struct dentry * dentry,struct inode * inode,const char * name,const void * value,size_t size,int flags)213 static int fuse_xattr_set(const struct xattr_handler *handler,
214 struct user_namespace *mnt_userns,
215 struct dentry *dentry, struct inode *inode,
216 const char *name, const void *value, size_t size,
217 int flags)
218 {
219 #ifdef CONFIG_FUSE_BPF
220 struct fuse_err_ret fer;
221
222 if (value)
223 fer = fuse_bpf_backing(inode, struct fuse_setxattr_in,
224 fuse_setxattr_initialize, fuse_setxattr_backing,
225 fuse_setxattr_finalize, dentry, name, value,
226 size, flags);
227 else
228 fer = fuse_bpf_backing(inode, struct fuse_dummy_io,
229 fuse_removexattr_initialize,
230 fuse_removexattr_backing,
231 fuse_removexattr_finalize,
232 dentry, name);
233 if (fer.ret)
234 return PTR_ERR(fer.result);
235 #endif
236
237 if (fuse_is_bad(inode))
238 return -EIO;
239
240 if (!value)
241 return fuse_removexattr(inode, name);
242
243 return fuse_setxattr(inode, name, value, size, flags, 0);
244 }
245
no_xattr_list(struct dentry * dentry)246 static bool no_xattr_list(struct dentry *dentry)
247 {
248 return false;
249 }
250
no_xattr_get(const struct xattr_handler * handler,struct dentry * dentry,struct inode * inode,const char * name,void * value,size_t size)251 static int no_xattr_get(const struct xattr_handler *handler,
252 struct dentry *dentry, struct inode *inode,
253 const char *name, void *value, size_t size)
254 {
255 return -EOPNOTSUPP;
256 }
257
no_xattr_set(const struct xattr_handler * handler,struct user_namespace * mnt_userns,struct dentry * dentry,struct inode * nodee,const char * name,const void * value,size_t size,int flags)258 static int no_xattr_set(const struct xattr_handler *handler,
259 struct user_namespace *mnt_userns,
260 struct dentry *dentry, struct inode *nodee,
261 const char *name, const void *value,
262 size_t size, int flags)
263 {
264 return -EOPNOTSUPP;
265 }
266
267 static const struct xattr_handler fuse_xattr_handler = {
268 .prefix = "",
269 .get = fuse_xattr_get,
270 .set = fuse_xattr_set,
271 };
272
273 const struct xattr_handler *fuse_xattr_handlers[] = {
274 &fuse_xattr_handler,
275 NULL
276 };
277
278 const struct xattr_handler *fuse_acl_xattr_handlers[] = {
279 &posix_acl_access_xattr_handler,
280 &posix_acl_default_xattr_handler,
281 &fuse_xattr_handler,
282 NULL
283 };
284
285 static const struct xattr_handler fuse_no_acl_access_xattr_handler = {
286 .name = XATTR_NAME_POSIX_ACL_ACCESS,
287 .flags = ACL_TYPE_ACCESS,
288 .list = no_xattr_list,
289 .get = no_xattr_get,
290 .set = no_xattr_set,
291 };
292
293 static const struct xattr_handler fuse_no_acl_default_xattr_handler = {
294 .name = XATTR_NAME_POSIX_ACL_DEFAULT,
295 .flags = ACL_TYPE_ACCESS,
296 .list = no_xattr_list,
297 .get = no_xattr_get,
298 .set = no_xattr_set,
299 };
300
301 const struct xattr_handler *fuse_no_acl_xattr_handlers[] = {
302 &fuse_no_acl_access_xattr_handler,
303 &fuse_no_acl_default_xattr_handler,
304 &fuse_xattr_handler,
305 NULL
306 };
307