->permission() sanitizing: don't pass flags to ->check_acl()
[linux-2.6.git] / fs / generic_acl.c
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 (!inode_owner_or_capable(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)
194 {
195         if (mask & MAY_NOT_BLOCK) {
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 };