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1 | /* |
2 | * (C) 2005 Andreas Gruenbacher <agruen@suse.de> |
3 | * |
4 | * This file is released under the GPL. |
5 | * |
6 | * Generic ACL support for in-memory filesystems. |
7 | */ |
8 | |
9 | #include <linux/sched.h> |
10 | #include <linux/gfp.h> |
11 | #include <linux/fs.h> |
12 | #include <linux/generic_acl.h> |
13 | #include <linux/posix_acl.h> |
14 | #include <linux/posix_acl_xattr.h> |
15 | |
16 | |
17 | static size_t |
18 | generic_acl_list(struct dentry *dentry, char *list, size_t list_size, |
19 | const char *name, size_t name_len, int type) |
20 | { |
21 | struct posix_acl *acl; |
22 | const char *xname; |
23 | size_t size; |
24 | |
25 | acl = get_cached_acl(dentry->d_inode, type); |
26 | if (!acl) |
27 | return 0; |
28 | posix_acl_release(acl); |
29 | |
30 | switch (type) { |
31 | case ACL_TYPE_ACCESS: |
32 | xname = POSIX_ACL_XATTR_ACCESS; |
33 | break; |
34 | case ACL_TYPE_DEFAULT: |
35 | xname = POSIX_ACL_XATTR_DEFAULT; |
36 | break; |
37 | default: |
38 | return 0; |
39 | } |
40 | size = strlen(xname) + 1; |
41 | if (list && size <= list_size) |
42 | memcpy(list, xname, size); |
43 | return size; |
44 | } |
45 | |
46 | static int |
47 | generic_acl_get(struct dentry *dentry, const char *name, void *buffer, |
48 | size_t size, int type) |
49 | { |
50 | struct posix_acl *acl; |
51 | int error; |
52 | |
53 | if (strcmp(name, "") != 0) |
54 | return -EINVAL; |
55 | |
56 | acl = get_cached_acl(dentry->d_inode, type); |
57 | if (!acl) |
58 | return -ENODATA; |
59 | error = posix_acl_to_xattr(acl, buffer, size); |
60 | posix_acl_release(acl); |
61 | |
62 | return error; |
63 | } |
64 | |
65 | static int |
66 | generic_acl_set(struct dentry *dentry, const char *name, const void *value, |
67 | size_t size, int flags, int type) |
68 | { |
69 | struct inode *inode = dentry->d_inode; |
70 | struct posix_acl *acl = NULL; |
71 | int error; |
72 | |
73 | if (strcmp(name, "") != 0) |
74 | return -EINVAL; |
75 | if (S_ISLNK(inode->i_mode)) |
76 | return -EOPNOTSUPP; |
77 | if (!is_owner_or_cap(inode)) |
78 | return -EPERM; |
79 | if (value) { |
80 | acl = posix_acl_from_xattr(value, size); |
81 | if (IS_ERR(acl)) |
82 | return PTR_ERR(acl); |
83 | } |
84 | if (acl) { |
85 | mode_t mode; |
86 | |
87 | error = posix_acl_valid(acl); |
88 | if (error) |
89 | goto failed; |
90 | switch (type) { |
91 | case ACL_TYPE_ACCESS: |
92 | mode = inode->i_mode; |
93 | error = posix_acl_equiv_mode(acl, &mode); |
94 | if (error < 0) |
95 | goto failed; |
96 | inode->i_mode = mode; |
97 | if (error == 0) { |
98 | posix_acl_release(acl); |
99 | acl = NULL; |
100 | } |
101 | break; |
102 | case ACL_TYPE_DEFAULT: |
103 | if (!S_ISDIR(inode->i_mode)) { |
104 | error = -EINVAL; |
105 | goto failed; |
106 | } |
107 | break; |
108 | } |
109 | } |
110 | set_cached_acl(inode, type, acl); |
111 | error = 0; |
112 | failed: |
113 | posix_acl_release(acl); |
114 | return error; |
115 | } |
116 | |
117 | /** |
118 | * generic_acl_init - Take care of acl inheritance at @inode create time |
