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7#include <linux/init.h>
8#include <linux/sched.h>
9#include <linux/slab.h>
10#include <linux/fs.h>
11#include "ext2.h"
12#include "xattr.h"
13#include "acl.h"
14
15
16
17
18static struct posix_acl *
19ext2_acl_from_disk(const void *value, size_t size)
20{
21 const char *end = (char *)value + size;
22 int n, count;
23 struct posix_acl *acl;
24
25 if (!value)
26 return NULL;
27 if (size < sizeof(ext2_acl_header))
28 return ERR_PTR(-EINVAL);
29 if (((ext2_acl_header *)value)->a_version !=
30 cpu_to_le32(EXT2_ACL_VERSION))
31 return ERR_PTR(-EINVAL);
32 value = (char *)value + sizeof(ext2_acl_header);
33 count = ext2_acl_count(size);
34 if (count < 0)
35 return ERR_PTR(-EINVAL);
36 if (count == 0)
37 return NULL;
38 acl = posix_acl_alloc(count, GFP_KERNEL);
39 if (!acl)
40 return ERR_PTR(-ENOMEM);
41 for (n=0; n < count; n++) {
42 ext2_acl_entry *entry =
43 (ext2_acl_entry *)value;
44 if ((char *)value + sizeof(ext2_acl_entry_short) > end)
45 goto fail;
46 acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag);
47 acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
48 switch(acl->a_entries[n].e_tag) {
49 case ACL_USER_OBJ:
50 case ACL_GROUP_OBJ:
51 case ACL_MASK:
52 case ACL_OTHER:
53 value = (char *)value +
54 sizeof(ext2_acl_entry_short);
55 break;
56
57 case ACL_USER:
58 value = (char *)value + sizeof(ext2_acl_entry);
59 if ((char *)value > end)
60 goto fail;
61 acl->a_entries[n].e_uid =
62 make_kuid(&init_user_ns,
63 le32_to_cpu(entry->e_id));
64 break;
65 case ACL_GROUP:
66 value = (char *)value + sizeof(ext2_acl_entry);
67 if ((char *)value > end)
68 goto fail;
69 acl->a_entries[n].e_gid =
70 make_kgid(&init_user_ns,
71 le32_to_cpu(entry->e_id));
72 break;
73
74 default:
75 goto fail;
76 }
77 }
78 if (value != end)
79 goto fail;
80 return acl;
81
82fail:
83 posix_acl_release(acl);
84 return ERR_PTR(-EINVAL);
85}
86
87
88
89
90static void *
91ext2_acl_to_disk(const struct posix_acl *acl, size_t *size)
92{
93 ext2_acl_header *ext_acl;
94 char *e;
95 size_t n;
96
97 *size = ext2_acl_size(acl->a_count);
98 ext_acl = kmalloc(sizeof(ext2_acl_header) + acl->a_count *
99 sizeof(ext2_acl_entry), GFP_KERNEL);
100 if (!ext_acl)
101 return ERR_PTR(-ENOMEM);
102 ext_acl->a_version = cpu_to_le32(EXT2_ACL_VERSION);
103 e = (char *)ext_acl + sizeof(ext2_acl_header);
104 for (n=0; n < acl->a_count; n++) {
105 const struct posix_acl_entry *acl_e = &acl->a_entries[n];
106 ext2_acl_entry *entry = (ext2_acl_entry *)e;
107 entry->e_tag = cpu_to_le16(acl_e->e_tag);
108 entry->e_perm = cpu_to_le16(acl_e->e_perm);
109 switch(acl_e->e_tag) {
110 case ACL_USER:
111 entry->e_id = cpu_to_le32(
112 from_kuid(&init_user_ns, acl_e->e_uid));
113 e += sizeof(ext2_acl_entry);
114 break;
115 case ACL_GROUP:
116 entry->e_id = cpu_to_le32(
117 from_kgid(&init_user_ns, acl_e->e_gid));
118 e += sizeof(ext2_acl_entry);
119 break;
120
121 case ACL_USER_OBJ:
122 case ACL_GROUP_OBJ:
123 case ACL_MASK:
124 case ACL_OTHER:
125 e += sizeof(ext2_acl_entry_short);
126 break;
127
128 default:
129 goto fail;
130 }
131 }
132 return (char *)ext_acl;
133
134fail:
135 kfree(ext_acl);
136 return ERR_PTR(-EINVAL);
137}
138
139
140
141
142struct posix_acl *
143ext2_get_acl(struct inode *inode, int type)
144{
145 int name_index;
146 char *value = NULL;
147 struct posix_acl *acl;
148 int retval;
149
150 switch (type) {
151 case ACL_TYPE_ACCESS:
152 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
153 break;
154 case ACL_TYPE_DEFAULT:
155 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
156 break;
157 default:
158 BUG();
159 }
160 retval = ext2_xattr_get(inode, name_index, "", NULL, 0);
161 if (retval > 0) {
162 value = kmalloc(retval, GFP_KERNEL);
163 if (!value)
164 return ERR_PTR(-ENOMEM);
165 retval = ext2_xattr_get(inode, name_index, "", value, retval);
166 }
167 if (retval > 0)
168 acl = ext2_acl_from_disk(value, retval);
169 else if (retval == -ENODATA || retval == -ENOSYS)
170 acl = NULL;
171 else
172 acl = ERR_PTR(retval);
173 kfree(value);
174
175 if (!IS_ERR(acl))
176 set_cached_acl(inode, type, acl);
177
178 return acl;
179}
180
181
182
183
184int
185ext2_set_acl(struct inode *inode, struct posix_acl *acl, int type)
186{
187 int name_index;
188 void *value = NULL;
189 size_t size = 0;
190 int error;
191
192 switch(type) {
193 case ACL_TYPE_ACCESS:
194 name_index = EXT2_XATTR_INDEX_POSIX_ACL_ACCESS;
195 if (acl) {
196 error = posix_acl_equiv_mode(acl, &inode->i_mode);
197 if (error < 0)
198 return error;
199 else {
200 inode->i_ctime = CURRENT_TIME_SEC;
201 mark_inode_dirty(inode);
202 if (error == 0)
203 acl = NULL;
204 }
205 }
206 break;
207
208 case ACL_TYPE_DEFAULT:
209 name_index = EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT;
210 if (!S_ISDIR(inode->i_mode))
211 return acl ? -EACCES : 0;
212 break;
213
214 default:
215 return -EINVAL;
216 }
217 if (acl) {
218 value = ext2_acl_to_disk(acl, &size);
219 if (IS_ERR(value))
220 return (int)PTR_ERR(value);
221 }
222
223 error = ext2_xattr_set(inode, name_index, "", value, size, 0);
224
225 kfree(value);
226 if (!error)
227 set_cached_acl(inode, type, acl);
228 return error;
229}
230
231
232
233
234
235
236
237int
238ext2_init_acl(struct inode *inode, struct inode *dir)
239{
240 struct posix_acl *default_acl, *acl;
241 int error;
242
243 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl);
244 if (error)
245 return error;
246
247 if (default_acl) {
248 error = ext2_set_acl(inode, default_acl, ACL_TYPE_DEFAULT);
249 posix_acl_release(default_acl);
250 }
251 if (acl) {
252 if (!error)
253 error = ext2_set_acl(inode, acl, ACL_TYPE_ACCESS);
254 posix_acl_release(acl);
255 }
256 return error;
257}
258
