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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 | inode->i_ctime = CURRENT_TIME; |
98 | if (error == 0) { |
99 | posix_acl_release(acl); |
100 | acl = NULL; |
101 | } |
102 | break; |
103 | case ACL_TYPE_DEFAULT: |
104 | if (!S_ISDIR(inode->i_mode)) { |
105 | error = -EINVAL; |
106 | goto failed; |
107 | } |
108 | break; |
109 | } |
110 | } |
111 | set_cached_acl(inode, type, acl); |
112 | error = 0; |
113 | failed: |
114 | posix_acl_release(acl); |
115 | return error; |
116 | } |
117 | |
118 | /** |
119 | * generic_acl_init - Take care of acl inheritance at @inode create time |
120 | * |
121 | * Files created inside a directory with a default ACL inherit the |
122 | * directory's default ACL. |
123 | */ |
124 | int |
125 | generic_acl_init(struct inode *inode, struct inode *dir) |
126 | { |
127 | struct posix_acl *acl = NULL; |
128 | mode_t mode = inode->i_mode; |
129 | int error; |
130 | |
131 | inode->i_mode = mode & ~current_umask(); |
132 | if (!S_ISLNK(inode->i_mode)) |
133 | acl = get_cached_acl(dir, ACL_TYPE_DEFAULT); |
134 | if (acl) { |
135 | struct posix_acl *clone; |
136 | |
137 | if (S_ISDIR(inode->i_mode)) { |
138 | clone = posix_acl_clone(acl, GFP_KERNEL); |
139 | error = -ENOMEM; |
140 | if (!clone) |
141 | goto cleanup; |
142 | set_cached_acl(inode, ACL_TYPE_DEFAULT, clone); |
143 | posix_acl_release(clone); |
144 | } |
145 | clone = posix_acl_clone(acl, GFP_KERNEL); |
146 | error = -ENOMEM; |
147 | if (!clone) |
148 | goto cleanup; |
149 | error = posix_acl_create_masq(clone, &mode); |
150 | if (error >= 0) { |
151 | inode->i_mode = mode; |
152 | if (error > 0) |
153 | set_cached_acl(inode, ACL_TYPE_ACCESS, clone); |
154 | } |
155 | posix_acl_release(clone); |
156 | } |
157 | error = 0; |
158 | |
159 | cleanup: |
160 | posix_acl_release(acl); |
161 | return error; |
162 | } |
163 | |
164 | /** |
165 | * generic_acl_chmod - change the access acl of @inode upon chmod() |
166 | * |
167 | * A chmod also changes the permissions of the owner, group/mask, and |
168 | * other ACL entries. |
169 | */ |
170 | int |
171 | generic_acl_chmod(struct inode *inode) |
172 | { |
173 | struct posix_acl *acl, *clone; |
174 | int error = 0; |
175 | |
176 | if (S_ISLNK(inode->i_mode)) |
177 | return -EOPNOTSUPP; |
178 | acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
179 | if (acl) { |
180 | clone = posix_acl_clone(acl, GFP_KERNEL); |
181 | posix_acl_release(acl); |
182 | if (!clone) |
183 | return -ENOMEM; |
184 | error = posix_acl_chmod_masq(clone, inode->i_mode); |
185 | if (!error) |
186 | set_cached_acl(inode, ACL_TYPE_ACCESS, clone); |
187 | posix_acl_release(clone); |
188 | } |
189 | return error; |
190 | } |
191 | |
192 | int |
193 | generic_check_acl(struct inode *inode, int mask, unsigned int flags) |
194 | { |
195 | if (flags & IPERM_FLAG_RCU) { |
196 | if (!negative_cached_acl(inode, ACL_TYPE_ACCESS)) |
197 | return -ECHILD; |
198 | } else { |
199 | struct posix_acl *acl; |
200 | |
201 | acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
202 | if (acl) { |
203 | int error = posix_acl_permission(inode, acl, mask); |
204 | posix_acl_release(acl); |
205 | return error; |
206 | } |
207 | } |
208 | return -EAGAIN; |
209 | } |
210 | |
211 | const struct xattr_handler generic_acl_access_handler = { |
212 | .prefix = POSIX_ACL_XATTR_ACCESS, |
213 | .flags = ACL_TYPE_ACCESS, |
214 | .list = generic_acl_list, |
215 | .get = generic_acl_get, |
216 | .set = generic_acl_set, |
217 | }; |
218 | |
219 | const struct xattr_handler generic_acl_default_handler = { |
220 | .prefix = POSIX_ACL_XATTR_DEFAULT, |
221 | .flags = ACL_TYPE_DEFAULT, |
222 | .list = generic_acl_list, |
223 | .get = generic_acl_get, |
224 | .set = generic_acl_set, |
225 | }; |
226 |
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