119 | * |
120 | * Files created inside a directory with a default ACL inherit the |
121 | * directory's default ACL. |
122 | */ |
123 | int |
124 | generic_acl_init(struct inode *inode, struct inode *dir) |
125 | { |
126 | struct posix_acl *acl = NULL; |
127 | mode_t mode = inode->i_mode; |
128 | int error; |
129 | |
130 | inode->i_mode = mode & ~current_umask(); |
131 | if (!S_ISLNK(inode->i_mode)) |
132 | acl = get_cached_acl(dir, ACL_TYPE_DEFAULT); |
133 | if (acl) { |
134 | struct posix_acl *clone; |
135 | |
136 | if (S_ISDIR(inode->i_mode)) { |
137 | clone = posix_acl_clone(acl, GFP_KERNEL); |
138 | error = -ENOMEM; |
139 | if (!clone) |
140 | goto cleanup; |
141 | set_cached_acl(inode, ACL_TYPE_DEFAULT, clone); |
142 | posix_acl_release(clone); |
143 | } |
144 | clone = posix_acl_clone(acl, GFP_KERNEL); |
145 | error = -ENOMEM; |
146 | if (!clone) |
147 | goto cleanup; |
148 | error = posix_acl_create_masq(clone, &mode); |
149 | if (error >= 0) { |
150 | inode->i_mode = mode; |
151 | if (error > 0) |
152 | set_cached_acl(inode, ACL_TYPE_ACCESS, clone); |
153 | } |
154 | posix_acl_release(clone); |
155 | } |
156 | error = 0; |
157 | |
158 | cleanup: |
159 | posix_acl_release(acl); |
160 | return error; |
161 | } |
162 | |
163 | /** |
164 | * generic_acl_chmod - change the access acl of @inode upon chmod() |
165 | * |
166 | * A chmod also changes the permissions of the owner, group/mask, and |
167 | * other ACL entries. |
168 | */ |
169 | int |
170 | generic_acl_chmod(struct inode *inode) |
171 | { |
172 | struct posix_acl *acl, *clone; |
173 | int error = 0; |
174 | |
175 | if (S_ISLNK(inode->i_mode)) |
176 | return -EOPNOTSUPP; |
177 | acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
178 | if (acl) { |
179 | clone = posix_acl_clone(acl, GFP_KERNEL); |
180 | posix_acl_release(acl); |
181 | if (!clone) |
182 | return -ENOMEM; |
183 | error = posix_acl_chmod_masq(clone, inode->i_mode); |
184 | if (!error) |
185 | set_cached_acl(inode, ACL_TYPE_ACCESS, clone); |
186 | posix_acl_release(clone); |
187 | } |
188 | return error; |
189 | } |
190 | |
191 | int |
192 | generic_check_acl(struct inode *inode, int mask) |
193 | { |
194 | struct posix_acl *acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
195 | |
196 | if (acl) { |
197 | int error = posix_acl_permission(inode, acl, mask); |
198 | posix_acl_release(acl); |
199 | return error; |
200 | } |
201 | return -EAGAIN; |
202 | } |
203 | |
204 | struct xattr_handler generic_acl_access_handler = { |
205 | .prefix = POSIX_ACL_XATTR_ACCESS, |
206 | .flags = ACL_TYPE_ACCESS, |
207 | .list = generic_acl_list, |
208 | .get = generic_acl_get, |
209 | .set = generic_acl_set, |
210 | }; |
211 | |
212 | struct xattr_handler generic_acl_default_handler = { |
213 | .prefix = POSIX_ACL_XATTR_DEFAULT, |
214 | .flags = ACL_TYPE_DEFAULT, |
215 | .list = generic_acl_list, |
216 | .get = generic_acl_get, |
217 | .set = generic_acl_set, |
218 | }; |
219 |
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